diff --git a/app/build.gradle b/app/build.gradle
index db00a26..b4c0ad2 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -2,6 +2,7 @@ plugins {
     id 'com.android.application'
     id 'org.jetbrains.kotlin.android'
     id 'kotlin-kapt'
+    id 'org.jetbrains.kotlin.plugin.serialization'
 }
 
 apply plugin: 'com.android.application'
@@ -86,4 +87,9 @@ dependencies {
     implementation "androidx.paging:paging-runtime-ktx:$paging_version"
     implementation "androidx.paging:paging-compose:$paging_version"
     implementation("androidx.room:room-paging:2.5.0")
+
+    implementation("com.squareup.retrofit2:retrofit:2.9.0")
+    implementation("com.squareup.okhttp3:logging-interceptor:4.11.0")
+    implementation("org.jetbrains.kotlinx:kotlinx-serialization-json:1.5.1")
+    implementation("com.jakewharton.retrofit:retrofit2-kotlinx-serialization-converter:1.0.0")
 }
\ No newline at end of file
diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index 7b80306..f5b4ac4 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -1,6 +1,9 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools">
+    
+    <uses-permission android:name="android.permission.INTERNET" />
+    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
 
     <application
         android:name=".DTFApp"
@@ -11,6 +14,7 @@
         android:label="@string/app_name"
         android:supportsRtl="true"
         android:theme="@style/Theme.DTF"
+        android:usesCleartextTraffic="true"
         tools:targetApi="31">
         <activity
             android:name=".MainActivity"
diff --git a/app/src/main/java/com/example/dtf/AppModule.kt b/app/src/main/java/com/example/dtf/AppModule.kt
index dc785fb..3013cbf 100644
--- a/app/src/main/java/com/example/dtf/AppModule.kt
+++ b/app/src/main/java/com/example/dtf/AppModule.kt
@@ -2,13 +2,12 @@ package com.example.dtf
 
 import android.app.Application
 import androidx.room.*
-import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.launch
-import androidx.sqlite.db.SupportSQLiteDatabase
+import com.example.dtf.api.ServerService
 import com.example.dtf.db.AppDatabase
-import com.example.dtf.models.User
 import com.example.dtf.repositories.*
+import com.example.dtf.repositories.offline.*
+import com.example.dtf.repositories.online.*
+import com.example.dtf.repositories.online.mediator.RestCategoryRepository
 import dagger.Module
 import dagger.Provides
 import dagger.hilt.InstallIn
@@ -32,21 +31,65 @@ object AppModule {
 
     @Provides
     @Singleton
-    fun provideCategoryRepository(db: AppDatabase) = CategoryRepository(db.categoryDao())
+    fun provideServerService(): ServerService = ServerService.getInstance()
 
     @Provides
     @Singleton
-    fun provideCommentRepository(db: AppDatabase) = CommentRepository(db.commentDao())
+    fun provideICategoryRepository(db: AppDatabase, serverService: ServerService): ICategoryRepository = RestCategoryRepository(db, serverService)
 
     @Provides
     @Singleton
-    fun provideLikeRepository(db: AppDatabase) = LikeRepository(db.likeDao())
+    fun provideICommentRepository(db: AppDatabase, serverService: ServerService): ICommentRepository = RestCommentRepository(db, serverService)
 
     @Provides
     @Singleton
-    fun providePostRepository(db: AppDatabase) = PostRepository(db.postDao())
+    fun provideILikeRepository(db: AppDatabase, serverService: ServerService): ILikeRepository = RestLikeRepository(db, serverService)
 
     @Provides
     @Singleton
-    fun proviveUserRepository(db: AppDatabase) = UserRepository(db.userDao())
+    fun provideIPostRepository(db: AppDatabase, serverService: ServerService): IPostRepository = RestPostRepository(db, serverService)
+
+    @Provides
+    @Singleton
+    fun provideIUserRepository(db: AppDatabase, serverService: ServerService): IUserRepository = RestUserRepository(db, serverService)
+
+    @Provides
+    @Singleton
+    fun provideOfflineCategoryRepository(db: AppDatabase): OfflineCategoryRepository = OfflineCategoryRepository(db.categoryDao())
+
+    @Provides
+    @Singleton
+    fun provideOfflineCommentRepository(db: AppDatabase): OfflineCommentRepository = OfflineCommentRepository(db.commentDao())
+
+    @Provides
+    @Singleton
+    fun provideOfflineLikeRepository(db: AppDatabase): OfflineLikeRepository = OfflineLikeRepository(db.likeDao())
+
+    @Provides
+    @Singleton
+    fun provideOfflinePostRepository(db: AppDatabase): OfflinePostRepository = OfflinePostRepository(db.postDao())
+
+    @Provides
+    @Singleton
+    fun provideOfflineUserRepository(db: AppDatabase): OfflineUserRepository = OfflineUserRepository(db.userDao())
+
+    @Provides
+    @Singleton
+    fun provideRestCategoryRepository(db: AppDatabase, serverService: ServerService): RestCategoryRepository = RestCategoryRepository(db, serverService)
+
+    @Provides
+    @Singleton
+    fun provideRestCommentRepository(db: AppDatabase, serverService: ServerService): RestCommentRepository = RestCommentRepository(db, serverService)
+
+    @Provides
+    @Singleton
+    fun provideRestLikeRepository(db: AppDatabase, serverService: ServerService): RestLikeRepository = RestLikeRepository(db, serverService)
+
+    @Provides
+    @Singleton
+    fun provideRestPostRepository(db: AppDatabase, serverService: ServerService): RestPostRepository = RestPostRepository(db, serverService)
+
+    @Provides
+    @Singleton
+    fun provideRestUserRepository(db: AppDatabase, serverService: ServerService): RestUserRepository = RestUserRepository(db, serverService)
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/api/ServerService.kt b/app/src/main/java/com/example/dtf/api/ServerService.kt
new file mode 100644
index 0000000..2d01cd5
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/api/ServerService.kt
@@ -0,0 +1,152 @@
+package com.example.dtf.api
+
+import com.example.dtf.dto.Credentials
+import com.example.dtf.dto.EditPostDto
+import com.example.dtf.dto.MeUser
+import com.example.dtf.dto.NewCommentDto
+import com.example.dtf.dto.NewPostDto
+import com.example.dtf.dto.Token
+import com.example.dtf.dto.remote.CategoriesResponse
+import com.example.dtf.dto.remote.CommentsResponse
+import com.example.dtf.dto.remote.PostsResponse
+import com.example.dtf.models.Category
+import com.example.dtf.models.Comment
+import com.example.dtf.models.Post
+import com.example.dtf.models.User
+import com.jakewharton.retrofit2.converter.kotlinx.serialization.asConverterFactory
+import okhttp3.OkHttpClient
+import okhttp3.logging.HttpLoggingInterceptor
+import retrofit2.http.POST
+import retrofit2.Retrofit
+import retrofit2.http.Body
+import retrofit2.http.GET
+import retrofit2.http.Path
+import retrofit2.http.Query
+import kotlinx.serialization.json.Json
+import okhttp3.MediaType.Companion.toMediaType
+import retrofit2.http.Header
+
+interface ServerService {
+    @POST("auth/login")
+    suspend fun login(
+        @Body credentials: Credentials
+    ): Token
+
+    @POST("auth/register")
+    suspend fun register(
+        @Body credentials: Credentials
+    ): String
+
+    @GET("user/me")
+    suspend fun getCurrentUser(): MeUser
+
+    @GET("category")
+    suspend fun getCategories(
+        @Query("offset") offset: Int?,
+        @Query("limit") limit: Int?
+    ): CategoriesResponse
+
+    @GET("post")
+    suspend fun getPosts(
+        @Query("category") category: Int?,
+        @Query("offset") offset: Int?,
+        @Query("limit") limit: Int?
+    ): PostsResponse
+
+    @GET("post/{postId}")
+    suspend fun getPost(
+        @Path("postId") postId: Int
+    ): Post
+
+    @POST("post")
+    suspend fun createPost(
+        @Body post: NewPostDto
+    )
+
+    @POST("post/{postId}")
+    suspend fun updatePost(
+        @Path("postId") postId: Int,
+        @Body post: EditPostDto
+    )
+
+    @GET("comment")
+    suspend fun getComments(
+        @Query("postId") postId: Int?,
+        @Query("offset") offset: Int?,
+        @Query("limit") limit: Int?
+    ): CommentsResponse
+
+    @GET("comment/{commentId}")
+    suspend fun getComment(
+        @Path("commentId") commentId: Int
+    ): Comment
+
+    @POST("comment")
+    suspend fun createComment(
+        @Body comment: NewCommentDto
+    )
+
+    @POST("post/{postId}/like")
+    suspend fun likePost(
+        @Path("postId") postId: Int
+    )
+
+    @GET("post/{postId}/liked")
+    suspend fun postIsLiked(
+        @Path("postId") postId: Int
+    ): Boolean
+
+    @GET("post/{postId}/likes")
+    suspend fun getPostLikes(
+        @Path("postId") postId: Int
+    ): Int
+
+    @GET("user/{userId}")
+    suspend fun getUser(
+        @Path("userId") userId: Int
+    ): User
+
+    companion object {
+        private const val BASE_URL = "http://192.168.1.9:8000/"
+
+        private var _token: String = ""
+
+        @Volatile
+        private var INSTANCE: ServerService? = null
+
+        fun getInstance(): ServerService {
+            return INSTANCE ?: synchronized(this) {
+                val logger = HttpLoggingInterceptor()
+                logger.level = HttpLoggingInterceptor.Level.BASIC
+                val client = OkHttpClient.Builder()
+                    .addInterceptor(logger)
+                    .addInterceptor {
+                        val originalRequest = it.request()
+                        if (_token.isEmpty()) {
+                            it.proceed(originalRequest)
+                        } else {
+                            it.proceed(
+                                originalRequest
+                                    .newBuilder()
+                                    .header("Authorization", "Bearer $_token")
+                                    .method(originalRequest.method, originalRequest.body)
+                                    .build()
+                            )
+                        }
+                    }
+                    .build()
+                return Retrofit.Builder()
+                    .baseUrl(BASE_URL)
+                    .client(client)
+                    .addConverterFactory(Json.asConverterFactory("application/json".toMediaType()))
+                    .build()
+                    .create(ServerService::class.java)
+                    .also { INSTANCE = it }
+            }
+        }
+
+        fun setToken(token: String) {
+            _token = token
+        }
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/dao/CategoryDao.kt b/app/src/main/java/com/example/dtf/dao/CategoryDao.kt
index 2463790..238be5c 100644
--- a/app/src/main/java/com/example/dtf/dao/CategoryDao.kt
+++ b/app/src/main/java/com/example/dtf/dao/CategoryDao.kt
@@ -1,12 +1,13 @@
 package com.example.dtf.dao
 
+import androidx.paging.PagingSource
 import androidx.room.*
 import com.example.dtf.models.*
 import kotlinx.coroutines.flow.Flow
 
 @Dao
 interface CategoryDao {
-    @Insert
+    @Insert(onConflict = OnConflictStrategy.REPLACE)
     suspend fun insert(category: Category)
 
     @Update
@@ -16,8 +17,14 @@ interface CategoryDao {
     suspend fun delete(category: Category)
 
     @Query("select * from category")
-    fun getAll() : Flow<List<Category>>
+    fun getAll() : PagingSource<Int, Category>
+
+    @Query("select * from category")
+    fun getAllCached() : Flow<List<Category>>
 
     @Query("select * from category where category.id = :id")
     fun getById(id: Int) : Flow<Category>
+
+    @Query("select * from category limit 1")
+    fun getFirst() : Flow<Category>
 }
diff --git a/app/src/main/java/com/example/dtf/dao/CommentDao.kt b/app/src/main/java/com/example/dtf/dao/CommentDao.kt
index 36a7eb1..d89a301 100644
--- a/app/src/main/java/com/example/dtf/dao/CommentDao.kt
+++ b/app/src/main/java/com/example/dtf/dao/CommentDao.kt
@@ -7,7 +7,7 @@ import kotlinx.coroutines.flow.Flow
 
 @Dao
 interface CommentDao {
-    @Insert
+    @Insert(onConflict = OnConflictStrategy.REPLACE)
     suspend fun insert(comment: Comment)
 
     @Update
@@ -16,12 +16,12 @@ interface CommentDao {
     @Delete
     suspend fun delete(comment: Comment)
 
-    @Query("select * from comment")
-    fun getAll() : Flow<List<Comment>>
-
     @Query("select * from comment where comment.id = :id")
     fun getById(id: Int) : Flow<Comment>
 
-    @Query("select * from comment where comment.post_id = :postId ORDER BY date DESC")
+    @Query("select * from comment where comment.post_id = :postId ORDER BY id DESC")
     fun getByPost(postId: Int) : PagingSource<Int, Comment>
+
+    @Query("delete from comment where post_id = :query")
+    fun deleteByQuery(query: String)
 }
diff --git a/app/src/main/java/com/example/dtf/dao/LikeDao.kt b/app/src/main/java/com/example/dtf/dao/LikeDao.kt
index 20e8d00..183f731 100644
--- a/app/src/main/java/com/example/dtf/dao/LikeDao.kt
+++ b/app/src/main/java/com/example/dtf/dao/LikeDao.kt
@@ -6,7 +6,7 @@ import kotlinx.coroutines.flow.Flow
 
 @Dao
 interface LikeDao {
-    @Insert
+    @Insert(onConflict = OnConflictStrategy.REPLACE)
     suspend fun insert(like: Like)
 
     @Delete
diff --git a/app/src/main/java/com/example/dtf/dao/PostDao.kt b/app/src/main/java/com/example/dtf/dao/PostDao.kt
index d7edb53..c2a762b 100644
--- a/app/src/main/java/com/example/dtf/dao/PostDao.kt
+++ b/app/src/main/java/com/example/dtf/dao/PostDao.kt
@@ -7,7 +7,7 @@ import kotlinx.coroutines.flow.Flow
 
 @Dao
 interface PostDao {
-    @Insert
+    @Insert(onConflict = OnConflictStrategy.REPLACE)
     suspend fun insert(post: Post)
 
     @Update
@@ -16,12 +16,12 @@ interface PostDao {
     @Delete
     suspend fun delete(post: Post)
 
-    @Query("select * from post")
-    fun getAll() : Flow<List<Post>>
-
     @Query("select * from post where post.id = :id")
     fun getById(id: Int) : Flow<Post>
 
     @Query("select * from post where post.category_id = :categoryId ORDER BY date DESC")
     fun getByCategory(categoryId: String) : PagingSource<Int, Post>
+
+    @Query("delete from post where category_id = :query")
+    fun deleteByQuery(query: String)
 }
diff --git a/app/src/main/java/com/example/dtf/dao/UserDao.kt b/app/src/main/java/com/example/dtf/dao/UserDao.kt
index 60ecc10..de080c6 100644
--- a/app/src/main/java/com/example/dtf/dao/UserDao.kt
+++ b/app/src/main/java/com/example/dtf/dao/UserDao.kt
@@ -6,7 +6,7 @@ import kotlinx.coroutines.flow.Flow
 
 @Dao
 interface UserDao {
-    @Insert
+    @Insert(onConflict = OnConflictStrategy.REPLACE)
     suspend fun insert(user: User)
 
     @Update
@@ -15,12 +15,6 @@ interface UserDao {
     @Delete
     suspend fun delete(user: User)
 
-    @Query("select * from user order by username collate nocase asc")
-    fun getAll() : Flow<List<User>>
-
     @Query("select * from user where user.id = :id")
     fun getById(id: Int): Flow<User>
-
-    @Query("select * from user where user.username = :username and user.password = :password")
-    fun getByUsernameAndPassword(username: String, password: String): Flow<User?>
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/db/AppDatabase.kt b/app/src/main/java/com/example/dtf/db/AppDatabase.kt
index 161f1f8..b3cd4d5 100644
--- a/app/src/main/java/com/example/dtf/db/AppDatabase.kt
+++ b/app/src/main/java/com/example/dtf/db/AppDatabase.kt
@@ -22,7 +22,7 @@ import java.util.Date
         Like::class,
         Comment::class
     ],
-    version = 2,
+    version = 4,
     exportSchema = false
 )
 @TypeConverters(Converter::class)
diff --git a/app/src/main/java/com/example/dtf/dto/Credentials.kt b/app/src/main/java/com/example/dtf/dto/Credentials.kt
new file mode 100644
index 0000000..e3a2c35
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/dto/Credentials.kt
@@ -0,0 +1,9 @@
+package com.example.dtf.dto
+
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class Credentials(
+    val username: String = "",
+    val password: String = ""
+)
diff --git a/app/src/main/java/com/example/dtf/dto/EditPostDto.kt b/app/src/main/java/com/example/dtf/dto/EditPostDto.kt
new file mode 100644
index 0000000..de4923d
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/dto/EditPostDto.kt
@@ -0,0 +1,9 @@
+package com.example.dtf.dto
+
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class EditPostDto(
+    val title: String,
+    val content: String
+)
diff --git a/app/src/main/java/com/example/dtf/dto/MeUser.kt b/app/src/main/java/com/example/dtf/dto/MeUser.kt
new file mode 100644
index 0000000..54eb68e
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/dto/MeUser.kt
@@ -0,0 +1,10 @@
+package com.example.dtf.dto
+
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class MeUser(
+    val id: Int,
+    val username: String,
+    val is_moderator: Boolean
+)
diff --git a/app/src/main/java/com/example/dtf/dto/NewCommentDto.kt b/app/src/main/java/com/example/dtf/dto/NewCommentDto.kt
new file mode 100644
index 0000000..d697e5b
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/dto/NewCommentDto.kt
@@ -0,0 +1,9 @@
+package com.example.dtf.dto
+
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class NewCommentDto(
+    val post_id: Int,
+    val content: String
+)
diff --git a/app/src/main/java/com/example/dtf/dto/NewPostDto.kt b/app/src/main/java/com/example/dtf/dto/NewPostDto.kt
new file mode 100644
index 0000000..84bbe42
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/dto/NewPostDto.kt
@@ -0,0 +1,10 @@
+package com.example.dtf.dto
+
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class NewPostDto(
+    val title: String,
+    val content: String,
+    val category_id: Int
+)
diff --git a/app/src/main/java/com/example/dtf/dto/Token.kt b/app/src/main/java/com/example/dtf/dto/Token.kt
new file mode 100644
index 0000000..f200831
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/dto/Token.kt
@@ -0,0 +1,8 @@
+package com.example.dtf.dto
+
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class Token(
+    val token: String
+)
diff --git a/app/src/main/java/com/example/dtf/dto/remote/CategoriesResponse.kt b/app/src/main/java/com/example/dtf/dto/remote/CategoriesResponse.kt
new file mode 100644
index 0000000..99c225f
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/dto/remote/CategoriesResponse.kt
@@ -0,0 +1,10 @@
+package com.example.dtf.dto.remote
+
+import com.example.dtf.models.Category
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class CategoriesResponse(
+    val categories: List<Category>,
+    val nextKey: Int?
+)
diff --git a/app/src/main/java/com/example/dtf/dto/remote/CommentsResponse.kt b/app/src/main/java/com/example/dtf/dto/remote/CommentsResponse.kt
new file mode 100644
index 0000000..03daa5a
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/dto/remote/CommentsResponse.kt
@@ -0,0 +1,10 @@
+package com.example.dtf.dto.remote
+
+import com.example.dtf.models.Comment
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class CommentsResponse(
+    val comments: List<Comment>,
+    val nextKey: Int?
+)
diff --git a/app/src/main/java/com/example/dtf/dto/remote/PostsResponse.kt b/app/src/main/java/com/example/dtf/dto/remote/PostsResponse.kt
new file mode 100644
index 0000000..654df0e
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/dto/remote/PostsResponse.kt
@@ -0,0 +1,10 @@
+package com.example.dtf.dto.remote
+
+import com.example.dtf.models.Post
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class PostsResponse(
+    val posts: List<Post>,
+    val nextKey: Int?
+)
diff --git a/app/src/main/java/com/example/dtf/models/Category.kt b/app/src/main/java/com/example/dtf/models/Category.kt
index 9700eca..2df43fd 100644
--- a/app/src/main/java/com/example/dtf/models/Category.kt
+++ b/app/src/main/java/com/example/dtf/models/Category.kt
@@ -1,8 +1,10 @@
 package com.example.dtf.models
 
 import androidx.room.*
+import kotlinx.serialization.Serializable
 
 @Entity(tableName = "category")
+@Serializable
 data class Category(
     @PrimaryKey(autoGenerate = true)
     @ColumnInfo
diff --git a/app/src/main/java/com/example/dtf/models/CategoryWithPosts.kt b/app/src/main/java/com/example/dtf/models/CategoryWithPosts.kt
deleted file mode 100644
index f666c25..0000000
--- a/app/src/main/java/com/example/dtf/models/CategoryWithPosts.kt
+++ /dev/null
@@ -1,10 +0,0 @@
-package com.example.dtf.models
-
-import androidx.room.Embedded
-import androidx.room.Relation
-
-data class CategoryWithPosts(
-    @Embedded val category: Category,
-    @Relation(parentColumn = "id", entityColumn = "category_id")
-    val posts: List<Post>
-)
diff --git a/app/src/main/java/com/example/dtf/models/Comment.kt b/app/src/main/java/com/example/dtf/models/Comment.kt
index fc3c6d7..203fb7f 100644
--- a/app/src/main/java/com/example/dtf/models/Comment.kt
+++ b/app/src/main/java/com/example/dtf/models/Comment.kt
@@ -1,21 +1,24 @@
 package com.example.dtf.models
 
 import androidx.room.*
-import java.util.Date
+import kotlinx.serialization.Serializable
 
 @Entity(tableName = "comment")
+@Serializable
 data class Comment(
     @PrimaryKey(autoGenerate = true)
     @ColumnInfo
     val id: Int?,
     @ColumnInfo(name = "user_id")
-    val userId: Int,
+    val user_id: Int,
     @ColumnInfo(name = "post_id")
-    val postId: Int,
+    val post_id: Int,
     @ColumnInfo
     val content: String,
     @ColumnInfo
-    val date: Date
+    val date: String,
+    @ColumnInfo
+    val author: String = ""
 ) {
     override fun equals(other: Any?): Boolean {
         if (this === other) return true
diff --git a/app/src/main/java/com/example/dtf/models/Post.kt b/app/src/main/java/com/example/dtf/models/Post.kt
index 25c3b6a..5cd092f 100644
--- a/app/src/main/java/com/example/dtf/models/Post.kt
+++ b/app/src/main/java/com/example/dtf/models/Post.kt
@@ -1,9 +1,7 @@
 package com.example.dtf.models
 
-import androidx.compose.runtime.collection.MutableVector
-import androidx.compose.runtime.collection.mutableVectorOf
 import androidx.room.*
-import java.util.Date
+import kotlinx.serialization.Serializable
 
 //private val posts = listOf(
 //    Post(
@@ -60,11 +58,9 @@ import java.util.Date
 //)
 
 @Entity(
-    tableName = "post",
-    foreignKeys = [
-        ForeignKey(User::class, ["id"], ["user_id"])
-    ]
+    tableName = "post"
 )
+@Serializable
 data class Post(
     @PrimaryKey(autoGenerate = true)
     @ColumnInfo
@@ -74,11 +70,13 @@ data class Post(
     @ColumnInfo
     val content: String,
     @ColumnInfo
-    val date: Date,
+    val date: String,
     @ColumnInfo(name = "user_id")
-    val userId: Int,
+    val user_id: Int,
     @ColumnInfo(name = "category_id")
-    val categoryId: Int
+    val category_id: Int,
+    @ColumnInfo
+    val likes: Int = 0,
 ) {
     override fun equals(other: Any?): Boolean {
         if (this === other) return true
diff --git a/app/src/main/java/com/example/dtf/models/PostWithComments.kt b/app/src/main/java/com/example/dtf/models/PostWithComments.kt
deleted file mode 100644
index ef64a9a..0000000
--- a/app/src/main/java/com/example/dtf/models/PostWithComments.kt
+++ /dev/null
@@ -1,10 +0,0 @@
-package com.example.dtf.models
-
-import androidx.room.Embedded
-import androidx.room.Relation
-
-data class PostWithComments(
-    @Embedded val post: Post,
-    @Relation(parentColumn = "id", entityColumn = "post_id")
-    val comments: List<Comment>
-)
diff --git a/app/src/main/java/com/example/dtf/models/User.kt b/app/src/main/java/com/example/dtf/models/User.kt
index f04ed75..d563c49 100644
--- a/app/src/main/java/com/example/dtf/models/User.kt
+++ b/app/src/main/java/com/example/dtf/models/User.kt
@@ -1,18 +1,16 @@
 package com.example.dtf.models
 
 import androidx.room.*
+import kotlinx.serialization.Serializable
 
 @Entity(tableName = "user")
+@Serializable
 data class User(
     @PrimaryKey(autoGenerate = true)
     @ColumnInfo
     val id: Int?,
     @ColumnInfo
     val username: String,
-    @ColumnInfo
-    val password: String,
-    @ColumnInfo
-    val isModerator: Boolean
 ) {
     override fun equals(other: Any?): Boolean {
         if (this === other) return true
diff --git a/app/src/main/java/com/example/dtf/repositories/CategoryRepository.kt b/app/src/main/java/com/example/dtf/repositories/CategoryRepository.kt
deleted file mode 100644
index 02dac8f..0000000
--- a/app/src/main/java/com/example/dtf/repositories/CategoryRepository.kt
+++ /dev/null
@@ -1,19 +0,0 @@
-package com.example.dtf.repositories
-
-import com.example.dtf.dao.CategoryDao
-import com.example.dtf.models.Category
-import javax.inject.Inject
-
-class CategoryRepository @Inject constructor(
-    private val categoryDao: CategoryDao
-) {
-    suspend fun insert(category: Category) = categoryDao.insert(category)
-
-    suspend fun update(category: Category) = categoryDao.update(category)
-
-    suspend fun delete(category: Category) = categoryDao.delete(category)
-
-    fun getAll() = categoryDao.getAll()
-
-    fun getById(id: Int) = categoryDao.getById(id)
-}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/repositories/CommentRepository.kt b/app/src/main/java/com/example/dtf/repositories/CommentRepository.kt
deleted file mode 100644
index 5852b51..0000000
--- a/app/src/main/java/com/example/dtf/repositories/CommentRepository.kt
+++ /dev/null
@@ -1,28 +0,0 @@
-package com.example.dtf.repositories
-
-import androidx.paging.*
-import com.example.dtf.dao.CommentDao
-import com.example.dtf.models.Comment
-import javax.inject.Inject
-
-class CommentRepository @Inject constructor(
-    private val commentDao: CommentDao
-) {
-    suspend fun insert(comment: Comment) = commentDao.insert(comment)
-
-    suspend fun update(comment: Comment) = commentDao.update(comment)
-
-    suspend fun delete(comment: Comment) = commentDao.delete(comment)
-
-    fun getAll() = commentDao.getAll()
-
-    fun getById(id: Int) = commentDao.getById(id)
-
-    fun getByPost(postId: Int) = Pager(
-        PagingConfig(
-            pageSize = 5,
-            enablePlaceholders = false
-        ),
-        pagingSourceFactory = { commentDao.getByPost(postId) }
-    ).flow
-}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/repositories/ICategoryRepository.kt b/app/src/main/java/com/example/dtf/repositories/ICategoryRepository.kt
new file mode 100644
index 0000000..a80af87
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/repositories/ICategoryRepository.kt
@@ -0,0 +1,12 @@
+package com.example.dtf.repositories
+
+import androidx.paging.PagingData
+import com.example.dtf.models.Category
+import kotlinx.coroutines.flow.Flow
+
+interface ICategoryRepository {
+    fun getAll(): Flow<PagingData<Category>>
+    fun getAllCached(): Flow<List<Category>>
+
+    fun getFirst(): Flow<Category?>
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/repositories/ICommentRepository.kt b/app/src/main/java/com/example/dtf/repositories/ICommentRepository.kt
new file mode 100644
index 0000000..fb4ad0a
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/repositories/ICommentRepository.kt
@@ -0,0 +1,12 @@
+package com.example.dtf.repositories
+
+import androidx.paging.PagingData
+import com.example.dtf.models.Comment
+import kotlinx.coroutines.flow.Flow
+
+interface ICommentRepository {
+    suspend fun insert(comment: Comment)
+
+    fun getById(id: Int): Flow<Comment>
+    fun getByPost(postId: Int): Flow<PagingData<Comment>>
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/repositories/ILikeRepository.kt b/app/src/main/java/com/example/dtf/repositories/ILikeRepository.kt
new file mode 100644
index 0000000..af3479d
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/repositories/ILikeRepository.kt
@@ -0,0 +1,12 @@
+package com.example.dtf.repositories
+
+import com.example.dtf.models.Like
+import kotlinx.coroutines.flow.Flow
+
+interface ILikeRepository {
+    suspend fun insert(like: Like)
+    suspend fun delete(like: Like)
+
+    fun countByPost(postId: Int): Flow<Int>
+    fun isLikedByUser(userId: Int, postId: Int): Flow<Boolean>
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/repositories/IPostRepository.kt b/app/src/main/java/com/example/dtf/repositories/IPostRepository.kt
new file mode 100644
index 0000000..ed06677
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/repositories/IPostRepository.kt
@@ -0,0 +1,13 @@
+package com.example.dtf.repositories
+
+import androidx.paging.PagingData
+import com.example.dtf.models.Post
+import kotlinx.coroutines.flow.Flow
+
+interface IPostRepository {
+    suspend fun insert(post: Post)
+    suspend fun update(post: Post)
+
+    fun getById(id: Int): Flow<Post>
+    fun getByCategory(categoryId: Int): Flow<PagingData<Post>>
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/repositories/IUserRepository.kt b/app/src/main/java/com/example/dtf/repositories/IUserRepository.kt
new file mode 100644
index 0000000..655ded1
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/repositories/IUserRepository.kt
@@ -0,0 +1,8 @@
+package com.example.dtf.repositories
+
+import com.example.dtf.models.User
+import kotlinx.coroutines.flow.Flow
+
+interface IUserRepository {
+    fun getById(id: Int) : Flow<User>
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/repositories/LikeRepository.kt b/app/src/main/java/com/example/dtf/repositories/LikeRepository.kt
deleted file mode 100644
index 24f107f..0000000
--- a/app/src/main/java/com/example/dtf/repositories/LikeRepository.kt
+++ /dev/null
@@ -1,17 +0,0 @@
-package com.example.dtf.repositories
-
-import com.example.dtf.dao.LikeDao
-import com.example.dtf.models.Like
-import javax.inject.Inject
-
-class LikeRepository @Inject constructor(
-    private val likeDao: LikeDao
-) {
-    suspend fun insert(like: Like) = likeDao.insert(like)
-
-    suspend fun delete(like: Like) = likeDao.delete(like)
-
-    fun countByPost(postId: Int) = likeDao.countByPost(postId)
-
-    fun isLikedByUser(userId: Int, postId: Int) = likeDao.isLikedByUser(userId, postId)
-}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/repositories/PostRepository.kt b/app/src/main/java/com/example/dtf/repositories/PostRepository.kt
deleted file mode 100644
index f12ee02..0000000
--- a/app/src/main/java/com/example/dtf/repositories/PostRepository.kt
+++ /dev/null
@@ -1,29 +0,0 @@
-package com.example.dtf.repositories
-
-import androidx.paging.*
-import com.example.dtf.dao.PostDao
-import com.example.dtf.models.Post
-import kotlinx.coroutines.flow.Flow
-import javax.inject.Inject
-
-class PostRepository @Inject constructor(
-    private val postDao: PostDao
-) {
-    suspend fun insert(post: Post) = postDao.insert(post)
-
-    suspend fun update(post: Post) = postDao.update(post)
-
-    suspend fun delete(post: Post) = postDao.delete(post)
-
-    fun getAll() = postDao.getAll()
-
-    fun getById(id: Int) = postDao.getById(id)
-
-    fun getByCategory(categoryId: Int) = Pager(
-        PagingConfig(
-            pageSize = 3,
-            enablePlaceholders = false
-        ),
-        pagingSourceFactory = { postDao.getByCategory(categoryId.toString()) }
-    ).flow
-}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/repositories/UserRepository.kt b/app/src/main/java/com/example/dtf/repositories/UserRepository.kt
deleted file mode 100644
index 028a762..0000000
--- a/app/src/main/java/com/example/dtf/repositories/UserRepository.kt
+++ /dev/null
@@ -1,22 +0,0 @@
-package com.example.dtf.repositories
-
-import com.example.dtf.dao.UserDao
-import com.example.dtf.models.User
-import kotlinx.coroutines.flow.Flow
-import javax.inject.Inject
-
-class UserRepository @Inject constructor(
-    private val userDao: UserDao
-)  {
-    suspend fun insert(user: User) = userDao.insert(user)
-
-    suspend fun update(user: User) = userDao.update(user)
-
-    suspend fun delete(user: User) = userDao.delete(user)
-
-    fun getAll() = userDao.getAll()
-
-    fun getById(id: Int) = userDao.getById(id)
-
-    fun getByUsernameAndPassword(username: String, password: String) = userDao.getByUsernameAndPassword(username, password)
-}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/repositories/offline/OfflineCategoryRepository.kt b/app/src/main/java/com/example/dtf/repositories/offline/OfflineCategoryRepository.kt
new file mode 100644
index 0000000..0e7dfca
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/repositories/offline/OfflineCategoryRepository.kt
@@ -0,0 +1,30 @@
+package com.example.dtf.repositories.offline
+
+import androidx.paging.Pager
+import androidx.paging.PagingConfig
+import com.example.dtf.dao.CategoryDao
+import com.example.dtf.models.Category
+import com.example.dtf.repositories.ICategoryRepository
+import kotlinx.coroutines.flow.Flow
+import javax.inject.Inject
+
+class OfflineCategoryRepository @Inject constructor(
+    private val categoryDao: CategoryDao
+) : ICategoryRepository {
+
+    override fun getAll() = Pager(
+        PagingConfig(
+            pageSize = 5,
+            enablePlaceholders = false
+        ),
+        pagingSourceFactory = { categoryDao.getAll() }
+    ).flow
+
+    override fun getAllCached(): Flow<List<Category>> {
+        return categoryDao.getAllCached()
+    }
+
+    override fun getFirst(): Flow<Category?> {
+        return categoryDao.getFirst()
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/repositories/offline/OfflineCommentRepository.kt b/app/src/main/java/com/example/dtf/repositories/offline/OfflineCommentRepository.kt
new file mode 100644
index 0000000..a448746
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/repositories/offline/OfflineCommentRepository.kt
@@ -0,0 +1,23 @@
+package com.example.dtf.repositories.offline
+
+import androidx.paging.*
+import com.example.dtf.dao.CommentDao
+import com.example.dtf.models.Comment
+import com.example.dtf.repositories.ICommentRepository
+import javax.inject.Inject
+
+class OfflineCommentRepository @Inject constructor(
+    private val commentDao: CommentDao
+) : ICommentRepository {
+    override suspend fun insert(comment: Comment) = commentDao.insert(comment)
+
+    override fun getById(id: Int) = commentDao.getById(id)
+
+    override fun getByPost(postId: Int) = Pager(
+        PagingConfig(
+            pageSize = 5,
+            enablePlaceholders = false
+        ),
+        pagingSourceFactory = { commentDao.getByPost(postId) }
+    ).flow
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/repositories/offline/OfflineLikeRepository.kt b/app/src/main/java/com/example/dtf/repositories/offline/OfflineLikeRepository.kt
new file mode 100644
index 0000000..e280123
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/repositories/offline/OfflineLikeRepository.kt
@@ -0,0 +1,18 @@
+package com.example.dtf.repositories.offline
+
+import com.example.dtf.dao.LikeDao
+import com.example.dtf.models.Like
+import com.example.dtf.repositories.ILikeRepository
+import javax.inject.Inject
+
+class OfflineLikeRepository @Inject constructor(
+    private val likeDao: LikeDao
+) : ILikeRepository {
+    override suspend fun insert(like: Like) = likeDao.insert(like)
+
+    override suspend fun delete(like: Like) = likeDao.delete(like)
+
+    override fun countByPost(postId: Int) = likeDao.countByPost(postId)
+
+    override fun isLikedByUser(userId: Int, postId: Int) = likeDao.isLikedByUser(userId, postId)
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/repositories/offline/OfflinePostRepository.kt b/app/src/main/java/com/example/dtf/repositories/offline/OfflinePostRepository.kt
new file mode 100644
index 0000000..b4e1661
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/repositories/offline/OfflinePostRepository.kt
@@ -0,0 +1,25 @@
+package com.example.dtf.repositories.offline
+
+import androidx.paging.*
+import com.example.dtf.dao.PostDao
+import com.example.dtf.models.Post
+import com.example.dtf.repositories.IPostRepository
+import javax.inject.Inject
+
+class OfflinePostRepository @Inject constructor(
+    private val postDao: PostDao
+) : IPostRepository {
+    override suspend fun insert(post: Post) = postDao.insert(post)
+
+    override suspend fun update(post: Post) = postDao.update(post)
+
+    override fun getById(id: Int) = postDao.getById(id)
+
+    override fun getByCategory(categoryId: Int) = Pager(
+        PagingConfig(
+            pageSize = 3,
+            enablePlaceholders = false
+        ),
+        pagingSourceFactory = { postDao.getByCategory(categoryId.toString()) }
+    ).flow
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/repositories/offline/OfflineUserRepository.kt b/app/src/main/java/com/example/dtf/repositories/offline/OfflineUserRepository.kt
new file mode 100644
index 0000000..1712f9e
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/repositories/offline/OfflineUserRepository.kt
@@ -0,0 +1,12 @@
+package com.example.dtf.repositories.offline
+
+import com.example.dtf.dao.UserDao
+import com.example.dtf.models.User
+import com.example.dtf.repositories.IUserRepository
+import javax.inject.Inject
+
+class OfflineUserRepository @Inject constructor(
+    private val userDao: UserDao
+) : IUserRepository {
+    override fun getById(id: Int) = userDao.getById(id)
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/repositories/online/RestCategoryRepository.kt b/app/src/main/java/com/example/dtf/repositories/online/RestCategoryRepository.kt
new file mode 100644
index 0000000..8f122a9
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/repositories/online/RestCategoryRepository.kt
@@ -0,0 +1,37 @@
+package com.example.dtf.repositories.online.mediator
+
+import androidx.paging.ExperimentalPagingApi
+import androidx.paging.Pager
+import androidx.paging.PagingConfig
+import androidx.paging.PagingData
+import com.example.dtf.api.ServerService
+import com.example.dtf.db.AppDatabase
+import com.example.dtf.models.Category
+import com.example.dtf.repositories.ICategoryRepository
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.flow
+import javax.inject.Inject
+
+class RestCategoryRepository @Inject constructor(
+    private val appDatabase: AppDatabase,
+    private val serverService: ServerService
+) : ICategoryRepository {
+
+    @OptIn(ExperimentalPagingApi::class)
+    override fun getAll(): Flow<PagingData<Category>> = Pager(
+        PagingConfig(
+            pageSize = 3,
+            enablePlaceholders = false
+        ),
+        remoteMediator = CategoryMediator(appDatabase, serverService),
+        pagingSourceFactory = { appDatabase.categoryDao().getAll() }
+    ).flow
+
+    override fun getAllCached(): Flow<List<Category>> {
+        return appDatabase.categoryDao().getAllCached()
+    }
+
+    override fun getFirst(): Flow<Category?> {
+        return appDatabase.categoryDao().getFirst()
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/repositories/online/RestCommentRepository.kt b/app/src/main/java/com/example/dtf/repositories/online/RestCommentRepository.kt
new file mode 100644
index 0000000..ae0549e
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/repositories/online/RestCommentRepository.kt
@@ -0,0 +1,41 @@
+package com.example.dtf.repositories.online
+
+import androidx.paging.ExperimentalPagingApi
+import androidx.paging.Pager
+import androidx.paging.PagingConfig
+import androidx.paging.PagingData
+import com.example.dtf.api.ServerService
+import com.example.dtf.db.AppDatabase
+import com.example.dtf.dto.NewCommentDto
+import com.example.dtf.models.Comment
+import com.example.dtf.repositories.ICommentRepository
+import com.example.dtf.repositories.online.mediator.CommentMediator
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.flow
+import javax.inject.Inject
+
+class RestCommentRepository @Inject constructor(
+    private val appDatabase: AppDatabase,
+    private val serverService: ServerService
+) : ICommentRepository {
+    override suspend fun insert(comment: Comment) {
+        serverService.createComment(
+            comment = NewCommentDto(post_id = comment.post_id, content = comment.content)
+        )
+        appDatabase.commentDao().insert(comment)
+    }
+
+    override fun getById(id: Int): Flow<Comment> {
+        return flow { emit(serverService.getComment(id)) }
+    }
+
+    @OptIn(ExperimentalPagingApi::class)
+    override fun getByPost(postId: Int): Flow<PagingData<Comment>> = Pager(
+        PagingConfig(
+            pageSize = 5,
+            enablePlaceholders = false,
+        ),
+        remoteMediator = CommentMediator(appDatabase, serverService, postId.toString()),
+        pagingSourceFactory = { appDatabase.commentDao().getByPost(postId) }
+    ).flow
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/repositories/online/RestLikeRepository.kt b/app/src/main/java/com/example/dtf/repositories/online/RestLikeRepository.kt
new file mode 100644
index 0000000..3e66320
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/repositories/online/RestLikeRepository.kt
@@ -0,0 +1,30 @@
+package com.example.dtf.repositories.online
+
+import com.example.dtf.api.ServerService
+import com.example.dtf.db.AppDatabase
+import com.example.dtf.models.Like
+import com.example.dtf.repositories.ILikeRepository
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.flow
+import javax.inject.Inject
+
+class RestLikeRepository @Inject constructor(
+    private val appDatabase: AppDatabase,
+    private val serverService: ServerService
+) : ILikeRepository {
+    override suspend fun insert(like: Like) {
+        serverService.likePost(like.postId)
+    }
+
+    override suspend fun delete(like: Like) {
+        serverService.likePost(like.postId)
+    }
+
+    override fun countByPost(postId: Int): Flow<Int> {
+        return flow { emit(serverService.getPostLikes(postId)) }
+    }
+
+    override fun isLikedByUser(userId: Int, postId: Int): Flow<Boolean> {
+        return flow { emit(serverService.postIsLiked(postId)) }
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/repositories/online/RestPostRepository.kt b/app/src/main/java/com/example/dtf/repositories/online/RestPostRepository.kt
new file mode 100644
index 0000000..87e21c1
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/repositories/online/RestPostRepository.kt
@@ -0,0 +1,49 @@
+package com.example.dtf.repositories.online
+
+import androidx.paging.ExperimentalPagingApi
+import androidx.paging.Pager
+import androidx.paging.PagingConfig
+import androidx.paging.PagingData
+import com.example.dtf.api.ServerService
+import com.example.dtf.db.AppDatabase
+import com.example.dtf.dto.EditPostDto
+import com.example.dtf.dto.NewPostDto
+import com.example.dtf.models.Post
+import com.example.dtf.repositories.IPostRepository
+import com.example.dtf.repositories.online.mediator.PostMediator
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.flow
+import javax.inject.Inject
+
+class RestPostRepository @Inject constructor(
+    private val appDatabase: AppDatabase,
+    private val serverService: ServerService
+) : IPostRepository {
+    override suspend fun insert(post: Post) {
+        serverService.createPost(
+            post = NewPostDto(post.title, post.content, post.category_id)
+        )
+    }
+
+    override suspend fun update(post: Post) {
+        serverService.updatePost(
+            postId = post.id!!,
+            post = EditPostDto(post.title, post.content)
+        )
+        appDatabase.postDao().update(post)
+    }
+
+    override fun getById(id: Int): Flow<Post> {
+        return flow { emit(serverService.getPost(id)) }
+    }
+
+    @OptIn(ExperimentalPagingApi::class)
+    override fun getByCategory(categoryId: Int): Flow<PagingData<Post>> = Pager(
+        PagingConfig(
+            pageSize = 4,
+            enablePlaceholders = false
+        ),
+        remoteMediator = PostMediator(appDatabase, serverService, categoryId.toString()),
+        pagingSourceFactory = { appDatabase.postDao().getByCategory(categoryId.toString()) }
+    ).flow
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/repositories/online/RestUserRepository.kt b/app/src/main/java/com/example/dtf/repositories/online/RestUserRepository.kt
new file mode 100644
index 0000000..4699adf
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/repositories/online/RestUserRepository.kt
@@ -0,0 +1,18 @@
+package com.example.dtf.repositories.online
+
+import com.example.dtf.api.ServerService
+import com.example.dtf.db.AppDatabase
+import com.example.dtf.models.User
+import com.example.dtf.repositories.IUserRepository
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.flow
+import javax.inject.Inject
+
+class RestUserRepository @Inject constructor(
+    private val appDatabase: AppDatabase,
+    private val serverService: ServerService
+) : IUserRepository {
+    override fun getById(id: Int): Flow<User> {
+        return flow { emit(serverService.getUser(id)) }
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/repositories/online/mediator/CategoryMediator.kt b/app/src/main/java/com/example/dtf/repositories/online/mediator/CategoryMediator.kt
new file mode 100644
index 0000000..445bb41
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/repositories/online/mediator/CategoryMediator.kt
@@ -0,0 +1,63 @@
+package com.example.dtf.repositories.online.mediator
+
+import androidx.paging.ExperimentalPagingApi
+import androidx.paging.LoadType
+import androidx.paging.PagingState
+import androidx.paging.RemoteMediator
+import androidx.room.withTransaction
+import com.example.dtf.api.ServerService
+import com.example.dtf.db.AppDatabase
+import com.example.dtf.models.Category
+import java.io.IOException
+
+@OptIn(ExperimentalPagingApi::class)
+class CategoryMediator (
+    private val database: AppDatabase,
+    private val serverService: ServerService
+) : RemoteMediator<Int, Category>(){
+
+    private val categoryDao = database.categoryDao()
+
+    override suspend fun load(
+        loadType: LoadType,
+        state: PagingState<Int, Category>
+    ): MediatorResult {
+        return try {
+            var loadKey = when (loadType) {
+                LoadType.REFRESH -> null
+                LoadType.PREPEND -> return MediatorResult.Success(endOfPaginationReached = true)
+                LoadType.APPEND -> {
+                    val lastItem = state.lastItemOrNull()
+                        ?: return MediatorResult.Success(endOfPaginationReached = true)
+
+                    lastItem.id
+                }
+            }
+
+            if (loadKey == null) {
+                loadKey = 0
+            }
+            val response = serverService.getCategories(
+                offset = loadKey,
+                limit = state.config.pageSize
+            )
+
+
+            database.withTransaction {
+                if (loadType == LoadType.REFRESH) {
+                    for (category in response.categories) {
+                        categoryDao.delete(category)
+                    }
+                }
+
+                for (category in response.categories) {
+                    categoryDao.insert(category)
+                }
+            }
+
+            MediatorResult.Success(endOfPaginationReached = response.nextKey == null)
+        } catch (e: IOException) {
+            MediatorResult.Error(e)
+        }
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/repositories/online/mediator/CommentMediator.kt b/app/src/main/java/com/example/dtf/repositories/online/mediator/CommentMediator.kt
new file mode 100644
index 0000000..8c28105
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/repositories/online/mediator/CommentMediator.kt
@@ -0,0 +1,63 @@
+package com.example.dtf.repositories.online.mediator
+
+import androidx.paging.ExperimentalPagingApi
+import androidx.paging.LoadType
+import androidx.paging.PagingState
+import androidx.paging.RemoteMediator
+import androidx.room.withTransaction
+import com.example.dtf.api.ServerService
+import com.example.dtf.db.AppDatabase
+import com.example.dtf.models.Comment
+import java.io.IOException
+
+@OptIn(ExperimentalPagingApi::class)
+class CommentMediator (
+    private val database: AppDatabase,
+    private val serverService: ServerService,
+    private val query: String
+) : RemoteMediator<Int, Comment>(){
+
+    private val commentDao = database.commentDao()
+
+    override suspend fun load(
+        loadType: LoadType,
+        state: PagingState<Int, Comment>
+    ): MediatorResult {
+        return try {
+            var loadKey = when (loadType) {
+                LoadType.REFRESH -> null
+                LoadType.PREPEND -> return MediatorResult.Success(endOfPaginationReached = true)
+                LoadType.APPEND -> {
+                    val lastItem = state.lastItemOrNull()
+                        ?: return MediatorResult.Success(endOfPaginationReached = true)
+
+                    lastItem.id
+                }
+            }
+
+            if (loadKey == null) {
+                loadKey = 0
+            }
+            val response = serverService.getComments(
+                postId = query.toInt(),
+                offset = loadKey,
+                limit = state.config.pageSize
+            )
+
+
+            database.withTransaction {
+                if (loadType == LoadType.REFRESH) {
+                    commentDao.deleteByQuery(query)
+                }
+
+                for (comment in response.comments) {
+                    commentDao.insert(comment)
+                }
+            }
+
+            MediatorResult.Success(endOfPaginationReached = response.nextKey == null)
+        } catch (e: IOException) {
+            MediatorResult.Error(e)
+        }
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/repositories/online/mediator/PostMediator.kt b/app/src/main/java/com/example/dtf/repositories/online/mediator/PostMediator.kt
new file mode 100644
index 0000000..97e166d
--- /dev/null
+++ b/app/src/main/java/com/example/dtf/repositories/online/mediator/PostMediator.kt
@@ -0,0 +1,63 @@
+package com.example.dtf.repositories.online.mediator
+
+import androidx.paging.ExperimentalPagingApi
+import androidx.paging.LoadType
+import androidx.paging.PagingState
+import androidx.paging.RemoteMediator
+import androidx.room.withTransaction
+import com.example.dtf.api.ServerService
+import com.example.dtf.db.AppDatabase
+import com.example.dtf.models.Post
+import java.io.IOException
+
+@OptIn(ExperimentalPagingApi::class)
+class PostMediator (
+    private val database: AppDatabase,
+    private val serverService: ServerService,
+    private val query: String
+) : RemoteMediator<Int, Post>(){
+
+    private val postDao = database.postDao()
+
+    override suspend fun load(
+        loadType: LoadType,
+        state: PagingState<Int, Post>
+    ): MediatorResult {
+        return try {
+            var loadKey = when (loadType) {
+                LoadType.REFRESH -> null
+                LoadType.PREPEND -> return MediatorResult.Success(endOfPaginationReached = true)
+                LoadType.APPEND -> {
+                    val lastItem = state.lastItemOrNull()
+                        ?: return MediatorResult.Success(endOfPaginationReached = true)
+
+                    lastItem.id
+                }
+            }
+
+            if (loadKey == null) {
+                loadKey = 0
+            }
+            val response = serverService.getPosts(
+                category = query.toInt(),
+                offset = loadKey,
+                limit = state.config.pageSize
+            )
+
+
+            database.withTransaction {
+                if (loadType == LoadType.REFRESH) {
+                    postDao.deleteByQuery(query)
+                }
+
+                for (comment in response.posts) {
+                    postDao.insert(comment)
+                }
+            }
+
+            MediatorResult.Success(endOfPaginationReached = response.nextKey == null)
+        } catch (e: IOException) {
+            MediatorResult.Error(e)
+        }
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/screens/NewPostScreen.kt b/app/src/main/java/com/example/dtf/screens/NewPostScreen.kt
index 6db9b89..f8c5bc7 100644
--- a/app/src/main/java/com/example/dtf/screens/NewPostScreen.kt
+++ b/app/src/main/java/com/example/dtf/screens/NewPostScreen.kt
@@ -18,6 +18,7 @@ import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.unit.*
 import androidx.hilt.navigation.compose.hiltViewModel
 import androidx.navigation.NavHostController
+import androidx.paging.compose.collectAsLazyPagingItems
 import com.example.dtf.PreferencesManager
 import com.example.dtf.models.Category
 import com.example.dtf.utils.ScreenPaths
@@ -36,9 +37,7 @@ fun NewPostScreen(navController: NavHostController) {
 
     val viewModel = hiltViewModel<NewPostViewModel>()
     val success = viewModel.addingPostState.observeAsState().value
-    val categories = viewModel.categories.observeAsState().value
-
-    viewModel.retrieveCategories()
+    val categories = viewModel.getCategories().collectAsState(initial = listOf())
 
     if (success == true) {
         navController.navigate(ScreenPaths.Posts.route) {
@@ -91,7 +90,9 @@ fun NewPostScreen(navController: NavHostController) {
             colors = ButtonDefaults.buttonColors(Color(0xFFFFFFFF)),
             border = BorderStroke(1.dp, Color(0xFF0085FF)),
             shape = RoundedCornerShape(15.dp),
-            modifier = Modifier.fillMaxWidth().padding(15.dp, 10.dp, 15.dp, 0.dp)
+            modifier = Modifier
+                .fillMaxWidth()
+                .padding(15.dp, 10.dp, 15.dp, 0.dp)
         ) {
             Text(
                 text = selectedCategory.value.name,
@@ -102,11 +103,13 @@ fun NewPostScreen(navController: NavHostController) {
                 )
             )
             DropdownMenu(
-                modifier = Modifier.fillMaxWidth().padding(horizontal = 15.dp),
+                modifier = Modifier
+                    .fillMaxWidth()
+                    .padding(horizontal = 15.dp),
                 expanded = expanded.value,
                 onDismissRequest = {expanded.value = false}
             ) {
-                categories?.forEach { category ->
+                categories.value.forEach { category ->
                     DropdownMenuItem(
                         onClick = {
                             selectedCategory.value = category
@@ -126,17 +129,23 @@ fun NewPostScreen(navController: NavHostController) {
             value = title,
             "Заголовок",
             onChanged = {title.value = it},
-            modifier = Modifier.fillMaxWidth().padding(horizontal = 15.dp),
+            modifier = Modifier
+                .fillMaxWidth()
+                .padding(horizontal = 15.dp),
             backgroundColor = Color(0xFFFEFEFE)
         )
         MyTextField(
             value = content,
             "Содержимое",
             onChanged = {content.value = it},
-            modifier = Modifier.fillMaxWidth().heightIn(min = 500.dp).padding(horizontal = 15.dp),
+            modifier = Modifier
+                .fillMaxWidth()
+                .heightIn(min = 400.dp)
+                .padding(horizontal = 15.dp),
             backgroundColor = Color(0xFFFEFEFE),
             false
         )
+
         Button(
             {
                 if (selectedCategory.value.id != null) {
diff --git a/app/src/main/java/com/example/dtf/screens/PostScreen.kt b/app/src/main/java/com/example/dtf/screens/PostScreen.kt
index e42b0be..18b0e70 100644
--- a/app/src/main/java/com/example/dtf/screens/PostScreen.kt
+++ b/app/src/main/java/com/example/dtf/screens/PostScreen.kt
@@ -19,23 +19,14 @@ import androidx.compose.ui.text.input.TextFieldValue
 import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.unit.*
 import androidx.hilt.navigation.compose.hiltViewModel
-import androidx.lifecycle.viewModelScope
 import androidx.navigation.NavHostController
 import androidx.paging.compose.collectAsLazyPagingItems
 import androidx.paging.compose.itemKey
 import com.example.dtf.PreferencesManager
-import com.example.dtf.db.AppDatabase
 import com.example.dtf.models.Comment
-import com.example.dtf.models.Post
-import com.example.dtf.models.PostWithComments
-import com.example.dtf.models.User
 import com.example.dtf.utils.ScreenPaths
 import com.example.dtf.viewmodels.PostViewModel
 import com.example.dtf.widgets.MyTextField
-import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.launch
-import kotlinx.coroutines.withContext
-import java.util.Date
 
 @Composable
 fun PostScreen(postId: Int, navController: NavHostController) {
@@ -89,16 +80,7 @@ fun PostScreen(postId: Int, navController: NavHostController) {
             ) {
                 if (post != null) {
                     Text(
-                        text = "day.month.year".replace(
-                            "day",
-                            post.date.day.toString()
-                        ).replace(
-                            "month",
-                            post.date.month.toString()
-                        ).replace(
-                            "year",
-                            post.date.year.toString()
-                        ),
+                        text = post.date,
                         fontSize = 14.sp,
                         color = Color(0xFFCECCCC)
                     )
@@ -115,16 +97,7 @@ fun PostScreen(postId: Int, navController: NavHostController) {
                     )
                 }
                 Row (
-                    modifier = Modifier.clickable {
-                        if (isLiked.value) {
-                            viewModel.unlikePost(sharedPref, postId)
-                            likes.intValue--
-                        } else {
-                            viewModel.likePost(sharedPref, postId)
-                            likes.intValue++
-                        }
-                        isLiked.value = !isLiked.value
-                    },
+                    modifier = Modifier,
                     horizontalArrangement = Arrangement.End
                 ) {
                     Text(
@@ -133,7 +106,16 @@ fun PostScreen(postId: Int, navController: NavHostController) {
                         color = Color.Green
                     )
                     Icon(
-                        modifier = Modifier.padding(start = 8.dp),
+                        modifier = Modifier.padding(start = 8.dp).clickable {
+                            if (isLiked.value) {
+                                viewModel.unlikePost(sharedPref, postId)
+                                likes.intValue--
+                            } else {
+                                viewModel.likePost(sharedPref, postId)
+                                likes.intValue++
+                            }
+                            isLiked.value = !isLiked.value
+                        },
                         imageVector = Icons.Default.ThumbUp,
                         contentDescription = null,
                         tint = if (isLiked.value) { Color(40, 200, 40, 255) } else {Color.Black}
@@ -202,20 +184,11 @@ private fun Comment(comment: Comment) {
             horizontalArrangement = Arrangement.SpaceBetween
         ) {
             Text(
-                text = user?.username ?: "Loading...",
+                text = comment.author.ifEmpty { user?.username ?: "Loading..." },
                 fontSize = 20.sp
             )
             Text(
-                text = "day.month.year".replace(
-                    "day",
-                    comment.date.day.toString()
-                ).replace(
-                    "month",
-                    comment.date.month.toString()
-                ).replace(
-                    "year",
-                    comment.date.year.toString()
-                ),
+                text = comment.date,
                 fontSize = 14.sp,
                 color = Color(0xFFCECCCC)
             )
diff --git a/app/src/main/java/com/example/dtf/screens/PostsScreen.kt b/app/src/main/java/com/example/dtf/screens/PostsScreen.kt
index 7866bec..05c8f26 100644
--- a/app/src/main/java/com/example/dtf/screens/PostsScreen.kt
+++ b/app/src/main/java/com/example/dtf/screens/PostsScreen.kt
@@ -3,6 +3,7 @@ package com.example.dtf.screens
 import androidx.compose.foundation.layout.*
 import androidx.compose.foundation.*
 import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.LazyRow
 import androidx.compose.material.*
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.ThumbUp
@@ -18,21 +19,14 @@ import androidx.compose.ui.unit.*
 import androidx.hilt.navigation.compose.hiltViewModel
 import androidx.navigation.NavHostController
 import androidx.paging.PagingData
-import androidx.paging.compose.LazyPagingItems
 import androidx.paging.compose.collectAsLazyPagingItems
 import androidx.paging.compose.itemKey
 import com.example.dtf.PreferencesManager
-import com.example.dtf.db.AppDatabase
 import com.example.dtf.models.Category
-import com.example.dtf.models.CategoryWithPosts
 import com.example.dtf.models.Post
 import com.example.dtf.utils.ScreenPaths
 import com.example.dtf.viewmodels.PostsViewModel
-import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.flow.Flow
-import kotlinx.coroutines.launch
-import kotlinx.coroutines.withContext
 
 @Composable
 fun PostsScreen(navController: NavHostController) {
@@ -47,19 +41,8 @@ fun PostsScreen(navController: NavHostController) {
         modifier = Modifier.fillMaxSize(),
         verticalArrangement = Arrangement.spacedBy(10.dp)
     ) {
-        Row(
-            modifier = Modifier
-                       .fillMaxWidth()
-                       .fillMaxHeight(0.1f)
-                       .horizontalScroll(
-                            rememberScrollState()
-                       )
-                       .background(Color.White),
-            horizontalArrangement = Arrangement.spacedBy(25.dp),
-            verticalAlignment = Alignment.CenterVertically
-        ) {
-            Categories(viewModel, currentCategory, posts)
-        }
+
+        Categories(viewModel, currentCategory, posts)
         Row(
             modifier = Modifier.fillMaxSize()
         ) {
@@ -72,36 +55,50 @@ fun PostsScreen(navController: NavHostController) {
 
 @Composable
 private fun Categories(viewModel: PostsViewModel, currentCategory: MutableState<Category?>, posts: MutableState<Flow<PagingData<Post>>?>) {
-    val categories = viewModel.getCategories().collectAsState(listOf()).value
+    val categories = viewModel.getCategoriesListUiState().collectAsLazyPagingItems()
 
-    if (categories.isNotEmpty() && currentCategory.value == null) {
-        currentCategory.value = categories[0]
-        posts.value = viewModel.getPostsListUiState(currentCategory.value!!.id!!)
-    }
 
-    Spacer(modifier = Modifier.width(5.dp))
-    categories.forEach {category ->
-        Text(
-            modifier = Modifier
-                .clickable {
-                    currentCategory.value = category
-                    posts.value = viewModel.getPostsListUiState(category.id!!)
-                }
-                .drawBehind {
-                    if (category.name == currentCategory.value?.name) {
-                        val strokeWidthPx = 2.dp.toPx()
-                        val verticalOffset = size.height + 2.sp.toPx()
-                        drawLine(
-                            color = Color(0xFF319CFF),
-                            strokeWidth = strokeWidthPx,
-                            start = Offset(0f, verticalOffset),
-                            end = Offset(size.width, verticalOffset)
-                        )
+    LazyRow(
+        modifier = Modifier
+            .fillMaxWidth()
+            .fillMaxHeight(0.1f)
+            .background(Color.White),
+        horizontalArrangement = Arrangement.spacedBy(25.dp),
+        verticalAlignment = Alignment.CenterVertically
+    ) {
+        item {
+            Spacer(modifier = Modifier.width(5.dp))
+        }
+        items(
+            count = categories.itemCount,
+            key = categories.itemKey()
+        ) {
+            if (currentCategory.value == null) {
+                currentCategory.value = categories[0]
+                posts.value = viewModel.getPostsListUiState(currentCategory.value!!.id!!)
+            }
+            Text(
+                modifier = Modifier
+                    .clickable {
+                        currentCategory.value = categories[it]!!
+                        posts.value = viewModel.getPostsListUiState(categories[it]!!.id!!)
                     }
-                },
-            text = category.name,
-            fontSize = 22.sp
-        )
+                    .drawBehind {
+                        if (categories[it]!!.name == currentCategory.value?.name) {
+                            val strokeWidthPx = 2.dp.toPx()
+                            val verticalOffset = size.height + 2.sp.toPx()
+                            drawLine(
+                                color = Color(0xFF319CFF),
+                                strokeWidth = strokeWidthPx,
+                                start = Offset(0f, verticalOffset),
+                                end = Offset(size.width, verticalOffset)
+                            )
+                        }
+                    },
+                text = categories[it]!!.name,
+                fontSize = 22.sp
+            )
+        }
     }
 }
 
@@ -129,7 +126,7 @@ private fun PostsByCategory(viewModel: PostsViewModel, navController: NavHostCon
 private fun Post(viewModel: PostsViewModel, navController: NavHostController, post: Post) {
     val sharedPref = PreferencesManager(LocalContext.current)
 
-    val likes = remember { mutableIntStateOf(0) }
+    val likes = remember { mutableIntStateOf(post.likes) }
     val isLiked = remember { mutableStateOf(false) }
 
     LaunchedEffect(Unit) {
@@ -162,41 +159,28 @@ private fun Post(viewModel: PostsViewModel, navController: NavHostController, po
             fontSize = 26.sp
         )
         Text(
-            modifier = Modifier.fillMaxHeight(0.6f).padding(10.dp, 0.dp, 10.dp, 0.dp),
+            modifier = Modifier
+                .fillMaxHeight(0.6f)
+                .padding(10.dp, 0.dp, 10.dp, 0.dp),
             text = post.content,
             fontSize = 20.sp,
             overflow = TextOverflow.Ellipsis
         )
         Row(
-            modifier = Modifier.fillMaxWidth().padding(10.dp),
+            modifier = Modifier
+                .fillMaxWidth()
+                .padding(10.dp),
             verticalAlignment = Alignment.Bottom,
             horizontalArrangement = Arrangement.SpaceBetween
         ) {
             Text(
-                text = "day.month.year".replace(
-                    "day",
-                    post.date.day.toString()
-                ).replace(
-                    "month",
-                    post.date.month.toString()
-                ).replace(
-                    "year",
-                    post.date.year.toString()
-                ),
+                text = post.date,
                 fontSize = 14.sp,
                 color = Color(0xFFCECCCC)
             )
             Row (
-                modifier = Modifier.fillMaxWidth().clickable {
-                    if (isLiked.value) {
-                        viewModel.unlikePost(sharedPref, post.id!!)
-                        likes.intValue--
-                    } else {
-                        viewModel.likePost(sharedPref, post.id!!)
-                        likes.intValue++
-                    }
-                    isLiked.value = !isLiked.value
-                },
+                modifier = Modifier
+                    .fillMaxWidth(),
                 horizontalArrangement = Arrangement.End
             ) {
                 Text(
@@ -205,7 +189,18 @@ private fun Post(viewModel: PostsViewModel, navController: NavHostController, po
                     color = Color.Green
                 )
                 Icon(
-                    modifier = Modifier.padding(start = 8.dp),
+                    modifier = Modifier
+                        .padding(start = 8.dp)
+                        .clickable {
+                            if (isLiked.value) {
+                                viewModel.unlikePost(sharedPref, post.id!!)
+                                likes.intValue--
+                            } else {
+                                viewModel.likePost(sharedPref, post.id!!)
+                                likes.intValue++
+                            }
+                            isLiked.value = !isLiked.value
+                        },
                     imageVector = Icons.Default.ThumbUp,
                     contentDescription = null,
                     tint = if (isLiked.value) { Color(40, 200, 40, 255) } else {Color.Black}
diff --git a/app/src/main/java/com/example/dtf/viewmodels/EditPostViewModel.kt b/app/src/main/java/com/example/dtf/viewmodels/EditPostViewModel.kt
index 9b42b6b..7b65e45 100644
--- a/app/src/main/java/com/example/dtf/viewmodels/EditPostViewModel.kt
+++ b/app/src/main/java/com/example/dtf/viewmodels/EditPostViewModel.kt
@@ -6,14 +6,14 @@ import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import com.example.dtf.PreferencesManager
 import com.example.dtf.models.Post
-import com.example.dtf.repositories.PostRepository
+import com.example.dtf.repositories.IPostRepository
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.launch
 import javax.inject.Inject
 
 @HiltViewModel
 class EditPostViewModel @Inject constructor(
-    private val postRepository: PostRepository
+    private val postRepository: IPostRepository
 ) : ViewModel() {
     private val _editingPostState = MutableLiveData<Boolean?>(null)
     val editingPostState: LiveData<Boolean?>
@@ -41,7 +41,7 @@ class EditPostViewModel @Inject constructor(
         viewModelScope.launch {
             if (title.isNotEmpty() && content.isNotEmpty()) {
                 postRepository.getById(postId).collect {
-                    postRepository.update(Post(postId, title, content, it.date, it.userId, it.categoryId))
+                    postRepository.update(Post(postId, title, content, it.date, it.user_id, it.category_id))
                     _editingPostState.postValue(true)
                 }
             } else {
diff --git a/app/src/main/java/com/example/dtf/viewmodels/LoginViewModel.kt b/app/src/main/java/com/example/dtf/viewmodels/LoginViewModel.kt
index 2da272f..9aeb8fa 100644
--- a/app/src/main/java/com/example/dtf/viewmodels/LoginViewModel.kt
+++ b/app/src/main/java/com/example/dtf/viewmodels/LoginViewModel.kt
@@ -5,55 +5,44 @@ import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import com.example.dtf.PreferencesManager
-import com.example.dtf.models.Category
-import com.example.dtf.models.User
-import com.example.dtf.repositories.CategoryRepository
-import com.example.dtf.repositories.UserRepository
+import com.example.dtf.api.ServerService
+import com.example.dtf.dto.Credentials
+import com.example.dtf.repositories.IUserRepository
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.launch
 import javax.inject.Inject
 
 @HiltViewModel
 class LoginViewModel @Inject constructor(
-    private val userRepository: UserRepository,
-    private val categoryRepository: CategoryRepository
+    private val serverService: ServerService,
 ) : ViewModel() {
     private val _successState = MutableLiveData<Boolean?>()
     val successState: LiveData<Boolean?>
         get() = _successState
 
-    init {
-        addAdmin()
-    }
-
     fun calmSuccessState() {
         _successState.postValue(null)
     }
 
     fun login(sharedPref: PreferencesManager, username: String, password: String) {
         viewModelScope.launch {
-            userRepository.getByUsernameAndPassword(username, password).collect {
-                if (it == null) {
-                    _successState.postValue(false)
-                } else {
-                    sharedPref.saveData("userId", it.id.toString())
-                    sharedPref.saveData("isModerator", it.isModerator.toString())
-                    _successState.postValue(true)
-                }
-            }
-        }
-    }
+            val token = serverService.login(Credentials(username, password))
 
-    private fun addAdmin() {
-        viewModelScope.launch {
-            userRepository.getAll().collect {
-                if (it.size == 0) {
-                    userRepository.insert(User(1, "admin", "admin", true))
-                    categoryRepository.insert(Category(1, "Аниме"))
-                    categoryRepository.insert(Category(2, "Игры"))
-                    categoryRepository.insert(Category(3, "Фильмы"))
-                }
+            if (token.token.isEmpty()) {
+                _successState.postValue(false)
+                return@launch
             }
+
+            ServerService.setToken(token.token)
+
+            val user = serverService.getCurrentUser()
+
+            sharedPref.saveData("token", token.token)
+            sharedPref.saveData("username", user.username)
+            sharedPref.saveData("isModerator", user.is_moderator.toString())
+            sharedPref.saveData("userId", user.id.toString())
+
+            _successState.postValue(true)
         }
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/viewmodels/NewPostViewModel.kt b/app/src/main/java/com/example/dtf/viewmodels/NewPostViewModel.kt
index 6ffca76..1cb04a0 100644
--- a/app/src/main/java/com/example/dtf/viewmodels/NewPostViewModel.kt
+++ b/app/src/main/java/com/example/dtf/viewmodels/NewPostViewModel.kt
@@ -5,36 +5,24 @@ import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import com.example.dtf.PreferencesManager
-import com.example.dtf.models.Category
 import com.example.dtf.models.Post
-import com.example.dtf.repositories.CategoryRepository
-import com.example.dtf.repositories.PostRepository
+import com.example.dtf.repositories.ICategoryRepository
+import com.example.dtf.repositories.IPostRepository
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.launch
-import java.time.LocalDate
 import java.util.Date
 import javax.inject.Inject
 
 @HiltViewModel
 class NewPostViewModel @Inject constructor(
-    private val postRepository: PostRepository,
-    private val categoryRepository: CategoryRepository
+    private val postRepository: IPostRepository,
+    private val categoryRepository: ICategoryRepository
 ) : ViewModel() {
     private val _addingPostState = MutableLiveData<Boolean?>(null)
     val addingPostState: LiveData<Boolean?>
         get() = _addingPostState
 
-    private val _categories = MutableLiveData<List<Category>>(listOf())
-    val categories: LiveData<List<Category>>
-        get() = _categories
-
-    fun retrieveCategories() {
-        viewModelScope.launch {
-            categoryRepository.getAll().collect {
-                _categories.postValue(it)
-            }
-        }
-    }
+    fun getCategories() = categoryRepository.getAllCached()
 
     fun calmAddingState() {
         _addingPostState.value = null
@@ -50,7 +38,7 @@ class NewPostViewModel @Inject constructor(
                         null,
                         title,
                         content,
-                        Date(),
+                        "${Date().year + 1900}-${Date().month + 1}-${Date().date}",
                         sharedPref.getData("userId", "0").toInt(),
                         categoryId
                     )
diff --git a/app/src/main/java/com/example/dtf/viewmodels/PostViewModel.kt b/app/src/main/java/com/example/dtf/viewmodels/PostViewModel.kt
index 0ffa1c7..7dd0262 100644
--- a/app/src/main/java/com/example/dtf/viewmodels/PostViewModel.kt
+++ b/app/src/main/java/com/example/dtf/viewmodels/PostViewModel.kt
@@ -4,16 +4,15 @@ import androidx.lifecycle.LiveData
 import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
-import androidx.lifecycle.viewmodel.compose.viewModel
 import androidx.paging.PagingData
 import com.example.dtf.PreferencesManager
 import com.example.dtf.models.Comment
 import com.example.dtf.models.Like
 import com.example.dtf.models.Post
-import com.example.dtf.repositories.CommentRepository
-import com.example.dtf.repositories.LikeRepository
-import com.example.dtf.repositories.PostRepository
-import com.example.dtf.repositories.UserRepository
+import com.example.dtf.repositories.ICommentRepository
+import com.example.dtf.repositories.ILikeRepository
+import com.example.dtf.repositories.IPostRepository
+import com.example.dtf.repositories.IUserRepository
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.launch
@@ -22,10 +21,10 @@ import javax.inject.Inject
 
 @HiltViewModel
 class PostViewModel @Inject constructor(
-    private val postRepository: PostRepository,
-    private val commentRepository: CommentRepository,
-    private val likeRepository: LikeRepository,
-    private val userRepository: UserRepository
+    private val postRepository: IPostRepository,
+    private val commentRepository: ICommentRepository,
+    private val likeRepository: ILikeRepository,
+    private val userRepository: IUserRepository
 ) : ViewModel() {
     private val _post = MutableLiveData<Post>()
     val post: LiveData<Post>
@@ -79,13 +78,14 @@ class PostViewModel @Inject constructor(
                     userId,
                     postId,
                     content,
-                    Date()
+                    "${Date().year + 1900}-${Date().month + 1}-${Date().date}",
+                    sharedPref.getData("username", "Unknown")
                 )
             )
         }
     }
 
-    fun getCommentsAuthor(comment: Comment) = userRepository.getById(comment.userId)
+    fun getCommentsAuthor(comment: Comment) = userRepository.getById(comment.user_id)
 
     fun getCommentsListUiState(postId: Int): Flow<PagingData<Comment>> = commentRepository.getByPost(postId)
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/viewmodels/PostsViewModel.kt b/app/src/main/java/com/example/dtf/viewmodels/PostsViewModel.kt
index 70cace9..2839bf6 100644
--- a/app/src/main/java/com/example/dtf/viewmodels/PostsViewModel.kt
+++ b/app/src/main/java/com/example/dtf/viewmodels/PostsViewModel.kt
@@ -4,18 +4,18 @@ import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import com.example.dtf.PreferencesManager
 import com.example.dtf.models.Like
-import com.example.dtf.repositories.CategoryRepository
-import com.example.dtf.repositories.LikeRepository
-import com.example.dtf.repositories.PostRepository
+import com.example.dtf.repositories.ICategoryRepository
+import com.example.dtf.repositories.ILikeRepository
+import com.example.dtf.repositories.IPostRepository
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.launch
 import javax.inject.Inject
 
 @HiltViewModel
 class PostsViewModel @Inject constructor(
-    private val postRepository: PostRepository,
-    private val categoryRepository: CategoryRepository,
-    private val likeRepository: LikeRepository
+    private val postRepository: IPostRepository,
+    private val categoryRepository: ICategoryRepository,
+    private val likeRepository: ILikeRepository
 ) : ViewModel() {
     fun getLikes(postId: Int) = likeRepository.countByPost(postId)
 
@@ -45,7 +45,9 @@ class PostsViewModel @Inject constructor(
         postId
     )
 
-    fun getCategories() = categoryRepository.getAll()
+    fun getCategoriesListUiState() = categoryRepository.getAll()
+
+    fun getInitialCategory() = categoryRepository.getFirst()
 
     fun getPostsListUiState(categoryId: Int) = postRepository.getByCategory(categoryId)
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/viewmodels/ProfileViewModel.kt b/app/src/main/java/com/example/dtf/viewmodels/ProfileViewModel.kt
index f1568cc..0b6b2bb 100644
--- a/app/src/main/java/com/example/dtf/viewmodels/ProfileViewModel.kt
+++ b/app/src/main/java/com/example/dtf/viewmodels/ProfileViewModel.kt
@@ -6,33 +6,26 @@ import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import com.example.dtf.PreferencesManager
 import com.example.dtf.models.User
-import com.example.dtf.repositories.UserRepository
+import com.example.dtf.repositories.offline.OfflineUserRepository
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.launch
 import javax.inject.Inject
 
 @HiltViewModel
 class ProfileViewModel @Inject constructor(
-    private val userRepository: UserRepository
+    private val userRepository: OfflineUserRepository
 ) : ViewModel() {
     private val _user = MutableLiveData<User>()
     val user: LiveData<User>
         get() = _user
 
     fun retrieveUser(sharedPref: PreferencesManager) {
-        val userId = sharedPref.getData("userId", "-1").toInt()
-
-        if (userId == -1) return
-
-        viewModelScope.launch {
-            userRepository.getById(userId).collect {
-                _user.postValue(it)
-            }
-        }
+        _user.postValue(User(null, sharedPref.getData("username", "Nickname")))
     }
 
     fun logout(sharedPref: PreferencesManager) {
-        sharedPref.deleteData("userId")
+        sharedPref.deleteData("token")
+        sharedPref.deleteData("username")
         sharedPref.deleteData("isModerator")
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/example/dtf/viewmodels/RegisterViewModel.kt b/app/src/main/java/com/example/dtf/viewmodels/RegisterViewModel.kt
index 8bf8b60..4cdfd7a 100644
--- a/app/src/main/java/com/example/dtf/viewmodels/RegisterViewModel.kt
+++ b/app/src/main/java/com/example/dtf/viewmodels/RegisterViewModel.kt
@@ -4,16 +4,16 @@ import androidx.lifecycle.LiveData
 import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
-import com.example.dtf.PreferencesManager
-import com.example.dtf.models.User
-import com.example.dtf.repositories.UserRepository
+import com.example.dtf.api.ServerService
+import com.example.dtf.dto.Credentials
+import com.example.dtf.repositories.offline.OfflineUserRepository
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.launch
 import javax.inject.Inject
 
 @HiltViewModel
 class RegisterViewModel @Inject constructor(
-    private val userRepository: UserRepository
+    private val serverService: ServerService
 ) : ViewModel() {
     private val _successState = MutableLiveData<Boolean?>()
     val successState: LiveData<Boolean?>
@@ -38,15 +38,11 @@ class RegisterViewModel @Inject constructor(
             _successState.postValue(false)
             return
         }
-
         viewModelScope.launch {
-            userRepository.getByUsernameAndPassword(username, password).collect {
-                if (it != null) {
-                    _successState.postValue(false)
-                } else {
-                    userRepository.insert(User(null, username, password, false))
-                    _successState.postValue(true)
-                }
+            if (serverService.register(Credentials(username, password)) == "NOT OK") {
+                _successState.postValue(false)
+            } else {
+                _successState.postValue(true)
             }
         }
     }
diff --git a/build.gradle b/build.gradle
index c4b0614..753531e 100644
--- a/build.gradle
+++ b/build.gradle
@@ -14,4 +14,6 @@ plugins {
     id 'com.android.application' version '7.4.2' apply false
     id 'com.android.library' version '7.4.2' apply false
     id 'org.jetbrains.kotlin.android' version '1.7.0' apply false
+    id 'org.jetbrains.kotlin.plugin.serialization' version '1.7.0' apply false
+    id 'org.jetbrains.kotlin.jvm' version '1.7.0' apply false
 }
\ No newline at end of file
diff --git a/local.properties b/local.properties
index f7299d2..bcd3b42 100644
--- a/local.properties
+++ b/local.properties
@@ -4,5 +4,5 @@
 # Location of the SDK. This is only used by Gradle.
 # For customization when using a Version Control System, please read the
 # header note.
-#Tue Nov 07 09:36:13 SAMT 2023
-sdk.dir=C\:\\Users\\Aqua\\AppData\\Local\\Android\\Sdk
+#Fri Dec 22 01:26:17 GMT+04:00 2023
+sdk.dir=D\:\\Programs\\Android