using AutoMapper;
using MagicCarpetContracts.DataModels;
using MagicCarpetContracts.Exceptions;
using MagicCarpetContracts.Mapper;
using MagicCarpetContracts.Resources;
using MagicCarpetContracts.StoragesContracts;
using MagicCarpetDatabase.Models;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Localization;
using Npgsql;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace MagicCarpetDatabase.Implementations;

internal class PostStorageContract(MagicCarpetDbContext dbContext, IStringLocalizer<Messages> localizer) : IPostStorageContract
{
    private readonly MagicCarpetDbContext _dbContext = dbContext;
    private readonly IStringLocalizer<Messages> _localizer = localizer;

    public List<PostDataModel> GetList()
    {
        try
        {
            return [.. _dbContext.Posts.Select(x => CustomMapper.MapObject<PostDataModel>(x))];
        }
        catch (Exception ex)
        {
            _dbContext.ChangeTracker.Clear();
            throw new StorageException(ex, _localizer);
        }
    }

    public List<PostDataModel> GetPostWithHistory(string postId)
    {
        try
        {
            return [.. _dbContext.Posts.Where(x => x.PostId == postId).Select(x => CustomMapper.MapObject<PostDataModel>(x))];
        }
        catch (Exception ex)
        {
            _dbContext.ChangeTracker.Clear();
            throw new StorageException(ex, _localizer);
        }
    }

    public PostDataModel? GetElementById(string id)
    {
        try
        {
            return CustomMapper.MapObjectWithNull<PostDataModel>(_dbContext.Posts.FirstOrDefault(x => x.PostId == id && x.IsActual));
        }
        catch (Exception ex)
        {
            _dbContext.ChangeTracker.Clear();
            throw new StorageException(ex, _localizer);
        }
    }

    public PostDataModel? GetElementByName(string name)
    {
        try
        {
            return CustomMapper.MapObjectWithNull<PostDataModel>(_dbContext.Posts.FirstOrDefault(x => x.PostName == name && x.IsActual));
        }
        catch (Exception ex)
        {
            _dbContext.ChangeTracker.Clear();
            throw new StorageException(ex, _localizer);
        }
    }

    public void AddElement(PostDataModel postDataModel)
    {
        try
        {
            var post = MapToEntity(postDataModel);
            post.IsActual = true;
            post.ChangeDate = DateTime.UtcNow;

            _dbContext.Posts.Add(post);
            _dbContext.SaveChanges();
        }
        catch (DbUpdateException ex) when (ex.InnerException is PostgresException { ConstraintName: "IX_Posts_PostName_IsActual" })
        {
            _dbContext.ChangeTracker.Clear();
            throw new ElementExistsException("PostName", postDataModel.PostName, _localizer);
        }
        catch (DbUpdateException ex) when (ex.InnerException is PostgresException { ConstraintName: "IX_Posts_PostId_IsActual" })
        {
            _dbContext.ChangeTracker.Clear();
            throw new ElementExistsException("PostId", postDataModel.Id, _localizer);
        }
        catch (Exception ex)
        {
            _dbContext.ChangeTracker.Clear();
            throw new StorageException(ex, _localizer);
        }
    }

    public void UpdElement(PostDataModel postDataModel)
    {
        try
        {
            var transaction = _dbContext.Database.BeginTransaction();
            try
            {
                var element = GetPostById(postDataModel.Id) ?? throw new ElementNotFoundException(postDataModel.Id, _localizer);
                if (!element.IsActual)
                {
                    throw new ElementDeletedException(postDataModel.Id, _localizer);
                }
                element.IsActual = false;
                _dbContext.SaveChanges();

                var newElement = MapToEntity(postDataModel);
                newElement.IsActual = true;
                newElement.ChangeDate = DateTime.UtcNow;

                _dbContext.Posts.Add(newElement);
                _dbContext.SaveChanges();
                transaction.Commit();
            }
            catch
            {
                transaction.Rollback();
                throw;
            }
        }
        catch (DbUpdateException ex) when (ex.InnerException is PostgresException { ConstraintName: "IX_Posts_PostName_IsActual" })
        {
            _dbContext.ChangeTracker.Clear();
            throw new ElementExistsException("PostName", postDataModel.PostName, _localizer);
        }
        catch (Exception ex) when (ex is ElementDeletedException || ex is ElementNotFoundException)
        {
            _dbContext.ChangeTracker.Clear();
            throw;
        }
        catch (Exception ex)
        {
            _dbContext.ChangeTracker.Clear();
            throw new StorageException(ex, _localizer);
        }
    }

    public void DelElement(string id)
    {
        try
        {
            var element = GetPostById(id) ?? throw new ElementNotFoundException(id, _localizer);
            if (!element.IsActual)
            {
                throw new ElementDeletedException(id, _localizer);
            }
            element.IsActual = false;
            _dbContext.SaveChanges();
        }
        catch
        {
            _dbContext.ChangeTracker.Clear();
            throw;
        }
    }

    public void ResElement(string id)
    {
        try
        {
            var element = GetPostById(id) ?? throw new ElementNotFoundException(id, _localizer);
            element.IsActual = true;
            _dbContext.SaveChanges();
        }
        catch
        {
            _dbContext.ChangeTracker.Clear();
            throw;
        }
    }

    private Post MapToEntity(PostDataModel model)
    {
        var post = CustomMapper.MapObject<Post>(model);
        post.PostId = model.Id;
        post.Configuration = model.ConfigurationModel;
        return post;
    }

    private Post? GetPostById(string id) => _dbContext.Posts.Where(x => x.PostId == id)
        .OrderByDescending(x => x.ChangeDate).FirstOrDefault();
}