using MedicalDatabaseContracts;
using MedicalDatabaseContracts.Models;
using Microsoft.Extensions.Logging;
using Npgsql;
using System.Diagnostics;

namespace MedicalPostgresqlDatabase
{
    public abstract class AbstractPostgresqlStorage<T> : IStorage<T> where T : AbstractModel
    {
        protected ILogger _logger;
        protected readonly string TABLE_NAME;
        protected readonly string PRIMARY_KEY_COLUMN_NAME;
        protected readonly string PRIMARY_KEY_SEQUENCE_NAME;

        protected AbstractPostgresqlStorage(
            ILogger<IStorage<T>> logger,
            string tableName,
            string primaryKeyColumnName,
            string primary_key_sequence_name)
        {
            _logger = logger;
            TABLE_NAME = tableName;
            PRIMARY_KEY_COLUMN_NAME = primaryKeyColumnName;
            PRIMARY_KEY_SEQUENCE_NAME = primary_key_sequence_name;
        }

        protected abstract T CreateEntityFromReader(NpgsqlDataReader reader);

        protected abstract Dictionary<string, string> GetEntityAttributesDictionary(T item);

        public virtual void Delete(int id)
        {
            Delete(id, out _);
        }
        public virtual void Delete(int id, out long elapsedMilliseconds)
        {
            using var connection = GetConnection();
            connection.Open();
            using var cmd = new NpgsqlCommand($"DELETE FROM {TABLE_NAME} WHERE {PRIMARY_KEY_COLUMN_NAME} = @id", connection);
            cmd.Parameters.AddWithValue("@id", id);
            Stopwatch stopwatch = new();
            stopwatch.Start();
            cmd.ExecuteNonQuery();
            stopwatch.Stop();
            elapsedMilliseconds = stopwatch.ElapsedMilliseconds;
        }
        public virtual T? Get(int id)
        {
            return Get(id, out _);
        }
        public virtual T? Get(int id, out long elapsedMilliseconds)
        {
            using var connection = GetConnection();
            connection.Open();
            using var cmd = new NpgsqlCommand($"SELECT * FROM {TABLE_NAME} WHERE {PRIMARY_KEY_COLUMN_NAME} = @id", connection);
            cmd.Parameters.AddWithValue("@id", id);
            Stopwatch stopwatch = new();
            stopwatch.Start();
            using var reader = cmd.ExecuteReader();
            stopwatch.Stop();
            elapsedMilliseconds = stopwatch.ElapsedMilliseconds;
            if (reader.Read())
            {
                return CreateEntityFromReader(reader);
            }
            return null;
        }
        public virtual List<T> GetAll()
        {
            return GetAll(out _);
        }
        public virtual List<T> GetAll(out long elapsedMilliseconds)
        {
            var items = new List<T>();
            using var connection = GetConnection();
            connection.Open();
            using var cmd = new NpgsqlCommand($"SELECT * FROM {TABLE_NAME} ORDER BY {PRIMARY_KEY_COLUMN_NAME}", connection);
            Stopwatch stopwatch = new();
            stopwatch.Start();
            using var reader = cmd.ExecuteReader();
            stopwatch.Stop();
            elapsedMilliseconds = stopwatch.ElapsedMilliseconds;
            while (reader.Read())
            {
                items.Add(CreateEntityFromReader(reader));
            }
            return items;
        }
        public virtual void Insert(T item)
        {
            Insert(item, out _);
        }
        public virtual void Insert(T item, out long elapsedMilliseconds)
        {
            using var connection = GetConnection();
            connection.Open();
            var dict = GetEntityAttributesDictionary(item);

            string namesString = "";
            string valuesString = "";
            foreach (var key in dict.Keys)
            {
                namesString = string.Join(", ", namesString, $"{key}");
                if (key == PRIMARY_KEY_COLUMN_NAME)
                    valuesString = string.Join(", ", valuesString, $"nextval('{PRIMARY_KEY_SEQUENCE_NAME}')");
                else
                    valuesString = string.Join(", ", valuesString, $"@{key}");
            }
            namesString = $"({namesString})";
            valuesString += $"({valuesString})";


            string[] queryBuilder = {
                "INSERT INTO",
                TABLE_NAME,
                namesString,
                "VALUES",
                valuesString
            };

            using var cmd = new NpgsqlCommand(string.Join(' ', queryBuilder), connection);

            foreach (var key in dict.Keys)
            {
                cmd.Parameters.AddWithValue($"@{key}", dict[key]);
            }
            Stopwatch stopwatch = new();
            stopwatch.Start();
            cmd.ExecuteNonQuery();
            stopwatch.Stop();
            elapsedMilliseconds = stopwatch.ElapsedMilliseconds;
        }
        public virtual void Update(T item)
        {
            Update(item, out _);
        }
        public virtual void Update(T item, out long elapsedMilliseconds)
        {
            using var connection = GetConnection();
            connection.Open();

            var dict = GetEntityAttributesDictionary(item);

            string setString = "";
            foreach (var key in dict.Keys)
            {
                if (key != PRIMARY_KEY_COLUMN_NAME)
                    setString = string.Join(", ", setString, $"{key} = @{key}");
            }
            setString = $"({setString})";

            string[] queryBuilder = {
                "UPDATE",
                TABLE_NAME,
                "SET",
                setString,
                "VALUES",
                setString,
                "WHERE",
                $"{PRIMARY_KEY_COLUMN_NAME} = @{PRIMARY_KEY_COLUMN_NAME}"
            };

            using var cmd = new NpgsqlCommand(string.Join(' ', queryBuilder), connection);

            foreach (var key in dict.Keys)
            {
                cmd.Parameters.AddWithValue($"@{key}", dict[key]);
            }

            Stopwatch stopwatch = new();
            stopwatch.Start();
            cmd.ExecuteNonQuery();
            stopwatch.Stop();
            elapsedMilliseconds = stopwatch.ElapsedMilliseconds;
        }

        protected NpgsqlConnection GetConnection()
        {
            return new NpgsqlConnection("Host=127.0.0.1;Port=5555;Username=postgres;Database=medicalbase;Password=postgres");
        }
    }
}