using System;
using System.Collections.Generic;
using System.IO;
using System.Threading;
using System.Threading.Tasks;
using MediaBrowser.Common.Configuration;
using MediaBrowser.Common.Extensions;
using MediaBrowser.Controller.Persistence;
using MediaBrowser.Model.Entities;
using MediaBrowser.Model.IO;
using MediaBrowser.Model.Logging;
using MediaBrowser.Model.Serialization;
using SQLitePCL.pretty;

namespace Emby.Server.Implementations.Data
{
    /// <summary>
    /// Class SQLiteDisplayPreferencesRepository
    /// </summary>
    public class SqliteDisplayPreferencesRepository : BaseSqliteRepository, IDisplayPreferencesRepository
    {
        private readonly IMemoryStreamFactory _memoryStreamProvider;

        public SqliteDisplayPreferencesRepository(ILogger logger, IJsonSerializer jsonSerializer, IApplicationPaths appPaths, IMemoryStreamFactory memoryStreamProvider)
            : base(logger)
        {
            _jsonSerializer = jsonSerializer;
            _memoryStreamProvider = memoryStreamProvider;
            DbFilePath = Path.Combine(appPaths.DataPath, "displaypreferences.db");
        }

        /// <summary>
        /// Gets the name of the repository
        /// </summary>
        /// <value>The name.</value>
        public string Name
        {
            get
            {
                return "SQLite";
            }
        }

        /// <summary>
        /// The _json serializer
        /// </summary>
        private readonly IJsonSerializer _jsonSerializer;

        /// <summary>
        /// Opens the connection to the database
        /// </summary>
        /// <returns>Task.</returns>
        public void Initialize()
        {
            using (var connection = CreateConnection())
            {
                connection.ExecuteAll(string.Join(";", new[]
               {
                                "PRAGMA page_size=4096",
                                "pragma default_temp_store = memory",
                                "pragma temp_store = memory"
                }));

                string[] queries = {

                    "create table if not exists userdisplaypreferences (id GUID, userId GUID, client text, data BLOB)",
                    "create unique index if not exists userdisplaypreferencesindex on userdisplaypreferences (id, userId, client)"
                               };

                connection.RunQueries(queries);
            }
        }

        /// <summary>
        /// Save the display preferences associated with an item in the repo
        /// </summary>
        /// <param name="displayPreferences">The display preferences.</param>
        /// <param name="userId">The user id.</param>
        /// <param name="client">The client.</param>
        /// <param name="cancellationToken">The cancellation token.</param>
        /// <returns>Task.</returns>
        /// <exception cref="System.ArgumentNullException">item</exception>
        public async Task SaveDisplayPreferences(DisplayPreferences displayPreferences, Guid userId, string client, CancellationToken cancellationToken)
        {
            if (displayPreferences == null)
            {
                throw new ArgumentNullException("displayPreferences");
            }
            if (string.IsNullOrWhiteSpace(displayPreferences.Id))
            {
                throw new ArgumentNullException("displayPreferences.Id");
            }

            cancellationToken.ThrowIfCancellationRequested();

            using (var connection = CreateConnection())
            {
                using (WriteLock.Write())
                {
                    connection.RunInTransaction(db =>
                    {
                        SaveDisplayPreferences(displayPreferences, userId, client, db);
                    }, TransactionMode);
                }
            }
        }

        private void SaveDisplayPreferences(DisplayPreferences displayPreferences, Guid userId, string client, IDatabaseConnection connection)
        {
            var serialized = _jsonSerializer.SerializeToBytes(displayPreferences, _memoryStreamProvider);

            using (var statement = connection.PrepareStatement("replace into userdisplaypreferences (id, userid, client, data) values (@id, @userId, @client, @data)"))
            {
                statement.TryBind("@id", displayPreferences.Id.ToGuidParamValue());
                statement.TryBind("@userId", userId.ToGuidParamValue());
                statement.TryBind("@client", client);
                statement.TryBind("@data", serialized);

                statement.MoveNext();
            }
        }

        /// <summary>
        /// Save all display preferences associated with a user in the repo
        /// </summary>
        /// <param name="displayPreferences">The display preferences.</param>
        /// <param name="userId">The user id.</param>
        /// <param name="cancellationToken">The cancellation token.</param>
        /// <returns>Task.</returns>
        /// <exception cref="System.ArgumentNullException">item</exception>
        public async Task SaveAllDisplayPreferences(IEnumerable<DisplayPreferences> displayPreferences, Guid userId, CancellationToken cancellationToken)
        {
            if (displayPreferences == null)
            {
                throw new ArgumentNullException("displayPreferences");
            }

            cancellationToken.ThrowIfCancellationRequested();

            using (var connection = CreateConnection())
            {
                using (WriteLock.Write())
                {
                    connection.RunInTransaction(db =>
                    {
                        foreach (var displayPreference in displayPreferences)
                        {
                            SaveDisplayPreferences(displayPreference, userId, displayPreference.Client, db);
                        }
                    }, TransactionMode);
                }
            }
        }

        /// <summary>
        /// Gets the display preferences.
        /// </summary>
        /// <param name="displayPreferencesId">The display preferences id.</param>
        /// <param name="userId">The user id.</param>
        /// <param name="client">The client.</param>
        /// <returns>Task{DisplayPreferences}.</returns>
        /// <exception cref="System.ArgumentNullException">item</exception>
        public DisplayPreferences GetDisplayPreferences(string displayPreferencesId, Guid userId, string client)
        {
            if (string.IsNullOrWhiteSpace(displayPreferencesId))
            {
                throw new ArgumentNullException("displayPreferencesId");
            }

            var guidId = displayPreferencesId.GetMD5();

            using (var connection = CreateConnection(true))
            {
                using (WriteLock.Read())
                {
                    using (var statement = connection.PrepareStatement("select data from userdisplaypreferences where id = @id and userId=@userId and client=@client"))
                    {
                        statement.TryBind("@id", guidId.ToGuidParamValue());
                        statement.TryBind("@userId", userId.ToGuidParamValue());
                        statement.TryBind("@client", client);

                        foreach (var row in statement.ExecuteQuery())
                        {
                            return Get(row);
                        }
                    }

                    return new DisplayPreferences
                    {
                        Id = guidId.ToString("N")
                    };
                }
            }
        }

        /// <summary>
        /// Gets all display preferences for the given user.
        /// </summary>
        /// <param name="userId">The user id.</param>
        /// <returns>Task{DisplayPreferences}.</returns>
        /// <exception cref="System.ArgumentNullException">item</exception>
        public IEnumerable<DisplayPreferences> GetAllDisplayPreferences(Guid userId)
        {
            var list = new List<DisplayPreferences>();

            using (var connection = CreateConnection(true))
            {
                using (WriteLock.Read())
                {
                    using (var statement = connection.PrepareStatement("select data from userdisplaypreferences where userId=@userId"))
                    {
                        statement.TryBind("@userId", userId.ToGuidParamValue());

                        foreach (var row in statement.ExecuteQuery())
                        {
                            list.Add(Get(row));
                        }
                    }
                }
            }

            return list;
        }

        private DisplayPreferences Get(IReadOnlyList<IResultSetValue> row)
        {
            using (var stream = _memoryStreamProvider.CreateNew(row[0].ToBlob()))
            {
                stream.Position = 0;
                return _jsonSerializer.DeserializeFromStream<DisplayPreferences>(stream);
            }
        }

        public Task SaveDisplayPreferences(DisplayPreferences displayPreferences, string userId, string client, CancellationToken cancellationToken)
        {
            return SaveDisplayPreferences(displayPreferences, new Guid(userId), client, cancellationToken);
        }

        public DisplayPreferences GetDisplayPreferences(string displayPreferencesId, string userId, string client)
        {
            return GetDisplayPreferences(displayPreferencesId, new Guid(userId), client);
        }
    }
}