using Discord.API.Rpc;
using Discord.Logging;
using Discord.Net.Converters;
using Discord.Rest;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.Linq;
using System.Threading.Tasks;
using System.Threading;

namespace Discord.Rpc
{
    public partial class DiscordRpcClient : BaseDiscordClient, IDiscordClient
    {
        private readonly JsonSerializer _serializer;
        private readonly ConnectionManager _connection;
        private readonly Logger _rpcLogger;
        private readonly SemaphoreSlim _stateLock, _authorizeLock;

        public ConnectionState ConnectionState { get; private set; }
        public IReadOnlyCollection<string> Scopes { get; private set; }
        public DateTimeOffset TokenExpiresAt { get; private set; }

        internal new API.DiscordRpcApiClient ApiClient => base.ApiClient as API.DiscordRpcApiClient;
        public new RestSelfUser CurrentUser { get { return base.CurrentUser as RestSelfUser; } private set { base.CurrentUser = value; } }
        public RestApplication ApplicationInfo { get; private set; }

        /// <summary> Creates a new RPC discord client. </summary>
        public DiscordRpcClient(string clientId, string origin) 
            : this(clientId, origin, new DiscordRpcConfig()) { }
        /// <summary> Creates a new RPC discord client. </summary>
        public DiscordRpcClient(string clientId, string origin, DiscordRpcConfig config)
            : base(config, CreateApiClient(clientId, origin, config))
        {
            _stateLock = new SemaphoreSlim(1, 1);
            _authorizeLock = new SemaphoreSlim(1, 1);
            _rpcLogger = LogManager.CreateLogger("RPC");
            _connection = new ConnectionManager(_stateLock, _rpcLogger, config.ConnectionTimeout, 
                OnConnectingAsync, OnDisconnectingAsync, x => ApiClient.Disconnected += x);
            _connection.Connected += () => _connectedEvent.InvokeAsync();
            _connection.Disconnected += (ex, recon) => _disconnectedEvent.InvokeAsync(ex);

            _serializer = new JsonSerializer { ContractResolver = new DiscordContractResolver() };
            _serializer.Error += (s, e) =>
            {
                _rpcLogger.WarningAsync(e.ErrorContext.Error).GetAwaiter().GetResult();
                e.ErrorContext.Handled = true;
            };
            
            ApiClient.SentRpcMessage += async opCode => await _rpcLogger.DebugAsync($"Sent {opCode}").ConfigureAwait(false);
            ApiClient.ReceivedRpcEvent += ProcessMessageAsync;
        }

        private static API.DiscordRpcApiClient CreateApiClient(string clientId, string origin, DiscordRpcConfig config)
            => new API.DiscordRpcApiClient(clientId, DiscordRestConfig.UserAgent, origin, config.RestClientProvider, config.WebSocketProvider);
        internal override void Dispose(bool disposing)
        {
            if (disposing)
            {
                StopAsync().GetAwaiter().GetResult();
                ApiClient.Dispose();
            }
        }

        public Task StartAsync() => _connection.StartAsync();
        public Task StopAsync() => _connection.StopAsync();

        private async Task OnConnectingAsync()
        {
            await _rpcLogger.DebugAsync("Connecting ApiClient").ConfigureAwait(false);
            await ApiClient.ConnectAsync().ConfigureAwait(false);

            await _connection.WaitAsync().ConfigureAwait(false);
        }
        private async Task OnDisconnectingAsync(Exception ex)
        {
            await _rpcLogger.DebugAsync("Disconnecting ApiClient").ConfigureAwait(false);
            await ApiClient.DisconnectAsync().ConfigureAwait(false);
        }

        public async Task<string> AuthorizeAsync(string[] scopes, string rpcToken = null, RequestOptions options = null)
        {
            await _authorizeLock.WaitAsync().ConfigureAwait(false);
            try
            {
                await _connection.StartAsync().ConfigureAwait(false);
                await _connection.WaitAsync().ConfigureAwait(false);
                var result = await ApiClient.SendAuthorizeAsync(scopes, rpcToken, options).ConfigureAwait(false);
                await _connection.StopAsync().ConfigureAwait(false);
                return result.Code;
            }
            finally
            {
                _authorizeLock.Release();
            }
        }

        public async Task SubscribeGlobal(RpcGlobalEvent evnt, RequestOptions options = null)
        {
            await ApiClient.SendGlobalSubscribeAsync(GetEventName(evnt), options).ConfigureAwait(false);
        }
        public async Task UnsubscribeGlobal(RpcGlobalEvent evnt, RequestOptions options = null)
        {
            await ApiClient.SendGlobalUnsubscribeAsync(GetEventName(evnt), options).ConfigureAwait(false);
        }
        public async Task SubscribeGuild(ulong guildId, RpcChannelEvent evnt, RequestOptions options = null)
        {
            await ApiClient.SendGuildSubscribeAsync(GetEventName(evnt), guildId, options).ConfigureAwait(false);
        }
        public async Task UnsubscribeGuild(ulong guildId, RpcChannelEvent evnt, RequestOptions options = null)
        {
            await ApiClient.SendGuildUnsubscribeAsync(GetEventName(evnt), guildId, options).ConfigureAwait(false);
        }
        public async Task SubscribeChannel(ulong channelId, RpcChannelEvent evnt, RequestOptions options = null)
        {
            await ApiClient.SendChannelSubscribeAsync(GetEventName(evnt), channelId).ConfigureAwait(false);
        }
        public async Task UnsubscribeChannel(ulong channelId, RpcChannelEvent evnt, RequestOptions options = null)
        {
            await ApiClient.SendChannelUnsubscribeAsync(GetEventName(evnt), channelId).ConfigureAwait(false);
        }

        public async Task<RpcGuild> GetRpcGuildAsync(ulong id, RequestOptions options = null)
        {
            var model = await ApiClient.SendGetGuildAsync(id, options).ConfigureAwait(false);
            return RpcGuild.Create(this, model);
        }
        public async Task<IReadOnlyCollection<RpcGuildSummary>> GetRpcGuildsAsync(RequestOptions options = null)
        {
            var models = await ApiClient.SendGetGuildsAsync(options).ConfigureAwait(false);
            return models.Guilds.Select(x => RpcGuildSummary.Create(x)).ToImmutableArray();
        }
        public async Task<RpcChannel> GetRpcChannelAsync(ulong id, RequestOptions options = null)
        {
            var model = await ApiClient.SendGetChannelAsync(id, options).ConfigureAwait(false);
            return RpcChannel.Create(this, model);
        }
        public async Task<IReadOnlyCollection<RpcChannelSummary>> GetRpcChannelsAsync(ulong guildId, RequestOptions options = null)
        {
            var models = await ApiClient.SendGetChannelsAsync(guildId, options).ConfigureAwait(false);
            return models.Channels.Select(x => RpcChannelSummary.Create(x)).ToImmutableArray();
        }

        public async Task<IMessageChannel> SelectTextChannelAsync(IChannel channel, RequestOptions options = null)
        {
            var model = await ApiClient.SendSelectTextChannelAsync(channel.Id, options).ConfigureAwait(false);
            return RpcChannel.Create(this, model) as IMessageChannel;
        }
        public async Task<IMessageChannel> SelectTextChannelAsync(RpcChannelSummary channel, RequestOptions options = null)
        {
            var model = await ApiClient.SendSelectTextChannelAsync(channel.Id, options).ConfigureAwait(false);
            return RpcChannel.Create(this, model) as IMessageChannel;
        }
        public async Task<IMessageChannel> SelectTextChannelAsync(ulong channelId, RequestOptions options = null)
        {
            var model = await ApiClient.SendSelectTextChannelAsync(channelId, options).ConfigureAwait(false);
            return RpcChannel.Create(this, model) as IMessageChannel;
        }

        public async Task<IRpcAudioChannel> SelectVoiceChannelAsync(IChannel channel, bool force = false, RequestOptions options = null)
        {
            var model = await ApiClient.SendSelectVoiceChannelAsync(channel.Id, force, options).ConfigureAwait(false);
            return RpcChannel.Create(this, model) as IRpcAudioChannel;
        }
        public async Task<IRpcAudioChannel> SelectVoiceChannelAsync(RpcChannelSummary channel, bool force = false, RequestOptions options = null)
        {
            var model = await ApiClient.SendSelectVoiceChannelAsync(channel.Id, force, options).ConfigureAwait(false);
            return RpcChannel.Create(this, model) as IRpcAudioChannel;
        }
        public async Task<IRpcAudioChannel> SelectVoiceChannelAsync(ulong channelId, bool force = false, RequestOptions options = null)
        {
            var model = await ApiClient.SendSelectVoiceChannelAsync(channelId, force, options).ConfigureAwait(false);
            return RpcChannel.Create(this, model) as IRpcAudioChannel;
        }

        public async Task<VoiceSettings> GetVoiceSettingsAsync(RequestOptions options = null)
        {
            var model = await ApiClient.GetVoiceSettingsAsync(options).ConfigureAwait(false);
            return VoiceSettings.Create(model);
        }
        public async Task SetVoiceSettingsAsync(Action<VoiceProperties> func, RequestOptions options = null)
        {
            if (func == null) throw new NullReferenceException(nameof(func));

            var settings = new VoiceProperties();
            settings.Input = new VoiceDeviceProperties();
            settings.Output = new VoiceDeviceProperties();
            settings.Mode = new VoiceModeProperties();
            func(settings);

            var model = new API.Rpc.VoiceSettings
            {
                AutomaticGainControl = settings.AutomaticGainControl,
                EchoCancellation = settings.EchoCancellation,
                NoiseSuppression = settings.NoiseSuppression,
                QualityOfService = settings.QualityOfService,
                SilenceWarning = settings.SilenceWarning
            };
            model.Input = new API.Rpc.VoiceDeviceSettings
            {
                DeviceId = settings.Input.DeviceId,
                Volume = settings.Input.Volume
            };
            model.Output = new API.Rpc.VoiceDeviceSettings
            {
                DeviceId = settings.Output.DeviceId,
                Volume = settings.Output.Volume
            };
            model.Mode = new API.Rpc.VoiceMode
            {
                AutoThreshold = settings.Mode.AutoThreshold,
                Delay = settings.Mode.Delay,
                Threshold = settings.Mode.Threshold,
                Type = settings.Mode.Type
            };

            if (settings.Input.AvailableDevices.IsSpecified)
                model.Input.AvailableDevices = settings.Input.AvailableDevices.Value.Select(x => x.ToModel()).ToArray();
            if (settings.Output.AvailableDevices.IsSpecified)
                model.Output.AvailableDevices = settings.Output.AvailableDevices.Value.Select(x => x.ToModel()).ToArray();
            if (settings.Mode.Shortcut.IsSpecified)
                model.Mode.Shortcut = settings.Mode.Shortcut.Value.Select(x => x.ToModel()).ToArray();

            await ApiClient.SetVoiceSettingsAsync(model, options).ConfigureAwait(false);
        }
        public async Task SetUserVoiceSettingsAsync(ulong userId, Action<UserVoiceProperties> func, RequestOptions options = null)
        {
            if (func == null) throw new NullReferenceException(nameof(func));

            var settings = new UserVoiceProperties();
            func(settings);

            var model = new API.Rpc.UserVoiceSettings
            {
                Mute = settings.Mute,
                UserId = settings.UserId,
                Volume = settings.Volume
            };
            if (settings.Pan.IsSpecified)
                model.Pan = settings.Pan.Value.ToModel();
            await ApiClient.SetUserVoiceSettingsAsync(userId, model, options).ConfigureAwait(false);
        }

        private static string GetEventName(RpcGlobalEvent rpcEvent)
        {
            switch (rpcEvent)
            {
                case RpcGlobalEvent.ChannelCreated: return "CHANNEL_CREATE";
                case RpcGlobalEvent.GuildCreated: return "GUILD_CREATE";
                case RpcGlobalEvent.VoiceSettingsUpdated: return "VOICE_SETTINGS_UPDATE";
                default:
                    throw new InvalidOperationException($"Unknown RPC Global Event: {rpcEvent}");
            }
        }
        private static string GetEventName(RpcGuildEvent rpcEvent)
        {
            switch (rpcEvent)
            {
                case RpcGuildEvent.GuildStatus: return "GUILD_STATUS";
                default:
                    throw new InvalidOperationException($"Unknown RPC Guild Event: {rpcEvent}");
            }
        }
        private static string GetEventName(RpcChannelEvent rpcEvent)
        {
            switch (rpcEvent)
            {
                case RpcChannelEvent.MessageCreate: return "MESSAGE_CREATE";
                case RpcChannelEvent.MessageUpdate: return "MESSAGE_UPDATE";
                case RpcChannelEvent.MessageDelete: return "MESSAGE_DELETE";
                case RpcChannelEvent.SpeakingStart: return "SPEAKING_START";
                case RpcChannelEvent.SpeakingStop: return "SPEAKING_STOP";
                case RpcChannelEvent.VoiceStateCreate: return "VOICE_STATE_CREATE";
                case RpcChannelEvent.VoiceStateUpdate: return "VOICE_STATE_UPDATE";
                case RpcChannelEvent.VoiceStateDelete: return "VOICE_STATE_DELETE";
                default:
                    throw new InvalidOperationException($"Unknown RPC Channel Event: {rpcEvent}");
            }
        }

        private async Task ProcessMessageAsync(string cmd, Optional<string> evnt, Optional<object> payload)
        {
            try
            {
                switch (cmd)
                {
                    case "DISPATCH":
                        switch (evnt.Value)
                        {
                            //Connection
                            case "READY":
                                {
                                    await _rpcLogger.DebugAsync("Received Dispatch (READY)").ConfigureAwait(false);
                                    var data = (payload.Value as JToken).ToObject<ReadyEvent>(_serializer);

                                    RequestOptions options = new RequestOptions
                                    {
                                        //CancellationToken = _cancelToken //TODO: Implement
                                    };

                                    if (ApiClient.LoginState == LoginState.LoggedIn)
                                    {
                                        var _ = Task.Run(async () =>
                                        {
                                            try
                                            {
                                                var response = await ApiClient.SendAuthenticateAsync(options).ConfigureAwait(false);
                                                CurrentUser = RestSelfUser.Create(this, response.User);
                                                ApiClient.CurrentUserId = CurrentUser.Id;
                                                ApplicationInfo = RestApplication.Create(this, response.Application);
                                                Scopes = response.Scopes;
                                                TokenExpiresAt = response.Expires;
                                                
                                                var __ = _connection.CompleteAsync();
                                                await _rpcLogger.InfoAsync("Ready").ConfigureAwait(false);
                                            }
                                            catch (Exception ex)
                                            {
                                                await _rpcLogger.ErrorAsync($"Error handling {cmd}{(evnt.IsSpecified ? $" ({evnt})" : "")}", ex).ConfigureAwait(false);
                                                return;
                                            }
                                        });
                                    }
                                    else
                                    {
                                        var _ = _connection.CompleteAsync();
                                        await _rpcLogger.InfoAsync("Ready").ConfigureAwait(false);
                                    }
                                }
                                break;

                            //Channels
                            case "CHANNEL_CREATE":
                                {
                                    await _rpcLogger.DebugAsync("Received Dispatch (CHANNEL_CREATE)").ConfigureAwait(false);
                                    var data = (payload.Value as JToken).ToObject<ChannelSummary>(_serializer);
                                    var channel = RpcChannelSummary.Create(data);

                                    await _channelCreatedEvent.InvokeAsync(channel).ConfigureAwait(false);
                                }
                                break;

                            //Guilds
                            case "GUILD_CREATE":
                                {
                                    await _rpcLogger.DebugAsync("Received Dispatch (GUILD_CREATE)").ConfigureAwait(false);
                                    var data = (payload.Value as JToken).ToObject<GuildSummary>(_serializer);
                                    var guild = RpcGuildSummary.Create(data);

                                    await _guildCreatedEvent.InvokeAsync(guild).ConfigureAwait(false);
                                }
                                break;
                            case "GUILD_STATUS":
                                {
                                    await _rpcLogger.DebugAsync("Received Dispatch (GUILD_STATUS)").ConfigureAwait(false);
                                    var data = (payload.Value as JToken).ToObject<GuildStatusEvent>(_serializer);
                                    var guildStatus = RpcGuildStatus.Create(data);

                                    await _guildStatusUpdatedEvent.InvokeAsync(guildStatus).ConfigureAwait(false);
                                }
                                break;

                            //Voice
                            case "VOICE_STATE_CREATE":
                                {
                                    await _rpcLogger.DebugAsync("Received Dispatch (VOICE_STATE_CREATE)").ConfigureAwait(false);
                                    var data = (payload.Value as JToken).ToObject<ExtendedVoiceState>(_serializer);
                                    var voiceState = RpcVoiceState.Create(this, data);

                                    await _voiceStateCreatedEvent.InvokeAsync(voiceState).ConfigureAwait(false);
                                }
                                break;
                            case "VOICE_STATE_UPDATE":
                                {
                                    await _rpcLogger.DebugAsync("Received Dispatch (VOICE_STATE_UPDATE)").ConfigureAwait(false);
                                    var data = (payload.Value as JToken).ToObject<ExtendedVoiceState>(_serializer);
                                    var voiceState = RpcVoiceState.Create(this, data);

                                    await _voiceStateUpdatedEvent.InvokeAsync(voiceState).ConfigureAwait(false);
                                }
                                break;
                            case "VOICE_STATE_DELETE":
                                {
                                    await _rpcLogger.DebugAsync("Received Dispatch (VOICE_STATE_DELETE)").ConfigureAwait(false);
                                    var data = (payload.Value as JToken).ToObject<ExtendedVoiceState>(_serializer);
                                    var voiceState = RpcVoiceState.Create(this, data);

                                    await _voiceStateDeletedEvent.InvokeAsync(voiceState).ConfigureAwait(false);
                                }
                                break;

                            case "SPEAKING_START":
                                {
                                    await _rpcLogger.DebugAsync("Received Dispatch (SPEAKING_START)").ConfigureAwait(false);
                                    var data = (payload.Value as JToken).ToObject<SpeakingEvent>(_serializer);

                                    await _speakingStartedEvent.InvokeAsync(data.UserId).ConfigureAwait(false);
                                }
                                break;
                            case "SPEAKING_STOP":
                                {
                                    await _rpcLogger.DebugAsync("Received Dispatch (SPEAKING_STOP)").ConfigureAwait(false);
                                    var data = (payload.Value as JToken).ToObject<SpeakingEvent>(_serializer);

                                    await _speakingStoppedEvent.InvokeAsync(data.UserId).ConfigureAwait(false);
                                }
                                break;
                            case "VOICE_SETTINGS_UPDATE":
                                {
                                    await _rpcLogger.DebugAsync("Received Dispatch (VOICE_SETTINGS_UPDATE)").ConfigureAwait(false);
                                    var data = (payload.Value as JToken).ToObject<API.Rpc.VoiceSettings>(_serializer);
                                    var settings = VoiceSettings.Create(data);

                                    await _voiceSettingsUpdated.InvokeAsync(settings).ConfigureAwait(false);
                                }
                                break;

                            //Messages
                            case "MESSAGE_CREATE":
                                {
                                    await _rpcLogger.DebugAsync("Received Dispatch (MESSAGE_CREATE)").ConfigureAwait(false);
                                    var data = (payload.Value as JToken).ToObject<MessageEvent>(_serializer);
                                    var msg = RpcMessage.Create(this, data.ChannelId, data.Message);

                                    await _messageReceivedEvent.InvokeAsync(msg).ConfigureAwait(false);
                                }
                                break;
                            case "MESSAGE_UPDATE":
                                {
                                    await _rpcLogger.DebugAsync("Received Dispatch (MESSAGE_UPDATE)").ConfigureAwait(false);
                                    var data = (payload.Value as JToken).ToObject<MessageEvent>(_serializer);
                                    var msg = RpcMessage.Create(this, data.ChannelId, data.Message);

                                    await _messageUpdatedEvent.InvokeAsync(msg).ConfigureAwait(false);
                                }
                                break;
                            case "MESSAGE_DELETE":
                                {
                                    await _rpcLogger.DebugAsync("Received Dispatch (MESSAGE_DELETE)").ConfigureAwait(false);
                                    var data = (payload.Value as JToken).ToObject<MessageEvent>(_serializer);

                                    await _messageDeletedEvent.InvokeAsync(data.ChannelId, data.Message.Id).ConfigureAwait(false);
                                }
                                break;

                            //Others
                            default:
                                await _rpcLogger.WarningAsync($"Unknown Dispatch ({evnt})").ConfigureAwait(false);
                                return;
                        }
                        break;

                    /*default: //Other opcodes are used for command responses
                        await _rpcLogger.WarningAsync($"Unknown OpCode ({cmd})").ConfigureAwait(false);
                        return;*/
                }
            }
            catch (Exception ex)
            {
                await _rpcLogger.ErrorAsync($"Error handling {cmd}{(evnt.IsSpecified ? $" ({evnt})" : "")}", ex).ConfigureAwait(false);
                return;
            }
        }

        //IDiscordClient
        ConnectionState IDiscordClient.ConnectionState => _connection.State;

        Task<IApplication> IDiscordClient.GetApplicationInfoAsync(RequestOptions options) => Task.FromResult<IApplication>(ApplicationInfo);

        async Task IDiscordClient.StartAsync()
            => await StartAsync().ConfigureAwait(false);
        async Task IDiscordClient.StopAsync()
            => await StopAsync().ConfigureAwait(false);
    }
}