using Jellyfin.Data;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Jellyfin.Database.Implementations.Enums;
using MediaBrowser.Controller.Entities;
using MediaBrowser.Controller.Library;
using MediaBrowser.Controller.LiveTv;
using MediaBrowser.Controller.Net;
using MediaBrowser.Controller.Session;
using MediaBrowser.Model.Session;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;

namespace Jellyfin.Plugin.Enigma2;

/// <summary>Per-user/device startup feedback; no tuner connections or stream URLs.</summary>
public sealed class PlaybackFeedback
{
    private readonly IHttpContextAccessor contexts;
    private readonly IAuthorizationContext authorization;
    private readonly ISessionManager sessions;
    private readonly StartupMessages messages;
    private readonly object gate = new();
    private readonly Dictionary<(Guid User, string Device, string Reference), Attempt> attempts = new();
    public PlaybackFeedback(IHttpContextAccessor contexts, IAuthorizationContext authorization, ISessionManager sessions, StartupMessages messages = null)
    { this.contexts = contexts; this.authorization = authorization; this.sessions = sessions; this.messages = messages ?? new StartupMessages(); }

    public async Task<Attempt> Begin(string reference, CancellationToken token)
    {
        // Scheduled recordings/background probes have no requesting viewer.
        // Never guess a destination or broadcast to all sessions of a user.
        var context = contexts.HttpContext;
        if (context == null) return null;
        AuthorizationInfo auth;
        try { auth = await authorization.GetAuthorizationInfo(context).WaitAsync(TimeSpan.FromSeconds(1), token); }
        catch (Exception error) when (error is not OperationCanceledException || !token.IsCancellationRequested) { return null; }
        if (auth.UserId == Guid.Empty || string.IsNullOrEmpty(auth.DeviceId) || auth.IsApiKey
            || auth.User == null || !auth.User.HasPermission(PermissionKind.EnableLiveTvAccess)) return null;
        string destination = null;
        var matches = sessions.Sessions.Where(s => s.UserId == auth.UserId && s.DeviceId == auth.DeviceId && s.IsActive).Take(2).ToArray();
        if ((Plugin.Instance?.Configuration?.ShowNativeStartupMessages ?? true) && matches.Length == 1 && IsAndroidTv(matches[0].Client)
            && matches[0].SupportedCommands?.Any(c => c == GeneralCommandType.DisplayMessage) == true) destination = matches[0].Id;
        var key = (auth.UserId, auth.DeviceId, reference);
        var language = messages.Resolve(auth.UserId, messages.ClientLanguage(auth.UserId, auth.DeviceId), context.Request.Headers.AcceptLanguage.ToString());
        var attempt = new Attempt(this, key, destination, language, token);
        lock (gate)
        {
            foreach (var expired in attempts.Where(x => DateTime.UtcNow - x.Value.UpdatedUtc > TimeSpan.FromSeconds(StartupBudget.WebSeconds + 15)).Select(x => x.Key).ToArray()) attempts.Remove(expired);
            if (attempts.Count >= 512 && !attempts.ContainsKey(key)) attempts.Remove(attempts.OrderBy(x => x.Value.UpdatedUtc).First().Key);
            attempts[key] = attempt;
        }
        attempt.Report("preparing");
        return attempt;
    }
    public static bool IsAndroidTv(string client) => (client ?? "").Replace(" ", "").Contains("AndroidTV", StringComparison.OrdinalIgnoreCase);
    public object Snapshot(Guid user, string device, string reference)
    {
        lock (gate)
        {
            if (!attempts.TryGetValue((user, device ?? "", reference), out var attempt) || DateTime.UtcNow - attempt.UpdatedUtc > TimeSpan.FromSeconds(StartupBudget.WebSeconds + 15))
                return new { Available = false, Phase = "preparing" };
            return new { Available = true, attempt.Phase, attempt.StartedUtc, attempt.UpdatedUtc };
        }
    }
    public async Task<T> AwaitStream<T>(Task<T> stream, Attempt attempt, CancellationToken token)
    {
        if (attempt == null) return await stream;
        attempt.Report("checking_stream");
        if (await Task.WhenAny(stream, Task.Delay(TimeSpan.FromSeconds(6), token)) != stream)
        {
            token.ThrowIfCancellationRequested();
            attempt.Report("waiting_for_stream");
        }
        return await stream;
    }
    private bool Current(Attempt attempt)
    { lock (gate) return attempts.TryGetValue(attempt.Key, out var current) && ReferenceEquals(current, attempt); }

    public sealed class Attempt
    {
        private readonly PlaybackFeedback owner;
        internal readonly (Guid User, string Device, string Reference) Key;
        private readonly string destination;
        private readonly string language;
        public string Language => language;
        private readonly CancellationToken token;
        private Task notifications = Task.CompletedTask;
        private int notificationCount;
        public DateTime StartedUtc { get; } = DateTime.UtcNow;
        public DateTime UpdatedUtc { get; private set; } = DateTime.UtcNow;
        public string Phase { get; private set; } = "preparing";
        internal Attempt(PlaybackFeedback owner, (Guid, string, string) key, string destination, string language, CancellationToken token)
        { this.owner = owner; Key = key; this.destination = destination; this.language = language; this.token = token; }
        public void Report(string phase)
        {
            lock (owner.gate)
            {
                if (!owner.Current(this)) return;
                Phase = phase; UpdatedUtc = DateTime.UtcNow;
                var message = phase switch
                {
                    "preparing" => owner.messages.Text(language, "native_preparing"),
                    "waiting_for_stream" => owner.messages.Text(language, "native_waiting"),
                    "ready" => owner.messages.Text(language, "native_ready"),
                    "failed" => owner.messages.Text(language, "native_failed"),
                    _ => null
                };
                if (destination == null || message == null || token.IsCancellationRequested || notificationCount >= 3) return;
                notificationCount++;
                notifications = notifications.ContinueWith(async _ =>
                {
                    if (token.IsCancellationRequested || !owner.Current(this)) return;
                    // Sending status must never hold up or fail actual playback.
                    using var deadline = CancellationTokenSource.CreateLinkedTokenSource(token);
                    deadline.CancelAfter(TimeSpan.FromMilliseconds(500));
                    try
                    {
                        var target = owner.sessions.Sessions.FirstOrDefault(s => s.Id == destination && s.UserId == Key.User && s.DeviceId == Key.Device && s.IsActive);
                        if (target != null) await owner.sessions.SendMessageCommand(destination, destination,
                            new MessageCommand { Header = owner.messages.Text(language, "header"), Text = message, TimeoutMs = 3000 }, deadline.Token).WaitAsync(deadline.Token);
                    }
                    catch { /* Optional feedback cannot break the channel. */ }
                }, CancellationToken.None, TaskContinuationOptions.None, TaskScheduler.Default).Unwrap();
            }
        }
    }
}

[ApiController]
[Route("DecoderIntegration/PlaybackProgress")]
[Authorize(Policy = "LiveTvAccess")]
public sealed class PlaybackFeedbackController : ControllerBase
{
    private readonly PlaybackFeedback feedback;
    private readonly ILibraryManager library;
    private readonly IUserManager users;
    private readonly IAuthorizationContext authorization;
    private readonly StartupMessages messages;
    public PlaybackFeedbackController(PlaybackFeedback feedback, ILibraryManager library, IUserManager users, IAuthorizationContext authorization, StartupMessages messages = null)
    { this.feedback = feedback; this.library = library; this.users = users; this.authorization = authorization; this.messages = messages ?? new StartupMessages(); }
    [HttpGet("/DecoderIntegration/StartupMessages")]
    [ResponseCache(NoStore = true, Location = ResponseCacheLocation.None)]
    public async Task<IActionResult> Messages([FromQuery] string language = null)
    {
        if (!Guid.TryParse(User.FindFirst("Jellyfin-UserId")?.Value, out var id) || users.GetUserById(id) is not { } user) return Unauthorized();
        if (!user.HasPermission(PermissionKind.EnableLiveTvAccess)) return Forbid();
        var selected = messages.Resolve(id, language, Request.Headers.AcceptLanguage.ToString());
        var auth = await authorization.GetAuthorizationInfo(HttpContext);
        if (auth.UserId == id && !auth.IsApiKey) messages.RememberClientLanguage(id, auth.DeviceId, language);
        return Ok(new { Language = selected, Texts = messages.Texts(selected), StartupTimeoutSeconds = StartupBudget.WebSeconds });
    }
    [HttpGet]
    [ResponseCache(NoStore = true, Location = ResponseCacheLocation.None)]
    public async Task<IActionResult> Get([FromQuery] Guid channelId)
    {
        if (!Guid.TryParse(User.FindFirst("Jellyfin-UserId")?.Value, out var id)) return Unauthorized();
        var user = users.GetUserById(id);
        if (user == null) return Unauthorized();
        if (!user.HasPermission(PermissionKind.EnableLiveTvAccess)) return Forbid();
        var item = channelId == Guid.Empty ? null : library.GetItemById<BaseItem>(channelId, user);
        if (item is not LiveTvChannel channel || !string.Equals(channel.ServiceName, "Enigma2", StringComparison.OrdinalIgnoreCase)) return NotFound();
        var auth = await authorization.GetAuthorizationInfo(HttpContext);
        if (auth.UserId != id || string.IsNullOrEmpty(auth.DeviceId)) return Unauthorized();
        return Ok(feedback.Snapshot(id, auth.DeviceId, channel.ExternalId));
    }
}