using System;
using System.Collections.ObjectModel;
using System.IO;
using System.Linq;
using System.Windows;
using Microsoft.Win32;
using ytLive.Helpers;
using ytLive.Models;
using ytLive.Services;
using ytLive.Services.Encoder;

namespace ytLive.ViewModels;

public partial class MainViewModel : ViewModelBase
{

    private readonly ChatOverlayLayer _chatLayer;
    private readonly AlertOverlayLayer _alertLayer;

    /// <summary>The live chat message buffer — the same collection the
    /// <see cref="ChatOverlayLayer"/> owns; here so XAML can bind it and the
    /// left panel can subscribe to its changes.</summary>
    public ObservableCollection<ChatMessage> ChatMessages => _chatLayer.Messages;

    /// <summary>The Add → YouTube Chat menu item: enabled only while no chat layer exists
    /// anywhere — one chat overlay per layout.</summary>
    public bool CanAddYouTubeChat
        => StagedScene != null
           && !Scenes.Any(s => s.Elements.OfType<Source>().Any(e => e.Type == SourceType.ChatBox));

    /// <summary>The Add → Stream Alerts menu item: one alert zone per layout
    /// (multiple zones would double-play every event).</summary>
    public bool CanAddAlerts
        => StagedScene != null
           && !Scenes.Any(s => s.Elements.OfType<Source>().Any(e => e.Type == SourceType.AlertBox));

    public bool ShowChatInactiveMessage => !IsLive;

    private void OnChatMessageReceived(ChatMessage message)
    {
        _chatLayer.OnMessageReceived(message, Scenes);
        _alertLayer.OnMessageReceived(message, Scenes);
    }

    private void UpdateChatBoxPreview(Source chatBox, IReadOnlyList<ChatMessage>? messages = null)
        => _chatLayer.UpdatePreview(chatBox, messages);

    private VideoFrame? RenderChatBox(Source chatBox)
        => _chatLayer.RenderFrame(chatBox);

    private void UpdateAlertBoxPreview(Source alertBox)
        => _alertLayer.UpdatePreview(alertBox);

    private VideoFrame? RenderAlertBox(Source alertBox)
        => _alertLayer.RenderFrame(alertBox);

    private void StartMockChatPreview()
        => _chatLayer.StartMockPreview(Scenes);

    private void StopMockChatPreview()
        => _chatLayer.StopMockPreview();

    private void UpdateActiveChatBoxPreviews()
        => _chatLayer.UpdateConfiguredBoxes(Scenes);

    private void UpdateActiveAlertBoxPreviews()
        => _alertLayer.UpdateConfiguredBoxes(Scenes);

    // ─── TASK 47: the alert clip (video) ───

    private string? _alertDefaultVideoId;
    private string? _defaultAlertClipScratch;

    /// <summary>Runtime clip resolution for one alert box: the Creator's OWN video
    /// is a plain path on disk (never stored — the 2026-09-26 decision); the shipped
    /// llama placeholder lives as a BLOB in the internal Asset table and is
    /// materialized to a temp file once. Null → the six celebratory animations.
    /// Called from the output pump's alert frame path.</summary>
    private string? ResolveAlertClipPath(Source box)
    {
        if (!box.AlertUseDefaultVideo
            && !string.IsNullOrWhiteSpace(box.AlertVideoPath)
            && File.Exists(box.AlertVideoPath))
            return box.AlertVideoPath;
        return MaterializeDefaultAlertClip();
    }

    private string? MaterializeDefaultAlertClip()
    {
        if (_defaultAlertClipScratch != null && File.Exists(_defaultAlertClipScratch))
            return _defaultAlertClipScratch;
        _alertDefaultVideoId ??= _layoutStore.GetAlertDefaultVideoId();
        if (_alertDefaultVideoId == null) return null;
        var bytes = _layoutStore.GetAssetBytes(_alertDefaultVideoId);
        if (bytes == null) return null;
        var scratch = Path.Combine(Path.GetTempPath(), $"ytLive-alert-{_alertDefaultVideoId}.mp4");
        try
        {
            File.WriteAllBytes(scratch, bytes);
            _defaultAlertClipScratch = scratch;
            return scratch;
        }
        catch (Exception ex)
        {
            AppLog.Write(ex, "Alert default materialization failed");
            return null;
        }
    }

    /// <summary>One decoder per play (the refcounted MediaVideoSourceManager sessions
    /// can't restart per replay). The clip is full-box in video + 48k stereo audio;
    /// both steams pace themselves to real time inside the decoder — the frame-rate
    /// probe is what makes the VIDEO pace (without it every frame dumps in ~1-2s and
    /// the box freezes on the last frame for the rest of the audio).</summary>
    private IAlertClipDecoder AlertClipDecoderFor(string path, int width, int height) =>
        new AlertClipDecoder(
            path, width, height,
            new FfmpegLocator(),
            () => new FfmpegDecodeProcess(),
            frameRateProbe: new FfmpegFrameRateProbe(new FfmpegLocator(), () => new FfmpegDecodeProcess()));

    /// <summary>Stamp the shipped llama placeholder into the Asset table at startup
    /// (idempotent — hash-keyed UpsertAsset dedupes). Best-effort: if it fails the
    /// alert box simply falls back to the six animations.</summary>
    private void StampDefaultAlertVideo()
    {
        try
        {
            _alertDefaultVideoId = _layoutStore.GetAlertDefaultVideoId();
            if (!string.IsNullOrWhiteSpace(_alertDefaultVideoId)) return;
            var bytes = ReadAlertDefaultVideoResource();
            if (bytes is null or { Length: 0 }) return;
            _alertDefaultVideoId = _layoutStore.EnsureAlertDefaultVideo(bytes);
        }
        catch (Exception ex)
        {
            AppLog.Write(ex, "Alert default video stamp failed");
        }
    }

    private static byte[]? ReadAlertDefaultVideoResource()
    {
        try
        {
            var uri = new Uri("pack://application:,,,/Assets/alert-default.mp4", UriKind.Absolute);
            using var stream = Application.GetResourceStream(uri)?.Stream;
            if (stream == null) return null;
            using var ms = new MemoryStream();
            stream.CopyTo(ms);
            return ms.ToArray();
        }
        catch (Exception ex)
        {
            AppLog.Write(ex, "Alert default video resource missing");
            return null;
        }
    }

    private void BrowseAlertVideo(Source? box)
    {
        if (box == null || box.Type != SourceType.AlertBox) return;
        var dialog = new OpenFileDialog
        {
            Title = "Choose the alert clip (mp4)",
            Filter = "Video files (*.mp4;*.mov;*.webm;*.mkv)|*.mp4;*.mov;*.webm;*.mkv|All files (*.*)|*.*"
        };
        if (dialog.ShowDialog() != true) return;
        box.AlertVideoPath = dialog.FileName;
        box.AlertUseDefaultVideo = false;
    }

    private void ResetAlertVideo(Source? box)
    {
        if (box == null || box.Type != SourceType.AlertBox) return;
        box.AlertVideoPath = null;
        box.AlertShowTicker = true;
        box.AlertUseDefaultVideo = true;
    }
}