using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Windows.Input;
using ytLive.Helpers;
using ytLive.Models;

namespace ytLive.Services;

/// <summary>
/// Backing VM for the broadcast metadata pull-out (the "Text" tab on the Live
/// screen). Owns the creator-editable liveBroadcast fields: every edit is
/// persisted to the Settings store immediately (pre-load on next run), and the
/// Update command pushes the whole snippet/status set to YouTube via
/// liveBroadcasts.update. The drawer open/close state lives here too so the
/// XAML binds one object.
/// </summary>
public sealed class LiveBroadcastFormViewModel : ViewModelBase
{
    private readonly Func<LayoutStore> _store;
    private readonly Func<YouTubeStreamService?> _streamService;
    private readonly Func<string?> _broadcastId;

    private string _title = string.Empty;
    private string _description = string.Empty;
    private string _tagsCsv = string.Empty;
    private string _visibility = "private";
    private bool _madeForKids;
    private DateTime? _scheduledStartTime;
    private bool _isDrawerOpen;
    private bool _isUpdating;
    private string? _updateError;

    public LiveBroadcastFormViewModel(
        Func<LayoutStore> store,
        Func<YouTubeStreamService?> streamService,
        Func<string?> broadcastId)
    {
        _store = store;
        _streamService = streamService;
        _broadcastId = broadcastId;
        UpdateBroadcastCommand = new RelayCommand(_ => _ = UpdateRemoteAsync(), _ => CanUpdateRemote);
        ToggleDrawerCommand = new RelayCommand(_ => IsDrawerOpen = !IsDrawerOpen);
        CloseDrawerCommand = new RelayCommand(_ => IsDrawerOpen = false);
    }

    public ICommand UpdateBroadcastCommand { get; }
    public RelayCommand ToggleDrawerCommand { get; }
    public RelayCommand CloseDrawerCommand { get; }

    public string Title { get => _title; set { if (SetProperty(ref _title, value)) Persist(); } }
    public string Description { get => _description; set { if (SetProperty(ref _description, value)) Persist(); } }
    public string TagsCsv { get => _tagsCsv; set { if (SetProperty(ref _tagsCsv, value)) Persist(); } }
    public bool MadeForKids { get => _madeForKids; set { if (SetProperty(ref _madeForKids, value)) Persist(); } }

    public string Visibility
    {
        get => _visibility;
        set { if (SetProperty(ref _visibility, value)) Persist(); }
    }

    public IReadOnlyList<string> VisibilityOptions { get; } = new[] { "private", "unlisted", "public" };

    public DateTime? ScheduledStartTime
    {
        get => _scheduledStartTime;
        private set => SetProperty(ref _scheduledStartTime, value);
    }

    public string ScheduledStartText => ScheduledStartTime?.ToLocalTime().ToString("g") ?? "set at Go Live";

    public bool IsDrawerOpen
    {
        get => _isDrawerOpen;
        set => SetProperty(ref _isDrawerOpen, value);
    }

    public bool IsUpdating
    {
        get => _isUpdating;
        private set
        {
            if (SetProperty(ref _isUpdating, value))
                OnPropertyChanged(nameof(CanUpdateRemote));
        }
    }

    public string? UpdateError
    {
        get => _updateError;
        private set => SetProperty(ref _updateError, value);
    }

    public bool CanUpdateRemote => !string.IsNullOrEmpty(_broadcastId()) && !IsUpdating;

    /// <summary>Pull everything from the store (startup / Go Live refresh).</summary>
    public void Load()
    {
        var meta = _store().LoadBroadcastMetadata();
        _title = meta.Title;
        _description = meta.Description;
        _tagsCsv = meta.TagsCsv;
        _visibility = meta.Visibility;
        _madeForKids = meta.MadeForKids;
        ScheduledStartTime = meta.ScheduledStartTime;
        OnPropertyChanged(nameof(Title));
        OnPropertyChanged(nameof(Description));
        OnPropertyChanged(nameof(TagsCsv));
        OnPropertyChanged(nameof(Visibility));
        OnPropertyChanged(nameof(MadeForKids));
        OnPropertyChanged(nameof(ScheduledStartText));
    }

    /// <summary>Called at Go Live with what was actually inserted remotely.</summary>
    public void CaptureGoLive(string title, string description, DateTime scheduledStart)
    {
        Title = title;
        Description = description;
        ScheduledStartTime = scheduledStart;
        UpdateError = null;
    }

    public BroadcastMetadata ToMetadata() => new()
    {
        Title = Title,
        Description = Description,
        TagsCsv = TagsCsv,
        Visibility = Visibility,
        MadeForKids = MadeForKids,
        ScheduledStartTime = ScheduledStartTime,
    };

    private void Persist()
    {
        try
        {
            _store().SaveBroadcastMetadata(ToMetadata());
        }
        catch (Exception ex)
        {
            AppLog.Write($"Broadcast metadata save failed: {ex.Message}");
        }
    }

    private async Task UpdateRemoteAsync()
    {
        var id = _broadcastId();
        var service = _streamService();
        if (id == null || service == null || IsUpdating) return;
        IsUpdating = true;
        UpdateError = null;
        try
        {
            var error = await service.UpdateBroadcast(id, ToMetadata());
            UpdateError = error;
        }
        catch (Exception ex)
        {
            AppLog.Write($"Broadcast update failed: {ex.Message}");
            UpdateError = ex.Message;
        }
        finally
        {
            IsUpdating = false;
        }
    }
}