deepdrft/DeepDrftPublic.Client/Controls/AudioPlayerBar/AudioPlayerBar.razor.cs

using DeepDrftModels.DTOs;
using DeepDrftPublic.Client.Services;
using Microsoft.AspNetCore.Components;
using MudBlazor;

namespace DeepDrftPublic.Client.Controls.AudioPlayerBar;

public partial class AudioPlayerBar : ComponentBase, IAsyncDisposable
{
    [CascadingParameter] public IStreamingPlayerService? PlayerService { get; set; }
    [Parameter] public bool Fixed { get; set; } = false;
    
    private bool _isMinimized = true;
    private bool _isSeeking = false;
    private double _seekPosition = 0;
    private IStreamingPlayerService? _subscribedService;

    private bool IsLoaded => PlayerService?.IsLoaded ?? false;
    private bool IsLoading => PlayerService?.IsLoading ?? false;

    /// <summary>
    /// A track is staged when it has been selected as the current track but not yet loaded into
    /// the audio context (the embed's pre-gesture state). The first play click loads + plays it.
    /// </summary>
    private bool IsStaged => PlayerService is { IsLoaded: false, IsLoading: false, CurrentTrack: not null };

    /// <summary>Play is available once a track is loaded, or staged and waiting for the first gesture.</summary>
    private bool CanPlay => IsLoaded || IsStaged;
    private bool IsStreaming => PlayerService?.CanStartStreaming ?? false;
    private bool IsStreamingMode => PlayerService?.IsStreamingMode ?? false;
    private double? Duration => PlayerService?.Duration;
    private TrackDto? CurrentTrack => PlayerService?.CurrentTrack;
    private double Volume => PlayerService?.Volume ?? 0;
    private double LoadProgress => PlayerService?.LoadProgress ?? 0;
    private string? ErrorMessage => PlayerService?.ErrorMessage;

    /// <summary>
    /// Display time - shows seek position while dragging, otherwise current playback time.
    /// </summary>
    private double DisplayTime => _isSeeking ? _seekPosition : (PlayerService?.CurrentTime ?? 0);
    private string PlayerModeClass => Fixed ? "player-fixed" : "player-docked";

    protected override void OnParametersSet()
    {
        if (Fixed)
        {
            _isMinimized = false;
        }
        
        // PlayerService is cascaded by AudioPlayerProvider; once it arrives,
        // wire our track-selection handler. The provider owns OnStateChanged —
        // we intentionally do NOT wrap or replace it. Because the cascade is
        // IsFixed, the provider's re-render does NOT reliably re-render this bar
        // (it has no incoming parameters that change), so we subscribe to the
        // multicast StateChanged side-channel to re-render ourselves.
        if (PlayerService != null && !ReferenceEquals(PlayerService, _subscribedService))
        {
            if (_subscribedService != null)
                _subscribedService.StateChanged -= OnPlayerStateChanged;

            PlayerService.OnTrackSelected = new EventCallback(this, Expand);
            PlayerService.StateChanged += OnPlayerStateChanged;
            _subscribedService = PlayerService;
        }
    }

    private void OnPlayerStateChanged() => InvokeAsync(StateHasChanged);

    private async Task Expand()
    {
        if (_isMinimized)
        {
            _isMinimized = false;
            StateHasChanged();
        }
    }

    private async Task TogglePlayPause()
    {
        if (PlayerService == null) return;

        // Gesture-gated start: a staged-but-unloaded track (the embed autoplay path) is loaded on
        // the first play click — the user gesture the browser requires before audio can start.
        if (IsStaged)
        {
            await PlayerService.SelectTrackStreaming(PlayerService.CurrentTrack!);
            return;
        }

        await PlayerService.TogglePlayPause();
    }

    private async Task Stop()
    {
        if (PlayerService == null) return;
        await PlayerService.Stop();
    }

    private void OnSeekStart()
    {
        if (PlayerService == null) return;
        _isSeeking = true;
        _seekPosition = PlayerService.CurrentTime;
    }

    private void OnSeekChange(double position)
    {
        _seekPosition = position;
        StateHasChanged();
    }

    private async Task OnSeekEnd(double position)
    {
        if (PlayerService == null) return;
        _isSeeking = false;
        await PlayerService.Seek(position);
    }

    private async Task OnVolumeChange(double volume)
    {
        if (PlayerService == null) return;
        await PlayerService.SetVolume(volume);
    }

    private void ClearError()
    {
        PlayerService?.ClearError();
    }

    private void ToggleMinimized()
    {
        _isMinimized = !_isMinimized;
        StateHasChanged();
    }

    private async Task Close()
    {
        if (PlayerService != null && PlayerService.IsLoaded)
        {
            await PlayerService.Unload();
        }

        if (!_isMinimized)
        {
            _isMinimized = true;
            StateHasChanged();
        }
    }
    
    public ValueTask DisposeAsync()
    {
        if (_subscribedService != null)
        {
            _subscribedService.StateChanged -= OnPlayerStateChanged;
            _subscribedService = null;
        }
        return ValueTask.CompletedTask;
    }
}