namespace MusicBridge.Agent.Media;

internal sealed record MediaCommand(string Type, double? Value = null, string? Id = null);
internal sealed record CommandResult(bool Success, string Code, string Message, string? Id = null);
internal sealed record PlayerCapabilities(bool Play = false, bool Pause = false,
    bool Toggle = false, bool Next = false, bool Previous = false, bool Seek = false);

internal sealed record MediaState
{
    public int ProtocolVersion { get; init; } = 1;
    public DateTimeOffset Timestamp { get; init; } = DateTimeOffset.UtcNow;
    public bool HasSession { get; init; }
    public string Title { get; init; } = "";
    public string Artist { get; init; } = "";
    public string Source { get; init; } = "";
    public string PlaybackStatus { get; init; } = "Closed";
    public double PositionSeconds { get; init; }
    public double StartSeconds { get; init; }
    public double EndSeconds { get; init; }
    public double MinSeekSeconds { get; init; }
    public double MaxSeekSeconds { get; init; }
    public double PlaybackRate { get; init; } = 1;
    public PlayerCapabilities Capabilities { get; init; } = new();
    public float? Volume { get; init; }
    public bool? Muted { get; init; }
    public string? MediaError { get; init; }
    public string? VolumeError { get; init; }
    public string? ArtworkId { get; init; }
    public string? ArtworkError { get; init; }
}

internal interface IMediaService
{
    event Action? Changed;
    Artwork? GetArtwork(string id);
    Task<MediaState> ReadAsync(CancellationToken cancellationToken);
    Task<CommandResult> ExecuteAsync(MediaCommand command, CancellationToken cancellationToken);
}

internal static class CommandValidation
{
    public static CommandResult? Validate(MediaCommand command)
    {
        if (command.Id?.Length > 64) return Error("invalid_command", "Id длиннее 64 символов.");
        var valid = command.Type switch
        {
            "play" or "pause" or "toggle" or "next" or "previous" or "toggleMute" => command.Value is null,
            "seek" => command.Value is double s && double.IsFinite(s) && s >= 0 && s <= TimeSpan.MaxValue.TotalSeconds / 2,
            "seekRelative" => command.Value is double d && double.IsFinite(d) && Math.Abs(d) <= 3600,
            "volume" => command.Value is double v && double.IsFinite(v) && v >= 0 && v <= 1,
            "volumeRelative" => command.Value is double d && double.IsFinite(d) && Math.Abs(d) <= 1,
            _ => false
        };
        return valid ? null : Error("invalid_command", "Неизвестная команда или недопустимое значение.");
    }

    public static CommandResult Error(string code, string message) => new(false, code, message);
}