internal import CPlaydate

/// The cached `playdate->graphics->videostream` C API table.
private var streamAPI: UnsafePointer<playdate_videostream> { Playdate.videoStreamAPI.unsafelyUnwrapped }

extension Graphics {
    /// Streams video (and audio) from a file or network connection.
    /// Wraps `LCDStreamPlayer`.
    public final class StreamPlayer {
        let pointer: OpaquePointer
        /// Retains the active source so it outlives the stream.
        private var retainedSource: AnyObject?

        public init() {
            pointer = streamAPI.pointee.newPlayer.unsafelyUnwrapped().unsafelyUnwrapped
        }

        deinit {
            streamAPI.pointee.freePlayer.unsafelyUnwrapped(pointer)
        }

        /// Sets the sizes of the stream's video and audio buffers, in bytes.
        public func setBufferSize(video: Int, audio: Int) {
            streamAPI.pointee.setBufferSize.unsafelyUnwrapped(pointer, Int32(video), Int32(audio))
        }

        /// Streams from an open file.
        public func setFile(_ file: File.Handle) {
            retainedSource = file
            streamAPI.pointee.setFile.unsafelyUnwrapped(pointer, file.pointer)
        }

        /// Streams from an HTTP connection.
        public func setHTTPConnection(_ connection: Network.HTTPConnection) {
            retainedSource = connection
            streamAPI.pointee.setHTTPConnection.unsafelyUnwrapped(pointer, connection.pointer)
        }

        /// Streams from a TCP connection.
        public func setTCPConnection(_ connection: Network.TCPConnection) {
            retainedSource = connection
            streamAPI.pointee.setTCPConnection.unsafelyUnwrapped(pointer, connection.pointer)
        }

        /// The player used for the stream's audio track. Owned by the stream.
        /// The same wrapper is returned on every access, so callbacks
        /// registered on it stay valid for the stream's lifetime.
        public var filePlayer: Sound.FilePlayer? {
            guard let player = streamAPI.pointee.getFilePlayer.unsafelyUnwrapped(pointer) else { return nil }
            if let cached = cachedFilePlayer, cached.pointer == player {
                return cached
            }
            let wrapper = Sound.FilePlayer(pointer: player, isOwned: false)
            cachedFilePlayer = wrapper
            return wrapper
        }

        private var cachedFilePlayer: Sound.FilePlayer?

        /// The player used for the stream's video track. Owned by the stream.
        public var videoPlayer: VideoPlayer? {
            guard let player = streamAPI.pointee.getVideoPlayer.unsafelyUnwrapped(pointer) else { return nil }
            return VideoPlayer(pointer: player, isOwned: false)
        }

        /// Advances the stream. Returns `true` if a frame was drawn.
        @discardableResult
        public func update() -> Bool {
            streamAPI.pointee.update.unsafelyUnwrapped(pointer)
        }

        /// The number of video frames currently buffered.
        public var bufferedFrameCount: Int {
            Int(streamAPI.pointee.getBufferedFrameCount.unsafelyUnwrapped(pointer))
        }

        /// The total number of bytes read from the source.
        public var bytesRead: UInt32 {
            streamAPI.pointee.getBytesRead.unsafelyUnwrapped(pointer)
        }
    }
}