namespace Agora.Rtc
{
    ///
    /// <summary>
    /// The metadata observer.
    /// </summary>
    ///
    public abstract class IMetadataObserver
    {
        ///
        /// <summary>
        /// Occurs when the SDK requests the maximum size of the metadata.
        /// After successfully complete the registration by calling RegisterMediaMetadataObserver , the SDK triggers this Callback once every video frame is sent. You need to specify the maximum size of the metadata in the return value of this Callback.
        /// </summary>
        ///
        /// <returns>
        /// The maximum size of the buffer of the metadata that you want to use. The highest value is 1024 bytes. Ensure that you set the return value.
        /// </returns>
        ///
        public virtual int GetMaxMetadataSize()
        {
            return 0;
        }

        ///
        /// <summary>
        /// Occurs when the SDK is ready to send metadata.
        /// This Callback is triggered when the SDK is ready to send metadata.
        /// </summary>
        ///
        /// <param name="source_type"> Video data type. See VIDEO_SOURCE_TYPE .</param>
        ///
        /// <param name="metadata"> The metadata the user wants to send. See Metadata .</param>
        ///
        /// <returns>
        /// true: Send it.false: Do not send it.
        /// </returns>
        ///
        public virtual bool OnReadyToSendMetadata(ref Metadata metadata, VIDEO_SOURCE_TYPE source_type)
        {
            return false;
        }

        ///
        /// <summary>
        /// Occurs when the local user receives the metadata.
        /// </summary>
        ///
        /// <param name="metadata"> The metadata received, see Metadata .</param>
        ///
        public virtual void OnMetadataReceived(Metadata metadata)
        {

        }
    }
}