using System.Drawing;
using System.Threading;
using System.Threading.Tasks;

namespace IPCamLib
{
    /// <summary>
    /// Receives frames from an ICamera.
    /// </summary>
    public interface ICameraObserver
    {
        /// <summary>
        /// Called when a frame has been decoded from an ICamera.
        /// </summary>
        /// <param name="image">The decoded image.</param>
        Task OnFrame(Image image);
    }
    
    
    /// <summary>
    /// Abstracts an IP camera stream.
    /// </summary>
    public interface ICamera
    {
        /// <summary>
        /// Starts receiving frames.
        /// </summary>
        /// <remarks>
        /// The implementation should continue receiving frames until it is disconnected (if streaming),
        /// a request fails (if polling) or the cancellationToken is cancelled. Reconnecting is done by
        /// the caller which will call Fetch again. Do not keep connection-specific state between calls to Fetch.
        /// Running on a separate thread is also handled by the caller, the returning Task should not complete until disconnected.
        /// </remarks>
        /// <param name="observer">The observer implementation to receive frames.</param>
        /// <param name="cancellationToken">A CancellationToken which will stop the camera stream when cancelled.</param>
        Task Fetch(ICameraObserver observer, CancellationToken cancellationToken);
    }
}