using System;
using System.Collections.Generic;

namespace fis.Vid
{
    public class DisplayChannel:IDisposable
    {
        private static readonly Dictionary<VidType, Func<string, IDisplayEngine>> EngineCreators = new Dictionary<VidType, Func<string, IDisplayEngine>>();

        private bool _disposed;

        public event EventHandler Disposing;
        
        public IDisplayEngine Engine { get; }

        public string ChannelId { get; }

        public byte[] BasicData { get; }

        public int ImageCount { get; }
        public byte[] ExtendedData { get; }
        static DisplayChannel()
        {
            EngineCreators.Add(VidType.VinnoVidSingle, s => new VidDisplayEngine(s));
            EngineCreators.Add(VidType.VinnoVidMovie, s => new VidDisplayEngine(s));
            EngineCreators.Add(VidType.ThirdVidSingle, s => new ThirdPartVidDisplayEngine(s));
            EngineCreators.Add(VidType.ThirdVidMovie, s => new ThirdPartVidDisplayEngine(s));
        }

        public DisplayChannel(VidType dataType, string filePath)
        {           
            ChannelId = Guid.NewGuid().ToString("N").ToUpper();
            if (!EngineCreators.ContainsKey(dataType))
            {
                throw new KeyNotFoundException($"Can not find engine creator of {dataType}");
            }
            var engine = EngineCreators[dataType](filePath);
            Engine = engine;
            ImageCount = Engine.ImageCount;
            BasicData = Engine.BasicData;
            ExtendedData = Engine.ExtendedData;
        }

        ~DisplayChannel()
        {
            Dispose(false);
        }

        public byte[] GetImageData(int index)
        {
            return  Engine.GetImageData(index);
        }

        protected void Dispose(bool disposing)
        {
            if (!_disposed)
            {
                Engine?.Close();               
            }

            _disposed = true;
        }

        public void Dispose()
        {
            OnDisposing();
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        public override string ToString()
        {
            return ChannelId;
        }

        protected virtual void OnDisposing()
        {
            Disposing?.Invoke(this, EventArgs.Empty);
        }
    }
}