using System.Collections.Generic;
using OpenCvSharp;
using Com.Lmc.ShuiYin.One.Converter;
using Com.Lmc.ShuiYin.One.Util;

namespace Com.Lmc.ShuiYin.One.Dencoder
{
    public abstract class Encoder
    {
        protected Converter.Converter converter; // protected for subclasses

        public Encoder(Converter.Converter converter)
        {
            this.converter = converter;
        }

        public Converter.Converter GetConverter()
        {
            return converter;
        }

        public void SetConverter(Converter.Converter converter)
        {
            this.converter = converter;
        }

        public void Encode(string image, string watermark, string output)
        {
            Mat src = Utils.Read(image, 1); // CV_8S -> Color (1)

            List<Mat> channel = new List<Mat>();
            List<Mat> newChannel = new List<Mat>();
            Cv2.Split(src, out Mat[] splitChannel);
            channel.AddRange(splitChannel);

            // Java: for (int i = 0; i < 3; i++)
            // OpenCvSharp Split returns array of Mats.
            
            // Ensure we have 3 channels? The loop is hardcoded to 3.
            for (int i = 0; i < 3 && i < channel.Count; i++)
            {
                Mat com = this.converter.Start(channel[i]).Clone();
                this.AddWatermark(com, watermark);
                this.converter.Inverse(com);
                // In Java: newChannel.add(i, com);
                newChannel.Add(com);
            }

            // If src has more than 3 channels (e.g. alpha), we should probably keep them?
            // The java code only loops 3 times.
            if (channel.Count > 3)
            {
                for (int i = 3; i < channel.Count; i++)
                {
                    newChannel.Add(channel[i]);
                }
            }

            Mat res = new Mat();
            Cv2.Merge(newChannel.ToArray(), res);

            if (res.Rows != src.Rows || res.Cols != src.Cols)
            {
                res = new Mat(res, new Rect(0, 0, src.Width, src.Height));
            }

            Cv2.ImWrite(output, res);
        }

        public abstract void AddWatermark(Mat com, string watermark);
    }
}