using System;
using System.Collections;
using System.Collections.Generic;
using System.IO.MemoryMappedFiles;
using System.Linq;
using UnityEngine;
using UnityEngine.UI;

public class CameraReceiverMemory : MonoBehaviour
{

    public ReceiverData[] Cameras;
    public string StreamFileName = "CameraReceiveStream";
    public float ScanTime = 0.04f;

    private MemoryMappedViewAccessor mapView;
    private MemoryMappedFile mapFile;
    private List<Texture2D> grabbedImages = new List<Texture2D>();
    private Texture2D checkTexture; 
    private List<int> imagePointers = new List<int>();
    private List<int> imageSizes = new List<int>();
    private int HeaderSize;    
    private bool isStreamingEnable = true;

    //---------------------------------------------------------------------------------
    void Start()
    {
        int totalimagesize = 0;
        checkTexture = new Texture2D(2, 2,TextureFormat.ARGB32,false);

        for (int i = 0; i < Cameras.Length; i++)
        {
            grabbedImages.Add(new Texture2D(Cameras[i].CameraSize.x, Cameras[i].CameraSize.y, TextureFormat.ARGB32, false));            
            Cameras[i].CameraSources.texture = grabbedImages[i];            
            imagePointers.Add(totalimagesize);
            var imagesize = 3 * Cameras[i].CameraSize.x * Cameras[i].CameraSize.y;
            imageSizes.Add(imagesize);
            totalimagesize += imagesize;
        }

        HeaderSize = sizeof(Int32) + sizeof(Int32) * 2 * Cameras.Length;
        mapFile = MemoryMappedFile.CreateOrOpen(StreamFileName, totalimagesize + HeaderSize);
        mapView = mapFile.CreateViewAccessor(0, totalimagesize + HeaderSize);
        mapView.Write(0, Cameras.Length);
        for (int i = 0; i < Cameras.Length; i++)
        {
            mapView.Write(4 + 8 * i, Cameras[i].CameraSize.x); //width
            mapView.Write(8 + 8 * i, Cameras[i].CameraSize.y);//height
        }
        StartCoroutine(Cameraframeloop());
    }

    //---------------------------------------------------------------------------------
    IEnumerator Cameraframeloop()
    {
        int i = 0;
        while (Application.isPlaying)
        {
            if (ScanTime > 0)
                yield return new WaitForSecondsRealtime(ScanTime);
            else
                yield return new WaitForEndOfFrame();

            if (!this.isStreamingEnable)
                continue;

            //READ MEMORY FILE CAMERA [I]            
            //LOAD CameraSources[i].texture 
            byte[] pixelValues = new byte[imageSizes[i]];
            mapView.ReadArray(
                HeaderSize + imagePointers[i],
                pixelValues,
                0,
                imageSizes[i]
            );

            //Debug.Log($"{Cameras[i].CameraSources.gameObject.name} pointer={HeaderSize + imagePointers[i]} pixels={pixelValues.Length} RGB:({pixelValues[0]}, {pixelValues[1]}, {pixelValues[2]}) - ({pixelValues[pixelValues.Length-3]}, {pixelValues[pixelValues.Length - 2]}, {pixelValues[pixelValues.Length - 1]})");

            //VERSION ORIGINAL:
            //Texture2D texture = new Texture2D(2,2,TextureFormat.RGB24,false);            
            //texture.LoadImage(pixelValues);
            //Cameras[i].CameraSources.texture = texture;

            //VERSION 1-13
            //Texture2D texture = new Texture2D(Cameras[i].CameraSize.x, Cameras[i].CameraSize.y,TextureFormat.RGB24,false);            
            //texture.LoadRawTextureData(pixelValues);
            //texture.Apply();
            //Cameras[i].CameraSources.texture = texture;

            //Version 1-14
            //if (Cameras[i].Protocol.ToUpper().Trim()=="RTSP")
            //    grabbedImages[i].LoadRawTextureData(pixelValues);            
            //else
            //    grabbedImages[i].LoadImage(pixelValues);
            //grabbedImages[i].Apply();

            //Version 1-15
            //Texture will be uploaded to the GPU automatically; there's no need to call Apply.
            //https://docs.unity3d.com/ScriptReference/ImageConversion.LoadImage.html

            ////CHECK IF IS A PNG IMAGE
            ////https://stackoverflow.com/questions/55869/determine-file-type-of-an-image/12451102#12451102
            //var png = new byte[] { 137, 80, 78, 71 }; // PNG 
            //byte[] check = new byte[4];
            //Array.Copy(pixelValues, 0, check, 0, 4);
            //if (!check.SequenceEqual(png))
            //{
            //    Debug.Log("PNG ERROR");
            //} 

            checkTexture.LoadImage(pixelValues);
            if (Cameras[i].CameraSize.x != checkTexture.width || Cameras[i].CameraSize.y != checkTexture.height)
            {
                //Debug.Log($"format={checkTexture.format} graphicsFormat={checkTexture.graphicsFormat} Size=({checkTexture.width},{checkTexture.height})");
            }
            else
            {
                if (checkTexture.format != grabbedImages[i].format)
                {
                    grabbedImages[i] = new Texture2D(Cameras[i].CameraSize.x, Cameras[i].CameraSize.y, checkTexture.format, false);
                    Cameras[i].CameraSources.texture = grabbedImages[i];
                    Debug.Log($"Texture Format changed to {checkTexture.format}");
                }
                Graphics.CopyTexture(checkTexture, grabbedImages[i]);                                
            }

            i++;
            if (i == Cameras.Length) i = 0;

        }
    }

}