using UnityEngine;
using System.Collections;
using System;
using System.Net;
using System.IO;
using UnityEngine.UI;

//SOURCE
//https://answers.unity.com/questions/1151512/show-video-from-ip-camera-source.html

public class WebStream : MonoBehaviour
{

    public RawImage image;    //Mesh for displaying video
    public string sourceURL = "http://192.168.86.38:10000";    
    public float fps { get { return _fps; } }

    [SerializeField]
    [Tooltip("Show FPS streaming performance")]
    private float _fps;    
    private Texture2D texture;
    private Stream stream;
    private System.Diagnostics.Stopwatch fpsStopwatch = new System.Diagnostics.Stopwatch();

    //---------------------------------------------------------------------------
    private void Start()
    {
        Debug.Log(">> Start()");
        System.Diagnostics.Stopwatch cronometro = new System.Diagnostics.Stopwatch();
        cronometro.Start();
        GetVideo();
        cronometro.Stop();
        Debug.Log($"<< Start() {cronometro.ElapsedMilliseconds}");
    }

    //---------------------------------------------------------------------------
    public void GetVideo()
    {
        Debug.Log(">> startCoroutine(GetFrame())");
        System.Diagnostics.Stopwatch cronometro = new System.Diagnostics.Stopwatch();
        cronometro.Start();
        StartCoroutine(GetFrame());
        cronometro.Stop();
        Debug.Log($"<< startCoroutine(GetFrame()) {cronometro.ElapsedMilliseconds}");
    }

    //---------------------------------------------------------------------------
    private void Connection()
    {
        texture = new Texture2D(2, 2);
        // create HTTP request
        Debug.Log($"Connecting {sourceURL}");
        HttpWebRequest req = (HttpWebRequest)WebRequest.Create(sourceURL);
        //Optional (if authorization is Digest)
        //req.Credentials = new NetworkCredential("username", "password");
        // get response
        WebResponse resp = req.GetResponse();
        // get response stream
        stream = resp.GetResponseStream();
    }
    
    //---------------------------------------------------------------------------
    // MAIN CORUTINE 
    // TODO: Poner un sleep (o equivalente) en el While?
    IEnumerator GetFrame()
    {        
        yield return new WaitForSeconds(UnityEngine.Random.Range(0.1f,0.5f));
        Connection(); //TARDA 2000 ms

        Byte[] JpegData = new Byte[65536];
        
        while (true)
        {
            int bytesToRead = FindLength(stream);            
            if (bytesToRead == -1)
            {
                Debug.Log("End of stream");
                yield break;
            }

            int leftToRead = bytesToRead;

            while (leftToRead > 0)
            {
                leftToRead -= stream.Read(JpegData, bytesToRead - leftToRead, leftToRead);
                yield return null;
            }

            MemoryStream ms = new MemoryStream(JpegData, 0, bytesToRead, false, true);

            texture.LoadImage(ms.GetBuffer());
            //image.material.mainTexture = texture;
            image.texture = texture;
            stream.ReadByte(); // CR after bytes
            stream.ReadByte(); // LF after bytes

            if (fpsStopwatch.IsRunning)
                _fps = Convert.ToSingle(1.0 / fpsStopwatch.Elapsed.TotalSeconds);
            fpsStopwatch.Restart();

        }
    }

    //---------------------------------------------------------------------------
    int FindLength(Stream stream)
    {
        int b;
        string line = "";
        int result = -1;
        bool atEOL = false;

        while ((b = stream.ReadByte()) != -1)
        {
            if (b == 10) continue; // ignore LF char
            if (b == 13)
            { // CR
                if (atEOL)
                {  // two blank lines means end of header
                    stream.ReadByte(); // eat last LF
                    return result;
                }
                if (line.StartsWith("Content-Length:"))
                {
                    result = Convert.ToInt32(line.Substring("Content-Length:".Length).Trim());
                }
                else
                {
                    line = "";
                }
                atEOL = true;
            }
            else
            {
                atEOL = false;
                line += (char)b;
            }
        }
        return -1;
    }
}