using System.Threading;

using UnityEngine;

using ZXing;
using ZXing.QrCode;

public class BarcodeCam : MonoBehaviour
{
    // Texture for encoding test
    public Texture2D encoded;

    private WebCamTexture camTexture;
    private Thread qrThread;

    private Color32[] c;
    private int W, H;

    private Rect screenRect;

    private bool isQuit;

    public string LastResult;
    private bool shouldEncodeNow;

    void OnGUI()
    {
        GUI.DrawTexture(screenRect, camTexture, ScaleMode.ScaleToFit);
    }

    void OnEnable()
    {
        camTexture = new WebCamTexture(WebCamTexture.devices[0].name, 400, 300);
        camTexture.Play();
        if (camTexture != null)
        {
            camTexture.Play();
            W = camTexture.width;
            H = camTexture.height;
        }
    }

    void OnDisable()
    {
        if (camTexture != null)
        {
            camTexture.Pause();
        }
    }

    void OnDestroy()
    {
        qrThread.Abort();
        camTexture.Stop();
    }

    // It's better to stop the thread by itself rather than abort it.
    void OnApplicationQuit()
    {
        isQuit = true;
    }

    void Start()
    {
        encoded = new Texture2D(256, 256);
        LastResult = "http://www.google.com";
        shouldEncodeNow = true;

        screenRect = new Rect(0, 0, Screen.width, Screen.height);

        camTexture = new WebCamTexture();
        camTexture.requestedHeight = Screen.height; // 480;
        camTexture.requestedWidth = Screen.width; //640;
        OnEnable();

        qrThread = new Thread(DecodeQR);
        qrThread.Start();
    }

    void Update()
    {
        if (c == null)
        {
            c = camTexture.GetPixels32();
        }

        // encode the last found
        var textForEncoding = LastResult;
        if (shouldEncodeNow &&
            textForEncoding != null)
        {
            var color32 = Encode(textForEncoding, encoded.width, encoded.height);
            encoded.SetPixels32(color32);
            encoded.Apply();
            shouldEncodeNow = false;
        }
    }

    void DecodeQR()
    {
        // create a reader with a custom luminance source
        var barcodeReader = new BarcodeReader { AutoRotate = false, TryHarder = false };

        while (true)
        {
            if (isQuit)
                break;

            try
            {
                // decode the current frame
                var result = barcodeReader.Decode(c, W, H);
                if (result != null)
                {
                    LastResult = result.Text;
                    shouldEncodeNow = true;
                    print(result.Text);
                }

                // Sleep a little bit and set the signal to get the next frame
                Thread.Sleep(200);
                c = null;
            }
            catch
            {
            }
        }
    }

    private static Color32[] Encode(string textForEncoding, int width, int height)
    {
        var writer = new BarcodeWriter
        {
            Format = BarcodeFormat.QR_CODE,
            Options = new QrCodeEncodingOptions
            {
                Height = height,
                Width = width
            }
        };
        return writer.Write(textForEncoding);
    }
}