package com.example.snapchat;

import android.Manifest;
import android.content.Context;
import android.content.pm.PackageManager;
import android.graphics.ImageFormat;
import android.graphics.SurfaceTexture;
import android.hardware.camera2.CameraAccessException;
import android.hardware.camera2.CameraCaptureSession;
import android.hardware.camera2.CameraCharacteristics;
import android.hardware.camera2.CameraDevice;
import android.hardware.camera2.CameraManager;
import android.hardware.camera2.CameraMetadata;
import android.hardware.camera2.CaptureRequest;
import android.hardware.camera2.TotalCaptureResult;
import android.hardware.camera2.params.StreamConfigurationMap;
import android.media.Image;
import android.media.ImageReader;
import android.os.Environment;
import android.os.Handler;
import android.os.HandlerThread;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Size;
import android.util.SparseIntArray;
import android.view.Surface;
import android.view.TextureView;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.UUID;

public class MainActivity extends AppCompatActivity {

private Button btnCapture;
private TextureView textureView;

//Check state orientation of output image
private static final SparseIntArray ORIENTATIONS = new SparseIntArray();
static{
    ORIENTATIONS.append(Surface.ROTATION_0,90);
    ORIENTATIONS.append(Surface.ROTATION_90,0);
    ORIENTATIONS.append(Surface.ROTATION_180,270);
    ORIENTATIONS.append(Surface.ROTATION_270,180);
}

private String cameraId;
private CameraDevice cameraDevice;
private CameraCaptureSession cameraCaptureSessions;
private CaptureRequest.Builder captureRequestBuilder;
private Size imageDimension;
private ImageReader imageReader;

//Save to FILE
private File file;
private static final int REQUEST_CAMERA_PERMISSION = 200;
private boolean mFlashSupported;
private Handler mBackgroundHandler;
private HandlerThread mBackgroundThread;

CameraDevice.StateCallback stateCallback = new CameraDevice.StateCallback() {
    @Override
    public void onOpened(@NonNull CameraDevice camera) {
        cameraDevice = camera;
        createCameraPreview();
    }

    @Override
    public void onDisconnected(@NonNull CameraDevice cameraDevice) {
        cameraDevice.close();
    }

    @Override
    public void onError(@NonNull CameraDevice cameraDevice, int i) {
        cameraDevice.close();
        cameraDevice=null;
    }
};


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    textureView = (TextureView)findViewById(R.id.textureView);
    //From Java 1.4 , you can use keyword 'assert' to check expression true or false
    assert textureView != null;
    textureView.setSurfaceTextureListener(textureListener);
    btnCapture = (Button)findViewById(R.id.btnCapture);
    btnCapture.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            takePicture();
        }
    });
}

private void takePicture() {
    if(cameraDevice == null)
        return;
    CameraManager manager = (CameraManager)getSystemService(Context.CAMERA_SERVICE);
    try{
        CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraDevice.getId());
        Size[] jpegSizes = null;
        if(characteristics != null)
            jpegSizes = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP)
                    .getOutputSizes(ImageFormat.JPEG);

        //Capture image with custom size
        int width = 640;
        int height = 480;
        if(jpegSizes != null && jpegSizes.length > 0)
        {
            width = jpegSizes[0].getWidth();
            height = jpegSizes[0].getHeight();
        }
        final ImageReader reader = ImageReader.newInstance(width,height,ImageFormat.JPEG,1);
        List<Surface> outputSurface = new ArrayList<>(2);
        outputSurface.add(reader.getSurface());
        outputSurface.add(new Surface(textureView.getSurfaceTexture()));

        final CaptureRequest.Builder captureBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);
        captureBuilder.addTarget(reader.getSurface());
        captureBuilder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);

        //Check orientation base on device
        int rotation = getWindowManager().getDefaultDisplay().getRotation();
        captureBuilder.set(CaptureRequest.JPEG_ORIENTATION,ORIENTATIONS.get(rotation));

        file = new File(Environment.getExternalStorageDirectory()+"/"+UUID.randomUUID().toString()+".jpg");
        ImageReader.OnImageAvailableListener readerListener = new ImageReader.OnImageAvailableListener() {
            @Override
            public void onImageAvailable(ImageReader imageReader) {
                Image image = null;
                try{
                    image = reader.acquireLatestImage();
                    ByteBuffer buffer = image.getPlanes()[0].getBuffer();
                    byte[] bytes = new byte[buffer.capacity()];
                    buffer.get(bytes);
                    save(bytes);

                }
                catch (FileNotFoundException e)
                {
                    e.printStackTrace();
                }
                catch (IOException e)
                {
                    e.printStackTrace();
                }
                finally {
                    {
                        if(image != null)
                            image.close();
                    }
                }
            }
            private void save(byte[] bytes) throws IOException {
                OutputStream outputStream = null;
                try{
                    outputStream = new FileOutputStream(file);
                    outputStream.write(bytes);
                }finally {
                    if(outputStream != null)
                        outputStream.close();
                }
            }
        };

        reader.setOnImageAvailableListener(readerListener,mBackgroundHandler);
        final CameraCaptureSession.CaptureCallback captureListener = new CameraCaptureSession.CaptureCallback() {
            @Override
            public void onCaptureCompleted(@NonNull CameraCaptureSession session, @NonNull CaptureRequest request, @NonNull TotalCaptureResult result) {
                super.onCaptureCompleted(session, request, result);
                Toast.makeText(MainActivity.this, "Saved "+file, Toast.LENGTH_SHORT).show();
                createCameraPreview();
            }
        };

        cameraDevice.createCaptureSession(outputSurface, new CameraCaptureSession.StateCallback() {
            @Override
            public void onConfigured(@NonNull CameraCaptureSession cameraCaptureSession) {
                try{
                    cameraCaptureSession.capture(captureBuilder.build(),captureListener,mBackgroundHandler);
                } catch (CameraAccessException e) {
                    e.printStackTrace();
                }
            }

            @Override
            public void onConfigureFailed(@NonNull CameraCaptureSession cameraCaptureSession) {

            }
        },mBackgroundHandler);


    } catch (CameraAccessException e) {
        e.printStackTrace();
    }
}

private void createCameraPreview() {
    try{
        SurfaceTexture texture = textureView.getSurfaceTexture();
        assert  texture != null;
        texture.setDefaultBufferSize(imageDimension.getWidth(),imageDimension.getHeight());
        Surface surface = new Surface(texture);
        captureRequestBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
        captureRequestBuilder.addTarget(surface);
        cameraDevice.createCaptureSession(Arrays.asList(surface), new CameraCaptureSession.StateCallback() {
            @Override
            public void onConfigured(@NonNull CameraCaptureSession cameraCaptureSession) {
                if(cameraDevice == null)
                    return;
                cameraCaptureSessions = cameraCaptureSession;
                updatePreview();
            }

            @Override
            public void onConfigureFailed(@NonNull CameraCaptureSession cameraCaptureSession) {
                Toast.makeText(MainActivity.this, "Changed", Toast.LENGTH_SHORT).show();
            }
        },null);
    } catch (CameraAccessException e) {
        e.printStackTrace();
    }
}

private void updatePreview() {
    if(cameraDevice == null)
        Toast.makeText(this, "Error", Toast.LENGTH_SHORT).show();
    captureRequestBuilder.set(CaptureRequest.CONTROL_MODE,CaptureRequest.CONTROL_MODE_AUTO);
    try{
        cameraCaptureSessions.setRepeatingRequest(captureRequestBuilder.build(),null,mBackgroundHandler);
    } catch (CameraAccessException e) {
        e.printStackTrace();
    }
}


private void openCamera() {
    CameraManager manager = (CameraManager)getSystemService(Context.CAMERA_SERVICE);
    try{
        cameraId = manager.getCameraIdList()[0];
        CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraId);
        StreamConfigurationMap map = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
        assert map != null;
        imageDimension = map.getOutputSizes(SurfaceTexture.class)[0];
        //Check realtime permission if run higher API 23
        if(ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED)
        {
            ActivityCompat.requestPermissions(this,new String[]{
                    Manifest.permission.CAMERA,
                    Manifest.permission.WRITE_EXTERNAL_STORAGE
            },REQUEST_CAMERA_PERMISSION);
            return;
        }
        manager.openCamera(cameraId,stateCallback,null);

    } catch (CameraAccessException e) {
        e.printStackTrace();
    }
}

TextureView.SurfaceTextureListener textureListener = new TextureView.SurfaceTextureListener() {
    @Override
    public void onSurfaceTextureAvailable(SurfaceTexture surfaceTexture, int i, int i1) {
        openCamera();
    }

    @Override
    public void onSurfaceTextureSizeChanged(SurfaceTexture surfaceTexture, int i, int i1) {

    }

    @Override
    public boolean onSurfaceTextureDestroyed(SurfaceTexture surfaceTexture) {
        return false;
    }

    @Override
    public void onSurfaceTextureUpdated(SurfaceTexture surfaceTexture) {

    }
};

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    if(requestCode == REQUEST_CAMERA_PERMISSION)
    {
        if(grantResults[0] != PackageManager.PERMISSION_GRANTED)
        {
            Toast.makeText(this, "You can't use camera without permission", Toast.LENGTH_SHORT).show();
            finish();
        }
    }
}

@Override
protected void onResume() {
    super.onResume();
    startBackgroundThread();
    if(textureView.isAvailable())
        openCamera();
    else
        textureView.setSurfaceTextureListener(textureListener);
}

@Override
protected void onPause() {
    stopBackgroundThread();
    super.onPause();
}

private void stopBackgroundThread() {
    mBackgroundThread.quitSafely();
    try{
        mBackgroundThread.join();
        mBackgroundThread= null;
        mBackgroundHandler = null;
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
}

private void startBackgroundThread() {
    mBackgroundThread = new HandlerThread("Camera Background");
    mBackgroundThread.start();
    mBackgroundHandler = new Handler(mBackgroundThread.getLooper());
}