/*
 * Copyright 2012-2015 the original author or authors.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package de.pixart.messenger.ui;

import android.Manifest;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.SurfaceTexture;
import android.hardware.Camera;
import android.hardware.Camera.CameraInfo;
import android.os.Build;
import android.os.Bundle;
import android.os.Handler;
import android.os.HandlerThread;
import android.os.Process;
import android.os.Vibrator;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.util.Log;
import android.view.KeyEvent;
import android.view.Surface;
import android.view.TextureView;
import android.view.TextureView.SurfaceTextureListener;
import android.view.View;
import android.view.WindowManager;
import android.widget.Toast;

import com.google.zxing.BinaryBitmap;
import com.google.zxing.DecodeHintType;
import com.google.zxing.PlanarYUVLuminanceSource;
import com.google.zxing.ReaderException;
import com.google.zxing.Result;
import com.google.zxing.ResultPointCallback;
import com.google.zxing.common.HybridBinarizer;
import com.google.zxing.qrcode.QRCodeReader;

import java.util.EnumMap;
import java.util.Map;

import de.pixart.messenger.Config;
import de.pixart.messenger.R;
import de.pixart.messenger.ui.service.CameraManager;
import de.pixart.messenger.ui.widget.ScannerView;

/**
 * @author Andreas Schildbach
 */
@SuppressWarnings("deprecation")
public final class ScanActivity extends Activity implements SurfaceTextureListener, ActivityCompat.OnRequestPermissionsResultCallback {
    public static final String INTENT_EXTRA_RESULT = "result";

    public static final int REQUEST_SCAN_QR_CODE = 0x0987;
    private static final int REQUEST_CAMERA_PERMISSIONS_TO_SCAN = 0x6789;

    private static final long VIBRATE_DURATION = 50L;
    private static final long AUTO_FOCUS_INTERVAL_MS = 2500L;
    private static boolean DISABLE_CONTINUOUS_AUTOFOCUS = Build.MODEL.equals("GT-I9100") // Galaxy S2
            || Build.MODEL.equals("SGH-T989") // Galaxy S2
            || Build.MODEL.equals("SGH-T989D") // Galaxy S2 X
            || Build.MODEL.equals("SAMSUNG-SGH-I727") // Galaxy S2 Skyrocket
            || Build.MODEL.equals("GT-I9300") // Galaxy S3
            || Build.MODEL.equals("GT-N7000"); // Galaxy Note
    private final CameraManager cameraManager = new CameraManager();
    private ScannerView scannerView;
    private TextureView previewView;
    private volatile boolean surfaceCreated = false;
    private Vibrator vibrator;
    private HandlerThread cameraThread;
    private volatile Handler cameraHandler;
    private final Runnable closeRunnable = new Runnable() {
        @Override
        public void run() {
            cameraHandler.removeCallbacksAndMessages(null);
            cameraManager.close();
        }
    };
    private final Runnable fetchAndDecodeRunnable = new Runnable() {
        private final QRCodeReader reader = new QRCodeReader();
        private final Map<DecodeHintType, Object> hints = new EnumMap<DecodeHintType, Object>(DecodeHintType.class);

        @Override
        public void run() {
            cameraManager.requestPreviewFrame((data, camera) -> decode(data));
        }

        private void decode(final byte[] data) {
            final PlanarYUVLuminanceSource source = cameraManager.buildLuminanceSource(data);
            final BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));

            try {
                hints.put(DecodeHintType.NEED_RESULT_POINT_CALLBACK, (ResultPointCallback) dot -> runOnUiThread(() -> scannerView.addDot(dot)));
                final Result scanResult = reader.decode(bitmap, hints);

                runOnUiThread(() -> handleResult(scanResult));
            } catch (final ReaderException x) {
                // retry
                cameraHandler.post(fetchAndDecodeRunnable);
            } finally {
                reader.reset();
            }
        }
    };
    private final Runnable openRunnable = new Runnable() {
        @Override
        public void run() {
            try {
                final Camera camera = cameraManager.open(previewView, displayRotation(), !DISABLE_CONTINUOUS_AUTOFOCUS);

                final Rect framingRect = cameraManager.getFrame();
                final RectF framingRectInPreview = new RectF(cameraManager.getFramePreview());
                framingRectInPreview.offsetTo(0, 0);
                final boolean cameraFlip = cameraManager.getFacing() == CameraInfo.CAMERA_FACING_FRONT;
                final int cameraRotation = cameraManager.getOrientation();

                runOnUiThread(() -> scannerView.setFraming(framingRect, framingRectInPreview, displayRotation(), cameraRotation, cameraFlip));

                final String focusMode = camera.getParameters().getFocusMode();
                final boolean nonContinuousAutoFocus = Camera.Parameters.FOCUS_MODE_AUTO.equals(focusMode)
                        || Camera.Parameters.FOCUS_MODE_MACRO.equals(focusMode);

                if (nonContinuousAutoFocus)
                    cameraHandler.post(new AutoFocusRunnable(camera));

                cameraHandler.post(fetchAndDecodeRunnable);
            } catch (final Exception x) {
                Log.d(Config.LOGTAG, "problem opening camera", x);
            }
        }

        private int displayRotation() {
            final int rotation = getWindowManager().getDefaultDisplay().getRotation();
            if (rotation == Surface.ROTATION_0)
                return 0;
            else if (rotation == Surface.ROTATION_90)
                return 90;
            else if (rotation == Surface.ROTATION_180)
                return 180;
            else if (rotation == Surface.ROTATION_270)
                return 270;
            else
                throw new IllegalStateException("rotation: " + rotation);
        }
    };

    @Override
    public void onCreate(final Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        vibrator = (Vibrator) getSystemService(Context.VIBRATOR_SERVICE);

        setContentView(R.layout.activity_scan);
        scannerView = findViewById(R.id.scan_activity_mask);
        previewView = findViewById(R.id.scan_activity_preview);
        previewView.setSurfaceTextureListener(this);

        cameraThread = new HandlerThread("cameraThread", Process.THREAD_PRIORITY_BACKGROUND);
        cameraThread.start();
        cameraHandler = new Handler(cameraThread.getLooper());
    }

    @Override
    protected void onResume() {
        super.onResume();
        maybeOpenCamera();
    }

    @Override
    protected void onPause() {
        cameraHandler.post(closeRunnable);

        super.onPause();
    }

    @Override
    protected void onDestroy() {
        // cancel background thread
        cameraHandler.removeCallbacksAndMessages(null);
        cameraThread.quit();

        previewView.setSurfaceTextureListener(null);

        super.onDestroy();
    }

    private void maybeOpenCamera() {
        if (surfaceCreated && ContextCompat.checkSelfPermission(this,
                Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED)
            cameraHandler.post(openRunnable);
    }

    @Override
    public void onSurfaceTextureAvailable(final SurfaceTexture surface, final int width, final int height) {
        surfaceCreated = true;
        maybeOpenCamera();
    }

    @Override
    public boolean onSurfaceTextureDestroyed(final SurfaceTexture surface) {
        surfaceCreated = false;
        return true;
    }

    @Override
    public void onSurfaceTextureSizeChanged(final SurfaceTexture surface, final int width, final int height) {
    }

    @Override
    public void onSurfaceTextureUpdated(final SurfaceTexture surface) {
    }

    @Override
    public void onAttachedToWindow() {
        getWindow().addFlags(WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED);
    }

    @Override
    public void onBackPressed() {
        scannerView.setVisibility(View.GONE);
        setResult(RESULT_CANCELED);
        postFinish();
    }

    @Override
    public boolean onKeyDown(final int keyCode, final KeyEvent event) {
        switch (keyCode) {
            case KeyEvent.KEYCODE_FOCUS:
            case KeyEvent.KEYCODE_CAMERA:
                // don't launch camera app
                return true;
            case KeyEvent.KEYCODE_VOLUME_DOWN:
            case KeyEvent.KEYCODE_VOLUME_UP:
                cameraHandler.post(() -> cameraManager.setTorch(keyCode == KeyEvent.KEYCODE_VOLUME_UP));
                return true;
        }

        return super.onKeyDown(keyCode, event);
    }

    public void handleResult(final Result scanResult) {
        vibrator.vibrate(VIBRATE_DURATION);

        scannerView.setIsResult(true);

        final Intent result = new Intent();
        result.putExtra(INTENT_EXTRA_RESULT, scanResult.getText());
        setResult(RESULT_OK, result);
        postFinish();
    }

    private void postFinish() {
        new Handler().postDelayed(this::finish, 50);
    }

    public static void scan(Activity activity) {
        if (ContextCompat.checkSelfPermission(activity, Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED) {
            Intent intent = new Intent(activity, ScanActivity.class);
            activity.startActivityForResult(intent, REQUEST_SCAN_QR_CODE);
        } else {
            ActivityCompat.requestPermissions(activity, new String[]{Manifest.permission.CAMERA}, REQUEST_CAMERA_PERMISSIONS_TO_SCAN);
        }

    }

    public static void onRequestPermissionResult(Activity activity, int requestCode, int[] grantResults) {
        if (requestCode != REQUEST_CAMERA_PERMISSIONS_TO_SCAN) {
            return;
        }
        if (grantResults.length > 0) {
            if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                scan(activity);
            } else {
                Toast.makeText(activity, R.string.qr_code_scanner_needs_access_to_camera, Toast.LENGTH_SHORT).show();
            }
        }
    }

    private final class AutoFocusRunnable implements Runnable {
        private final Camera camera;
        private final Camera.AutoFocusCallback autoFocusCallback = new Camera.AutoFocusCallback() {
            @Override
            public void onAutoFocus(final boolean success, final Camera camera) {
                // schedule again
                cameraHandler.postDelayed(AutoFocusRunnable.this, AUTO_FOCUS_INTERVAL_MS);
            }
        };

        public AutoFocusRunnable(final Camera camera) {
            this.camera = camera;
        }

        @Override
        public void run() {
            try {
                camera.autoFocus(autoFocusCallback);
            } catch (final Exception x) {
                Log.d(Config.LOGTAG, "problem with auto-focus, will not schedule again", x);
            }
        }
    }
}