/*
 * Copyright 2014 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.example.android.camera2video;

import android.app.Activity;
import android.app.AlertDialog;
import android.app.Dialog;
import android.app.DialogFragment;
import android.app.Fragment;
import android.content.Context;
import android.content.DialogInterface;
import android.content.res.Configuration;
import android.graphics.Matrix;
import android.graphics.RectF;
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.params.StreamConfigurationMap;
import android.media.MediaRecorder;
import android.os.Bundle;
import android.os.Handler;
import android.os.HandlerThread;
import android.util.Size;
import android.util.SparseIntArray;
import android.view.LayoutInflater;
import android.view.Surface;
import android.view.TextureView;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.Toast;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class Camera2VideoFragment extends Fragment implements View.OnClickListener {

    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);
    }

    /**
     * An {@link AutoFitTextureView} for camera preview.
     */
    private AutoFitTextureView mTextureView;

    /**
     * Button to record video
     */
    private Button mButtonVideo;

    /**
     * A refernce to the opened {@link android.hardware.camera2.CameraDevice}.
     */
    private CameraDevice mCameraDevice;

    /**
     * A reference to the current {@link android.hardware.camera2.CameraCaptureSession} for preview.
     */
    private CameraCaptureSession mPreviewSession;

    /**
     * {@link TextureView.SurfaceTextureListener} handles several lifecycle events on a
     * {@link TextureView}.
     */
    private TextureView.SurfaceTextureListener mSurfaceTextureListener
            = new TextureView.SurfaceTextureListener() {

        @Override
        public void onSurfaceTextureAvailable(SurfaceTexture surfaceTexture,
                                              int width, int height) {
            configureTransform(width, height);
            startPreview();
        }

        @Override
        public void onSurfaceTextureSizeChanged(SurfaceTexture surfaceTexture,
                                                int width, int height) {
            configureTransform(width, height);
            startPreview();
        }

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

        @Override
        public void onSurfaceTextureUpdated(SurfaceTexture surfaceTexture) {
        }

    };

    /**
     * The {@link android.util.Size} of camera preview.
     */
    private Size mPreviewSize;

    /**
     * Camera preview.
     */
    private CaptureRequest.Builder mPreviewBuilder;

    /**
     * MediaRecorder
     */
    private MediaRecorder mMediaRecorder;

    /**
     * Whether the app is recording video now
     */
    private boolean mIsRecordingVideo;

    /**
     * Whether the app is currently trying to open camera
     */
    private boolean mOpeningCamera;

    /**
     * {@link CameraDevice.StateListener} is called when {@link CameraDevice} changes its status.
     */
    private CameraDevice.StateListener mStateListener = new CameraDevice.StateListener() {

        @Override
        public void onOpened(CameraDevice cameraDevice) {
            mCameraDevice = cameraDevice;
            startPreview();
            mOpeningCamera = false;
            if (null != mTextureView) {
                configureTransform(mTextureView.getWidth(), mTextureView.getHeight());
            }
        }

        @Override
        public void onDisconnected(CameraDevice cameraDevice) {
            cameraDevice.close();
            mCameraDevice = null;
            mOpeningCamera = false;
        }

        @Override
        public void onError(CameraDevice cameraDevice, int error) {
            cameraDevice.close();
            mCameraDevice = null;
            Activity activity = getActivity();
            if (null != activity) {
                activity.finish();
            }
            mOpeningCamera = false;
        }

    };

    public static Camera2VideoFragment newInstance() {
        Camera2VideoFragment fragment = new Camera2VideoFragment();
        fragment.setRetainInstance(true);
        return fragment;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_camera2_video, container, false);
    }

    @Override
    public void onViewCreated(final View view, Bundle savedInstanceState) {
        mTextureView = (AutoFitTextureView) view.findViewById(R.id.texture);
        mTextureView.setSurfaceTextureListener(mSurfaceTextureListener);
        mButtonVideo = (Button) view.findViewById(R.id.video);
        mButtonVideo.setOnClickListener(this);
        view.findViewById(R.id.info).setOnClickListener(this);
    }

    @Override
    public void onResume() {
        super.onResume();
        openCamera();
    }

    @Override
    public void onPause() {
        super.onPause();
        if (null != mCameraDevice) {
            mCameraDevice.close();
            mCameraDevice = null;
        }
    }

    @Override
    public void onClick(View view) {
        switch (view.getId()) {
            case R.id.video: {
                if (mIsRecordingVideo) {
                    stopRecordingVideo();
                } else {
                    startRecordingVideo();
                }
                break;
            }
            case R.id.info: {
                Activity activity = getActivity();
                if (null != activity) {
                    new AlertDialog.Builder(activity)
                            .setMessage(R.string.intro_message)
                            .setPositiveButton(android.R.string.ok, null)
                            .show();
                }
                break;
            }
        }
    }

    /**
     * Tries to open a {@link CameraDevice}. The result is listened by `mStateListener`.
     */
    private void openCamera() {
        final Activity activity = getActivity();
        if (null == activity || activity.isFinishing() || mOpeningCamera) {
            return;
        }
        mOpeningCamera = true;
        CameraManager manager = (CameraManager) activity.getSystemService(Context.CAMERA_SERVICE);
        try {
            String cameraId = manager.getCameraIdList()[0];
            CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraId);
            StreamConfigurationMap map = characteristics
                    .get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
            mPreviewSize = map.getOutputSizes(SurfaceTexture.class)[0];
            int orientation = getResources().getConfiguration().orientation;
            if (orientation == Configuration.ORIENTATION_LANDSCAPE) {
                mTextureView.setAspectRatio(mPreviewSize.getWidth(), mPreviewSize.getHeight());
            } else {
                mTextureView.setAspectRatio(mPreviewSize.getHeight(), mPreviewSize.getWidth());
            }
            manager.openCamera(cameraId, mStateListener, null);
        } catch (CameraAccessException e) {
            Toast.makeText(activity, "Cannot access the camera.", Toast.LENGTH_SHORT).show();
            activity.finish();
        } catch (NullPointerException e) {
            // Currently an NPE is thrown when the Camera2API is used but not supported on the
            // device this code runs.
            new ErrorDialog().show(getFragmentManager(), "dialog");
        }
    }

    /**
     * Start the camera preview.
     */
    private void startPreview() {
        if (null == mCameraDevice || !mTextureView.isAvailable() || null == mPreviewSize) {
            return;
        }
        try {
            SurfaceTexture texture = mTextureView.getSurfaceTexture();
            assert texture != null;
            texture.setDefaultBufferSize(mPreviewSize.getWidth(), mPreviewSize.getHeight());
            mPreviewBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
            Surface surface = new Surface(texture);
            List<Surface> surfaces = new ArrayList<Surface>();
            surfaces.add(surface);
            mPreviewBuilder.addTarget(surface);
            mCameraDevice.createCaptureSession(surfaces, new CameraCaptureSession.StateListener() {

                @Override
                public void onConfigured(CameraCaptureSession cameraCaptureSession) {
                    mPreviewSession = cameraCaptureSession;
                    updatePreview();
                }

                @Override
                public void onConfigureFailed(CameraCaptureSession cameraCaptureSession) {
                    Activity activity = getActivity();
                    if (null != activity) {
                        Toast.makeText(activity, "Failed", Toast.LENGTH_SHORT).show();
                    }
                }
            }, null);
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
    }

    /**
     * Update the camera preview. {@link #startPreview()} needs to be called in advance.
     */
    private void updatePreview() {
        if (null == mCameraDevice) {
            return;
        }
        try {
            setUpCaptureRequestBuilder(mPreviewBuilder);
            HandlerThread thread = new HandlerThread("CameraPreview");
            thread.start();
            Handler backgroundHandler = new Handler(thread.getLooper());
            mPreviewSession.setRepeatingRequest(mPreviewBuilder.build(), null, backgroundHandler);
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
    }

    private void setUpCaptureRequestBuilder(CaptureRequest.Builder builder) {
        builder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);
    }

    /**
     * Configures the necessary {@link android.graphics.Matrix} transformation to `mTextureView`.
     * This method should not to be called until the camera preview size is determined in
     * openCamera, or until the size of `mTextureView` is fixed.
     *
     * @param viewWidth  The width of `mTextureView`
     * @param viewHeight The height of `mTextureView`
     */
    private void configureTransform(int viewWidth, int viewHeight) {
        Activity activity = getActivity();
        if (null == mTextureView || null == mPreviewSize || null == activity) {
            return;
        }
        int rotation = activity.getWindowManager().getDefaultDisplay().getRotation();
        Matrix matrix = new Matrix();
        RectF viewRect = new RectF(0, 0, viewWidth, viewHeight);
        RectF bufferRect = new RectF(0, 0, mPreviewSize.getHeight(), mPreviewSize.getWidth());
        float centerX = viewRect.centerX();
        float centerY = viewRect.centerY();
        if (Surface.ROTATION_90 == rotation || Surface.ROTATION_270 == rotation) {
            bufferRect.offset(centerX - bufferRect.centerX(), centerY - bufferRect.centerY());
            matrix.setRectToRect(viewRect, bufferRect, Matrix.ScaleToFit.FILL);
            float scale = Math.max(
                    (float) viewHeight / mPreviewSize.getHeight(),
                    (float) viewWidth / mPreviewSize.getWidth());
            matrix.postScale(scale, scale, centerX, centerY);
            matrix.postRotate(90 * (rotation - 2), centerX, centerY);
        }
        mTextureView.setTransform(matrix);
    }

    private void startRecordingVideo() {
        final Activity activity = getActivity();
        if (null == activity) {
            return;
        }
        mMediaRecorder = new MediaRecorder();
        final File file = getVideoFile(activity);
        try {
            // UI
            mButtonVideo.setText(R.string.stop);
            mIsRecordingVideo = true;
            // Configure the MediaRecorder
            mMediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
            mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.SURFACE);
            mMediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
            mMediaRecorder.setOutputFile(file.getAbsolutePath());
            mMediaRecorder.setVideoEncodingBitRate(10000000);
            mMediaRecorder.setVideoFrameRate(30);
            mMediaRecorder.setVideoSize(1440, 1080);
            mMediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264);
            mMediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
            int rotation = activity.getWindowManager().getDefaultDisplay().getRotation();
            int orientation = ORIENTATIONS.get(rotation);
            mMediaRecorder.setOrientationHint(orientation);
            mMediaRecorder.prepare();
            Surface surface = mMediaRecorder.getSurface();
            // Set up the CaptureRequest
            final CaptureRequest.Builder builder =
                    mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_RECORD);
            builder.addTarget(surface);
            Surface previewSurface = new Surface(mTextureView.getSurfaceTexture());
            builder.addTarget(previewSurface);
            mCameraDevice.createCaptureSession(Arrays.asList(surface, previewSurface),
                    new CameraCaptureSession.StateListener() {
                        @Override
                        public void onConfigured(CameraCaptureSession session) {
                            // Start recording
                            try {
                                session.setRepeatingRequest(builder.build(), null, null);
                                mMediaRecorder.start();
                            } catch (CameraAccessException e) {
                                e.printStackTrace();
                            }
                        }

                        @Override
                        public void onConfigureFailed(CameraCaptureSession session) {
                            Toast.makeText(activity, "Failed.", Toast.LENGTH_SHORT).show();
                        }
                    }, null
            );
        } catch (IllegalStateException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
    }

    private File getVideoFile(Context context) {
        return new File(context.getExternalFilesDir(null), "video.mp4");
    }

    private void stopRecordingVideo() {
        // UI
        mIsRecordingVideo = false;
        mButtonVideo.setText(R.string.record);
        // Stop recording
        mMediaRecorder.stop();
        mMediaRecorder.release();
        mMediaRecorder = null;
        Activity activity = getActivity();
        if (null != activity) {
            Toast.makeText(activity, "Video saved: " + getVideoFile(activity),
                    Toast.LENGTH_SHORT).show();
        }
        startPreview();
    }

    public static class ErrorDialog extends DialogFragment {

        @Override
        public Dialog onCreateDialog(Bundle savedInstanceState) {
            final Activity activity = getActivity();
            return new AlertDialog.Builder(activity)
                    .setMessage("This device doesn't support Camera2 API.")
                    .setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialogInterface, int i) {
                            activity.finish();
                        }
                    })
                    .create();
        }

    }

}