/*
 * Copyright (C) 2008 ZXing authors
 *
 * 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.yiwen.mobike.qrcode.zxing.camera;

import android.Manifest;
import android.content.Context;
import android.content.pm.PackageManager;
import android.graphics.PixelFormat;
import android.graphics.Point;
import android.graphics.Rect;
import android.hardware.Camera;
import android.os.Build;
import android.os.Handler;
import android.util.Log;
import android.view.SurfaceHolder;

import com.yiwen.mobike.qrcode.zxing.view.ViewfinderView;

import java.io.IOException;
import java.util.List;



/**
 * This object wraps the Camera service object and expects to be the only one talking to it. The
 * implementation encapsulates the steps needed to take preview-sized images, which are used for
 * both preview and decoding.
 */
public final class CameraManager {

    static final int SDK_INT; // Later we can use Build.VERSION.SDK_INT
    private static final String TAG = CameraManager.class.getSimpleName();
    private static final int MIN_FRAME_WIDTH = 240;
    private static final int MIN_FRAME_HEIGHT = 240;
    private static final int MAX_FRAME_WIDTH = 675;
    private static final int MAX_FRAME_HEIGHT = 675; // = 5/8 * 1080
    private static CameraManager cameraManager;

    static {
        int sdkInt;
        try {
            sdkInt = Integer.parseInt(Build.VERSION.SDK);
        } catch (NumberFormatException nfe) {
            // Just to be safe
            sdkInt = 10000;
        }
        SDK_INT = sdkInt;
    }

    private final Context context;
    private final CameraConfigurationManager configManager;
    private final boolean useOneShotPreviewCallback;
    /**
     * Preview frames are delivered here, which we pass on to the registered handler. Make sure to
     * clear the handler so it will only receive one message.
     */
    private final PreviewCallback previewCallback;
    /**
     * Autofocus callbacks arrive here, and are dispatched to the Handler which requested them.
     */
    private final AutoFocusCallback autoFocusCallback;
    private Camera camera;
    private Rect framingRect;
    private Rect framingRectInPreview;
    private boolean initialized;
    private boolean previewing;

    private CameraManager(Context context) {

        this.context = context;
        this.configManager = new CameraConfigurationManager(context);

        // Camera.setOneShotPreviewCallback() has getUrl race condition in Cupcake, so we use the older
        // Camera.setPreviewCallback() on 1.5 and earlier. For Donut and later, we need to use
        // the more efficient one shot callback, as the older one can swamp the system and cause it
        // to run out of memory. We can't use SDK_INT because it was introduced in the Donut SDK.
        //useOneShotPreviewCallback = Integer.parseInt(Build.VERSION.SDK) > Build.VERSION_CODES.CUPCAKE;
        useOneShotPreviewCallback = Integer.parseInt(Build.VERSION.SDK) > 3; // 3 = Cupcake

        previewCallback = new PreviewCallback(configManager, useOneShotPreviewCallback);
        autoFocusCallback = new AutoFocusCallback();
    }

    /**
     * Initializes this static object with the Context of the calling Activity.
     *
     * @param context The Activity which wants to use the camera.
     */
    public static void init(Context context) {
        if (cameraManager == null) {
            cameraManager = new CameraManager(context);
        }
    }

    /**
     * Gets the CameraManager singleton instance.
     *
     * @return A reference to the CameraManager singleton.
     */
    public static CameraManager get() {
        return cameraManager;
    }

    /**
     * Opens the camera driver and initializes the hardware parameters.
     *
     * @param holder The surface object which the camera will draw preview frames into.
     * @throws IOException Indicates the camera driver failed to open.
     */
    public void openDriver(SurfaceHolder holder) throws IOException {
        if (camera == null) {
            camera = Camera.open();
            if (camera == null) {
                throw new IOException();
            }
            camera.setPreviewDisplay(holder);

            if (!initialized) {
                initialized = true;
                configManager.initFromCameraParameters(camera);
            }
            configManager.setDesiredCameraParameters(camera);

            //FIXME

            FlashlightManager.enableFlashlight();
        }
    }

    /**
     * Closes the camera driver if still in use.
     */
    public void closeDriver() {
        if (camera != null) {
            FlashlightManager.disableFlashlight();
            camera.release();
            camera = null;
        }
    }

    /**
     * Asks the camera hardware to begin drawing preview frames to the screen.
     */
    public void startPreview() {
        if (camera != null && !previewing) {
            camera.startPreview();
            previewing = true;
        }
    }

    /**
     * Tells the camera to stop drawing preview frames.
     */
    public void stopPreview() {
        if (camera != null && previewing) {
            if (!useOneShotPreviewCallback) {
                camera.setPreviewCallback(null);
            }
            camera.stopPreview();
            previewCallback.setHandler(null, 0);
            autoFocusCallback.setHandler(null, 0);
            previewing = false;
        }
    }

    /**
     * A single preview frame will be returned to the handler supplied. The data will arrive as byte[]
     * in the message.obj field, with width and height encoded as message.arg1 and message.arg2,
     * respectively.
     *
     * @param handler The handler to send the message to.
     * @param message The what field of the message to be sent.
     */
    public void requestPreviewFrame(Handler handler, int message) {
        if (camera != null && previewing) {
            previewCallback.setHandler(handler, message);
            if (useOneShotPreviewCallback) {
                camera.setOneShotPreviewCallback(previewCallback);
            } else {
                camera.setPreviewCallback(previewCallback);
            }
        }
    }

    /**
     * Asks the camera hardware to perform an autofocus.
     *
     * @param handler The Handler to notify when the autofocus completes.
     * @param message The message to deliver.
     */
    public void requestAutoFocus(Handler handler, int message) {
        if (camera != null && previewing) {
            autoFocusCallback.setHandler(handler, message);
            //Log.d(TAG, "Requesting auto-focus callback");
            camera.autoFocus(autoFocusCallback);
        }
    }

    /**
     * Calculates the framing rect which the UI should draw to show the user where to place the
     * barcode. This target helps with alignment as well as forces the user to hold the device
     * far enough away to ensure the image will be in focus.
     *
     * @return The rectangle to draw on screen in window coordinates.
     *
     * 获取扫描框显示位置 默认位置为屏幕中间
     */
    public Rect getFramingRect(int offsetX, int offsetY) {
        Point screenResolution = configManager.getScreenResolution();
        if (framingRect == null) {
            // 魅族等机型拒绝camera权限后screenResolution返回null
            if (screenResolution == null) {
                return null;
            }
            if (camera == null) {
                return null;
            }
            int width = screenResolution.x * 3 / 4;
            if (width < MIN_FRAME_WIDTH) {
                width = MIN_FRAME_WIDTH;
            } else if (width > MAX_FRAME_WIDTH) {
                width = MAX_FRAME_WIDTH;
            }
            int height = screenResolution.y * 3 / 4;
            if (height < MIN_FRAME_HEIGHT) {
                height = MIN_FRAME_HEIGHT;
            } else if (height > MAX_FRAME_HEIGHT) {
                height = MAX_FRAME_HEIGHT;
            }
            int leftOffset = (screenResolution.x - width) / 2;
            int topOffset = (screenResolution.y - height) / 2;
            framingRect = new Rect(leftOffset + offsetX,
                    topOffset + offsetY,
                    leftOffset + width + offsetX,
                    topOffset + height + offsetY);
            Log.d(TAG, "Calculated framing rect: " + framingRect);
        }
        return framingRect;
    }

    /**
     * Like {@link #getFramingRect} but coordinates are in terms of the preview frame,
     * not UI / screen.
     *
     * 获取扫描实际有效区域
     */
    public Rect getFramingRectInPreview() {
        if (framingRectInPreview == null) {
            Rect rect = new Rect(getFramingRect(ViewfinderView.RECT_OFFSET_X, ViewfinderView.RECT_OFFSET_Y));
            Point cameraResolution = configManager.getCameraResolution();
            Point screenResolution = configManager.getScreenResolution();
            //modify here
//      rect.left = rect.left * cameraResolution.x / screenResolution.x;
//      rect.right = rect.right * cameraResolution.x / screenResolution.x;
//      rect.top = rect.top * cameraResolution.y / screenResolution.y;
//      rect.bottom = rect.bottom * cameraResolution.y / screenResolution.y;
            rect.left = rect.left * cameraResolution.y / screenResolution.x;
            rect.right = rect.right * cameraResolution.y / screenResolution.x;
            rect.top = rect.top * cameraResolution.x / screenResolution.y;
            rect.bottom = rect.bottom * cameraResolution.x / screenResolution.y;
            framingRectInPreview = rect;
        }
        return framingRectInPreview;
    }

    /**
     * Converts the result points from still resolution coordinates to screen coordinates.
     *
     * @param points The points returned by the Reader subclass through Result.getResultPoints().
     * @return An array of Points scaled to the size of the framing rect and offset appropriately
     *         so they can be drawn in screen coordinates.
     */
  /*
  public Point[] convertResultPoints(ResultPoint[] points) {
    Rect frame = getFramingRectInPreview();
    int count = points.length;
    Point[] output = new Point[count];
    for (int x = 0; x < count; x++) {
      output[x] = new Point();
      output[x].x = frame.left + (int) (points[x].getX() + 0.5f);
      output[x].y = frame.top + (int) (points[x].getY() + 0.5f);
    }
    return output;
  }
   */

    /**
     * A factory method to build the appropriate LuminanceSource object based on the format
     * of the preview buffers, as described by Camera.Parameters.
     *
     * @param data   A preview frame.
     * @param width  The width of the image.
     * @param height The height of the image.
     * @return A PlanarYUVLuminanceSource instance.
     */
    public PlanarYUVLuminanceSource buildLuminanceSource(byte[] data, int width, int height) {
        Rect rect = getFramingRectInPreview();
        int previewFormat = configManager.getPreviewFormat();
        String previewFormatString = configManager.getPreviewFormatString();
        switch (previewFormat) {
            // This is the standard Android format which all devices are REQUIRED to support.
            // In theory, it's the only one we should ever care about.
            case PixelFormat.YCbCr_420_SP:
                // This format has never been seen in the wild, but is compatible as we only care
                // about the Y channel, so allow it.
            case PixelFormat.YCbCr_422_SP:
                return new PlanarYUVLuminanceSource(data, width, height, rect.left, rect.top,
                        rect.width(), rect.height());
            default:
                // The Samsung Moment incorrectly uses this variant instead of the 'sp' version.
                // Fortunately, it too has all the Y data up front, so we can read it.
                if ("yuv420p".equals(previewFormatString)) {
                    return new PlanarYUVLuminanceSource(data, width, height, rect.left, rect.top,
                            rect.width(), rect.height());
                }
        }
        throw new IllegalArgumentException("Unsupported picture format: " +
                previewFormat + '/' + previewFormatString);
    }

    public Context getContext() {
        return context;
    }

    /**
     * 打开或关闭闪光灯
     *
     * @param open 控制是否打开
     * @return 打开或关闭失败，则返回false。
     */
    public boolean setFlashLight(boolean open) {
        if (camera == null) {
            return false;
        }
        Camera.Parameters parameters = camera.getParameters();
        if (parameters == null) {
            return false;
        }
        List<String> flashModes = parameters.getSupportedFlashModes();
        // Check if camera flash exists
        if (null == flashModes || 0 == flashModes.size()) {
            // Use the screen as getUrl flashlight (next best thing)
            return false;
        }
        String flashMode = parameters.getFlashMode();
        if (open) {
            if (Camera.Parameters.FLASH_MODE_TORCH.equals(flashMode)) {
                return true;
            }
            // Turn on the flash
            if (flashModes.contains(Camera.Parameters.FLASH_MODE_TORCH)) {
                parameters.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);
                camera.setParameters(parameters);
                return true;
            } else {
                return false;
            }
        } else {
            if (Camera.Parameters.FLASH_MODE_OFF.equals(flashMode)) {
                return true;
            }
            // Turn on the flash
            if (flashModes.contains(Camera.Parameters.FLASH_MODE_OFF)) {
                parameters.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
                camera.setParameters(parameters);
                return true;
            } else
                return false;
        }
    }

    /**
     * 检查是否获得摄像头权限
     * @return
     */
    public int checkCameraPermission() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            return context.checkSelfPermission(Manifest.permission.CAMERA);
        } else {
            if (camera == null) {
                return PackageManager.PERMISSION_DENIED;
            }
        }
        return PackageManager.PERMISSION_GRANTED;
    }

    /**
     * 是否已开启预览模式
     * @return
     */
    public boolean isPreviewing() {
        return previewing;
    }

}