/*
 * Copyright (C) 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.android.systemui.recents.views;

import android.content.Context;
import android.content.res.Configuration;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.ColorMatrix;
import android.graphics.ColorMatrixColorFilter;
import android.graphics.LightingColorFilter;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.Shader;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewDebug;

import com.android.systemui.R;
import com.android.systemui.recents.events.EventBus;
import com.android.systemui.recents.events.ui.TaskSnapshotChangedEvent;
import com.android.systemui.recents.misc.Utilities;
import com.android.systemui.recents.model.Task;
import com.android.systemui.recents.model.ThumbnailData;
import java.io.PrintWriter;


/**
 * The task thumbnail view.  It implements an image view that allows for animating the dim and
 * alpha of the thumbnail image.
 */
public class TaskViewThumbnail extends View {

    private static final ColorMatrix TMP_FILTER_COLOR_MATRIX = new ColorMatrix();
    private static final ColorMatrix TMP_BRIGHTNESS_COLOR_MATRIX = new ColorMatrix();

    private Task mTask;

    private int mDisplayOrientation = Configuration.ORIENTATION_UNDEFINED;
    private Rect mDisplayRect = new Rect();

    // Drawing
    @ViewDebug.ExportedProperty(category="recents")
    protected Rect mTaskViewRect = new Rect();
    @ViewDebug.ExportedProperty(category="recents")
    protected Rect mThumbnailRect = new Rect();
    @ViewDebug.ExportedProperty(category="recents")
    protected float mThumbnailScale;
    private float mFullscreenThumbnailScale = 1f;
    /** The height, in pixels, of the task view's title bar. */
    private int mTitleBarHeight;
    private boolean mSizeToFit = false;
    private boolean mOverlayHeaderOnThumbnailActionBar = true;
    private ThumbnailData mThumbnailData;

    protected int mCornerRadius;
    @ViewDebug.ExportedProperty(category="recents")
    private float mDimAlpha;
    private Matrix mMatrix = new Matrix();
    private Paint mDrawPaint = new Paint();
    protected Paint mLockedPaint = new Paint();
    protected Paint mBgFillPaint = new Paint();
    protected BitmapShader mBitmapShader;
    protected boolean mUserLocked = false;
    private LightingColorFilter mLightingColorFilter = new LightingColorFilter(0xffffffff, 0);

    // Clip the top of the thumbnail against the opaque header bar that overlaps this view
    private View mTaskBar;

    // Visibility optimization, if the thumbnail height is less than the height of the header
    // bar for the task view, then just mark this thumbnail view as invisible
    @ViewDebug.ExportedProperty(category="recents")
    private boolean mInvisible;

    @ViewDebug.ExportedProperty(category="recents")
    private boolean mDisabledInSafeMode;

    public TaskViewThumbnail(Context context) {
        this(context, null);
    }

    public TaskViewThumbnail(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public TaskViewThumbnail(Context context, AttributeSet attrs, int defStyleAttr) {
        this(context, attrs, defStyleAttr, 0);
    }

    public TaskViewThumbnail(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
        mDrawPaint.setColorFilter(mLightingColorFilter);
        mDrawPaint.setFilterBitmap(true);
        mDrawPaint.setAntiAlias(true);
        Resources res = getResources();
        mCornerRadius = res.getDimensionPixelSize(R.dimen.recents_task_view_rounded_corners_radius);
        mBgFillPaint.setColor(Color.WHITE);
        mLockedPaint.setColor(Color.WHITE);
        mTitleBarHeight = res.getDimensionPixelSize(R.dimen.recents_grid_task_view_header_height);
    }

    /**
     * Called when the task view frame changes, allowing us to move the contents of the header
     * to match the frame changes.
     */
    public void onTaskViewSizeChanged(int width, int height) {
        // Return early if the bounds have not changed
        if (mTaskViewRect.width() == width && mTaskViewRect.height() == height) {
            return;
        }

        mTaskViewRect.set(0, 0, width, height);
        setLeftTopRightBottom(0, 0, width, height);
        updateThumbnailMatrix();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        if (mInvisible) {
            return;
        }

        int viewWidth = mTaskViewRect.width();
        int viewHeight = mTaskViewRect.height();
        int thumbnailWidth = Math.min(viewWidth,
                (int) (mThumbnailRect.width() * mThumbnailScale));
        int thumbnailHeight = Math.min(viewHeight,
                (int) (mThumbnailRect.height() * mThumbnailScale));

        if (mUserLocked) {
            canvas.drawRoundRect(0, 0, viewWidth, viewHeight, mCornerRadius, mCornerRadius,
                    mLockedPaint);
        } else if (mBitmapShader != null && thumbnailWidth > 0 && thumbnailHeight > 0) {
            int topOffset = 0;
            if (mTaskBar != null && mOverlayHeaderOnThumbnailActionBar) {
                topOffset = mTaskBar.getHeight() - mCornerRadius;
            }

            // Draw the background, there will be some small overdraw with the thumbnail
            if (thumbnailWidth < viewWidth) {
                // Portrait thumbnail on a landscape task view
                canvas.drawRoundRect(Math.max(0, thumbnailWidth - mCornerRadius), topOffset,
                        viewWidth, viewHeight,
                        mCornerRadius, mCornerRadius, mBgFillPaint);
            }
            if (thumbnailHeight < viewHeight) {
                // Landscape thumbnail on a portrait task view
                canvas.drawRoundRect(0, Math.max(topOffset, thumbnailHeight - mCornerRadius),
                        viewWidth, viewHeight,
                        mCornerRadius, mCornerRadius, mBgFillPaint);
            }

            // Draw the thumbnail
            canvas.drawRoundRect(0, topOffset, thumbnailWidth, thumbnailHeight,
                    mCornerRadius, mCornerRadius, mDrawPaint);
        } else {
            canvas.drawRoundRect(0, 0, viewWidth, viewHeight, mCornerRadius, mCornerRadius,
                    mBgFillPaint);
        }
    }

    /** Sets the thumbnail to a given bitmap. */
    void setThumbnail(ThumbnailData thumbnailData) {
        if (thumbnailData != null && thumbnailData.thumbnail != null) {
            Bitmap bm = thumbnailData.thumbnail;
            bm.prepareToDraw();
            mFullscreenThumbnailScale = thumbnailData.scale;
            mBitmapShader = new BitmapShader(bm, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
            mDrawPaint.setShader(mBitmapShader);
            mThumbnailRect.set(0, 0,
                    bm.getWidth() - thumbnailData.insets.left - thumbnailData.insets.right,
                    bm.getHeight() - thumbnailData.insets.top - thumbnailData.insets.bottom);
            mThumbnailData = thumbnailData;
            updateThumbnailMatrix();
            updateThumbnailPaintFilter();
        } else {
            mBitmapShader = null;
            mDrawPaint.setShader(null);
            mThumbnailRect.setEmpty();
            mThumbnailData = null;
        }
    }

    /** Updates the paint to draw the thumbnail. */
    void updateThumbnailPaintFilter() {
        if (mInvisible) {
            return;
        }
        int mul = (int) ((1.0f - mDimAlpha) * 255);
        if (mBitmapShader != null) {
            if (mDisabledInSafeMode) {
                // Brightness: C-new = C-old*(1-amount) + amount
                TMP_FILTER_COLOR_MATRIX.setSaturation(0);
                float scale = 1f - mDimAlpha;
                float[] mat = TMP_BRIGHTNESS_COLOR_MATRIX.getArray();
                mat[0] = scale;
                mat[6] = scale;
                mat[12] = scale;
                mat[4] = mDimAlpha * 255f;
                mat[9] = mDimAlpha * 255f;
                mat[14] = mDimAlpha * 255f;
                TMP_FILTER_COLOR_MATRIX.preConcat(TMP_BRIGHTNESS_COLOR_MATRIX);
                ColorMatrixColorFilter filter = new ColorMatrixColorFilter(TMP_FILTER_COLOR_MATRIX);
                mDrawPaint.setColorFilter(filter);
                mBgFillPaint.setColorFilter(filter);
                mLockedPaint.setColorFilter(filter);
            } else {
                mLightingColorFilter.setColorMultiply(Color.argb(255, mul, mul, mul));
                mDrawPaint.setColorFilter(mLightingColorFilter);
                mDrawPaint.setColor(0xFFffffff);
                mBgFillPaint.setColorFilter(mLightingColorFilter);
                mLockedPaint.setColorFilter(mLightingColorFilter);
            }
        } else {
            int grey = mul;
            mDrawPaint.setColorFilter(null);
            mDrawPaint.setColor(Color.argb(255, grey, grey, grey));
        }
        if (!mInvisible) {
            invalidate();
        }
    }

    /**
     * Updates the scale of the bitmap relative to this view.
     */
    public void updateThumbnailMatrix() {
        mThumbnailScale = 1f;
        if (mBitmapShader != null && mThumbnailData != null) {
            // We consider this a stack task if it is not freeform (ie. has no bounds) or has been
            // dragged into the stack from the freeform workspace
            boolean isStackTask = !mTask.isFreeformTask() || mTask.bounds == null;
            int xOffset, yOffset = 0;
            if (mTaskViewRect.isEmpty()) {
                // If we haven't measured , skip the thumbnail drawing and only draw the background
                // color
                mThumbnailScale = 0f;
            } else if (mSizeToFit) {
                // Make sure we fill the entire space regardless of the orientation.
                float viewAspectRatio = (float) mTaskViewRect.width() /
                        (float) (mTaskViewRect.height() - mTitleBarHeight);
                float thumbnailAspectRatio =
                        (float) mThumbnailRect.width() / (float) mThumbnailRect.height();
                if (viewAspectRatio > thumbnailAspectRatio) {
                    mThumbnailScale =
                            (float) mTaskViewRect.width() / (float) mThumbnailRect.width();
                } else {
                    mThumbnailScale = (float) (mTaskViewRect.height() - mTitleBarHeight)
                            / (float) mThumbnailRect.height();
                }
            } else if (isStackTask) {
                float invThumbnailScale = 1f / mFullscreenThumbnailScale;
                if (mDisplayOrientation == Configuration.ORIENTATION_PORTRAIT) {
                    if (mThumbnailData.orientation == Configuration.ORIENTATION_PORTRAIT) {
                        // If we are in the same orientation as the screenshot, just scale it to the
                        // width of the task view
                        mThumbnailScale = (float) mTaskViewRect.width() / mThumbnailRect.width();
                    } else {
                        // Scale the landscape thumbnail up to app size, then scale that to the task
                        // view size to match other portrait screenshots
                        mThumbnailScale = invThumbnailScale *
                                ((float) mTaskViewRect.width() / mDisplayRect.width());
                    }
                } else {
                    // Otherwise, scale the screenshot to fit 1:1 in the current orientation
                    mThumbnailScale = invThumbnailScale;
                }
            } else {
                // Otherwise, if this is a freeform task with task bounds, then scale the thumbnail
                // to fit the entire bitmap into the task bounds
                mThumbnailScale = Math.min(
                        (float) mTaskViewRect.width() / mThumbnailRect.width(),
                        (float) mTaskViewRect.height() / mThumbnailRect.height());
            }
            mMatrix.setTranslate(-mThumbnailData.insets.left * mFullscreenThumbnailScale,
                    -mThumbnailData.insets.top * mFullscreenThumbnailScale);
            mMatrix.postScale(mThumbnailScale, mThumbnailScale);
            mBitmapShader.setLocalMatrix(mMatrix);
        }
        if (!mInvisible) {
            invalidate();
        }
    }

    /** Sets whether the thumbnail should be resized to fit the task view in all orientations. */
    public void setSizeToFit(boolean flag) {
        mSizeToFit = flag;
    }

    /**
     * Sets whether the header should overlap (and hide) the action bar in the thumbnail, or
     * be stacked just above it.
     */
    public void setOverlayHeaderOnThumbnailActionBar(boolean flag) {
        mOverlayHeaderOnThumbnailActionBar = flag;
    }

    /** Updates the clip rect based on the given task bar. */
    void updateClipToTaskBar(View taskBar) {
        mTaskBar = taskBar;
        invalidate();
    }

    /** Updates the visibility of the the thumbnail. */
    void updateThumbnailVisibility(int clipBottom) {
        boolean invisible = mTaskBar != null && (getHeight() - clipBottom) <= mTaskBar.getHeight();
        if (invisible != mInvisible) {
            mInvisible = invisible;
            if (!mInvisible) {
                updateThumbnailPaintFilter();
            }
        }
    }

    /**
     * Sets the dim alpha, only used when we are not using hardware layers.
     * (see RecentsConfiguration.useHardwareLayers)
     */
    public void setDimAlpha(float dimAlpha) {
        mDimAlpha = dimAlpha;
        updateThumbnailPaintFilter();
    }

    /**
     * Returns the {@link Paint} used to draw a task screenshot, or {@link #mLockedPaint} if the
     * thumbnail shouldn't be drawn because it belongs to a locked user.
     */
    protected Paint getDrawPaint() {
        if (mUserLocked) {
            return mLockedPaint;
        }
        return mDrawPaint;
    }

    /**
     * Binds the thumbnail view to the task.
     */
    void bindToTask(Task t, boolean disabledInSafeMode, int displayOrientation, Rect displayRect) {
        mTask = t;
        mDisabledInSafeMode = disabledInSafeMode;
        mDisplayOrientation = displayOrientation;
        mDisplayRect.set(displayRect);
        if (t.colorBackground != 0) {
            mBgFillPaint.setColor(t.colorBackground);
        }
        if (t.colorPrimary != 0) {
            mLockedPaint.setColor(t.colorPrimary);
        }
        mUserLocked = t.isLocked;
        EventBus.getDefault().register(this);
    }

    /**
     * Called when the bound task's data has loaded and this view should update to reflect the
     * changes.
     */
    void onTaskDataLoaded(ThumbnailData thumbnailData) {
        setThumbnail(thumbnailData);
    }

    /** Unbinds the thumbnail view from the task */
    void unbindFromTask() {
        mTask = null;
        setThumbnail(null);
        EventBus.getDefault().unregister(this);
    }

    public final void onBusEvent(TaskSnapshotChangedEvent event) {
        if (mTask == null || event.taskId != mTask.key.id || event.thumbnailData == null
                || event.thumbnailData.thumbnail == null) {
            return;
        }
        setThumbnail(event.thumbnailData);
    }

    public void dump(String prefix, PrintWriter writer) {
        writer.print(prefix); writer.print("TaskViewThumbnail");
        writer.print(" mTaskViewRect="); writer.print(Utilities.dumpRect(mTaskViewRect));
        writer.print(" mThumbnailRect="); writer.print(Utilities.dumpRect(mThumbnailRect));
        writer.print(" mThumbnailScale="); writer.print(mThumbnailScale);
        writer.print(" mDimAlpha="); writer.print(mDimAlpha);
        writer.println();
    }
}