/*
 * Copyright (C) 2010 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.server;  // TODO: use com.android.server.wm, once things move there

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.Rect;
import android.util.DisplayMetrics;
import android.util.Slog;
import android.view.Display;
import android.view.Surface;
import android.view.SurfaceSession;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.view.animation.Transformation;

class ScreenRotationAnimation {
    static final String TAG = "ScreenRotationAnimation";
    static final boolean DEBUG = false;

    final Context mContext;
    final Display mDisplay;
    Surface mSurface;
    int mWidth, mHeight;

    int mSnapshotRotation;
    int mSnapshotDeltaRotation;
    int mOriginalRotation;
    int mOriginalWidth, mOriginalHeight;
    int mCurRotation;

    Animation mExitAnimation;
    final Transformation mExitTransformation = new Transformation();
    Animation mEnterAnimation;
    final Transformation mEnterTransformation = new Transformation();
    boolean mStarted;

    final DisplayMetrics mDisplayMetrics = new DisplayMetrics();
    final Matrix mSnapshotInitialMatrix = new Matrix();
    final Matrix mSnapshotFinalMatrix = new Matrix();
    final float[] mTmpFloats = new float[9];

    public ScreenRotationAnimation(Context context, Display display, SurfaceSession session) {
        mContext = context;
        mDisplay = display;

        display.getMetrics(mDisplayMetrics);

        Bitmap screenshot = Surface.screenshot(0, 0);

        if (screenshot != null) {
            // Screenshot does NOT include rotation!
            mSnapshotRotation = 0;
            mWidth = screenshot.getWidth();
            mHeight = screenshot.getHeight();
        } else {
            // Just in case.
            mSnapshotRotation = display.getRotation();
            mWidth = mDisplayMetrics.widthPixels;
            mHeight = mDisplayMetrics.heightPixels;
        }

        mOriginalRotation = display.getRotation();
        mOriginalWidth = mDisplayMetrics.widthPixels;
        mOriginalHeight = mDisplayMetrics.heightPixels;

        Surface.openTransaction();
        if (mSurface != null) {
            mSurface.destroy();
            mSurface = null;
        }
        try {
            mSurface = new Surface(session, 0, "FreezeSurface",
                    -1, mWidth, mHeight, PixelFormat.OPAQUE, 0);
        } catch (Surface.OutOfResourcesException e) {
            Slog.w(TAG, "Unable to allocate freeze surface", e);
        }
        mSurface.setLayer(WindowManagerService.TYPE_LAYER_MULTIPLIER * 200);
        setRotation(display.getRotation());

        Rect dirty = new Rect(0, 0, mWidth, mHeight);
        Canvas c = null;
        try {
            c = mSurface.lockCanvas(dirty);
        } catch (IllegalArgumentException e) {
            Slog.w(TAG, "Unable to lock surface", e);
            return;
        } catch (Surface.OutOfResourcesException e) {
            Slog.w(TAG, "Unable to lock surface", e);
            return;
        }
        if (c == null) {
            Slog.w(TAG, "Null surface");
            return;
        }

        if (screenshot != null) {
            c.drawBitmap(screenshot, 0, 0, new Paint(0));
        } else {
            c.drawColor(Color.GREEN);
        }

        mSurface.unlockCanvasAndPost(c);
        Surface.closeTransaction();

        screenshot.recycle();
    }

    static int deltaRotation(int oldRotation, int newRotation) {
        int delta = newRotation - oldRotation;
        if (delta < 0) delta += 4;
        return delta;
    }

    void setSnapshotTransform(Matrix matrix, float alpha) {
        matrix.getValues(mTmpFloats);
        mSurface.setPosition((int)mTmpFloats[Matrix.MTRANS_X],
                (int)mTmpFloats[Matrix.MTRANS_Y]);
        mSurface.setMatrix(
                mTmpFloats[Matrix.MSCALE_X], mTmpFloats[Matrix.MSKEW_Y],
                mTmpFloats[Matrix.MSKEW_X], mTmpFloats[Matrix.MSCALE_Y]);
        mSurface.setAlpha(alpha);
        if (DEBUG) {
            float[] srcPnts = new float[] { 0, 0, mWidth, mHeight };
            float[] dstPnts = new float[4];
            matrix.mapPoints(dstPnts, srcPnts);
            Slog.i(TAG, "Original  : (" + srcPnts[0] + "," + srcPnts[1]
                    + ")-(" + srcPnts[2] + "," + srcPnts[3] + ")");
            Slog.i(TAG, "Transformed: (" + dstPnts[0] + "," + dstPnts[1]
                    + ")-(" + dstPnts[2] + "," + dstPnts[3] + ")");
        }
    }

    // Must be called while in a transaction.
    public void setRotation(int rotation) {
        mCurRotation = rotation;

        // Compute the transformation matrix that must be applied
        // to the snapshot to make it stay in the same original position
        // with the current screen rotation.
        int delta = deltaRotation(rotation, mSnapshotRotation);
        switch (delta) {
            case Surface.ROTATION_0:
                mSnapshotInitialMatrix.reset();
                break;
            case Surface.ROTATION_90:
                mSnapshotInitialMatrix.setRotate(90, 0, 0);
                mSnapshotInitialMatrix.postTranslate(mHeight, 0);
                break;
            case Surface.ROTATION_180:
                mSnapshotInitialMatrix.setRotate(180, 0, 0);
                mSnapshotInitialMatrix.postTranslate(mWidth, mHeight);
                break;
            case Surface.ROTATION_270:
                mSnapshotInitialMatrix.setRotate(270, 0, 0);
                mSnapshotInitialMatrix.postTranslate(0, mWidth);
                break;
        }

        if (DEBUG) Slog.v(TAG, "**** ROTATION: " + delta);
        setSnapshotTransform(mSnapshotInitialMatrix, 1.0f);
    }

    /**
     * Returns true if animating.
     */
    public boolean dismiss(long maxAnimationDuration, float animationScale) {
        // Figure out how the screen has moved from the original rotation.
        int delta = deltaRotation(mCurRotation, mOriginalRotation);
        if (false && delta == 0) {
            // Nothing changed, just remove the snapshot.
            if (mSurface != null) {
                mSurface.destroy();
                mSurface = null;
            }
            return false;
        }

        switch (delta) {
            case Surface.ROTATION_0:
                mExitAnimation = AnimationUtils.loadAnimation(mContext,
                        com.android.internal.R.anim.screen_rotate_0_exit);
                mEnterAnimation = AnimationUtils.loadAnimation(mContext,
                        com.android.internal.R.anim.screen_rotate_0_enter);
                break;
            case Surface.ROTATION_90:
                mExitAnimation = AnimationUtils.loadAnimation(mContext,
                        com.android.internal.R.anim.screen_rotate_plus_90_exit);
                mEnterAnimation = AnimationUtils.loadAnimation(mContext,
                        com.android.internal.R.anim.screen_rotate_plus_90_enter);
                break;
            case Surface.ROTATION_180:
                mExitAnimation = AnimationUtils.loadAnimation(mContext,
                        com.android.internal.R.anim.screen_rotate_180_exit);
                mEnterAnimation = AnimationUtils.loadAnimation(mContext,
                        com.android.internal.R.anim.screen_rotate_180_enter);
                break;
            case Surface.ROTATION_270:
                mExitAnimation = AnimationUtils.loadAnimation(mContext,
                        com.android.internal.R.anim.screen_rotate_minus_90_exit);
                mEnterAnimation = AnimationUtils.loadAnimation(mContext,
                        com.android.internal.R.anim.screen_rotate_minus_90_enter);
                break;
        }

        mDisplay.getMetrics(mDisplayMetrics);

        // Initialize the animations.  This is a hack, redefining what "parent"
        // means to allow supplying the last and next size.  In this definition
        // "%p" is the original (let's call it "previous") size, and "%" is the
        // screen's current/new size.
        mEnterAnimation.initialize(mDisplayMetrics.widthPixels, mDisplayMetrics.heightPixels,
                mOriginalWidth, mOriginalHeight);
        mExitAnimation.initialize(mDisplayMetrics.widthPixels, mDisplayMetrics.heightPixels,
                mOriginalWidth, mOriginalHeight);
        mStarted = false;

        mExitAnimation.restrictDuration(maxAnimationDuration);
        mExitAnimation.scaleCurrentDuration(animationScale);
        mEnterAnimation.restrictDuration(maxAnimationDuration);
        mEnterAnimation.scaleCurrentDuration(animationScale);

        return true;
    }

    public void kill() {
        if (mSurface != null) {
            mSurface.destroy();
            mSurface = null;
        }
        if (mExitAnimation != null) {
            mExitAnimation.cancel();
            mExitAnimation = null;
        }
        if (mEnterAnimation != null) {
            mEnterAnimation.cancel();
            mEnterAnimation = null;
        }
    }

    public boolean isAnimating() {
        return mEnterAnimation != null || mExitAnimation != null;
    }

    public boolean stepAnimation(long now) {
        if (mEnterAnimation == null && mExitAnimation == null) {
            return false;
        }

        if (!mStarted) {
            mEnterAnimation.setStartTime(now);
            mExitAnimation.setStartTime(now);
            mStarted = true;
        }

        mExitTransformation.clear();
        boolean moreExit = false;
        if (mExitAnimation != null) {
            moreExit = mExitAnimation.getTransformation(now, mExitTransformation);
            if (DEBUG) Slog.v(TAG, "Stepped exit: " + mExitTransformation);
            if (!moreExit) {
                if (DEBUG) Slog.v(TAG, "Exit animation done!");
                mExitAnimation.cancel();
                mExitAnimation = null;
                mExitTransformation.clear();
                if (mSurface != null) {
                    mSurface.destroy();
                    mSurface = null;
                }
            }
        }

        mEnterTransformation.clear();
        boolean moreEnter = false;
        if (mEnterAnimation != null) {
            moreEnter = mEnterAnimation.getTransformation(now, mEnterTransformation);
            if (!moreEnter) {
                mEnterAnimation.cancel();
                mEnterAnimation = null;
                mEnterTransformation.clear();
            }
        }

        if (mSurface != null) {
            mSnapshotFinalMatrix.setConcat(mExitTransformation.getMatrix(), mSnapshotInitialMatrix);
            setSnapshotTransform(mSnapshotFinalMatrix, mExitTransformation.getAlpha());
        }

        return moreEnter || moreExit;
    }

    public Transformation getEnterTransformation() {
        return mEnterTransformation;
    }
}
