/*
 * Copyright (C) 2013 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 android.view;

import android.graphics.Bitmap;
import android.graphics.Rect;
import android.graphics.SurfaceTexture;
import android.os.Trace;
import android.view.Surface.OutOfResourcesException;
import android.view.View.AttachInfo;

import java.io.PrintWriter;

/**
 * Hardware renderer that proxies the rendering to a render thread. Most calls
 * are currently synchronous.
 * TODO: Make draw() async.
 * TODO: Figure out how to share the DisplayList between two threads (global lock?)
 *
 * The UI thread can block on the RenderThread, but RenderThread must never
 * block on the UI thread.
 *
 * ThreadedRenderer creates an instance of RenderProxy. RenderProxy in turn creates
 * and manages a CanvasContext on the RenderThread. The CanvasContext is fully managed
 * by the lifecycle of the RenderProxy.
 *
 * Note that although currently the EGL context & surfaces are created & managed
 * by the render thread, the goal is to move that into a shared structure that can
 * be managed by both threads. EGLSurface creation & deletion should ideally be
 * done on the UI thread and not the RenderThread to avoid stalling the
 * RenderThread with surface buffer allocation.
 *
 * @hide
 */
public class ThreadedRenderer extends HardwareRenderer {
    private static final String LOGTAG = "ThreadedRenderer";

    private static final Rect NULL_RECT = new Rect();

    private static final long NANOS_PER_MS = 1000000;

    // Keep in sync with DrawFrameTask.h SYNC_* flags
    // Nothing interesting to report
    private static final int SYNC_OK = 0x0;
    // Needs a ViewRoot invalidate
    private static final int SYNC_INVALIDATE_REQUIRED = 0x1;

    private int mWidth, mHeight;
    private long mNativeProxy;
    private boolean mInitialized = false;
    private RenderNode mRootNode;
    private Choreographer mChoreographer;

    ThreadedRenderer(boolean translucent) {
        long rootNodePtr = nCreateRootRenderNode();
        mRootNode = RenderNode.adopt(rootNodePtr);
        mRootNode.setClipToBounds(false);
        mNativeProxy = nCreateProxy(translucent, rootNodePtr);

        // Setup timing
        mChoreographer = Choreographer.getInstance();
        nSetFrameInterval(mNativeProxy, mChoreographer.getFrameIntervalNanos());
    }

    @Override
    void destroy(boolean full) {
        mInitialized = false;
        updateEnabledState(null);
        nDestroyCanvasAndSurface(mNativeProxy);
    }

    private void updateEnabledState(Surface surface) {
        if (surface == null || !surface.isValid()) {
            setEnabled(false);
        } else {
            setEnabled(mInitialized);
        }
    }

    @Override
    boolean initialize(Surface surface) throws OutOfResourcesException {
        mInitialized = true;
        updateEnabledState(surface);
        return nInitialize(mNativeProxy, surface);
    }

    @Override
    void updateSurface(Surface surface) throws OutOfResourcesException {
        updateEnabledState(surface);
        nUpdateSurface(mNativeProxy, surface);
    }

    @Override
    void pauseSurface(Surface surface) {
        nPauseSurface(mNativeProxy, surface);
    }

    @Override
    void destroyHardwareResources(View view) {
        destroyResources(view);
        // TODO: GLES20Canvas.flushCaches(GLES20Canvas.FLUSH_CACHES_LAYERS);
    }

    private static void destroyResources(View view) {
        view.destroyHardwareResources();

        if (view instanceof ViewGroup) {
            ViewGroup group = (ViewGroup) view;

            int count = group.getChildCount();
            for (int i = 0; i < count; i++) {
                destroyResources(group.getChildAt(i));
            }
        }
    }

    @Override
    void invalidate(Surface surface) {
        updateSurface(surface);
    }

    @Override
    boolean safelyRun(Runnable action) {
        nRunWithGlContext(mNativeProxy, action);
        return true;
    }

    @Override
    void setup(int width, int height) {
        mWidth = width;
        mHeight = height;
        mRootNode.setLeftTopRightBottom(0, 0, mWidth, mHeight);
        nSetup(mNativeProxy, width, height);
    }

    @Override
    int getWidth() {
        return mWidth;
    }

    @Override
    int getHeight() {
        return mHeight;
    }

    @Override
    void dumpGfxInfo(PrintWriter pw) {
        // TODO Auto-generated method stub
    }

    @Override
    long getFrameCount() {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    boolean loadSystemProperties() {
        return nLoadSystemProperties(mNativeProxy);
    }

    private void updateRootDisplayList(View view, HardwareDrawCallbacks callbacks) {
        view.mPrivateFlags |= View.PFLAG_DRAWN;

        view.mRecreateDisplayList = (view.mPrivateFlags & View.PFLAG_INVALIDATED)
                == View.PFLAG_INVALIDATED;
        view.mPrivateFlags &= ~View.PFLAG_INVALIDATED;

        Trace.traceBegin(Trace.TRACE_TAG_VIEW, "getDisplayList");
        HardwareCanvas canvas = mRootNode.start(mWidth, mHeight);
        try {
            callbacks.onHardwarePostDraw(canvas);
            canvas.drawDisplayList(view.getDisplayList());
            callbacks.onHardwarePostDraw(canvas);
        } finally {
            mRootNode.end(canvas);
            Trace.traceEnd(Trace.TRACE_TAG_VIEW);
        }

        view.mRecreateDisplayList = false;
    }

    @Override
    void draw(View view, AttachInfo attachInfo, HardwareDrawCallbacks callbacks, Rect dirty) {
        attachInfo.mIgnoreDirtyState = true;
        long frameTimeNanos = mChoreographer.getFrameTimeNanos();
        attachInfo.mDrawingTime = frameTimeNanos / NANOS_PER_MS;

        updateRootDisplayList(view, callbacks);

        attachInfo.mIgnoreDirtyState = false;

        if (dirty == null) {
            dirty = NULL_RECT;
        }
        int syncResult = nSyncAndDrawFrame(mNativeProxy, frameTimeNanos,
                dirty.left, dirty.top, dirty.right, dirty.bottom);
        if ((syncResult & SYNC_INVALIDATE_REQUIRED) != 0) {
            attachInfo.mViewRootImpl.invalidate();
        }
    }

    @Override
    void detachFunctor(long functor) {
        // no-op, we never attach functors to need to detach them
    }

    @Override
    void attachFunctor(AttachInfo attachInfo, long functor) {
        invokeFunctor(functor, true);
    }

    @Override
    void invokeFunctor(long functor, boolean waitForCompletion) {
        nInvokeFunctor(mNativeProxy, functor, waitForCompletion);
    }

    @Override
    HardwareLayer createDisplayListLayer(int width, int height) {
        long layer = nCreateDisplayListLayer(mNativeProxy, width, height);
        return HardwareLayer.adoptDisplayListLayer(this, layer);
    }

    @Override
    HardwareLayer createTextureLayer() {
        long layer = nCreateTextureLayer(mNativeProxy);
        return HardwareLayer.adoptTextureLayer(this, layer);
    }

    @Override
    SurfaceTexture createSurfaceTexture(final HardwareLayer layer) {
        final SurfaceTexture[] ret = new SurfaceTexture[1];
        nRunWithGlContext(mNativeProxy, new Runnable() {
            @Override
            public void run() {
                ret[0] = layer.createSurfaceTexture();
            }
        });
        return ret[0];
    }

    @Override
    boolean copyLayerInto(final HardwareLayer layer, final Bitmap bitmap) {
        return nCopyLayerInto(mNativeProxy,
                layer.getDeferredLayerUpdater(), bitmap.mNativeBitmap);
    }

    @Override
    void pushLayerUpdate(HardwareLayer layer) {
        // TODO: Remove this, it's not needed outside of GLRenderer
    }

    @Override
    void onLayerCreated(HardwareLayer layer) {
        // TODO: Is this actually useful?
    }

    @Override
    void flushLayerUpdates() {
        // TODO: Figure out what this should do or remove it
    }

    @Override
    void onLayerDestroyed(HardwareLayer layer) {
        nDestroyLayer(mNativeProxy, layer.getDeferredLayerUpdater());
    }

    @Override
    void setName(String name) {
    }

    @Override
    void fence() {
        nFence(mNativeProxy);
    }

    @Override
    protected void finalize() throws Throwable {
        try {
            nDeleteProxy(mNativeProxy);
            mNativeProxy = 0;
        } finally {
            super.finalize();
        }
    }

    /** @hide */
    public static native void postToRenderThread(Runnable runnable);

    private static native long nCreateRootRenderNode();
    private static native long nCreateProxy(boolean translucent, long rootRenderNode);
    private static native void nDeleteProxy(long nativeProxy);

    private static native void nSetFrameInterval(long nativeProxy, long frameIntervalNanos);
    private static native boolean nLoadSystemProperties(long nativeProxy);

    private static native boolean nInitialize(long nativeProxy, Surface window);
    private static native void nUpdateSurface(long nativeProxy, Surface window);
    private static native void nPauseSurface(long nativeProxy, Surface window);
    private static native void nSetup(long nativeProxy, int width, int height);
    private static native void nSetDisplayListData(long nativeProxy, long displayList,
            long newData);
    private static native int nSyncAndDrawFrame(long nativeProxy, long frameTimeNanos,
            int dirtyLeft, int dirtyTop, int dirtyRight, int dirtyBottom);
    private static native void nRunWithGlContext(long nativeProxy, Runnable runnable);
    private static native void nDestroyCanvasAndSurface(long nativeProxy);

    private static native void nInvokeFunctor(long nativeProxy, long functor, boolean waitForCompletion);

    private static native long nCreateDisplayListLayer(long nativeProxy, int width, int height);
    private static native long nCreateTextureLayer(long nativeProxy);
    private static native boolean nCopyLayerInto(long nativeProxy, long layer, long bitmap);
    private static native void nDestroyLayer(long nativeProxy, long layer);

    private static native void nFence(long nativeProxy);
}