/* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

package org.mozilla.gecko.gfx;

import java.nio.ByteBuffer;
import java.nio.IntBuffer;
import java.util.ArrayList;

import org.mozilla.gecko.AndroidGamepadManager;
import org.mozilla.gecko.annotation.RobocopTarget;
import org.mozilla.gecko.annotation.WrapForJNI;
import org.mozilla.gecko.AppConstants;
import org.mozilla.gecko.AppConstants.Versions;
import org.mozilla.gecko.EventDispatcher;
import org.mozilla.gecko.GeckoAccessibility;
import org.mozilla.gecko.GeckoAppShell;
import org.mozilla.gecko.GeckoEvent;
import org.mozilla.gecko.GeckoThread;
import org.mozilla.gecko.PrefsHelper;
import org.mozilla.gecko.Tab;
import org.mozilla.gecko.Tabs;
import org.mozilla.gecko.ZoomConstraints;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Point;
import android.graphics.PointF;
import android.graphics.Rect;
import android.graphics.SurfaceTexture;
import android.util.AttributeSet;
import android.util.Log;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.TextureView;
import android.view.View;
import android.view.ViewGroup;
import android.view.InputDevice;
import android.widget.LinearLayout;
import android.widget.ScrollView;

/**
 * A view rendered by the layer compositor.
 */
public class LayerView extends ScrollView implements Tabs.OnTabsChangedListener {
    private static final String LOGTAG = "GeckoLayerView";

    private GeckoLayerClient mLayerClient;
    private PanZoomController mPanZoomController;
    private DynamicToolbarAnimator mToolbarAnimator;
    private GLController mGLController;
    private LayerRenderer mRenderer;
    /* Must be a PAINT_xxx constant */
    private int mPaintState;
    private int mBackgroundColor;
    private FullScreenState mFullScreenState;

    private SurfaceView mSurfaceView;
    private TextureView mTextureView;
    private View mFillerView;

    private Listener mListener;

    private PointF mInitialTouchPoint;

    private float mSurfaceTranslation;

    /* This should only be modified on the Java UI thread. */
    private final Overscroll mOverscroll;

    /* Flags used to determine when to show the painted surface. */
    public static final int PAINT_START = 0;
    public static final int PAINT_BEFORE_FIRST = 1;
    public static final int PAINT_AFTER_FIRST = 2;

    public boolean shouldUseTextureView() {
        // Disable TextureView support for now as it causes panning/zooming
        // performance regressions (see bug 792259). Uncomment the code below
        // once this bug is fixed.
        return false;

        /*
        // we can only use TextureView on ICS or higher
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
            Log.i(LOGTAG, "Not using TextureView: not on ICS+");
            return false;
        }

        try {
            // and then we can only use it if we have a hardware accelerated window
            Method m = View.class.getMethod("isHardwareAccelerated", (Class[]) null);
            return (Boolean) m.invoke(this);
        } catch (Exception e) {
            Log.i(LOGTAG, "Not using TextureView: caught exception checking for hw accel: " + e.toString());
            return false;
        } */
    }

    public LayerView(Context context, AttributeSet attrs) {
        super(context, attrs);

        mPaintState = PAINT_START;
        mBackgroundColor = Color.WHITE;
        mFullScreenState = FullScreenState.NONE;

        if (Versions.feature14Plus) {
            mOverscroll = new OverscrollEdgeEffect(this);
        } else {
            mOverscroll = null;
        }
        Tabs.registerOnTabsChangedListener(this);
    }

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

    public void initializeView(EventDispatcher eventDispatcher) {
        mLayerClient = new GeckoLayerClient(getContext(), this, eventDispatcher);
        if (mOverscroll != null) {
            mLayerClient.setOverscrollHandler(mOverscroll);
        }

        mPanZoomController = mLayerClient.getPanZoomController();
        mToolbarAnimator = mLayerClient.getDynamicToolbarAnimator();

        mRenderer = new LayerRenderer(this);

        setFocusable(true);
        setFocusableInTouchMode(true);

        GeckoAccessibility.setDelegate(this);
        GeckoAccessibility.setAccessibilityStateChangeListener(getContext());
    }

    /**
     * MotionEventHelper dragAsync() robocop tests can instruct
     * PanZoomController not to generate longpress events.
     */
    public void setIsLongpressEnabled(boolean isLongpressEnabled) {
        mPanZoomController.setIsLongpressEnabled(isLongpressEnabled);
    }

    private static Point getEventRadius(MotionEvent event) {
        return new Point((int)event.getToolMajor() / 2,
                         (int)event.getToolMinor() / 2);
    }

    private boolean sendEventToGecko(MotionEvent event) {
        if (!mLayerClient.isGeckoReady()) {
            return false;
        }

        int action = event.getActionMasked();
        PointF point = new PointF(event.getX(), event.getY());
        if (action == MotionEvent.ACTION_DOWN) {
            mInitialTouchPoint = point;
        }

        if (mInitialTouchPoint != null && action == MotionEvent.ACTION_MOVE) {
            Point p = getEventRadius(event);

            if (PointUtils.subtract(point, mInitialTouchPoint).length() <
                Math.max(PanZoomController.CLICK_THRESHOLD, Math.min(Math.min(p.x, p.y), PanZoomController.PAN_THRESHOLD))) {
                // Don't send the touchmove event if if the users finger hasn't moved far.
                // Necessary for Google Maps to work correctly. See bug 771099.
                return true;
            } else {
                mInitialTouchPoint = null;
            }
        }

        GeckoAppShell.sendEventToGecko(GeckoEvent.createMotionEvent(event, false));
        return true;
    }

    public void showSurface() {
        // Fix this if TextureView support is turned back on above
        mSurfaceView.setVisibility(View.VISIBLE);
    }

    public void hideSurface() {
        // Fix this if TextureView support is turned back on above
        mSurfaceView.setVisibility(View.INVISIBLE);
    }

    public void destroy() {
        if (mLayerClient != null) {
            mLayerClient.destroy();
        }
        if (mRenderer != null) {
            mRenderer.destroy();
        }
        if (mGLController != null) {
            if (mGLController.mView == this) {
                mGLController.mView = null;
            }
            mGLController = null;
        }
        Tabs.unregisterOnTabsChangedListener(this);
    }

    @Override
    public void dispatchDraw(final Canvas canvas) {
        super.dispatchDraw(canvas);

        // We must have a layer client to get valid viewport metrics
        if (mLayerClient != null && mOverscroll != null) {
            mOverscroll.draw(canvas, getViewportMetrics());
        }
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        if (event.getActionMasked() == MotionEvent.ACTION_DOWN) {
            requestFocus();
        }
        event.offsetLocation(0, -mSurfaceTranslation);

        if (mToolbarAnimator != null && mToolbarAnimator.onInterceptTouchEvent(event)) {
            return true;
        }
        if (AppConstants.MOZ_ANDROID_APZ && !mLayerClient.isGeckoReady()) {
            // If gecko isn't loaded yet, don't try sending events to the
            // native code because it's just going to crash
            return true;
        }
        if (mPanZoomController != null && mPanZoomController.onTouchEvent(event)) {
            return true;
        }
        return sendEventToGecko(event);
    }

    @Override
    public boolean onHoverEvent(MotionEvent event) {
        // If we get a touchscreen hover event, and accessibility is not enabled,
        // don't send it to gecko.
        if (event.getSource() == InputDevice.SOURCE_TOUCHSCREEN &&
            !GeckoAccessibility.isEnabled()) {
            return false;
        }

        event.offsetLocation(0, -mSurfaceTranslation);

        return sendEventToGecko(event);
    }

    @Override
    public boolean onGenericMotionEvent(MotionEvent event) {
        event.offsetLocation(0, -mSurfaceTranslation);

        if (AndroidGamepadManager.handleMotionEvent(event)) {
            return true;
        }
        if (AppConstants.MOZ_ANDROID_APZ && !mLayerClient.isGeckoReady()) {
            // If gecko isn't loaded yet, don't try sending events to the
            // native code because it's just going to crash
            return true;
        }
        if (mPanZoomController != null && mPanZoomController.onMotionEvent(event)) {
            return true;
        }
        return false;
    }

    @Override
    protected void onAttachedToWindow() {
        // We are adding descendants to this LayerView, but we don't want the
        // descendants to affect the way LayerView retains its focus.
        setDescendantFocusability(FOCUS_BLOCK_DESCENDANTS);

        // This check should not be done before the view is attached to a window
        // as hardware acceleration will not be enabled at that point.
        // We must create and add the SurfaceView instance before the view tree
        // is fully created to avoid flickering (see bug 801477).
        if (shouldUseTextureView()) {
            mTextureView = new TextureView(getContext());
            mTextureView.setSurfaceTextureListener(new SurfaceTextureListener());

            // The background is set to this color when the LayerView is
            // created, and it will be shown immediately at startup. Shortly
            // after, the tab's background color will be used before any content
            // is shown.
            mTextureView.setBackgroundColor(Color.WHITE);
            addView(mTextureView, ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
        } else {
            // This will stop PropertyAnimator from creating a drawing cache (i.e. a bitmap)
            // from a SurfaceView, which is just not possible (the bitmap will be transparent).
            setWillNotCacheDrawing(false);

            mSurfaceView = new LayerSurfaceView(getContext(), this);
            mSurfaceView.setBackgroundColor(Color.WHITE);
            Log.i("GeckoBug1151102", "Initialized surfaceview");

            // The "filler" view sits behind the URL bar and should never be
            // visible. It exists solely to make this LayerView actually
            // scrollable so that we can shift the surface around on the screen.
            // Once we drop support for pre-Honeycomb Android versions this
            // should not be needed; we can just turn LayerView back into a
            // FrameLayout that holds mSurfaceView and nothing else.
            mFillerView = new View(getContext()) {
                @Override protected void onMeasure(int aWidthSpec, int aHeightSpec) {
                    setMeasuredDimension(0, Math.round(mToolbarAnimator.getMaxTranslation()));
                }
            };
            mFillerView.setBackgroundColor(Color.RED);

            LinearLayout container = new LinearLayout(getContext());
            container.setOrientation(LinearLayout.VERTICAL);
            container.addView(mFillerView);
            container.addView(mSurfaceView, new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));
            addView(container, new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));

            SurfaceHolder holder = mSurfaceView.getHolder();
            holder.addCallback(new SurfaceListener());
        }
    }

    // Don't expose GeckoLayerClient to things outside this package; only expose it as an Object
    GeckoLayerClient getLayerClient() { return mLayerClient; }

    public PanZoomController getPanZoomController() { return mPanZoomController; }
    public DynamicToolbarAnimator getDynamicToolbarAnimator() { return mToolbarAnimator; }

    public ImmutableViewportMetrics getViewportMetrics() {
        return mLayerClient.getViewportMetrics();
    }

    public void abortPanning() {
        if (mPanZoomController != null) {
            mPanZoomController.abortPanning();
        }
    }

    public PointF convertViewPointToLayerPoint(PointF viewPoint) {
        return mLayerClient.convertViewPointToLayerPoint(viewPoint);
    }

    int getBackgroundColor() {
        return mBackgroundColor;
    }

    @Override
    public void setBackgroundColor(int newColor) {
        mBackgroundColor = newColor;
        requestRender();
    }

    void setSurfaceBackgroundColor(int newColor) {
        if (mSurfaceView != null) {
            mSurfaceView.setBackgroundColor(newColor);
        }
    }

    public void setZoomConstraints(ZoomConstraints constraints) {
        mLayerClient.setZoomConstraints(constraints);
    }

    public void setIsRTL(boolean aIsRTL) {
        mLayerClient.setIsRTL(aIsRTL);
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (AppConstants.MOZ_ANDROID_APZ && !mLayerClient.isGeckoReady()) {
            // If gecko isn't loaded yet, don't try sending events to the
            // native code because it's just going to crash
            return true;
        }
        if (mPanZoomController != null && mPanZoomController.onKeyEvent(event)) {
            return true;
        }
        return false;
    }

    public void requestRender() {
        if (mListener != null) {
            mListener.renderRequested();
        }
    }

    public void addLayer(Layer layer) {
        mRenderer.addLayer(layer);
    }

    public void removeLayer(Layer layer) {
        mRenderer.removeLayer(layer);
    }

    public void postRenderTask(RenderTask task) {
        mRenderer.postRenderTask(task);
    }

    public void removeRenderTask(RenderTask task) {
        mRenderer.removeRenderTask(task);
    }

    public int getMaxTextureSize() {
        return mRenderer.getMaxTextureSize();
    }

    /** Used by robocop for testing purposes. Not for production use! */
    @RobocopTarget
    public IntBuffer getPixels() {
        return mRenderer.getPixels();
    }

    /* paintState must be a PAINT_xxx constant. */
    public void setPaintState(int paintState) {
        mPaintState = paintState;
    }

    public int getPaintState() {
        return mPaintState;
    }

    public LayerRenderer getRenderer() {
        return mRenderer;
    }

    public void setListener(Listener listener) {
        mListener = listener;
    }

    Listener getListener() {
        return mListener;
    }

    public void setGLController(final GLController glController) {
        mGLController = glController;
        glController.mView = this;

        final NativePanZoomController npzc = AppConstants.MOZ_ANDROID_APZ ?
                (NativePanZoomController) mPanZoomController : null;

        if (GeckoThread.isStateAtLeast(GeckoThread.State.PROFILE_READY)) {
            glController.attachToJava(mLayerClient, npzc);
        } else {
            GeckoThread.queueNativeCallUntil(GeckoThread.State.PROFILE_READY,
                    glController, "attachToJava",
                    GeckoLayerClient.class, mLayerClient,
                    NativePanZoomController.class, npzc);
        }
    }

    public GLController getGLController() {
        return mGLController;
    }

    /* When using a SurfaceView (mSurfaceView != null), resizing happens in two
     * phases. First, the LayerView changes size, then, often some frames later,
     * the SurfaceView changes size. Because of this, we need to split the
     * resize into two phases to avoid jittering.
     *
     * The first phase is the LayerView size change. mListener is notified so
     * that a synchronous draw can be performed (otherwise a blank frame will
     * appear).
     *
     * The second phase is the SurfaceView size change. At this point, the
     * backing GL surface is resized and another synchronous draw is performed.
     * Gecko is also sent the new window size, and this will likely cause an
     * extra draw a few frames later, after it's re-rendered and caught up.
     *
     * In the case that there is no valid GL surface (for example, when
     * resuming, or when coming back from the awesomescreen), or we're using a
     * TextureView instead of a SurfaceView, the first phase is skipped.
     */
    private void onSizeChanged(int width, int height) {
        if (!mGLController.isServerSurfaceValid() || mSurfaceView == null) {
            surfaceChanged(width, height);
            return;
        }

        if (mListener != null) {
            mListener.sizeChanged(width, height);
        }

        if (mOverscroll != null) {
            mOverscroll.setSize(width, height);
        }
    }

    private void surfaceChanged(int width, int height) {
        mGLController.serverSurfaceChanged(width, height);

        if (mListener != null) {
            mListener.surfaceChanged(width, height);
        }

        if (mOverscroll != null) {
            mOverscroll.setSize(width, height);
        }
    }

    private void onDestroyed() {
        mGLController.serverSurfaceDestroyed();
    }

    public Object getNativeWindow() {
        if (mSurfaceView != null)
            return mSurfaceView.getHolder();

        return mTextureView.getSurfaceTexture();
    }

    //This method is called on the Gecko main thread.
    @WrapForJNI(allowMultithread = true, stubName = "updateZoomedView")
    public static void updateZoomedView(ByteBuffer data) {
        LayerView layerView = GeckoAppShell.getLayerView();
        if (layerView != null) {
            LayerRenderer layerRenderer = layerView.getRenderer();
            if (layerRenderer != null) {
                layerRenderer.updateZoomedView(data);
            }
        }
    }

    public interface Listener {
        void renderRequested();
        void sizeChanged(int width, int height);
        void surfaceChanged(int width, int height);
    }

    private class SurfaceListener implements SurfaceHolder.Callback {
        @Override
        public void surfaceChanged(SurfaceHolder holder, int format, int width,
                                                int height) {
            onSizeChanged(width, height);
        }

        @Override
        public void surfaceCreated(SurfaceHolder holder) {
        }

        @Override
        public void surfaceDestroyed(SurfaceHolder holder) {
            onDestroyed();
        }
    }

    @Override
    protected void onMeasure(int aWidthSpec, int aHeightSpec) {
        super.onMeasure(aWidthSpec, aHeightSpec);
        if (mSurfaceView != null) {
            // Because of the crazy setup where this LayerView is a ScrollView
            // and the SurfaceView is inside a LinearLayout, the SurfaceView
            // doesn't get the right information to size itself the way we want.
            // We always want it to be the same size as this LayerView, so we
            // use a hack to make sure it sizes itself that way.
            ((LayerSurfaceView)mSurfaceView).overrideSize(getMeasuredWidth(), getMeasuredHeight());
        }
    }

    /* A subclass of SurfaceView to listen to layout changes, as
     * View.OnLayoutChangeListener requires API level 11.
     */
    private class LayerSurfaceView extends SurfaceView {
        private LayerView mParent;
        private int mForcedWidth;
        private int mForcedHeight;

        public LayerSurfaceView(Context aContext, LayerView aParent) {
            super(aContext);
            mParent = aParent;
        }

        void overrideSize(int aWidth, int aHeight) {
            if (mForcedWidth != aWidth || mForcedHeight != aHeight) {
                mForcedWidth = aWidth;
                mForcedHeight = aHeight;
                requestLayout();
            }
        }

        @Override
        protected void onMeasure(int aWidthSpec, int aHeightSpec) {
            setMeasuredDimension(mForcedWidth, mForcedHeight);
        }

        @Override
        protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
            super.onLayout(changed, left, top, right, bottom);
            if (changed) {
                mParent.surfaceChanged(right - left, bottom - top);
            }
        }
    }

    private class SurfaceTextureListener implements TextureView.SurfaceTextureListener {
        @Override
        public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {
            // We don't do this for surfaceCreated above because it is always followed by a surfaceChanged,
            // but that is not the case here.
            onSizeChanged(width, height);
        }

        @Override
        public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {
            onDestroyed();
            return true; // allow Android to call release() on the SurfaceTexture, we are done drawing to it
        }

        @Override
        public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {
            onSizeChanged(width, height);
        }

        @Override
        public void onSurfaceTextureUpdated(SurfaceTexture surface) {

        }
    }

    @RobocopTarget
    public void addDrawListener(DrawListener listener) {
        mLayerClient.addDrawListener(listener);
    }

    @RobocopTarget
    public void removeDrawListener(DrawListener listener) {
        mLayerClient.removeDrawListener(listener);
    }

    @RobocopTarget
    public static interface DrawListener {
        public void drawFinished();
    }

    @Override
    public void setOverScrollMode(int overscrollMode) {
        super.setOverScrollMode(overscrollMode);
        if (mPanZoomController != null) {
            mPanZoomController.setOverScrollMode(overscrollMode);
        }
    }

    @Override
    public int getOverScrollMode() {
        if (mPanZoomController != null) {
            return mPanZoomController.getOverScrollMode();
        }

        return super.getOverScrollMode();
    }

    @Override
    public void onFocusChanged (boolean gainFocus, int direction, Rect previouslyFocusedRect) {
        super.onFocusChanged(gainFocus, direction, previouslyFocusedRect);
        GeckoAccessibility.onLayerViewFocusChanged(this, gainFocus);
    }

    public void setFullScreenState(FullScreenState state) {
        mFullScreenState = state;
    }

    public boolean isFullScreen() {
        return mFullScreenState != FullScreenState.NONE;
    }

    public FullScreenState getFullScreenState() {
        return mFullScreenState;
    }

    public void setMaxTranslation(float aMaxTranslation) {
        mToolbarAnimator.setMaxTranslation(aMaxTranslation);
        if (mFillerView != null) {
            mFillerView.requestLayout();
        }
    }

    public void setSurfaceTranslation(float translation) {
        // Once we drop support for pre-Honeycomb Android versions, we can
        // revert bug 1197811 and just use ViewHelper here.
        if (mSurfaceTranslation != translation) {
            mSurfaceTranslation = translation;
            scrollTo(0, Math.round(mToolbarAnimator.getMaxTranslation() - translation));
        }
    }

    public float getSurfaceTranslation() {
        return mSurfaceTranslation;
    }

    @Override
    public void onTabChanged(Tab tab, Tabs.TabEvents msg, Object data) {
        if (msg == Tabs.TabEvents.VIEWPORT_CHANGE && Tabs.getInstance().isSelectedTab(tab) && mLayerClient != null) {
            setZoomConstraints(tab.getZoomConstraints());
            setIsRTL(tab.getIsRTL());
        }
    }

    // Public hooks for dynamic toolbar translation

    public interface DynamicToolbarListener {
        public void onTranslationChanged(float aToolbarTranslation, float aLayerViewTranslation);
        public void onPanZoomStopped();
        public void onMetricsChanged(ImmutableViewportMetrics viewport);
    }

    // Public hooks for zoomed view

    public interface ZoomedViewListener {
        public void requestZoomedViewRender();
        public void updateView(ByteBuffer data);
    }

    public void addZoomedViewListener(ZoomedViewListener listener) {
        mRenderer.addZoomedViewListener(listener);
    }

    public void removeZoomedViewListener(ZoomedViewListener listener) {
        mRenderer.removeZoomedViewListener(listener);
    }

}
