/*
 * 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.media.cts;

import android.graphics.SurfaceTexture;
import android.opengl.EGL14;
import android.opengl.EGLConfig;
import android.opengl.EGLContext;
import android.opengl.EGLDisplay;
import android.opengl.EGLSurface;
import android.util.Log;
import android.view.Surface;


/**
 * Holds state associated with a Surface used for MediaCodec decoder output.
 * <p>
 * The (width,height) constructor for this class will prepare GL, create a SurfaceTexture,
 * and then create a Surface for that SurfaceTexture.  The Surface can be passed to
 * MediaCodec.configure() to receive decoder output.  When a frame arrives, we latch the
 * texture with updateTexImage, then render the texture with GL to a pbuffer.
 * <p>
 * The no-arg constructor skips the GL preparation step and doesn't allocate a pbuffer.
 * Instead, it just creates the Surface and SurfaceTexture, and when a frame arrives
 * we just draw it on whatever surface is current.
 * <p>
 * By default, the Surface will be using a BufferQueue in asynchronous mode, so we
 * can potentially drop frames.
 */
class OutputSurface implements SurfaceTexture.OnFrameAvailableListener {
    private static final String TAG = "OutputSurface";
    private static final boolean VERBOSE = false;

    private EGLDisplay mEGLDisplay = EGL14.EGL_NO_DISPLAY;
    private EGLContext mEGLContext = EGL14.EGL_NO_CONTEXT;
    private EGLSurface mEGLSurface = EGL14.EGL_NO_SURFACE;

    private SurfaceTexture mSurfaceTexture;
    private Surface mSurface;

    private Object mFrameSyncObject = new Object();     // guards mFrameAvailable
    private boolean mFrameAvailable;

    private TextureRender mTextureRender;

    /**
     * Creates an OutputSurface backed by a pbuffer with the specifed dimensions.  The new
     * EGL context and surface will be made current.  Creates a Surface that can be passed
     * to MediaCodec.configure().
     */
    public OutputSurface(int width, int height) {
        if (width <= 0 || height <= 0) {
            throw new IllegalArgumentException();
        }

        eglSetup(width, height);
        makeCurrent();

        setup();
    }

    /**
     * Creates an OutputSurface using the current EGL context (rather than establishing a
     * new one).  Creates a Surface that can be passed to MediaCodec.configure().
     */
    public OutputSurface() {
        setup();
    }

    /**
     * Creates instances of TextureRender and SurfaceTexture, and a Surface associated
     * with the SurfaceTexture.
     */
    private void setup() {
        mTextureRender = new TextureRender();
        mTextureRender.surfaceCreated();

        // Even if we don't access the SurfaceTexture after the constructor returns, we
        // still need to keep a reference to it.  The Surface doesn't retain a reference
        // at the Java level, so if we don't either then the object can get GCed, which
        // causes the native finalizer to run.
        if (VERBOSE) Log.d(TAG, "textureID=" + mTextureRender.getTextureId());
        mSurfaceTexture = new SurfaceTexture(mTextureRender.getTextureId());

        // This doesn't work if OutputSurface is created on the thread that CTS started for
        // these test cases.
        //
        // The CTS-created thread has a Looper, and the SurfaceTexture constructor will
        // create a Handler that uses it.  The "frame available" message is delivered
        // there, but since we're not a Looper-based thread we'll never see it.  For
        // this to do anything useful, OutputSurface must be created on a thread without
        // a Looper, so that SurfaceTexture uses the main application Looper instead.
        //
        // Java language note: passing "this" out of a constructor is generally unwise,
        // but we should be able to get away with it here.
        mSurfaceTexture.setOnFrameAvailableListener(this);

        mSurface = new Surface(mSurfaceTexture);
    }

    /**
     * Prepares EGL.  We want a GLES 2.0 context and a surface that supports pbuffer.
     */
    private void eglSetup(int width, int height) {
        mEGLDisplay = EGL14.eglGetDisplay(EGL14.EGL_DEFAULT_DISPLAY);
        if (mEGLDisplay == EGL14.EGL_NO_DISPLAY) {
            throw new RuntimeException("unable to get EGL14 display");
        }
        int[] version = new int[2];
        if (!EGL14.eglInitialize(mEGLDisplay, version, 0, version, 1)) {
            mEGLDisplay = null;
            throw new RuntimeException("unable to initialize EGL14");
        }

        // Configure EGL for pbuffer and OpenGL ES 2.0.  We want enough RGB bits
        // to be able to tell if the frame is reasonable.
        int[] attribList = {
                EGL14.EGL_RED_SIZE, 8,
                EGL14.EGL_GREEN_SIZE, 8,
                EGL14.EGL_BLUE_SIZE, 8,
                EGL14.EGL_RENDERABLE_TYPE, EGL14.EGL_OPENGL_ES2_BIT,
                EGL14.EGL_SURFACE_TYPE, EGL14.EGL_PBUFFER_BIT,
                EGL14.EGL_NONE
        };
        EGLConfig[] configs = new EGLConfig[1];
        int[] numConfigs = new int[1];
        if (!EGL14.eglChooseConfig(mEGLDisplay, attribList, 0, configs, 0, configs.length,
                numConfigs, 0)) {
            throw new RuntimeException("unable to find RGB888+recordable ES2 EGL config");
        }

        // Configure context for OpenGL ES 2.0.
        int[] attrib_list = {
                EGL14.EGL_CONTEXT_CLIENT_VERSION, 2,
                EGL14.EGL_NONE
        };
        mEGLContext = EGL14.eglCreateContext(mEGLDisplay, configs[0], EGL14.EGL_NO_CONTEXT,
                attrib_list, 0);
        checkEglError("eglCreateContext");
        if (mEGLContext == null) {
            throw new RuntimeException("null context");
        }

        // Create a pbuffer surface.  By using this for output, we can use glReadPixels
        // to test values in the output.
        int[] surfaceAttribs = {
                EGL14.EGL_WIDTH, width,
                EGL14.EGL_HEIGHT, height,
                EGL14.EGL_NONE
        };
        mEGLSurface = EGL14.eglCreatePbufferSurface(mEGLDisplay, configs[0], surfaceAttribs, 0);
        checkEglError("eglCreatePbufferSurface");
        if (mEGLSurface == null) {
            throw new RuntimeException("surface was null");
        }
    }

    /**
     * Discard all resources held by this class, notably the EGL context.
     */
    public void release() {
        if (mEGLDisplay != EGL14.EGL_NO_DISPLAY) {
            EGL14.eglDestroySurface(mEGLDisplay, mEGLSurface);
            EGL14.eglDestroyContext(mEGLDisplay, mEGLContext);
            EGL14.eglReleaseThread();
            EGL14.eglTerminate(mEGLDisplay);
        }

        mSurface.release();

        // this causes a bunch of warnings that appear harmless but might confuse someone:
        //  W BufferQueue: [unnamed-3997-2] cancelBuffer: BufferQueue has been abandoned!
        //mSurfaceTexture.release();

        mEGLDisplay = EGL14.EGL_NO_DISPLAY;
        mEGLContext = EGL14.EGL_NO_CONTEXT;
        mEGLSurface = EGL14.EGL_NO_SURFACE;

        mTextureRender = null;
        mSurface = null;
        mSurfaceTexture = null;
    }

    /**
     * Makes our EGL context and surface current.
     */
    public void makeCurrent() {
        if (!EGL14.eglMakeCurrent(mEGLDisplay, mEGLSurface, mEGLSurface, mEGLContext)) {
            throw new RuntimeException("eglMakeCurrent failed");
        }
    }

    /**
     * Returns the Surface that we draw onto.
     */
    public Surface getSurface() {
        return mSurface;
    }

    /**
     * Replaces the fragment shader.
     */
    public void changeFragmentShader(String fragmentShader) {
        mTextureRender.changeFragmentShader(fragmentShader);
    }

    /**
     * Latches the next buffer into the texture.  Must be called from the thread that created
     * the OutputSurface object, after the onFrameAvailable callback has signaled that new
     * data is available.
     */
    public void awaitNewImage() {
        final int TIMEOUT_MS = 500;

        synchronized (mFrameSyncObject) {
            while (!mFrameAvailable) {
                try {
                    // Wait for onFrameAvailable() to signal us.  Use a timeout to avoid
                    // stalling the test if it doesn't arrive.
                    mFrameSyncObject.wait(TIMEOUT_MS);
                    if (!mFrameAvailable) {
                        // TODO: if "spurious wakeup", continue while loop
                        throw new RuntimeException("Surface frame wait timed out");
                    }
                } catch (InterruptedException ie) {
                    // shouldn't happen
                    throw new RuntimeException(ie);
                }
            }
            mFrameAvailable = false;
        }

        // Latch the data.
        mTextureRender.checkGlError("before updateTexImage");
        mSurfaceTexture.updateTexImage();
    }

    /**
     * Wait up to given timeout until new image become available.
     * @param timeoutMs
     * @return true if new image is available. false for no new image until timeout.
     */
    public boolean checkForNewImage(int timeoutMs) {
        synchronized (mFrameSyncObject) {
            while (!mFrameAvailable) {
                try {
                    // Wait for onFrameAvailable() to signal us.  Use a timeout to avoid
                    // stalling the test if it doesn't arrive.
                    mFrameSyncObject.wait(timeoutMs);
                    if (!mFrameAvailable) {
                        return false;
                    }
                } catch (InterruptedException ie) {
                    // shouldn't happen
                    throw new RuntimeException(ie);
                }
            }
            mFrameAvailable = false;
        }

        // Latch the data.
        mTextureRender.checkGlError("before updateTexImage");
        mSurfaceTexture.updateTexImage();
        return true;
    }

    /**
     * Draws the data from SurfaceTexture onto the current EGL surface.
     */
    public void drawImage() {
        mTextureRender.drawFrame(mSurfaceTexture);
    }

    @Override
    public void onFrameAvailable(SurfaceTexture st) {
        if (VERBOSE) Log.d(TAG, "new frame available");
        synchronized (mFrameSyncObject) {
            if (mFrameAvailable) {
                throw new RuntimeException("mFrameAvailable already set, frame could be dropped");
            }
            mFrameAvailable = true;
            mFrameSyncObject.notifyAll();
        }
    }

    /**
     * Checks for EGL errors.
     */
    private void checkEglError(String msg) {
        int error;
        if ((error = EGL14.eglGetError()) != EGL14.EGL_SUCCESS) {
            throw new RuntimeException(msg + ": EGL error: 0x" + Integer.toHexString(error));
        }
    }
}