/*
 *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

package org.webrtc.videoengine;

import java.util.concurrent.locks.ReentrantLock;

import javax.microedition.khronos.egl.EGL10;
import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.egl.EGLContext;
import javax.microedition.khronos.egl.EGLDisplay;
import javax.microedition.khronos.opengles.GL10;

import android.app.ActivityManager;
import android.content.Context;
import android.content.pm.ConfigurationInfo;
import android.opengl.GLSurfaceView;
import android.util.Log;

public class ViEAndroidGLES20 extends GLSurfaceView
    implements GLSurfaceView.Renderer {
  // True if onSurfaceCreated has been called.
  private boolean surfaceCreated = false;
  private boolean openGLCreated = false;
  // True if NativeFunctionsRegistered has been called.
  private boolean nativeFunctionsRegisted = false;
  private ReentrantLock nativeFunctionLock = new ReentrantLock();
  // Address of Native object that will do the drawing.
  private long nativeObject = 0;
  private int viewWidth = 0;
  private int viewHeight = 0;

  public static boolean UseOpenGL2(Object renderWindow) {
    return ViEAndroidGLES20.class.isInstance(renderWindow);
  }

  public ViEAndroidGLES20(Context context) {
    super(context);

    // Setup the context factory for 2.0 rendering.
    // See ContextFactory class definition below
    setEGLContextFactory(new ContextFactory());

    // We need to choose an EGLConfig that matches the format of
    // our surface exactly. This is going to be done in our
    // custom config chooser. See ConfigChooser class definition below
    // Use RGB 565 without an alpha channel.
    setEGLConfigChooser( new ConfigChooser(5, 6, 5, 0, 0, 0) );

    this.setRenderer(this);
    this.setRenderMode(GLSurfaceView.RENDERMODE_WHEN_DIRTY);
  }

  // IsSupported
  // Return true if this device support Open GL ES 2.0 rendering.
  public static boolean IsSupported(Context context) {
    ActivityManager am =
        (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
    ConfigurationInfo info = am.getDeviceConfigurationInfo();
    if(info.reqGlEsVersion >= 0x20000) {
      // Open GL ES 2.0 is supported.
      return true;
    }
    return false;
  }

  public void onDrawFrame(GL10 gl) {
    nativeFunctionLock.lock();
    if(!nativeFunctionsRegisted || !surfaceCreated) {
      nativeFunctionLock.unlock();
      return;
    }

    if(!openGLCreated) {
      if(0 != CreateOpenGLNative(nativeObject, viewWidth, viewHeight)) {
        return; // Failed to create OpenGL
      }
      openGLCreated = true; // Created OpenGL successfully
    }
    DrawNative(nativeObject); // Draw the new frame
    nativeFunctionLock.unlock();
  }

  public void onSurfaceChanged(GL10 gl, int width, int height) {
    surfaceCreated = true;
    viewWidth = width;
    viewHeight = height;

    nativeFunctionLock.lock();
    if(nativeFunctionsRegisted) {
      if(CreateOpenGLNative(nativeObject,width,height) == 0)
        openGLCreated = true;
    }
    nativeFunctionLock.unlock();
  }

  public void onSurfaceCreated(GL10 gl, EGLConfig config) {
  }

  public void RegisterNativeObject(long nativeObject) {
    nativeFunctionLock.lock();
    nativeObject = nativeObject;
    nativeFunctionsRegisted = true;
    nativeFunctionLock.unlock();
  }

  public void DeRegisterNativeObject() {
    nativeFunctionLock.lock();
    nativeFunctionsRegisted = false;
    openGLCreated = false;
    nativeObject = 0;
    nativeFunctionLock.unlock();
  }

  public void ReDraw() {
    if(surfaceCreated) {
      // Request the renderer to redraw using the render thread context.
      this.requestRender();
    }
  }

  // EGL Context factory used for creating EGL 2.0 context
  // on Android 2.1(and later,
  // though there are simpler ways in 2.2)
  // Code is from the NDK samples\hello-gl2\src\com\android\gl2jni.
  private static class ContextFactory
      implements GLSurfaceView.EGLContextFactory {
    private static int EGL_CONTEXT_CLIENT_VERSION = 0x3098;
    public EGLContext createContext(EGL10 egl,
                                    EGLDisplay display,
                                    EGLConfig eglConfig) {
      //checkEglError("Before eglCreateContext", egl);
      int[] attrib_list = {EGL_CONTEXT_CLIENT_VERSION, 2, EGL10.EGL_NONE };
      // Create an Open GL ES 2.0 context
      EGLContext context = egl.eglCreateContext(display,
                                                eglConfig,
                                                EGL10.EGL_NO_CONTEXT,
                                                attrib_list);
      checkEglError("ContextFactory eglCreateContext", egl);
      return context;
    }

    public void destroyContext(EGL10 egl, EGLDisplay display,
                               EGLContext context) {
      egl.eglDestroyContext(display, context);
    }
  }

  private static void checkEglError(String prompt, EGL10 egl) {
    int error;
    while ((error = egl.eglGetError()) != EGL10.EGL_SUCCESS) {
      Log.e("*WEBRTC*", String.format("%s: EGL error: 0x%x", prompt, error));
    }
  }

  // Code is from the NDK samples\hello-gl2\src\com\android\gl2jni
  private static class ConfigChooser
      implements GLSurfaceView.EGLConfigChooser {

    public ConfigChooser(int r, int g, int b, int a, int depth, int stencil) {
      mRedSize = r;
      mGreenSize = g;
      mBlueSize = b;
      mAlphaSize = a;
      mDepthSize = depth;
      mStencilSize = stencil;
    }

    // This EGL config specification is used to specify 2.0 rendering.
    // We use a minimum size of 4 bits for red/green/blue, but will
    // perform actual matching in chooseConfig() below.
    private static int EGL_OPENGL_ES2_BIT = 4;
    private static int[] s_configAttribs2 =
    {
      EGL10.EGL_RED_SIZE, 4,
      EGL10.EGL_GREEN_SIZE, 4,
      EGL10.EGL_BLUE_SIZE, 4,
      EGL10.EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
      EGL10.EGL_NONE
    };

    public EGLConfig chooseConfig(EGL10 egl, EGLDisplay display) {

      // Get the number of minimally matching EGL configurations
      int[] num_config = new int[1];
      egl.eglChooseConfig(display, s_configAttribs2, null, 0, num_config);

      int numConfigs = num_config[0];

      if (numConfigs <= 0) {
        throw new IllegalArgumentException("No configs match configSpec");
      }

      // Allocate then read the array of minimally matching EGL configs
      EGLConfig[] configs = new EGLConfig[numConfigs];
      egl.eglChooseConfig(display, s_configAttribs2, configs,
                          numConfigs, num_config);

      // Now return the "best" one
      return chooseConfig(egl, display, configs);
    }

    public EGLConfig chooseConfig(EGL10 egl, EGLDisplay display,
                                  EGLConfig[] configs) {
      for(EGLConfig config : configs) {
        int d = findConfigAttrib(egl, display, config,
                                 EGL10.EGL_DEPTH_SIZE, 0);
        int s = findConfigAttrib(egl, display, config,
                                 EGL10.EGL_STENCIL_SIZE, 0);

        // We need at least mDepthSize and mStencilSize bits
        if (d < mDepthSize || s < mStencilSize)
          continue;

        // We want an *exact* match for red/green/blue/alpha
        int r = findConfigAttrib(egl, display, config,
                                 EGL10.EGL_RED_SIZE, 0);
        int g = findConfigAttrib(egl, display, config,
                                 EGL10.EGL_GREEN_SIZE, 0);
        int b = findConfigAttrib(egl, display, config,
                                 EGL10.EGL_BLUE_SIZE, 0);
        int a = findConfigAttrib(egl, display, config,
                                 EGL10.EGL_ALPHA_SIZE, 0);

        if (r == mRedSize && g == mGreenSize &&
            b == mBlueSize && a == mAlphaSize)
          return config;
      }
      return null;
    }

    private int findConfigAttrib(EGL10 egl, EGLDisplay display,
                                 EGLConfig config, int attribute,
                                 int defaultValue) {

      if (egl.eglGetConfigAttrib(display, config, attribute, mValue)) {
        return mValue[0];
      }
      return defaultValue;
    }

    // Subclasses can adjust these values:
    protected int mRedSize;
    protected int mGreenSize;
    protected int mBlueSize;
    protected int mAlphaSize;
    protected int mDepthSize;
    protected int mStencilSize;
    private int[] mValue = new int[1];
  }

  private native int CreateOpenGLNative(long nativeObject,
                                        int width, int height);
  private native void DrawNative(long nativeObject);

}