package com.example.mp4composer.composer;

import android.opengl.EGL14;
import android.opengl.EGLConfig;
import android.opengl.EGLContext;
import android.opengl.EGLDisplay;
import android.opengl.EGLExt;
import android.opengl.EGLSurface;
import android.view.Surface;

// Refer : https://android.googlesource.com/platform/cts/+/lollipop-release/tests/tests/media/src/android/media/cts/InputSurface.java

/**
 * Holds state associated with a Surface used for MediaCodec encoder input.
 * <p>
 * The constructor takes a Surface obtained from MediaCodec.createInputSurface(), and uses that
 * to create an EGL window surface.  Calls to eglSwapBuffers() cause a frame of data to be sent
 * to the video encoder.
 */
class EncoderSurface {

    private static final int EGL_RECORDABLE_ANDROID = 0x3142;
    private EGLDisplay eglDisplay = EGL14.EGL_NO_DISPLAY;
    private EGLContext eglContext = EGL14.EGL_NO_CONTEXT;
    private EGLSurface eglSurface = EGL14.EGL_NO_SURFACE;
    private Surface surface;

    /**
     * Creates an EncoderSurface from a Surface.
     */
    EncoderSurface(Surface surface, EGLContext shareContext) {
        if (surface == null) {
            throw new NullPointerException();
        }
        this.surface = surface;
        eglSetup(shareContext);
    }

    /**
     * Prepares EGL.  We want a GLES 2.0 context and a surface that supports recording.
     */
    private void eglSetup(EGLContext shareContext) {
        eglDisplay = EGL14.eglGetDisplay(EGL14.EGL_DEFAULT_DISPLAY);
        if (eglDisplay == EGL14.EGL_NO_DISPLAY) {
            throw new RuntimeException("unable to get EGL14 display");
        }
        int[] version = new int[2];
        if (!EGL14.eglInitialize(eglDisplay, version, 0, version, 1)) {
            eglDisplay = null;
            throw new RuntimeException("unable to initialize EGL14");
        }
        // Configure EGL for recordable and OpenGL ES 2.0.  We want enough RGB bits
        // to minimize artifacts from possible YUV conversion.
        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,
                EGL_RECORDABLE_ANDROID, 1,
                EGL14.EGL_NONE
        };
        EGLConfig[] configs = new EGLConfig[1];
        int[] numConfigs = new int[1];
        if (!EGL14.eglChooseConfig(eglDisplay, 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
        };
        eglContext = EGL14.eglCreateContext(eglDisplay, configs[0], shareContext != null ? shareContext : EGL14.EGL_NO_CONTEXT,
                attrib_list, 0);
        checkEglError("eglCreateContext");
        if (eglContext == null) {
            throw new RuntimeException("null context");
        }
        // Create a window surface, and attach it to the Surface we received.
        int[] surfaceAttribs = {
                EGL14.EGL_NONE
        };
        eglSurface = EGL14.eglCreateWindowSurface(eglDisplay, configs[0], surface,
                surfaceAttribs, 0);
        checkEglError("eglCreateWindowSurface");
        if (eglSurface == null) {
            throw new RuntimeException("surface was null");
        }
    }

    /**
     * Discard all resources held by this class, notably the EGL context.  Also releases the
     * Surface that was passed to our constructor.
     */
    public void release() {
        if (eglDisplay != EGL14.EGL_NO_DISPLAY) {
            EGL14.eglDestroySurface(eglDisplay, eglSurface);
            EGL14.eglDestroyContext(eglDisplay, eglContext);
            EGL14.eglReleaseThread();
            EGL14.eglTerminate(eglDisplay);
        }
        surface.release();
        eglDisplay = EGL14.EGL_NO_DISPLAY;
        eglContext = EGL14.EGL_NO_CONTEXT;
        eglSurface = EGL14.EGL_NO_SURFACE;
        surface = null;
    }

    /**
     * Makes our EGL context and surface current.
     */
    void makeCurrent() {
        if (!EGL14.eglMakeCurrent(eglDisplay, eglSurface, eglSurface, eglContext)) {
            throw new RuntimeException("eglMakeCurrent failed");
        }
    }

    /**
     * Calls eglSwapBuffers.  Use this to "publish" the current frame.
     */
    void swapBuffers() {
        EGL14.eglSwapBuffers(eglDisplay, eglSurface);
    }

    /**
     * Sends the presentation time stamp to EGL.  Time is expressed in nanoseconds.
     */
    void setPresentationTime(long nsecs) {
        EGLExt.eglPresentationTimeANDROID(eglDisplay, eglSurface, nsecs);
    }

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