// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-FileCopyrightText: Copyright (C) 2008-2009 The Android Open Source Project
// SPDX-License-Identifier: BSD-3-Clause AND Apache-2.0
package com.kitware.JavaVTK;

import android.content.Context;
import android.graphics.PixelFormat;
import android.opengl.GLSurfaceView;
import android.util.AttributeSet;
import android.util.Log;
import android.view.KeyEvent;
import android.view.MotionEvent;

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;

/**
 * A simple GLSurfaceView sub-class that demonstrate how to perform
 * OpenGL ES 2.0 rendering into a GL Surface. Note the following important
 * details:
 *
 * - The class must use a custom context factory to enable 2.0 rendering.
 *   See ContextFactory class definition below.
 *
 * - The class must use a custom EGLConfigChooser to be able to select
 *   an EGLConfig that supports 2.0. This is done by providing a config
 *   specification to eglChooseConfig() that has the attribute
 *   EGL10.ELG_RENDERABLE_TYPE containing the EGL_OPENGL_ES2_BIT flag
 *   set. See ConfigChooser class definition below.
 *
 * - The class must select the surface's format, then choose an EGLConfig
 *   that matches it exactly (with regards to red/green/blue/alpha channels
 *   bit depths). Failure to do so would result in an EGL_BAD_MATCH error.
 */
class JavaVTKView extends GLSurfaceView
{
    private static String TAG = "JavaVTKView";
    private Renderer myRenderer;

    public JavaVTKView(Context context)
    {
        super(context);
        setFocusable(true);
        setFocusableInTouchMode(true);

        this.getHolder().setFormat(PixelFormat.TRANSLUCENT);
        setEGLContextFactory(new ContextFactory());
        setEGLConfigChooser(new ConfigChooser(8, 8, 8, 0, 8, 0));

        /* Set the renderer responsible for frame rendering */
        this.myRenderer = new Renderer();
        this.setRenderer(myRenderer);
        this.setRenderMode(RENDERMODE_WHEN_DIRTY);
    }

    private static class ContextFactory implements GLSurfaceView.EGLContextFactory
    {
        private static int EGL_CONTEXT_CLIENT_VERSION = 0x3098;
        public EGLContext createContext(EGL10 egl, EGLDisplay display, EGLConfig eglConfig)
        {
            Log.w(TAG, "creating OpenGL ES 2.0 context");
            checkEglError("Before eglCreateContext", egl);
            int[] attrib_list = {EGL_CONTEXT_CLIENT_VERSION, 2, EGL10.EGL_NONE };
            EGLContext context = egl.eglCreateContext(display, eglConfig, EGL10.EGL_NO_CONTEXT, attrib_list);
            checkEglError("After 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(TAG, String.format("%s: EGL error: 0x%x", prompt, error));
            }
    }

    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 static class Renderer implements GLSurfaceView.Renderer
    {
        private long vtkContext;

        public void onDrawFrame(GL10 gl)
        {
            JavaVTKLib.render(vtkContext);
        }

        // forward events to VTK for it to handle
        public void onKeyEvent(boolean down, KeyEvent ke)
        {
            JavaVTKLib.onKeyEvent(vtkContext, down, ke.getKeyCode(),
                ke.getMetaState(),
                ke.getRepeatCount());
        }

        // forward events to VTK for it to handle
        public void onMotionEvent(final MotionEvent me)
        {
            try {
                int numPtrs = me.getPointerCount();
                float [] xPos = new float[numPtrs];
                float [] yPos = new float[numPtrs];
                int [] ids = new int[numPtrs];
                for (int i = 0; i < numPtrs; ++i)
                    {
                        ids[i] = me.getPointerId(i);
                        xPos[i] = me.getX(i);
                        yPos[i] = me.getY(i);
                    }

                int actionIndex = me.getActionIndex();
                int actionMasked = me.getActionMasked();
                int actionId = me.getPointerId(actionIndex);

                if (actionMasked != 2)
                {
                    Log.e(TAG, "Got action " + actionMasked + " on index " + actionIndex + " has id " + actionId);
                }
                JavaVTKLib.onMotionEvent(vtkContext,
                                         actionMasked,
                                         actionId,
                                         numPtrs, xPos, yPos, ids,
                                         me.getMetaState());
            } catch (IllegalArgumentException e) {
                Log.e(TAG, "Bogus motion event");
            }
        }

        public void onSurfaceChanged(GL10 gl, int width, int height)
        {
            vtkContext = JavaVTKLib.init(width, height);
        }

        public void onSurfaceCreated(GL10 gl, EGLConfig config)
        {
            // Do nothing.
        }
    }

    // forward events to rendering thread for it to handle
    public boolean onKeyUp(int keyCode, KeyEvent event)
    {
        final KeyEvent keyEvent = event;
        queueEvent(new Runnable()
            {
            public void run()
                {
                myRenderer.onKeyEvent(false, keyEvent);
                }
            });
        return true;
    }

    // forward events to rendering thread for it to handle
    public boolean onKeyDown(int keyCode, KeyEvent event)
    {
        final KeyEvent keyEvent = event;
        queueEvent(new Runnable()
            {
            public void run()
                {
                myRenderer.onKeyEvent(true, keyEvent);
                }
            });
        return true;
    }

    // forward events to rendering thread for it to handle
    public boolean onTouchEvent(MotionEvent event)
    {
        final MotionEvent motionEvent = event;
        queueEvent(new Runnable()
            {
            public void run()
                {
                myRenderer.onMotionEvent(motionEvent);
                }
            });
        return true;
    }
}
