package org.retroarch.browser;

import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;

import android.app.Activity;
import android.content.SharedPreferences;
import android.opengl.GLES20;
import android.opengl.GLSurfaceView;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.util.Log;
import android.view.WindowManager;
import android.widget.Toast;

public class DisplayRefreshRateTest extends Activity {

	private class Renderer implements GLSurfaceView.Renderer {
		private static final String TAG = "GLESRenderer";
		private static final double WARMUP_SECONDS = 2.0;
		private static final double TEST_SECONDS = 10.0;
		// Test states
		private static final int STATE_START = 0;
		private static final int STATE_WARMUP = 1;
		private static final int STATE_TEST = 2;
		private static final int STATE_DONE = 3;
		private static final int STATE_DEAD = 4;
		private int mState = STATE_START;
		private double mStartTime = 0.0;
		private int mNumFrames = 0;
		
		private Activity activity;
		
		public Renderer(Activity activity) {
			this.activity = activity;
		}
		
		private void setFPSSetting(double fps) {
			SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getBaseContext());
			SharedPreferences.Editor edit = prefs.edit();
			edit.putString("video_refresh_rate", Double.valueOf(fps).toString());
			edit.commit();
		}

		@Override
		public void onDrawFrame(GL10 gl) {
			double t = System.nanoTime() * 1.0e-9;
			switch (mState) {
			case STATE_START:
				mStartTime = t;
				mState = STATE_WARMUP;
				break;

			case STATE_WARMUP:
				if ((t - mStartTime) >= WARMUP_SECONDS) {
					mStartTime = t;
					mNumFrames = 0;
					mState = STATE_TEST;
				}
				break;

			case STATE_TEST:
				mNumFrames++;
				double elapsed = t - mStartTime;
				if (elapsed >= TEST_SECONDS) {
					double fps = (double)mNumFrames / elapsed;
					Log.i(TAG, "Measured FPS to: " + fps);
					setFPSSetting(fps);
					mState = STATE_DONE;
				}
				break;

			case STATE_DONE:
				activity.runOnUiThread(new Runnable() {
					public void run() {
						finish();
					}
				});
				mState = STATE_DEAD;
				break;
				
			case STATE_DEAD:
				break;
			}

			float luma = (float)Math.sin((double)mNumFrames * 0.10);
			luma *= 0.2f;
			luma += 0.5f;
			GLES20.glClearColor(luma, luma, luma, 1.0f);
			GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
		}

		@Override
		public void onSurfaceChanged(GL10 gl, int width, int height) {
			// TODO Auto-generated method stub
		}

		@Override
		public void onSurfaceCreated(GL10 gl, EGLConfig config) {
			// TODO Auto-generated method stub
		}
	}

	private GLSurfaceView surfaceView;
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		Toast.makeText(this, "Touch the screen with your fingers for more accurate measurements.", Toast.LENGTH_LONG).show();
		surfaceView = new GLSurfaceView(this);
		surfaceView.setEGLContextClientVersion(2);
		surfaceView.setRenderer(new Renderer(this));
		getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
		setTitle("Refresh rate calibration");
		setContentView(surfaceView);
	}
	
	@Override
	protected void onDestroy() {
		SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getBaseContext());
		String fps = prefs.getString("video_refresh_rate", "ERROR");
		Toast.makeText(this, "Refresh rate measured to: " + fps + " Hz.", Toast.LENGTH_LONG).show();
		super.onDestroy();
	}
}