package net.mrpizzacake.futura.graphics;

import com.sun.org.apache.xalan.internal.xsltc.compiler.CompilerException;
import org.lwjgl.BufferUtils;
import org.lwjgl.opengl.GL20;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.nio.IntBuffer;

import static org.lwjgl.opengl.GL11.*;
import static org.lwjgl.opengl.GL20.*;

public final class Shader
{
	private int id;
	private int vertShader;
	private int fragShader;

	public Shader(File vertSourceFile, File fragSourceFile) throws Exception
	{
		id = glCreateProgram();

		vertShader = glCreateShader(GL_VERTEX_SHADER);
		fragShader = glCreateShader(GL_FRAGMENT_SHADER);

		StringBuilder vertSourceBuilder = new StringBuilder();
		StringBuilder fragSourceBuilder = new StringBuilder();

		String line;

		BufferedReader vertReader = new BufferedReader(new FileReader(vertSourceFile));
		while ((line = vertReader.readLine()) != null)
			vertSourceBuilder.append(line).append('\n');
		vertReader.close();

		BufferedReader fragReader = new BufferedReader(new FileReader(fragSourceFile));
		while ((line = fragReader.readLine()) != null)
			fragSourceBuilder.append(line).append('\n');
		fragReader.close();

		String vertSource = vertSourceBuilder.toString();
		String fragSource = fragSourceBuilder.toString();

		make(vertShader, vertSource);
		make(fragShader, fragSource);
	}

	public Shader(String vertSource, String fragSource)
	{
		id = glCreateProgram();

		vertShader = glCreateShader(GL_VERTEX_SHADER);
		System.out.println(vertShader);
		if (vertShader == 0)
			System.err.println("Shader wasn't created properly");

		fragShader = glCreateShader(GL_FRAGMENT_SHADER);
		System.out.println(fragShader);
		if (fragShader == 0)
			System.err.println("Shader wasn't created properly");

		make(vertShader, vertSource);
		make(fragShader, fragSource);

		glLinkProgram(id);
		if (glGetProgrami(id, GL_LINK_STATUS) == GL_FALSE)
			System.err.println("Shader program wasn't linked properly");

		glValidateProgram(id);
		if (glGetProgrami(id, GL_VALIDATE_STATUS) == GL_FALSE)
			System.err.println("Shader program wasn't validated properly");

		System.out.println(glGetProgramInfoLog(id));
	}

	private void make(int shader, String source)
	{
		glShaderSource(shader, source);
		glCompileShader(shader);
		if (glGetShaderi(shader, GL20.GL_COMPILE_STATUS) == GL_FALSE)
				System.err.println("Shader wasn't compiled properly");

		glAttachShader(id, shader);
		System.out.println(glGetShaderInfoLog(shader));
	}

	public void use()
	{
		glUseProgram(id);
	}
}