#include "Shader.hpp"

#include <fstream>
#include <iostream>
#include <sstream>


Shader::Shader(std::string const& vertexPath, std::string const& fragmentPath)
{
	std::string fragmentFileContents;
	std::string vertexFileContents;

	// Read in the vertex shader
	std::ifstream vertex_file;

	vertex_file.open(vertexPath);
	std::stringstream vertex_file_stream;
	vertex_file_stream << vertex_file.rdbuf();
	vertex_file.close();
	vertexFileContents = vertex_file_stream.str();

	// Read in the fragment shader
	std::ifstream fragment_file;

	fragment_file.open(fragmentPath);
	std::stringstream fragment_file_stream;
	fragment_file_stream << fragment_file.rdbuf();
	fragment_file.close();
	fragmentFileContents = fragment_file_stream.str();

	GLuint vertex_shader = glCreateShader(GL_VERTEX_SHADER);

	const GLchar* vertex_shader_source = vertexFileContents.c_str();
	glShaderSource(vertex_shader, 1, &vertex_shader_source, nullptr);
	glCompileShader(vertex_shader);

	int success;
	char infoLog[512];
	glGetShaderiv(vertex_shader, GL_COMPILE_STATUS, &success);

	if (!success)
	{
		glGetShaderInfoLog(vertex_shader, 512, nullptr, infoLog);
		std::cerr << "Error compiling vertex shader: " << infoLog << "\n";
	}


	GLuint fragment_shader = glCreateShader(GL_FRAGMENT_SHADER);

	const GLchar* fragment_shader_source = fragmentFileContents.c_str();
	glShaderSource(fragment_shader, 1, &fragment_shader_source, nullptr);
	glCompileShader(fragment_shader);
	glGetShaderiv(fragment_shader, GL_COMPILE_STATUS, &success);

	if (!success)
	{
		glGetShaderInfoLog(fragment_shader, 512, nullptr, infoLog);
		std::cerr << "Error compiling fragment shader: " << infoLog << "\n";
	}


	mId = glCreateProgram();

	glAttachShader(mId, vertex_shader);
	glAttachShader(mId, fragment_shader);
	glLinkProgram(mId);
	glGetProgramiv(mId, GL_LINK_STATUS, &success);

	if (!success)
	{
		glGetProgramInfoLog(mId, 512, nullptr, infoLog);
		std::cerr << "Error linking shaders: " << infoLog << "\n";
	}

	glDeleteShader(vertex_shader);
	glDeleteShader(fragment_shader);
}

void Shader::Activate()
{
	glUseProgram(mId);
}