#include "Shader.h"

#include "Exception.h"

namespace charcoal
{
	Shader::Shader(const std::string& source, ShaderType type)
	{
		GLenum gl_shader_type;
		switch (type)
		{
		case VERTEX_SHADER:
			gl_shader_type = GL_VERTEX_SHADER;
			break;
		case FRAGMENT_SHADER:
			gl_shader_type = GL_FRAGMENT_SHADER;
			break;
		default:
			throw "Invalid Shader Type Specified";
		}

		m_shader = glCreateShader(gl_shader_type);

		const char* c_str = source.c_str();

		glShaderSource(m_shader, 1, &c_str, NULL);
		glCompileShader(m_shader);

		// Make sure that the shader has been compiled successfully
		GLint compiled;
		glGetShaderiv(m_shader, GL_COMPILE_STATUS, &compiled);
		if (compiled != GL_TRUE)
		{
			GLsizei log_length = 0;
			GLchar message[1024];
			glGetShaderInfoLog(m_shader, 1023, &log_length, message);
			message[log_length] = '\0'; // Add null terminator
			OutputDebugString("Error Compiling Shader:\n");
			OutputDebugString(message);
			OutputDebugString("\nSource:\n");
			OutputDebugString(source.c_str());
			OutputDebugString("\n");
			m_shader = 0;
			throw EXCEPTION("Error compiling shader.");
		}
	}

	Shader::~Shader() {}

	GLuint Shader::get_shader() const
	{
		return m_shader;
	}
}