#include "ShaderProgram.h"

#include <string>

#include "OpenGL.h"

ShaderProgram::ShaderProgram() {
	program = glCreateProgram();
}

void ShaderProgram::attachShader(const char* fileName, uint type) {
	std::fstream file(fileName);
	std::string fileContents = "";

    //Loading file into string
	if (file.is_open()) {
		std::string line;
		while (std::getline(file, line)) {
			fileContents += line + '\n';
		}
		file.close();
	} else {
		PRINT_ERROR << "Could not load " << fileName << "!\n";
		return;
	}

	const GLchar* text = fileContents.c_str();
	GLint length       = fileContents.length();

	GLuint shader = glCreateShader(type);
	glShaderSource(shader, 1, &text, &length);
	glCompileShader(shader);

	GLint isCompiled = 0;
	glGetShaderiv(shader, GL_COMPILE_STATUS, &isCompiled);
	if(isCompiled == GL_FALSE) {
		GLint maxLength = 0;
		glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &maxLength);

		char* errorLog = new char[maxLength];
		glGetShaderInfoLog(shader, maxLength, &maxLength, &errorLog[0]);
		PRINT_ERROR << "Shader failed to compile with message:\n" << errorLog << '\n';
		delete errorLog;

		glDeleteShader(shader);
		return;
	}

	glAttachShader(program, shader);

	glBindAttribLocation(program, 0, "position");

	glLinkProgram(program);

	GLint isLinked = 0;
	glGetProgramiv(program, GL_LINK_STATUS, (int *)&isLinked);
	if(isLinked == GL_FALSE) {
		GLint maxLength = 0;
		glGetProgramiv(program, GL_INFO_LOG_LENGTH, &maxLength);

		char* infoLog = new char[maxLength];
		glGetProgramInfoLog(program, maxLength, &maxLength, &infoLog[0]);
		PRINT_ERROR << "Program failed to link with message:\n" << infoLog << '\n';
		delete infoLog;

		glDeleteShader(shader);
		return;
	}

	shaders.push_back(shader);
}

void ShaderProgram::use() const {
	glUseProgram(program);
}

int ShaderProgram::getLocation(const char* name) {
	const auto loc = uniforms.find(name);
	int location;
	if (loc == uniforms.end()) {
		location = glGetUniformLocation(program, name);
		uniforms[name] = location;
	} else
		location = loc->second;
	return location;
}

void ShaderProgram::setUniform(const char* name, int value) {
	glUniform1i(getLocation(name), value);
}
void ShaderProgram::setUniform(const char* name, float value) {
	glUniform1f(getLocation(name), value);
}
void ShaderProgram::setUniform(const char* name, const glm::vec2& value) {
	glUniform2f(getLocation(name), value.x, value.y);
}
void ShaderProgram::setUniform(const char* name, const glm::vec3& value) {
	glUniform3f(getLocation(name), value.x, value.y, value.z);
}
void ShaderProgram::setUniform(const char* name, const glm::vec4& value) {
	glUniform4f(getLocation(name), value.x, value.y, value.z, value.w);
}

void ShaderProgram::setUniform(const char* name, const glm::mat2& value) {
	glUniformMatrix2fv(getLocation(name), 1, GL_FALSE, &value[0][0]);
}
void ShaderProgram::setUniform(const char* name, const glm::mat3& value) {
	glUniformMatrix3fv(getLocation(name), 1, GL_FALSE, &value[0][0]);
}
void ShaderProgram::setUniform(const char* name, const glm::mat4& value) {
	glUniformMatrix4fv(getLocation(name), 1, GL_FALSE, &value[0][0]);
}

ShaderProgram::~ShaderProgram() {
	for (uint shader : shaders)
		glDeleteShader(shader);
	glDeleteProgram(program);
}