#include "Shader.h"

namespace NB{

ShaderError::ShaderError(
    const std::string& msg,
    const char* shad,
    const std::string& file,
    int line
) : std::runtime_error(formatString(msg, shad, file, line)) {}

std::string ShaderError::formatString(
    const std::string& msg,
    const char* shad,
    const std::string& file,
    int line
) {
    std::string ret = "";
    if (file != "") {
        ret += "In file " + file;
        if (line >= 0) {
            ret += " at line " + std::to_string(line);
        }
        ret += ":\n\t";
    }
    ret += msg;
    if (shad != nullptr) {
        ret += " with shader error: " + std::string(shad);
    }
    return ret;
}

Shader::Shader(const char* vertexPath, const char* fragmentPath) {
    std::string vertexCode, fragmentCode;
    std::ifstream vShaderFile, fShaderFile;

    vShaderFile.exceptions(std::ifstream::failbit | std::ifstream::badbit);
    fShaderFile.exceptions(std::ifstream::failbit | std::ifstream::badbit);

    try {
        vShaderFile.open(vertexPath);
        fShaderFile.open(fragmentPath);
        std::stringstream vShaderStream, fShaderStream;
        vShaderStream << vShaderFile.rdbuf();
        fShaderStream << fShaderFile.rdbuf();
        vShaderFile.close();
        fShaderFile.close();
        vertexCode = vShaderStream.str();
        fragmentCode = fShaderStream.str();
    } catch (std::ifstream::failure e) {
        throw ShaderError("Could not read Shader files.");
    }

    const char* vShaderCode = vertexCode.c_str();
    const char* fShaderCode = fragmentCode.c_str();

    unsigned int vertex, fragment; 
    int success;
    char infoLog[512];

    vertex = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertex, 1, &vShaderCode, NULL);
    glCompileShader(vertex);
    glGetShaderiv(vertex, GL_COMPILE_STATUS, &success);
    if(!success) {
        glGetShaderInfoLog(vertex, 512, NULL, infoLog);
        throw ShaderError("Could not compile Vertex shader", infoLog);
    }

    fragment = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragment, 1, &fShaderCode, NULL);
    glCompileShader(fragment);
    glGetShaderiv(fragment, GL_COMPILE_STATUS, &success);
    if(!success) {
        glGetShaderInfoLog(fragment, 512, NULL, infoLog);
        throw ShaderError("Could not compile Fragment shader", infoLog);
    }

    id = glCreateProgram();
    glAttachShader(id, vertex);
    glAttachShader(id, fragment);
    glLinkProgram(id);
    glGetProgramiv(id, GL_LINK_STATUS, &success);
    if (!success) {
        glGetProgramInfoLog(id, 512, NULL, infoLog);
        throw ShaderError("Could not link shader program", infoLog);
    }

    glDeleteShader(vertex);
    glDeleteShader(fragment);
}

Shader::Shader() { id = 0x0; }

Shader::Shader(const Shader& cpy_shader) { id = cpy_shader.id; }

Shader& Shader::operator=(const Shader& cpy_shader) { id = cpy_shader.id; return *this; }

void Shader::use() const{
    glUseProgram(id);
}

void Shader::setBool(const std::string& name, bool value) const {
    glUniform1i(glGetUniformLocation(id, name.c_str()), (int)value);
}

void Shader::setInt(const std::string& name, int value) const {
    glUniform1i(glGetUniformLocation(id, name.c_str()), (int)value);
}

void Shader::setFloat(const std::string& name, float value) const {
    glUniform1f(glGetUniformLocation(id, name.c_str()), (int)value);
}

void Shader::setMat4(const std::string& name, glm::mat4& value) const {
    glUniformMatrix4fv(glGetUniformLocation(id, name.c_str()), 1, GL_FALSE, glm::value_ptr(value));
}

}