#include <fstream>

#include "rendering/Shader.h"
#include "utils/Logger.h"
#include "wrapper/GL.h"

Shader::Shader() : shaders(0), program(0) {
}

Shader::~Shader() {
    for(GL::Shader shader : shaders) {
        GL::deleteShader(shader);
    }
    GL::deleteProgram(program);
}

static bool endsWith(const char* path, int length, const char* ending) {
    int endingLength = strlen(ending);
    if(length < endingLength) {
        return false;
    }
    return strcmp(path + (length - endingLength), ending) == 0;
}

GL::ShaderType Shader::getShaderType(const char* path) const {
    int length = strlen(path);
    if(endsWith(path, length, ".vs")) {
        return GL::VERTEX_SHADER;
    } else if(endsWith(path, length, ".fs")) {
        return GL::FRAGMENT_SHADER;
    } else if(endsWith(path, length, ".gs")) {
        return GL::GEOMETRY_SHADER;
    } else if(endsWith(path, length, ".tcs")) {
        return GL::TESSELATION_CONTROL_SHADER;
    } else if(endsWith(path, length, ".tes")) {
        return GL::TESSELATION_EVALUATION_SHADER;
    }
    return GL::NO_SHADER;
}

Error Shader::readAndCompile(const char* path, GL::Shader& s,
                             GL::ShaderType st) {
    List<char> code;
    Error error = readFile(code, path);
    if(error.has()) {
        return error;
    }
    return compileType(s, code, st);
}

Error Shader::readFile(List<char>& code, const char* path) const {
    std::ifstream in;
    in.open(path);
    if(!in.good()) {
        return {"cannot read file"};
    }
    while(true) {
        int c = in.get();
        if(c == EOF) {
            break;
        }
        code.add(c);
    }
    code.add('\0');
    return {};
}

Error Shader::compileType(GL::Shader& s, const List<char>& code,
                          GL::ShaderType st) {
    s = GL::createShader(st);
    GL::compileShader(s, code.begin());
    Error error = GL::getError("compile error");
    if(error.has()) {
        return error;
    }
    return GL::getCompileError(s);
}

void Shader::use() const {
    GL::useProgram(program);
}

void Shader::setMatrix(const char* name, const float* data) {
    GL::setMatrix(program, name, data);
}

void Shader::setInt(const char* name, int data) {
    GL::setInt(program, name, data);
}

void Shader::setFloat(const char* name, float data) {
    GL::setFloat(program, name, data);
}

void Shader::setVector(const char* name, const Vector2& v) {
    GL::set2Float(program, name, &(v[0]));
}

void Shader::setVector(const char* name, const Vector3& v) {
    GL::set3Float(program, name, &(v[0]));
}

void Shader::setVector(const char* name, const Vector4& v) {
    GL::set4Float(program, name, &(v[0]));
}