#include "OpenGLShaderProgram.h"

#include <QOpenGLShaderProgram>
#include <QDir>
#include "OpenGLFunctions.h"
#include "OpenGLRenderer.h"
#include "OpenGLSharedState.h"
#include "Texture2D.h"
#include "Texture3D.h"
#include "Texture4D.h"
#include "Color.h"
#include "Logs.h"

OpenGLShaderProgram::OpenGLShaderProgram(const std::string &name, OpenGLRenderer *renderer)
    : renderer(renderer), name(name) {
    program = new QOpenGLShaderProgram();
    functions = renderer->getOpenGlFunctions();
    compiled = false;
}

OpenGLShaderProgram::~OpenGLShaderProgram() {
    delete program;
}

void OpenGLShaderProgram::addVertexSource(QString path) {
    QFile file(QString(":/shaders/%1.vert").arg(path));
    if (file.open(QIODevice::ReadOnly | QIODevice::Text)) {
        source_vertex += QString(file.readAll()).toStdString();
    } else {
        Logs::error() << "[OpenGL] Can't open vertex file " << file.fileName().toStdString() << std::endl;
    }
}

void OpenGLShaderProgram::addFragmentSource(QString path) {
    QFile file(QString(":/shaders/%1.frag").arg(path));
    if (file.open(QIODevice::ReadOnly | QIODevice::Text)) {
        source_fragment += QString(file.readAll()).toStdString();
    } else {
        Logs::error() << "[OpenGL] Can't open fragment file " << file.fileName().toStdString() << std::endl;
    }
}

void OpenGLShaderProgram::compile() {
    program->addShaderFromSourceCode(QOpenGLShader::Vertex, QString::fromStdString(source_vertex));
    program->addShaderFromSourceCode(QOpenGLShader::Fragment, QString::fromStdString(source_fragment));

    if (not program->link()) {
        Logs::warning() << "[OpenGL] Error while compiling shader " << name << std::endl
                        << program->log().toStdString() << std::endl;
    } else if (program->log().length() > 0) {
        Logs::debug() << "[OpenGL] Shader " << name << " compilation output:" << std::endl
                      << program->log().toStdString() << std::endl;
    } else {
        Logs::debug() << "[OpenGL] Shader " << name << " compiled" << std::endl;
    }
}

bool OpenGLShaderProgram::bind() {
    if (not compiled) {
        compile();
        compiled = true;
    }

    if (program->bind()) {
        int texture_unit = 0;
        renderer->getSharedState()->apply(this, texture_unit);
        return true;
    } else {
        return false;
    }
}

void OpenGLShaderProgram::release() {
    program->release();
}

void OpenGLShaderProgram::drawTriangles(float *vertices, int triangle_count) {
    if (bind()) {
        GLuint vertex = program->attributeLocation("vertex");
        program->setAttributeArray(vertex, GL_FLOAT, vertices, 3);
        program->enableAttributeArray(vertex);

        functions->glDrawArrays(GL_TRIANGLES, 0, triangle_count * 3);

        program->disableAttributeArray(vertex);

        release();
    }
}

void OpenGLShaderProgram::drawTriangleStrip(float *vertices, int vertex_count) {
    if (bind()) {
        GLuint vertex = program->attributeLocation("vertex");
        program->setAttributeArray(vertex, GL_FLOAT, vertices, 3);
        program->enableAttributeArray(vertex);

        functions->glDrawArrays(GL_TRIANGLE_STRIP, 0, vertex_count);

        program->disableAttributeArray(vertex);

        release();
    }
}