#ifndef GAMEENGINE_H
#define GAMEENGINE_H

#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include <iostream>
#include <string>
#include <fstream>
#include <cstring>
#include "../math/Matrix3D.h"
#include "Camera.h"
#include "Texture.h"

using namespace std;

static const uint64_t NANOS_PER_TICK = 50000000;
static const int MAX_TICKS_PER_FRAME = 5;

typedef void (*InitFunction) ();
typedef void (*TickFunction) ();
typedef void (*RenderTickFunction) (float);

class DirectRenderer;

class GameEngine
{
public:
    static void start(int width, int height, const char* name, InitFunction init, TickFunction tick, RenderTickFunction renderTick);
    static Camera& getCamera();
    static DirectRenderer& getDirectRenderer();

    static void setTextureEnabled(bool use);
    static void setColorEnabled(bool use);
    static void setMixColorEnabled(bool use);
    static void setMixColor(float r, float g, float b, float a);

    static void printError();
    static void stop();

    friend Camera;
    friend Texture;
    friend DirectRenderer;
private:
    GameEngine();

    static void onKeyEvent(GLFWwindow* w, int key, int scancode, int action, int mods);
    static void onMouseClick(GLFWwindow* w, int button, int action, int mods);
    static void onWindowResize(GLFWwindow* w, int width, int height);

    static GLchar* readFile(const char* name);
    static bool checkShaderErrors(const char* name, GLuint shader);
    static GLuint compileProgram(const GLchar* vertex, const GLchar* fragment);
    static GLuint createProgram();

    static void updateProjection();
    static void updateView(Matrix3D& m);

    static void onInit();
    static void onTick();
    static void onTerm();

    static void updateScale();

    static InitFunction init;
    static TickFunction tick;
    static RenderTickFunction renderTick;

    static GLuint vShader;
    static GLuint fShader;

    static GLFWwindow* window;
    static GLuint program;

    static int scale;
    static int width;
    static int height;
    static float fovY;
    static float nearClip;
    static float farClip;
    static Matrix3D proj;

    static Camera camera;

    static DirectRenderer directRenderer;

    // uniforms
    static GLint unifProjMatrix;
    static GLint unifViewMatrix;
    static GLint unifUseTexture;
    static GLint unifUseColor;
    static GLint unifUseMixColor;
    static GLint unifMixColorLoc;
};

class DirectRenderer
{
public:
    DirectRenderer();
    DirectRenderer(const DirectRenderer& orig);
    virtual ~DirectRenderer();

    void prepare();
    void drawRectangle(float minX, float minY, float maxX, float maxY,
            float tMinX, float tMinY, float tMaxX, float tMaxY,
            float r, float g, float b, float a);
    void drawColoredRectangle(float minX, float minY, float maxX, float maxY,
            float r, float g, float b, float a);
    void drawTexturedRectangle(float minX, float minY, float maxX, float maxY,
            float tMinX, float tMinY, float tMaxX, float tMaxY);

    friend GameEngine;
private:
    void init();

    static const int OBJECT_LENGTH = 144;
    static const int BUFFER_LENGTH = 256 * 1024 * OBJECT_LENGTH;

    GLuint vba = 0;
    GLuint vbo = 0;

    unsigned int offset = BUFFER_LENGTH - OBJECT_LENGTH;

    Matrix3D view;
    Matrix3D proj;
};

#endif