#include <ctime>

#include <cstdlib>

#include <string>

#include <iostream>

#include <GL/gl.h>

#include <SDL2/SDL.h>

#include "geometry.h"

#include "scene.h"

class Main {

public:

    bool sdl_initialized;

    SDL_Window *mainWindow;

    SDL_GLContext mainContext;

    Scene *scene;

    Main():

        sdl_initialized(),

        mainWindow(),

        mainContext(),

        scene()

    { }

    ~Main() { deinit(); }

    bool init() {

        srand(time(NULL));

        if (SDL_Init(SDL_INIT_VIDEO) < 0) {

            std::cerr << "SDL_Init failed" << std::endl;

            deinit();

            return false;

        }

        sdl_initialized = true;

        mainWindow = SDL_CreateWindow(

            "simu",

            SDL_WINDOWPOS_CENTERED,

            SDL_WINDOWPOS_CENTERED,

            512,

            512,

            SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE );

        if (!mainWindow)

        {

            std::cerr << "cannot create window" << std::endl;

            std::cerr << SDL_GetError() << std::endl;

            SDL_ClearError();

            deinit();

            return false;

        }

        mainContext = SDL_GL_CreateContext(mainWindow);

        SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);

        SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);

        SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2);

        SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);

        // vsync

        SDL_GL_SetSwapInterval(1);

        scene = new Scene();

        glClearColor(0.0, 0.0, 0.0, 0.0);

        glEnable(GL_LINE_SMOOTH);

        glEnable(GL_POINT_SMOOTH);

        glHint(GL_LINE_SMOOTH_HINT, GL_NICEST);

        glHint(GL_POINT_SMOOTH_HINT, GL_NICEST);

        glEnable(GL_NORMALIZE);

        glDisable(GL_DEPTH_TEST);

        glEnable(GL_LIGHT0);

        float light0[] = {1, 1, 1, 0};

        glLightfv(GL_LIGHT0, GL_POSITION, light0);

        glEnable(GL_LIGHT1);

        float light1[] = {-1, -1, -1, 0};

        float color[] = {0.5, 0.5, 0.5, 1};

        glLightfv(GL_LIGHT1, GL_POSITION, light1);

        glLightfv(GL_LIGHT1, GL_DIFFUSE, color);

        //glLightfv(GL_LIGHT1, GL_SPECULAR, color);

        glEnable(GL_COLOR_MATERIAL);

        resize(512, 512);

        return true;

    }

    void deinit() {

        if (scene) { delete scene; scene = 0; }

        if (mainContext) { SDL_GL_DeleteContext(mainContext); mainContext = 0; }

        if (mainWindow) { SDL_DestroyWindow(mainWindow); mainWindow = 0; }

        if (sdl_initialized) { SDL_Quit(); sdl_initialized = false; }

    }

    void resize(int width, int height) {

        glViewport(0, 0, width, height);

        glMatrixMode(GL_PROJECTION);

        glLoadMatrixd( Matrix4::perspective(90.0, (Real)width/height, 0.1, 100).a );

        glMatrixMode(GL_MODELVIEW);

    }

    void loop() {

        bool quit = false;

        Uint32 prev_time = SDL_GetTicks();

        while(!quit) {

            SDL_Event event;

            while (SDL_PollEvent(&event)) {

                if (event.type == SDL_QUIT)

                    quit = true;

                if (event.type == SDL_WINDOWEVENT) {

                    if (event.window.event == SDL_WINDOWEVENT_RESIZED) {

                        resize(event.window.data1, event.window.data2);

                    }

                }

                if (event.type == SDL_KEYDOWN) {

                    switch (event.key.keysym.sym) {

                    case SDLK_ESCAPE:

                        quit = true;

                        break;

                    case SDLK_w:

                        scene->wireframe = !scene->wireframe;

                        break;

                    case SDLK_r:

                        scene->generate();

                        break;

                    default:

                        break;

                    }

                }

                if (event.type == SDL_MOUSEMOTION) {

                    if (event.motion.state & SDL_BUTTON_LMASK) {

                        scene->angles.z += event.motion.xrel;

                        scene->angles.x += event.motion.yrel;

                    }

                    if (event.motion.state & SDL_BUTTON_RMASK) {

                        scene->offset.z *= pow(2, event.motion.yrel/100.0);

                    }

                    if (event.motion.state & SDL_BUTTON_MMASK) {

                        scene->offset.x += 0.1*event.motion.xrel;

                        scene->offset.y -= 0.1*event.motion.yrel;

                    }

                }

            }

            Uint32 curr_time = SDL_GetTicks();

            double dt = (curr_time - prev_time)/1000.0;

            prev_time = curr_time;

            scene->update(dt);

            glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

            scene->draw();

            SDL_GL_SwapWindow(mainWindow);

        }

    }

};

int main(int argc, char **argv)

{

    Main app;

    if (!app.init()) return -1;

    app.loop();

    return 0;

}