/* std */
#include <iostream>
#include <vector>
#include <string>
#include <stdlib.h>
#include <unistd.h>  
#include <cmath>  

/* OpenGL */
#include "glad/glad.h"
#include <GLFW/glfw3.h>

/* Project classes */
#include "Helper.hpp"
#include "Config.hpp"
#include "Cell.hpp"
#include "Particle.hpp"
#include "ComputeShader.hpp"
#include "Application.hpp"
#include "Buffer.hpp"
#include "Canvas.hpp"

constexpr float deg_to_rad = (float) (3.141592653589793 / 180.0);

int main(int argc, char *argv[]){
    srand(0);
    std::string filename;
    Application app;
    Config config;
    ComputeShader cs_particles_update;
    ComputeShader cs_map_update;
    ComputeShader cs_map_reset;
    ComputeShader cs_draw;
    Buffer particles_buffer;
    Buffer map_buffer;
    Canvas canvas;

    config = {
        .map_width=1500,
        .map_height=1200,

        .population=5000000,

        .increase=10.0f,
        .decay=0.5f,
        .diffusion=5.0f,

        .speed=60.0f,
        .steering=180.0f * deg_to_rad,
        .sensing_distance=3.0f,
        .sensing_angle=45.0f * deg_to_rad,
    };
    float average_population = (float)config.population / (float)(config.map_width * config.map_height);
    float average_pheromone = (float)config.increase * average_population;

    printf("Avg pop %08f - Avg phe %08f\n", average_population, average_pheromone);
    
    app = Application(config.map_width, config.map_height);
    app.init();
    app.create_window();

    /* Load and compile particles update shader */
    cs_particles_update.load("./shaders/particles_update.glsl");
    cs_particles_update.compile();

    /* Load and compile map update shader */
    cs_map_update.load("./shaders/map_update.glsl");
    cs_map_update.compile();

    /* Load and compile map reset shader */
    cs_map_reset.load("./shaders/map_reset.glsl");
    cs_map_reset.compile();

    /* Load and compile draw shader */
    cs_draw.load("./shaders/draw.glsl");
    cs_draw.compile();

    /* Particles init */
    std::vector<Particle> particles(config.population);
    for(auto &particle : particles){
        particle.pos_x = random_float(0.0f, config.map_width);
        particle.pos_y = random_float(0.0f, config.map_height);

        float angle = random_float(0, 360) * deg_to_rad;
        particle.dir_x = cosf(angle);
        particle.dir_y = sinf(angle);
    }

    /* Create and fill particles buffer */
    particles_buffer.create();
    particles_buffer.set(particles.data(), particles.size(), sizeof(particles[0]));

    /* Map init */
    std::vector<Cell> map(config.map_width * config.map_height);
    for(auto &cell : map){
        cell = {
            .pheromone = 0,
            .result = 0,
            .population = 0,
        };
    }

    /* Create and fill map buffer */
    map_buffer.create();
    map_buffer.set(map.data(), map.size(), sizeof(map[0]));

    /* Create Canvas */
    canvas = Canvas(config.map_width, config.map_width);
    canvas.create();

    /* Bind buffers to compute shaders */
    particles_buffer.bind_base(cs_particles_update.get_program(), "particles_buffer", 1);
    map_buffer.bind_base(cs_particles_update.get_program(), "map_buffer", 2);
    
    map_buffer.bind_base(cs_map_update.get_program(), "map_buffer", 2);
    
    particles_buffer.bind_base(cs_draw.get_program(), "particles_buffer", 1);
    map_buffer.bind_base(cs_draw.get_program(), "map_buffer", 2);
    
    map_buffer.bind_base(cs_map_reset.get_program(), "map_buffer", 2);

    /* Main loop */
    float pervious_time;
    float current_time = app.time();
    int key_previous_status;
    int key_current_status = GLFW_RELEASE;
    while(app.running()){
        pervious_time = current_time;
        current_time = app.time();

        float dt = current_time - pervious_time;

        /* Update uniforms */
        particle_uniform(config, cs_particles_update);    
        map_update_uniform(config, cs_map_update);    
        map_reset_uniform(config, cs_map_reset);    
        cs_draw.set_uniform("map_width", config.map_width);    
        cs_draw.set_uniform("map_height", config.map_height);    
        cs_draw.set_uniform("display_population_value", average_population);
        cs_draw.set_uniform("display_pheromone_value", average_pheromone);

        /* Update particles */
        cs_particles_update.set_uniform("dt", dt);
        cs_particles_update.execute(config.population, 256);
        ComputeShader::wait();

        /* Update map */
        cs_map_update.set_uniform("dt", dt);
        cs_map_update.execute(config.map_width, config.map_height, 16, 16);
        ComputeShader::wait();
        // Particle bob;
        // particles_buffer.get(&bob, 1, sizeof(bob));
        // size_t i = floor(bob.pos_y) * config.map_width + floor(bob.pos_x);
        // map_buffer.get(map.data(), i+1, sizeof(map[0]));
        // ComputeShader::wait();
        // printf("Bob[%6f,%6f], Map[%ld] = {.pop=%d,.phe=%f}\n", 
        //     bob.pos_x, bob.pos_y, i, map[i].population, map[i].pheromone);


        /* Draw map */
        cs_draw.activate();
        canvas.bind();
        cs_draw.execute(config.map_width, config.map_height, 16, 16);
        ComputeShader::wait();
        canvas.draw();

        /* Reset map */
        cs_map_reset.execute(config.map_width * config.map_height, 256);
        ComputeShader::wait();

        /* Display, move on */
        app.update();

        key_previous_status = key_current_status;
        key_current_status = app.key_status(GLFW_KEY_R);
        if(key_current_status != key_previous_status
           && key_current_status == GLFW_RELEASE){
            printf("Reloading draw Shader\n");
            cs_draw.load("./shaders/draw.glsl");
            cs_draw.compile();
            particles_buffer.bind_base(cs_draw.get_program(), "particles_buffer", 1);
            map_buffer.bind_base(cs_draw.get_program(), "map_buffer", 2);
        }
    }
    
    cs_particles_update.release();
    particles_buffer.release();


    return 0;
}