#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>

#ifdef PLATFORM_WEB
  #include RAYLIB_SRC
#else
  #include <raylib.h>
#endif

typedef uint32_t u32;

#define MOONS_CAP 4
#define PLANETS_CAP 10

int SW = 1200;
int SH = 800;

#define OFF_Y (7*SH/9)

int sector_len = 16;
u32 seed = 0;

typedef struct {
    int diameter;
    u32 color;
    bool ring;
    int moons[MOONS_CAP];
} planet_t;

typedef struct {
    int diameter;
    u32 color;
} star_t;

star_t star_gen();
void planets_gen(planet_t *planets);

uint32_t lehmer();
int rnd_int(int max, int min);

#define HEX_TO_COL(col) {((col) >> 16) & 0xFF,  \
                         ((col) >> 8)  & 0xFF,  \
                         (col) & 0xFF, 0xFF}

int main(void)
{
    InitWindow(SW, SH, "Procedural Generation");
    SetTargetFPS(30);
    SetWindowState(FLAG_WINDOW_RESIZABLE);

    int offset_x = 0;
    int offset_y = 0;

    while (!WindowShouldClose())
    {
        SW = GetScreenWidth();
        SH = GetScreenHeight();

        int sectors_x = SW/sector_len;
        int sectors_y = SH/sector_len;

        sector_len += (int)GetMouseWheelMove();
        if(sector_len <= 0) sector_len = 1;

        if(IsKeyDown(KEY_W)) offset_y -= 1;
        if(IsKeyDown(KEY_A)) offset_x -= 1;
        if(IsKeyDown(KEY_S)) offset_y += 1;
        if(IsKeyDown(KEY_D)) offset_x += 1;

        static bool extra_info = false;
        star_t info_star; planet_t info_planets[PLANETS_CAP];
        if(IsMouseButtonPressed(MOUSE_BUTTON_LEFT)) extra_info = false;

        BeginDrawing();
            ClearBackground(BLACK);

            // gen each sector
            for(int i = 0; i < sectors_x; i++)
                for(int j = 0; j < sectors_y; j++) {
                    seed = ((i+offset_x) & 0xFFFF) << 16 | ((j+offset_y) & 0xFFFF);
                    if(rnd_int(25, 0) != 0) continue;

                    star_t star = star_gen();

                    int x = i * sector_len + (sector_len/2);
                    int y = j * sector_len + (sector_len/2);
                    float diam = (float)star.diameter*sector_len/96;

                    DrawCircle(x, y, diam, (Color)HEX_TO_COL(star.color));

                    // hover over star
                    if(GetMouseX()/sector_len == i && GetMouseY()/sector_len == j) {
                        DrawCircleLines(x, y, diam + 4, (Color)HEX_TO_COL(star.color));

                        // click on star
                        if(IsMouseButtonPressed(MOUSE_BUTTON_LEFT)) {
                            extra_info = true;
                            info_star = star;
                            planets_gen(info_planets);
                        }
                    }
                }

            // extra info rec
            if(extra_info) {
                DrawRectangle(0, 2*SH/3, SW, SH/3, BLUE);

                // draw star
                int body_offset = 50 + info_star.diameter;
                DrawCircle(body_offset, OFF_Y, info_star.diameter,
                           (Color)HEX_TO_COL(info_star.color));
                body_offset += 90 + info_star.diameter;

                // draw planets
                for(int i = 0; i < PLANETS_CAP; i++) {
                    if(info_planets[i].diameter == 0) continue;

                    body_offset += info_planets[i].diameter;
                    DrawCircle(body_offset, OFF_Y, info_planets[i].diameter,
                               (Color)HEX_TO_COL(info_planets[i].color));

                    if(info_planets[i].ring) {
                        DrawCircleLines(body_offset, OFF_Y,
                                        info_planets[i].diameter + 6,
                                        (Color)HEX_TO_COL(info_planets[i].color));
                        DrawCircleLines(body_offset, OFF_Y,
                                        info_planets[i].diameter + 7,
                                        (Color)HEX_TO_COL(info_planets[i].color));
                    }

                    // draw moons
                    int y_off = info_planets[i].diameter + 10;
                    for(int j = 0; j < MOONS_CAP; j++) {
                        if(info_planets[i].moons[j] == 0) continue;

                        y_off += info_planets[i].moons[j];
                        DrawCircle(body_offset, OFF_Y + y_off,
                                   info_planets[i].moons[j], GRAY);
                        y_off += 10 + info_planets[i].moons[j];
                    }

                    body_offset += 50 + info_planets[i].diameter;
                }
            }

            DrawFPS(10, 10);
        EndDrawing();
    }
    CloseWindow();
}

star_t star_gen()
{
    star_t star;
    star.diameter = rnd_int(80, 20);
    star.color = rnd_int(0xFFFFFF, 0);
    return star;
}

void planets_gen(planet_t *planets)
{
    int n = rnd_int(PLANETS_CAP, 0);
    for(int i = 0; i < PLANETS_CAP; i++) {
        if(i >= n) {
            planets[i].diameter = 0;
            continue;
        }

        planets[i].diameter = rnd_int(40, 10);
        planets[i].color = rnd_int(0xFFFFFF, 0);
        planets[i].ring = (rnd_int(5, 0) == 1);

        for(int j = 0; j < MOONS_CAP; j++)
            planets[i].moons[j] = rnd_int(15, 0);
    }
}

uint32_t lehmer()
{
    seed += 0xe120fc15;
    uint64_t tmp;
    tmp = (uint64_t)seed * 0x4a39b70d;
    uint32_t m1 = (tmp >> 32) ^ tmp;
    tmp = (uint64_t)m1 * 0x12fad5c9;
    uint32_t m2 = (tmp >> 32) ^ tmp;
    return m2;
}

int rnd_int(int max, int min)
{
    return (lehmer() % (max - min)) + min;
}