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

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

// game coords to screen coords
#define GTOS(n) ((n) * (SH) / 2)
#define GTOSV(n) ((Vector2){(GTOS(n.x)), (GTOS(n.y))})
// screen coords to game coords
#define STOG(n) ((n) / (SH) * 2)
#define STOGV(n) ((Vector2){(STOG(n.x)), (STOG(n.y))})

#define IN_RANGE(x, y, z) (((x) > ((y) - (z))) && ((x) < ((y) + (z))))
#define IN_RANGEV(a, b, c) ((IN_RANGE(a.x, b.x, c)) && (IN_RANGE(a.y, b.y, c)))

int SW = 1200;
int SH =  800;
int MAX_ITER = 50;

Vector2 a = {-1, 0};
Vector2 b = { 1, 0};

char text[1024];

Vector2 median(Vector2 p1, Vector2 p2)
{
    return (Vector2){(p1.x + p2.x)/2, (p1.y + p2.y)/2};
}

void calc_points(Vector2 p1, Vector2 p2, Vector2 q)
{
    static int iter = 0;
    if(iter++ >= MAX_ITER) {
        sprintf(text, "iter: %d; x: %f; y: %f", iter-1, p1.x, -p1.y);
        iter = 0;
        return;
    }

    DrawLineV(GTOSV(p1), GTOSV(p2), (iter % 2 == 0) ? RED : BLUE);

    calc_points(q, median(p1, p2), p2);
}

int main(void)
{
    InitWindow(SW, SH, "circle thingy");
    SetTargetFPS(60);
    SetWindowState(FLAG_WINDOW_RESIZABLE);

    printf("\n----------------------- Instructions -----------------------\n");
    printf("Use WASD to move around\n");
    printf("Use Q and E increase or decrease the iterations\n");
    printf("Use the mouse to move the points and to zoom in or out\n");
    printf("------------------------------------------------------------\n");

    Camera2D camera = {0};
    camera.zoom = 1.0f;

    while (!WindowShouldClose())
    {
        // for resizing
        SW = GetScreenWidth();
        SH = GetScreenHeight();
        camera.offset = (Vector2){SW/2.0f, SH/2.0f};

        if(IsKeyDown(KEY_W)) camera.target.y -= 500.0f * GetFrameTime();
        if(IsKeyDown(KEY_A)) camera.target.x -= 500.0f * GetFrameTime();
        if(IsKeyDown(KEY_S)) camera.target.y += 500.0f * GetFrameTime();
        if(IsKeyDown(KEY_D)) camera.target.x += 500.0f * GetFrameTime();
        if(IsKeyPressed(KEY_Q)) MAX_ITER++;
        if(IsKeyPressed(KEY_E)) MAX_ITER--;
        camera.zoom += ((float)GetMouseWheelMove()*0.05f);

        static bool a_moving = false;
        static bool b_moving = false;

        BeginDrawing();
        ClearBackground(RAYWHITE);

        BeginMode2D(camera);
            DrawCircleLines(0, 0, GTOS(1), BLACK);
            DrawLine(GTOS(0), GTOS(1), GTOS(0), GTOS(-1), BLACK);
            DrawLine(GTOS(1), GTOS(0), GTOS(-1), GTOS(0), BLACK);

            DrawCircleV(GTOSV(a), 10, BLUE);
            DrawCircleV(GTOSV(b), 10, RED);

            // moving the point a
            if(IN_RANGEV(GetScreenToWorld2D(GetMousePosition(), camera), GTOSV(a), 10)
               || a_moving) {
                DrawCircleLines(GTOS(a.x), GTOS(a.y), 13, BLUE);

                if(IsMouseButtonDown(MOUSE_BUTTON_LEFT) && !b_moving) {
                    a = STOGV(GetScreenToWorld2D(GetMousePosition(), camera));
                    a_moving = true;
                } else a_moving = false;
            }

            // moving the point b
            if(IN_RANGEV(GetScreenToWorld2D(GetMousePosition(), camera), GTOSV(b), 10)
               || b_moving) {
                DrawCircleLines(GTOS(b.x), GTOS(b.y), 13, RED);

                if(IsMouseButtonDown(MOUSE_BUTTON_LEFT) && !a_moving) {
                    b = STOGV(GetScreenToWorld2D(GetMousePosition(), camera));
                    b_moving = true;
                } else b_moving = false;
            }

            calc_points((Vector2){0, -1}, a, b);
        EndMode2D();

        DrawFPS(10, 10);
        DrawText(text, 100, 10, 30, DARKGREEN);
        EndDrawing();
    }

    CloseWindow();
    return 0;
}