GRAVITY :: Vector2.{0, 3000};
RECT_SIZE :: 10;
SPAWN_UPS :: 1.0 / 60;

particle :: struct {
    pos : Vector2;
    vel : Vector2;
}

main :: () {
    InitWindow(800, 600, "Droplets");
    defer CloseWindow();
    SetTargetFPS(240);
    high_fps := true;

    particles: [..]particle;

    mouse_drag := new_ring();
    defer array_free(mouse_drag.data);

    spawn_d := SPAWN_UPS;

    while !WindowShouldClose() {
        dt := GetFrameTime();
        width := GetScreenWidth();
        height := GetScreenHeight();

        if IsMouseButtonPressed(.MOUSE_BUTTON_MIDDLE) {
            if !high_fps SetTargetFPS(240);
            if high_fps SetTargetFPS(60);
            high_fps = !high_fps;
        }
        if IsMouseButtonDown(.MOUSE_BUTTON_RIGHT) {
            spawn_d -= dt;
            if spawn_d < 0 {
                pos := GetMousePosition();
                array_add(*particles, .{pos, .{0, 0}});
                spawn_d = SPAWN_UPS;
            }
        }
        if IsMouseButtonReleased(.MOUSE_BUTTON_RIGHT) {
            spawn_d = SPAWN_UPS;
        }
        if IsMouseButtonDown(.MOUSE_BUTTON_LEFT) {
            del := GetMouseDelta() / dt;
            ring_add(*mouse_drag, del);
        }
        if IsMouseButtonReleased(.MOUSE_BUTTON_LEFT) {
            pos := GetMousePosition();

            {
                max_x := cast(float) GetScreenWidth();
                max_y := cast(float) GetScreenHeight();
                using pos;
                if x > max_x x = max_x;
                if x < 0 x = 0;
                if y > max_y y = max_y;
                if y < 0 y = 0;
            }

            vel := ring_avg(*mouse_drag);
            ring_reset(*mouse_drag);
            
            array_add(*particles, .{pos, vel});
        }

        for *p : particles {
            using p;

            if pos.y + RECT_SIZE < xx height 
                vel += GRAVITY * dt;

            pos += vel * dt;

            if pos.x <= 0 {
                vel.x = -(vel.x * 0.5);
                pos.x = 0;
            }

            if pos.x + RECT_SIZE >= xx width {
                vel.x = -(vel.x * 0.5);
                pos.x = xx (width - RECT_SIZE);
            }

            if pos.y <= 0 {
                vel.y = -(vel.y * 0.5);
                vel.x *= 0.75;
                pos.y = 0;
            }

            if pos.y + RECT_SIZE > xx height {
                vel.y = -(vel.y * 0.5);
                vel.x *= 0.75;
                if abs(vel.y) < abs((GRAVITY * dt).y)
                    vel = .{0, 0};
                pos.y = xx (height - RECT_SIZE);
            }
        }

        BeginDrawing();
        ClearBackground(RAYWHITE);
        for p : particles {
            DrawRectangleV(p.pos, .{RECT_SIZE, RECT_SIZE}, SKYBLUE);
        }
        EndDrawing();
    }
}

#import "raylib";
#import "Basic";