#include <stdio.h>

#include "raylib.h"
#include "raymath.h"

#define ROPE_LEN 20
#define ROPE_WIDTH 10

#define NB_ROPE 50
Vector2 ropes[NB_ROPE];
Vector2 forces[NB_ROPE];

int main()
{
    InitWindow(1920, 1080, "speedrun");
    SetWindowState(FLAG_FULLSCREEN_MODE|FLAG_WINDOW_RESIZABLE);
    SetTargetFPS(60);

    while (!WindowShouldClose()) {
        BeginDrawing();
        {
            ClearBackground(GRAY);

            ropes[0] = GetMousePosition();
            DrawCircleV(ropes[0], 5, YELLOW);

            for (int i = 1; i < NB_ROPE; i++) {
                Vector2 old = ropes[i];

                if (!IsKeyDown(KEY_SPACE))
                    forces[i].y += 9.8*69*GetFrameTime();

                ropes[i] = Vector2Add(ropes[i], forces[i]);

                float dist = Vector2Distance(ropes[i-1], ropes[i]);
                if (!dist) dist = ROPE_LEN;
                ropes[i] = Vector2Lerp(ropes[i-1], ropes[i], ROPE_LEN/dist);

                Vector2 snap = Vector2Subtract(old, ropes[i]);
                snap = Vector2Negate(snap);
                snap = Vector2Scale(snap, GetFrameTime()*37);

                forces[i] = snap;

                DrawCircleV(ropes[i], ROPE_WIDTH/2, YELLOW);
                DrawLineEx(ropes[i-1], ropes[i], ROPE_WIDTH, YELLOW);

                // DEBUG:
                // DrawLineEx(old, ropes[i], ROPE_WIDTH, RED);
                // DrawText(TextFormat("%.3f %.3f", forces[i].x, forces[i].y), 0, (i-1)*25, 25, ORANGE);
            }

            DrawText(" Mode: ", 0, 1080-25, 25, ORANGE);
            if (IsKeyDown(KEY_SPACE)) {
                DrawText("SPACE", MeasureText(" Mode: ", 25), 1080-25, 25, DARKBLUE);
            } else {
                DrawText("GRAVITY", MeasureText(" Mode: ", 25), 1080-25, 25, BROWN);
            }
        }
        EndDrawing();
    }
}