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

typedef enum {
    ABSOLUTE,
    DELTA,
    NUM_INPUT_TYPE
} InputType;

typedef struct {
    double x;
    double y;
} Point;

typedef struct {
    Point pt;
    double fuel;
} Car;

double calc_dist(Point *p1, Point *p2) {
    double x2 = (p1->x - p2->x) * (p1->x - p2->x);
    double y2 = (p1->y - p2->y) * (p1->y - p2->y);
    return sqrt(x2 + y2);
}

void get_info(Car *c) {
    printf("Current Position: (%.2f, %.2f)\nFuel Available: %.2f Liter\n",
        c->pt.x,
        c->pt.y,
        c->fuel
    );
}

int move(Car *c, Point *dest) {
    double d = calc_dist(&c->pt, dest);
    if (d > c->fuel) return 0;

    c->pt = *dest;
    c->fuel -= d;
    return 1;
}

int main(void) {

    Car myCar = {{0.0,0.0}, 90.0};
    Point pt = {0};

    while(1) {
        get_info(&myCar);
        char c;
        printf("Continue? [y/n]: ");
        scanf("%1[a-zA-Z]", &c);
        if (c == 'n') break;
        InputType t;
        bool isValidInput = false;
        while (!isValidInput) {
            printf("Select mode [0 = Absolute Position / 1 = Relative Position]: ");
            scanf("%u", (unsigned int*)&t);
            if (t < NUM_INPUT_TYPE) isValidInput = true;
            else puts("Invalid mode!");
        }
        printf("Input x coordinate: ");
        scanf("%lf", &pt.x);
        printf("Input y coordinate: ");
        scanf("%lf", &pt.y);
        switch (t) {
            case ABSOLUTE:
                break;
            case DELTA:
                pt.x += myCar.pt.x;
                pt.y += myCar.pt.y;
                break;
            default:
                break;
        }
        int res = move(&myCar, &pt);
        if (res == 0) {
            puts("Low Fuel!");
        }
        getchar(); // environment specific fix
    }

    return 0;
}