#include <stdio.h>
#include <stdlib.h>

enum passage_status {
    OPEN,
    CLOSED
};

struct tank {
    int volume;
    enum passage_status left_passage;
    enum passage_status right_passage;
    struct tank *next;
};

void print_tanks(struct tank *tanks);
struct tank *init_tanks(int n_tanks, char *tank_volumes[]);

void toggle_passage(struct tank *tanks, int position);

// DO NOT CHANGE THIS MAIN FUNCTION
int main(int argc, char *argv[]) {
    struct tank *tanks = init_tanks(argc - 1, &argv[1]);
    print_tanks(tanks);

    int position;
    printf("Enter passage: ");
    while (scanf("%d", &position) == 1) {
        toggle_passage(tanks, position);
        print_tanks(tanks);
        printf("Enter passage: ");
    }
    return 0;
}

void toggle_passage(struct tank *tanks, int position) {
    // TODO: Implement this.
}

// DO NOT CHANGE THIS FUNCTION
// prints a linked list of tanks in a formatted fashion.
void print_tanks(struct tank *tanks) {
    printf("Tanks:\n");

    // Top level of tanks (roof)
    struct tank *curr = tanks;
    while (curr != NULL) {
        printf("/----\\");
        curr = curr->next;
    }
    printf("\n");

    // Middle level of tanks (volumes & passages)
    curr = tanks;
    while (curr != NULL) {
        printf(
            "%c %02d %c",
            curr->left_passage == CLOSED ? '|' : ' ',
            curr->volume,
            curr->right_passage == CLOSED ? '|' : ' '
        );

        curr = curr->next;
    }
    printf("\n");

    // Bottom level of tanks (floor)
    curr = tanks;
    while (curr != NULL) {
        printf("\\----/");
        curr = curr->next;
    }
    curr = tanks;
    printf("\n");
}

// DO NOT CHANGE THIS FUNCTION
// Given an array of strings, creates a linked list of tanks containing
// volumes specified in these strings.
struct tank *init_tanks(int n_tanks, char *tank_volumes[]) {
    struct tank *head = NULL;
    struct tank *tail = NULL;
    for (int i = 0; i < n_tanks; ++i) {
        struct tank *new_tank = malloc(sizeof(struct tank));
        new_tank->volume = atoi(tank_volumes[i]);
        new_tank->left_passage = CLOSED;
        new_tank->right_passage = CLOSED;
        new_tank->next = NULL;

        if (head == NULL) {
            head = new_tank;
            tail = new_tank;
        } else {
            tail->next = new_tank;
            tail = tail->next;
        }
    }

    return head;
}