#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "a4.h"

int error = 0;

typedef struct Tree {
    char text[SIZE];
    int isAnswer;
    struct Tree *yes;
    struct Tree *no;
} Tree;

// uvolnenie pamate
void freeTree(Tree *node) {
    if (!node) return;

    freeTree(node->yes);
    freeTree(node->no);
    free(node);
}

// citanie stromu (preorder)
Tree* readTree() {
    char line[SIZE];

    if (fgets(line, SIZE, stdin) == NULL) {
        error = 1;
        return NULL;
    }

    // odstranenie konca riadku
    line[strcspn(line, "\r\n")] = '\0';

    // prazdny riadok = chyba
    if (line[0] == '\0') {
        error = 1;
        return NULL;
    }

    Tree *node = (Tree*)malloc(sizeof(Tree));

    if (!node) {
        error = 1;
        return NULL;
    }

    node->yes = NULL;
    node->no = NULL;

    // list
    if (line[0] == '*') {
        node->isAnswer = 1;
        strcpy(node->text, line + 1);
    }
    // otazka
    else {
        node->isAnswer = 0;
        strcpy(node->text, line);

        node->yes = readTree();
        node->no = readTree();

        if (!node->yes || !node->no) {
            error = 1;
            freeTree(node);
            return NULL;
        }
    }

    return node;
}

// kontrola prazdneho riadku po strome
int EmptyLine() {
    char line[SIZE];

    if (fgets(line, SIZE, stdin) == NULL)
        return 1;

    return strcmp(line, "\n") == 0 ||
           strcmp(line, "\r\n") == 0;
}

// pocet listov
int Leaves(Tree *node) {
    if (!node) return 0;

    if (node->isAnswer)
        return 1;

    return Leaves(node->yes) + Leaves(node->no);
}

// hra
void start(Tree *node) {
    char input[SIZE];

    while (node && !node->isAnswer) {

        printf("%s\n", node->text);

        if (fgets(input, SIZE, stdin) == NULL) {
            printf("Koniec vstupu\n");
            return;
        }

        int i = 0;

        while (input[i] == ' ' || input[i] == '\t')
            i++;

        if (input[i] == 'a' || input[i] == 'A') {
            node = node->yes;
        }
        else if (input[i] == 'n' || input[i] == 'N') {
            node = node->no;
        }
        else {
            printf("Nerozumiem\n");
            return;
        }
    }

    if (node && node->isAnswer) {
        printf("%s\n", node->text);
        printf("Koniec\n");
    }
}

int main() {

    printf("Expert z bufetu to vie.\n");

    Tree *root = readTree();

    if (!root || error) {
        printf("Chybna databaza\n");
        freeTree(root);
        return 0;
    }

    // po strome musi byt prazdny riadok
    if (!EmptyLine()) {
        printf("Chybna databaza\n");
        freeTree(root);
        return 0;
    }

    printf("Pozna %d druhov ovocia a zeleniny.\n", Leaves(root));
    printf("Odpovedajte 'a' pre prvu moznost alebo 'n' pre druhu moznost.\n");

    start(root);

    freeTree(root);

    return 0;
}