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

#define HASH_BASE 31 // Hashovací základ pro lepší rozložení hodnot

// Hešovací funkce, která převede hodnotu na index
int select_track(struct station* station, const char* target) {
    unsigned long hash = 0;
    while (*target) {
        hash = hash * HASH_BASE + (unsigned char)(*target);
        target++;
    }
    return hash % station->track_count;
}

// Inicializace stanice
struct station* create_station() {
    struct station* station = calloc(1, sizeof(struct station));
    station->tracks = calloc(STATION_SIZE, sizeof(struct car*));
    station->track_count = STATION_SIZE;
    return station;
}

// Zrušení stanice a uvolnění paměti
void destroy_station(struct station* station) {
    for (int i = 0; i < station->track_count; i++) {
        struct car* current = station->tracks[i];
        while (current != NULL) {
            struct car* next = current->next;
            free(current);
            current = next;
        }
    }
    free(station->tracks);
    free(station);
}

// Přidání nebo aktualizace kapacity pro stanici
void add_target_capacity(struct station* station, const char* target, int capacity) {
    int track_index = select_track(station, target);
    struct car* current = station->tracks[track_index];

    // Najdeme, zda již existuje záznam pro daný cíl
    while (current != NULL) {
        if (strcmp(current->value, target) == 0) {
            current->capacity += capacity; // Zvýšení kapacity
            return;
        }
        current = current->next;
    }

    // Pokud neexistuje, přidáme nový záznam
    struct car* new_car = malloc(sizeof(struct car));
    strncpy(new_car->value, target, TARGET_SIZE - 1);
    new_car->value[TARGET_SIZE - 1] = '\0';
    new_car->capacity = capacity;
    new_car->next = station->tracks[track_index];
    station->tracks[track_index] = new_car;
}

// Vyhledání kapacity pro stanici
int get_target_capacity(struct station* station, const char* target) {
    int track_index = select_track(station, target);
    struct car* current = station->tracks[track_index];

    while (current != NULL) {
        if (strcmp(current->value, target) == 0) {
            return current->capacity;
        }
        current = current->next;
    }
    return 0; // Stanice nenalezena
}

// Počet různých destinací
int count_targets(struct station* station) {
    int count = 0;
    for (int i = 0; i < station->track_count; i++) {
        struct car* current = station->tracks[i];
        while (current != NULL) {
            count++;
            current = current->next;
        }
    }
    return count;
}

// Celková kapacita všech destinací
int count_capacity(struct station* station) {
    int total_capacity = 0;
    for (int i = 0; i < station->track_count; i++) {
        struct car* current = station->tracks[i];
        while (current != NULL) {
            total_capacity += current->capacity;
            current = current->next;
        }
    }
    return total_capacity;
}

// Načtení existující databáze z textového souboru
void load_database(struct station* station, const char* filename) {
    FILE* file = fopen(filename, "r");
    if (!file) {
        perror("Chyba při otevírání souboru");
        return;
    }

    char target[TARGET_SIZE];
    int capacity;

    while (fscanf(file, "%s %d", target, &capacity) == 2) {
        add_target_capacity(station, target, capacity);
    }

    fclose(file);
}

// Výpis aktuálního stavu stanice (pro ladění)
void print_station(struct station* station) {
    printf("station>>>\n");
    for (int i = 0; i < station->track_count; i++) {
        struct car* current = station->tracks[i];
        printf("[%d] ", i);
        while (current != NULL) {
            printf("%s (%d) -> ", current->value, current->capacity);
            current = current->next;
        }
        printf("NULL\n");
    }
    printf("<<<station\n");
}