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

struct station* create_station(){
   struct station* station = (struct station*)calloc(1,sizeof(struct station));
   if (station == NULL) return NULL;
   station->tracks = (struct car**)calloc(STATION_SIZE, sizeof(struct car*));
   if (station->tracks == NULL) return free(station), NULL;
   station->track_count = STATION_SIZE;
   return station;
}

void destroy_station(struct station* station){
    if (station == NULL) return;
    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);
}

int select_track(struct station* station, const char* target){
    unsigned int hash = 0;
    if (station == NULL || target == NULL) return 0;
    while (*target != '\0') {
        hash = hash * 31u + (unsigned char)*target;
        target++;
    }
    return (int)(hash % (unsigned int)station->track_count);
}

void add_target_capacity(struct station* station,const char* target, int capacity){
    if (station == NULL || target == NULL) return;
    int index = select_track(station, target);
    struct car* current = station->tracks[index];
    while (current != NULL) {
        if (strcmp(current->value, target) == 0) {
            current->capacity += capacity;
            return;
        }
        current = current->next;
    }
    struct car* node = (struct car*)calloc(1, sizeof(struct car));
    if (node == NULL) return;
    strncpy(node->value, target, TARGET_SIZE - 1);
    node->capacity = capacity;
    node->next = station->tracks[index];
    station->tracks[index] = node;
}

int get_target_capacity(struct station* station,const char* target){
    if (station == NULL || target == NULL) return 0;
    struct car* current = station->tracks[select_track(station, target)];
    while (current != NULL) {
        if (strcmp(current->value, target) == 0) return current->capacity;
        current = current->next;
    }
    return 0;
}

int count_targets(struct station* station){
    int count = 0;
    if (station == NULL) return 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;
}

int count_capacity(struct station* station){
    int sum = 0;
    if (station == NULL) return 0;
    for (int i = 0; i < station->track_count; i++) {
        struct car* current = station->tracks[i];
        while (current != NULL) {
            sum += current->capacity;
            current = current->next;
        }
    }
    return sum;
}