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

int select_track(struct station* station, const char* target) 
{
    if (station==NULL || target==NULL) 
    {
        return 0;
    }
    unsigned long hash=5381;
    int c;
    while ((c=*target++)) 
    {
        hash=((hash<<5)+hash)+c;
    }
    return (int)(hash % station->track_count);
}

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

void add_target_capacity(struct station* station, const char* target, int capacity) 
{
    if (station==NULL || target==NULL) 
    {
        return;
    }
    int track=select_track(station, target);
    if (track<0 || track>=station->track_count) 
    {
        return;
    }
    struct car* current=station->tracks[track];
    struct car* prev=NULL;
    while (current!=NULL) 
    {
        if (strcmp(current->value, target)==0) 
        {
            current->capacity+=capacity;
            return;
        }
        prev=current;
        current=current->next;
    }
    struct car* new_car=(struct car*)malloc(sizeof(struct car));
    if (new_car==NULL) 
    {
        return;
    }
    new_car->capacity=capacity;
    strncpy(new_car->value, target, TARGET_SIZE-1);
    new_car->value[TARGET_SIZE-1]='\0';
    new_car->next=NULL;
    if (prev==NULL) 
    {
        station->tracks[track]=new_car;
    } 
    else 
    {
        prev->next=new_car;
    }
}

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

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

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