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

static unsigned long hash_string(const char* t){
    unsigned long h=0;int c;
    while((c=*t++)){h=h*31+c;}
    return h;
}

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

void destroy_station(struct station* s){
    if(s==NULL)return;
    for(int i=0;i<s->track_count;i++){
        struct car* c=s->tracks[i];
        while(c!=NULL){
            struct car* n=c->next;
            free(c);
            c=n;
        }
    }
    free(s->tracks);
    free(s);
}

int select_track(struct station* s,const char* t){
    if(s==NULL||t==NULL)return 0;
    unsigned long h=hash_string(t);
    return (int)(h%s->track_count);
}

void add_target_capacity(struct station* s,const char* t,int cap){
    if(s==NULL||t==NULL)return;
    int tr=select_track(s,t);
    struct car* c=s->tracks[tr];
    struct car* p=NULL;
    while(c!=NULL){
        if(strcmp(c->value,t)==0){c->capacity+=cap;return;}
        p=c;c=c->next;
    }
    struct car* n=malloc(sizeof(struct car));
    if(n==NULL)return;
    strncpy(n->value,t,TARGET_SIZE-1);
    n->value[TARGET_SIZE-1]='\0';
    n->capacity=cap;
    n->next=NULL;
    if(p==NULL)s->tracks[tr]=n;else p->next=n;
}

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

int count_targets(struct station* s){
    if(s==NULL)return 0;
    int cnt=0;
    for(int i=0;i<s->track_count;i++){
        struct car* c=s->tracks[i];
        while(c!=NULL){cnt++;c=c->next;}
    }
    return cnt;
}

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