#include <string.h>
#include <assert.h>
#include "user_data.h"


struct user_data{
	i64 userid;

	int *fds;
	i64 fds_cap,fds_len;
};

struct hash_item{
	struct user_data data;
	struct hash_item *next;
};

#define USER_HASH_SIZE (16)
static struct hash_item *user_hash[USER_HASH_SIZE];


static struct hash_item* find_userdata(i64 userid){
	struct hash_item *item=user_hash[userid%USER_HASH_SIZE];
	while(item&&item->data.userid!=userid)item=item->next;
	return item;
}

void userdata_register(i64 userid,int fd){
	struct hash_item *item=find_userdata(userid);
	if(item){
		for(i64 i=0;i<item->data.fds_len;i++){
			if(item->data.fds[i]==fd){
				die("userdata_register(%lld, %d) while pair already existed",userid,fd);
			}
		}
		if(item->data.fds_len==item->data.fds_cap){
			item->data.fds_cap*=2;
			item->data.fds=realloc(item->data.fds,item->data.fds_cap,int);
		}
		item->data.fds[item->data.fds_len++]=fd;
	} else {
		item=malloc(1,struct hash_item);
		item->data.userid=userid;
		item->data.fds_cap=2;
		item->data.fds_len=1;
		item->data.fds=malloc(item->data.fds_cap,int);
		item->data.fds[0]=fd;
		item->next=user_hash[userid%USER_HASH_SIZE];
		user_hash[userid%USER_HASH_SIZE]=item;
	}
}

void userdata_unregister(i64 userid,int fd){
	struct hash_item *item=find_userdata(userid);
	assert(item);
	i64 i;
	for(i=0;i<item->data.fds_len;i++){
		if(item->data.fds[i]==fd)break;
	}
	if(i==item->data.fds_len){
		die("userdata_unregister(%lld, %d) while nonexistent",userid,fd);
	}
	memmove(item->data.fds+i,item->data.fds+i+1,item->data.fds_len-i-1);
	item->data.fds_len--;
}

const int* userdata_online(i64 userid,i64 *nfds){
	struct hash_item *item=find_userdata(userid);
	if(!item){
		*nfds=0;
		return NULL;
	}
	assert(item->data.fds_len!=0);
	*nfds=item->data.fds_len;
	return item->data.fds;
}