#include <string.h>
#include "event.h"


struct cbs_chain{
	event_callback_t *cb;
	struct cbs_chain *prev,*next;
};

struct cbs_chain *callbacks=NULL,*callbacks_last=NULL;


static struct cbs_chain* find_chain_item(event_callback_t *cb){
	struct cbs_chain *item=callbacks;
	while(item&&item->cb!=cb)item=item->next;
	return item;
}


void event_register(event_callback_t *cb){
	struct cbs_chain *item=find_chain_item(cb);
	if(item!=NULL){
		debug("event_register: callback %p already registered!",cb);
		return;
	}
	item=malloc(1,struct cbs_chain);
	item->cb=cb;
	item->prev=item->next=NULL;
	if(callbacks){
		item->prev=callbacks_last;
		callbacks_last->next=item;
		callbacks_last=item;
	} else {
		callbacks=callbacks_last=item;
	}
}

void event_unregister(event_callback_t *cb){
	struct cbs_chain *item=find_chain_item(cb);
	if(item==NULL){
		debug("event_unregister: callback %p was not registered!",cb);
		return;
	}
	if(item->prev)item->prev->next=item->next;
	if(item->next)item->next->prev=item->prev;
	if(callbacks==item)callbacks=item->next;
	if(callbacks_last==item)callbacks_last=item->prev;
	free(item);
}

struct event_item* event_item_alloc(void){
	struct event_item *event=malloc(1,struct event_item);
	memset(event,0,sizeof(struct event_item));
	return event;
}

void event_item_free(struct event_item *event){
	if(event->message)free(event->message);
	if(event->user)free(event->user);
	if(event->room)free(event->room);
	free(event);
}

void event_emit(const struct event_item *event){
	for(struct cbs_chain *item=callbacks;item!=NULL;item=item->next){
		item->cb(event);
	}
}

void event_emit_message(i64 timestamp,const char *message,const char *user,const char *room,i64 replyid){
	struct event_item *event=event_item_alloc();
	event->type=EVENT_MESSAGE;
	event->timestamp=timestamp;
	event->message=strdup(message);
	event->user=strdup(user);
	event->room=strdup(room);
	event->replyid=replyid;
	event_emit(event);
	event_item_free(event);
}

void event_emit_online(i64 timestamp,const char *user,i64 numonline){
	struct event_item *event=event_item_alloc();
	event->type=EVENT_ONLINE;
	event->timestamp=timestamp;
	event->user=strdup(user);
	event->num=numonline;
	event_emit(event);
	event_item_free(event);
}

void event_emit_join(i64 timestamp,const char *user,const char *room){
	struct event_item *event=event_item_alloc();
	event->type=EVENT_JOIN;
	event->timestamp=timestamp;
	event->user=strdup(user);
	event->room=strdup(room);
	event_emit(event);
	event_item_free(event);
}

void event_emit_leave(i64 timestamp,const char *user,const char *room){
	struct event_item *event=event_item_alloc();
	event->type=EVENT_LEAVE;
	event->timestamp=timestamp;
	event->user=strdup(user);
	event->room=strdup(room);
	event_emit(event);
	event_item_free(event);
}