from collections import deque

from cfg import config
from db_util import get_page_id
import sql

def can_reach(title, connection):
	page = get_page_id(title, connection)
	cursor = connection.cursor()
	cursor.execute(sql.statements["count_links_to"], (page, ))
	count = cursor.fetchone()[0]
	return count > 0

def shortest_path(center, title, connection):
	if(not can_reach(title, connection)):
		return []

	cursor = connection.cursor()
	current_page = get_page_id(title, connection)
	center_page = get_page_id(center, connection)
	path = deque()
	while(current_page != center_page):
		path.append(current_page)
		cursor.execute(sql.statements["dijkstra_backtrack_one"], (current_page,))
		current_page = cursor.fetchone()[0]
	return list(reversed(path))