// This version of the crawler only

// checks links in the "domain" urbanc

import io.Source

import scala.util.matching.Regex

import scala.util._

// gets the first 10K of a web-page

def get_page(url: String) : String = {

  Try(Source.fromURL(url).take(10000).mkString) getOrElse 

    { println(s"  Problem with: $url"); ""}

}

// regexes for URLs and "my" domain

val http_pattern = """"https?://[^"]*"""".r

val my_urls = """urbanc""".r

def unquote(s: String) = s.drop(1).dropRight(1)

def get_all_URLs(page: String) : Set[String] = 

  http_pattern.findAllIn(page).map(unquote).toSet

def crawl(url: String, n: Int) : Unit = {

  if (n == 0) ()

  else if (my_urls.findFirstIn(url) == None) { 

    println(s"Visiting: $n $url")

    get_page(url); () 

  }

  else {

    println(s"Visiting: $n $url")

    for (u <- get_all_URLs(get_page(url))) crawl(u, n - 1)

  }

}

// starting URL for the crawler

val startURL = """http://www.inf.kcl.ac.uk/staff/urbanc"""

// can now deal with depth 3 and beyond

crawl(startURL, 3)