require 'uri'

Net::HTTP.version_1_2

GOOGLE_WAP_LINK = /<a accesskey="(\d)" href=".*?u=(.*?)">(.*?)<\/a>/im

class SearchPlugin < Plugin
  BotConfig.register BotConfigIntegerValue.new('google.hits',
    :default => 3,
    :desc => "Number of hits to return from Google searches")
  BotConfig.register BotConfigIntegerValue.new('google.first_par',
    :default => 0,
    :desc => "When set to n > 0, the bot will return the first paragraph from the first n search hits")
  BotConfig.register BotConfigIntegerValue.new('wikipedia.hits',
    :default => 3,
    :desc => "Number of hits to return from Wikipedia searches")
  BotConfig.register BotConfigIntegerValue.new('wikipedia.first_par',
    :default => 1,
    :desc => "When set to n > 0, the bot will return the first paragraph from the first n wikipedia search hits")

  def help(plugin, topic="")
    case topic
    when "search", "google"
      "#{topic} <string> => search google for <string>"
    when "wp"
      "wp [<code>] <string> => search for <string> on Wikipedia. You can select a national <code> to only search the national Wikipedia"
    else
      "search <string> (or: google <string>) => search google for <string> | wp <string> => search for <string> on Wikipedia"
    end
  end

  def google(m, params)
    what = params[:words].to_s
    searchfor = URI.escape what
    # This method is also called by other methods to restrict searching to some sites
    if params[:site]
      site = "site:#{params[:site]}+"
    else
      site = ""
    end
    # It is also possible to choose a filter to remove constant parts from the titles
    # e.g.: "Wikipedia, the free encyclopedia" when doing Wikipedia searches
    filter = params[:filter] || ""

    url = "http://www.google.com/wml/search?q=#{site}#{searchfor}"

    hits = params[:hits] || @bot.config['google.hits']

    begin
      wml = @bot.httputil.get_cached(url)
    rescue => e
      m.reply "error googling for #{what}"
      return
    end
    results = wml.scan(GOOGLE_WAP_LINK)
    if results.length == 0
      m.reply "no results found for #{what}"
      return
    end
    urls = Array.new
    results = results[0...hits].map { |res|
      n = res[0]
      t = Utils.decode_html_entities res[2].gsub(filter, '').strip
      u = URI.unescape res[1]
      urls.push(u)
      "#{n}. #{Bold}#{t}#{Bold}: #{u}"
    }.join(" | ")

    m.reply "Results for #{what}: #{results}", :split_at => /\s+\|\s+/

    first_pars = params[:firstpar] || @bot.config['google.first_par']

    idx = 0
    while first_pars > 0 and urls.length > 0
      url.replace(urls.shift)
      idx += 1

      # FIXME what happens if some big file is returned? We should share
      # code with the url plugin to only retrieve partial file content!
      xml = @bot.httputil.get_cached(url)
      if xml.nil?
        debug "Unable to retrieve #{url}"
        next
      end
      par = Utils.ircify_first_html_par(xml)
      if par.empty?
        debug "No first par found\n#{xml}"
	# FIXME only do this if the 'url' plugin is loaded
	par = @bot.plugins['url'].get_title_from_html(xml)
        next if par.empty?
      end
      m.reply "[#{idx}] #{par}", :overlong => :truncate
      first_pars -=1
    end
  end

  def wikipedia(m, params)
    lang = params[:lang]
    site = "#{lang.nil? ? '' : lang + '.'}wikipedia.org"
    debug "Looking up things on #{site}"
    params[:site] = site
    params[:filter] = / - Wikipedia.*$/
    params[:hits] = @bot.config['wikipedia.hits']
    params[:firstpar] = @bot.config['wikipedia.first_par']
    return google(m, params)
  end
end

plugin = SearchPlugin.new

plugin.map "search *words", :action => 'google'
plugin.map "google *words", :action => 'google'
plugin.map "wp :lang *words", :action => 'wikipedia', :requirements => { :lang => /^\w\w\w?$/ }
plugin.map "wp *words", :action => 'wikipedia'