class GeocoderController < ApplicationController
  require 'uri'
  require 'net/http'
  require 'rexml/document'

  def search
    query = params[:query]
    results = Array.new

    if query.match(/^\d{5}(-\d{4})?$/)
      results.push search_us_postcode(query)
    elsif query.match(/(GIR 0AA|[A-PR-UWYZ]([0-9]{1,2}|([A-HK-Y][0-9]|[A-HK-Y][0-9]([0-9]|[ABEHMNPRV-Y]))|[0-9][A-HJKS-UW])\s*[0-9][ABD-HJLNP-UW-Z]{2})/i)
      results.push search_uk_postcode(query)
    elsif query.match(/[A-Z]\d[A-Z]\s*\d[A-Z]\d/i)
      results.push search_ca_postcode(query)
    else
      results.push search_osm_namefinder(query)
      results.push search_geonames(query)
    end

    results_count = count_results(results)

    render :update do |page|
      page.replace_html :search_results_content, :partial => 'results', :object => results

      if results_count == 1
        position = results.collect { |s| s[:results] }.compact.flatten[0]
        page.call "setPosition", position[:lat], position[:lon], position[:zoom]
      else
        page.call "openSearchResults"
      end
    end
  end
  
  def description
    results = Array.new

    lat = params[:lat]
    lon = params[:lon]

    results.push description_osm_namefinder("cities", lat, lon, 2)
    results.push description_osm_namefinder("towns", lat, lon, 4)
    results.push description_osm_namefinder("places", lat, lon, 10)
    results.push description_geonames(lat, lon)

    render :update do |page|
      page.replace_html :search_results_content, :partial => 'results', :object => results
      page.call "openSearchResults"
    end
  end

private

  def search_us_postcode(query)
    results = Array.new

    # ask geocoder.us (they have a non-commercial use api)
    response = fetch_text("http://rpc.geocoder.us/service/csv?zip=#{URI.escape(query)}")

    # parse the response
    unless response.match(/couldn't find this zip/)
      data = response.split(/\s*,\s+/) # lat,long,town,state,zip
      results.push({:lat => data[0], :lon => data[1], :zoom => 12,
                    :prefix => "#{data[2]}, #{data[3]}, ",
                    :name => data[4]})
    end

    return { :source => "Geocoder.us", :url => "http://geocoder.us/", :results => results }
  rescue Exception => ex
    return { :source => "Geocoder.us", :url => "http://geocoder.us/", :error => "Error contacting rpc.geocoder.us: #{ex.to_s}" }
  end

  def search_uk_postcode(query)
    results = Array.new

    # ask npemap.org.uk to do a combined npemap + freethepostcode search
    response = fetch_text("http://www.npemap.org.uk/cgi/geocoder.fcgi?format=text&postcode=#{URI.escape(query)}")

    # parse the response
    unless response.match(/Error/)
      dataline = response.split(/\n/)[1]
      data = dataline.split(/,/) # easting,northing,postcode,lat,long
      results.push({:lat => data[3], :lon => data[4], :zoom => 12,
                    :name => data[2].gsub(/'/, "")})
    end

    return { :source => "NPEMap / FreeThePostcode", :url => "http://www.npemap.org.uk/", :results => results }
  rescue Exception => ex
    return { :source => "NPEMap / FreeThePostcode", :url => "http://www.npemap.org.uk/", :error => "Error contacting www.npemap.org.uk: #{ex.to_s}" }
  end

  def search_ca_postcode(query)
    results = Array.new

    # ask geocoder.ca (note - they have a per-day limit)
    response = fetch_xml("http://geocoder.ca/?geoit=XML&postal=#{URI.escape(query)}")

    # parse the response
    unless response.get_elements("geodata/error")
      results.push({:lat => response.get_text("geodata/latt").to_s,
                    :lon => response.get_text("geodata/longt").to_s,
                    :zoom => 12,
                    :name => query.upcase})
    end

    return { :source => "Geocoder.CA", :url => "http://geocoder.ca/", :results => results }
  rescue Exception => ex
    return { :source => "Geocoder.CA", :url => "http://geocoder.ca/", :error => "Error contacting geocoder.ca: #{ex.to_s}" }
  end

  def search_osm_namefinder(query)
    results = Array.new

    # ask OSM namefinder
    response = fetch_xml("http://www.frankieandshadow.com/osm/search.xml?find=#{URI.escape(query)}")

    # parse the response
    response.elements.each("searchresults/named") do |named|
      lat = named.attributes["lat"].to_s
      lon = named.attributes["lon"].to_s
      zoom = named.attributes["zoom"].to_s
      place = named.elements["place/named"] || named.elements["nearestplaces/named"]
      type = named.attributes["info"].to_s.capitalize
      name = named.attributes["name"].to_s
      description = named.elements["description"].to_s
      if name.empty?
        prefix = ""
        name = type
      else
        prefix = "#{type} "
      end
      if place
        distance = format_distance(place.attributes["approxdistance"].to_i)
        direction = format_direction(place.attributes["direction"].to_i)
        placename = place.attributes["name"].to_s
        suffix = ", #{distance} #{direction} of #{placename}"
      else
        suffix = ""
      end
      results.push({:lat => lat, :lon => lon, :zoom => zoom,
                    :prefix => prefix, :name => name, :suffix => suffix,
                    :description => description})
    end

    return { :source => "OpenStreetMap Namefinder", :url => "http://www.frankieandshadow.com/osm/", :results => results }
  rescue Exception => ex
    return { :source => "OpenStreetMap Namefinder", :url => "http://www.frankieandshadow.com/osm/", :error => "Error contacting www.frankieandshadow.com: #{ex.to_s}" }
  end

  def search_geonames(query)
    results = Array.new

    # ask geonames.org
    response = fetch_xml("http://ws.geonames.org/search?q=#{URI.escape(query)}&maxRows=20")

    # parse the response
    response.elements.each("geonames/geoname") do |geoname|
      lat = geoname.get_text("lat").to_s
      lon = geoname.get_text("lng").to_s
      name = geoname.get_text("name").to_s
      country = geoname.get_text("countryName").to_s
      results.push({:lat => lat, :lon => lon, :zoom => 12,
                    :name => name,
                    :suffix => ", #{country}"})
    end

    return { :source => "GeoNames", :url => "http://www.geonames.org/", :results => results }
  rescue Exception => ex
    return { :source => "GeoNames", :url => "http://www.geonames.org/", :error => "Error contacting ws.geonames.org: #{ex.to_s}" }
  end

  def description_osm_namefinder(types, lat, lon, max)
    results = Array.new

    # ask OSM namefinder
    response = fetch_xml("http://www.frankieandshadow.com/osm/search.xml?find=#{types}+near+#{lat},#{lon}&max=#{max}")

    # parse the response
    response.elements.each("searchresults/named") do |named|
      lat = named.attributes["lat"].to_s
      lon = named.attributes["lon"].to_s
      zoom = named.attributes["zoom"].to_s
      place = named.elements["place/named"] || named.elements["nearestplaces/named"]
      type = named.attributes["info"].to_s
      name = named.attributes["name"].to_s
      description = named.elements["description"].to_s
      distance = format_distance(place.attributes["approxdistance"].to_i)
      direction = format_direction((place.attributes["direction"].to_i - 180) % 360)
      prefix = "#{distance} #{direction} of #{type} "
      results.push({:lat => lat, :lon => lon, :zoom => zoom,
                    :prefix => prefix.capitalize, :name => name,
                    :description => description})
    end

    return { :type => types.capitalize, :source => "OpenStreetMap Namefinder", :url => "http://www.frankieandshadow.com/osm/", :results => results }
  rescue Exception => ex
    return { :type => types.capitalize, :source => "OpenStreetMap Namefinder", :url => "http://www.frankieandshadow.com/osm/", :error => "Error contacting www.frankieandshadow.com: #{ex.to_s}" }
  end

  def description_geonames(lat, lon)
    results = Array.new

    # ask geonames.org
    response = fetch_xml("http://ws.geonames.org/countrySubdivision?lat=#{lat}&lng=#{lon}")

    # parse the response
    response.elements.each("geonames/countrySubdivision") do |geoname|
      name = geoname.get_text("adminName1").to_s
      country = geoname.get_text("countryName").to_s
      results.push({:prefix => "#{name}, #{country}"})
    end

    return { :type => "Location", :source => "GeoNames", :url => "http://www.geonames.org/", :results => results }
  rescue Exception => ex
    return { :type => types.capitalize, :source => "OpenStreetMap Namefinder", :url => "http://www.frankieandshadow.com/osm/", :error => "Error contacting www.frankieandshadow.com: #{ex.to_s}" }
  end

  def fetch_text(url)
    return Net::HTTP.get(URI.parse(url))
  end

  def fetch_xml(url)
    return REXML::Document.new(fetch_text(url))
  end

  def format_distance(distance)
    return "less than 1km" if distance == 0
    return "about #{distance}km"
  end

  def format_direction(bearing)
    return "south-west" if bearing >= 22.5 and bearing < 67.5
    return "south" if bearing >= 67.5 and bearing < 112.5
    return "south-east" if bearing >= 112.5 and bearing < 157.5
    return "east" if bearing >= 157.5 and bearing < 202.5
    return "north-east" if bearing >= 202.5 and bearing < 247.5
    return "north" if bearing >= 247.5 and bearing < 292.5
    return "north-west" if bearing >= 292.5 and bearing < 337.5
    return "west"
  end

  def count_results(results)
    count = 0

    results.each do |source|
      count += source[:results].length if source[:results]
    end

    return count
  end
end