class ApiController < ApplicationController

  session :off
  before_filter :check_read_availability, :except => [:capabilities]
  after_filter :compress_output

  #COUNT is the number of map requests to allow before exiting and starting a new process
  @@count = COUNT

  # The maximum area you're allowed to request, in square degrees
  MAX_REQUEST_AREA = 0.25


  # Number of GPS trace/trackpoints returned per-page
  TRACEPOINTS_PER_PAGE = 5000
  
  def trackpoints
    @@count+=1
    #retrieve the page number
    page = params['page'].to_i
    unless page
        page = 0;
    end

    unless page >= 0
        report_error("Page number must be greater than or equal to 0")
        return
    end

    offset = page * TRACEPOINTS_PER_PAGE

    # Figure out the bbox
    bbox = params['bbox']
    unless bbox and bbox.count(',') == 3
      report_error("The parameter bbox is required, and must be of the form min_lon,min_lat,max_lon,max_lat")
      return
    end

    bbox = bbox.split(',')

    min_lon = bbox[0].to_f
    min_lat = bbox[1].to_f
    max_lon = bbox[2].to_f
    max_lat = bbox[3].to_f

    # check the bbox is sane
    unless min_lon <= max_lon
      report_error("The minimum longitude must be less than the maximum longitude, but it wasn't")
      return
    end
    unless min_lat <= max_lat
      report_error("The minimum latitude must be less than the maximum latitude, but it wasn't")
      return
    end
    unless min_lon >= -180 && min_lat >= -90 && max_lon <= 180 && max_lat <= 90
      report_error("The latitudes must be between -90 and 90, and longitudes between -180 and 180")
      return
    end

    # check the bbox isn't too large
    requested_area = (max_lat-min_lat)*(max_lon-min_lon)
    if requested_area > MAX_REQUEST_AREA
      report_error("The maximum bbox size is " + MAX_REQUEST_AREA.to_s + ", and your request was too large. Either request a smaller area, or use planet.osm")
      return
    end

    # get all the points
    points = Tracepoint.find_by_area(min_lat, min_lon, max_lat, max_lon, :offset => offset, :limit => TRACEPOINTS_PER_PAGE, :order => "timestamp DESC" )

    doc = XML::Document.new
    doc.encoding = 'UTF-8'
    root = XML::Node.new 'gpx'
    root['version'] = '1.0'
    root['creator'] = 'OpenStreetMap.org'
    root['xmlns'] = "http://www.topografix.com/GPX/1/0/"
    
    doc.root = root

    track = XML::Node.new 'trk'
    doc.root << track

    trkseg = XML::Node.new 'trkseg'
    track << trkseg

    points.each do |point|
      trkseg << point.to_xml_node()
    end

    #exit when we have too many requests
    if @@count > MAX_COUNT
      render :text => doc.to_s, :content_type => "text/xml"
      @@count = COUNT
      exit!
    end

    render :text => doc.to_s, :content_type => "text/xml"

  end

  def map
    GC.start
    @@count+=1

    # Figure out the bbox
    bbox = params['bbox']
    unless bbox and bbox.count(',') == 3
      report_error("The parameter bbox is required, and must be of the form min_lon,min_lat,max_lon,max_lat")
      return
    end

    bbox = bbox.split(',')

    min_lon = bbox[0].to_f
    min_lat = bbox[1].to_f
    max_lon = bbox[2].to_f
    max_lat = bbox[3].to_f

    # check the bbox is sane
    unless min_lon <= max_lon
      report_error("The minimum longitude must be less than the maximum longitude, but it wasn't")
      return
    end
    unless min_lat <= max_lat
      report_error("The minimum latitude must be less than the maximum latitude, but it wasn't")
      return
    end
    unless min_lon >= -180 && min_lat >= -90 && max_lon <= 180 && max_lat <= 90
      report_error("The latitudes must be between -90 and 90, and longitudes between -180 and 180")
      return
    end

    # check the bbox isn't too large
    requested_area = (max_lat-min_lat)*(max_lon-min_lon)
    if requested_area > MAX_REQUEST_AREA
      report_error("The maximum bbox size is " + MAX_REQUEST_AREA.to_s + 
        ", and your request was too large. Either request a smaller area, or use planet.osm")
      return
    end

    # get all the nodes
    nodes = Node.find_by_area(min_lat, min_lon, max_lat, max_lon, :conditions => "visible = 1")

    node_ids = nodes.collect {|node| node.id }

    if node_ids.length > 50_000
      report_error("You requested too many nodes (limit is 50,000). Either request a smaller area, or use planet.osm")
      return
    end

    if node_ids.length == 0
      render :text => "<osm version='0.5'></osm>", :content_type => "text/xml"
      return
    end

    relations = Array.new

    doc = OSM::API.new.get_xml_doc

    # get ways
    # find which ways are needed
    ways = Array.new
    if node_ids.length > 0
      way_nodes = WayNode.find_all_by_node_id(node_ids)
      way_ids = way_nodes.collect {|way_node| way_node.id }
      ways = Way.find(way_ids)

      list_of_way_nodes = ways.collect { |way|
	way.way_nodes.collect { |way_node| way_node.node_id }
      }
      list_of_way_nodes.flatten!

    else
      list_of_way_nodes = Array.new
    end

    # - [0] in case some thing links to node 0 which doesn't exist. Shouldn't actually ever happen but it does. FIXME: file a ticket for this
    nodes_to_fetch = (list_of_way_nodes.uniq - node_ids) - [0]

    if nodes_to_fetch.length > 0
      nodes += Node.find(nodes_to_fetch)
    end

    visible_nodes = {}
    user_display_name_cache = {}

    nodes.each do |node|
      if node.visible?
        doc.root << node.to_xml_node(user_display_name_cache)
        visible_nodes[node.id] = node
      end
    end

    way_ids = Array.new
    ways.each do |way|
      if way.visible?
        doc.root << way.to_xml_node(visible_nodes, user_display_name_cache)
        way_ids << way.id
      end
    end 

    # collect relationships. currently done in one big block at the end;
    # may need to move this upwards if people want automatic completion of
    # relationships, i.e. deliver referenced objects like we do with ways...
    relations = Array.new
    if visible_nodes.length > 0
        relations += Relation.find_by_sql("select e.* from current_relations e,current_relation_members em where " +
            "e.visible=1 and " +
            "em.id = e.id and em.member_type='node' and em.member_id in (#{visible_nodes.keys.join(',')})")
    end
    if way_ids.length > 0
        relations += Relation.find_by_sql("select e.* from current_relations e,current_relation_members em where " +
            "e.visible=1 and " +
            "em.id = e.id and em.member_type='way' and em.member_id in (#{way_ids.join(',')})")
    end
    # we do not normally return the "other" partners referenced by an relation, 
    # e.g. if we return a way A that is referenced by relation X, and there's 
    # another way B also referenced, that is not returned. But we do make 
    # an exception for cases where an relation references another *relation*; 
    # in that case we return that as well (but we don't go recursive here)
    relation_ids = relations.collect { |relation| relation.id }
    if relation_ids.length > 0
        relations += Relation.find_by_sql("select e.* from current_relations e,current_relation_members em where " +
            "e.visible=1 and " +
            "em.id = e.id and em.member_type='relation' and em.member_id in (#{relation_ids.join(',')})")
    end

    # this "uniq" may be slightly inefficient; it may be better to first collect and output
    # all node-related relations, then find the *not yet covered* way-related ones etc.
    relations.uniq.each do |relation|
      doc.root << relation.to_xml_node(user_display_name_cache)
    end

    render :text => doc.to_s, :content_type => "text/xml"
    
    #exit when we have too many requests
    if @@count > MAX_COUNT
      @@count = COUNT
      
      exit!
    end
  end

  def changes
    zoom = (params[:zoom] || '12').to_i

    if params.include?(:start) and params.include?(:end)
      starttime = Time.parse(params[:start])
      endtime = Time.parse(params[:end])
    else
      hours = (params[:hours] || '1').to_i.hours
      endtime = Time.now
      starttime = endtime - hours
    end

    if zoom >= 1 and zoom <= 16 and
       endtime >= starttime and endtime - starttime <= 24.hours
      mask = (1 << zoom) - 1

      tiles = Node.count(:conditions => ["timestamp BETWEEN ? AND ?", starttime, endtime],
                         :group => "maptile_for_point(latitude, longitude, #{zoom})")

      doc = OSM::API.new.get_xml_doc
      changes = XML::Node.new 'changes'
      changes["starttime"] = starttime.xmlschema
      changes["endtime"] = endtime.xmlschema

      tiles.each do |tile, count|
        x = (tile.to_i >> zoom) & mask
        y = tile.to_i & mask

        t = XML::Node.new 'tile'
        t["x"] = x.to_s
        t["y"] = y.to_s
        t["z"] = zoom.to_s
        t["changes"] = count.to_s

        changes << t
      end

      doc.root << changes

      render :text => doc.to_s, :content_type => "text/xml"
    else
      render :nothing => true, :status => :bad_request
    end
  end

  def capabilities
    doc = OSM::API.new.get_xml_doc

    api = XML::Node.new 'api'
    version = XML::Node.new 'version'
    version['minimum'] = '0.5';
    version['maximum'] = '0.5';
    api << version
    area = XML::Node.new 'area'
    area['maximum'] = MAX_REQUEST_AREA.to_s;
    api << area
    
    doc.root << api

    render :text => doc.to_s, :content_type => "text/xml"
  end
end