#!/usr/bin/ruby

require 'rubygems'
require 'date'
require 'hpricot'
require 'open-uri'

def uri_and_times_from_status(server)
  file = open("http://#{server}/server-status").read
  doc = Hpricot.parse(file)
  tables = doc / 'table'
  rows = (tables[0] / 'tr')[1..-1]
  data = rows.collect { |r| (r  / 'td').collect(&:inner_html) }
  # filter where the PID is numeric, status is 'W' and host matches the server
  matching_data = data.select { |r| (r[1].to_i > 0) && r[3].match(/W/) && r[11].match(server) }
  # return URI and number of seconds processing for each request
  matching_data.collect { |r| [r[12], r[5].to_i] }
end

CALL_TYPES = {
  :map => "Map API calls",
  :upload => "Changeset diff uploads",
  :amf => "AMF API calls",
  :history => "Element history fetches",
  :full => "Full element fetches",
  :trkpts => "GPX trackpoints calls",
  :web => "Web site traffic",
  :other => "Other API calls"
}

def categorise_uri(line)
  uri = line.split(" ")[1]

  case uri
  when /api\/0\.6\/map/ then :map
  when /api\/0\.6\/changeset\/[0-9]*\/upload/ then :upload
  when /api\/0\.6\/amf/ then :amf
  when /api\/0\.6\/(node|way|relation)\/[0-9]*\/history/ then :history
  when /api\/0\.6\/(node|way|relation)\/[0-9]*\/full/ then :full
  when /api\/0\.6\/trackpoints/ then :trkpts
  when /api\/0\.6\// then :other
  else :web
  end
end

server = $PROGRAM_NAME.match("api_waits_(.*)")[1]

if ARGV[0] == 'config'
  puts "graph_title Wait times for active requests"
  puts "graph_vlabel Average time of requests"
  puts "graph_category api"
  CALL_TYPES.each { |k, v| puts "#{k}.label #{v}" }

else
  counts = uri_and_times_from_status(server)
           .collect { |x, y| [categorise_uri(x), y] }
           .each_with_object(Hash.new) do |h, e|
    category, time = e
    if h.key? category
      h[category] += [time]
    else
      h[category] = [time]
    end
  end

  CALL_TYPES.keys.each do |type|
    count = counts[type] || [0]
    avg = count.inject(0) { |a, e| a + e } / (1.0 * count.length)
    puts "#{type}.value #{avg}"
  end
end