#!/usr/bin/ruby

require "apache_log_regex"
require "file-tail"
require "json"

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

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

parser = ApacheLogRegex.new('%h %l %u %t \"%r\" %>s %O \"%{Referer}i\" \"%{User-Agent}i\" %Dus %{UNIQUE_ID}e %{SSL_PROTOCOL}x %{SSL_CIPHER}x')
last_write = Time.now
statistics = { :status => Hash.new(0), :uri => Hash.new(0) }

File::Tail::Logfile.tail("/var/log/apache2/access.log") do |line|
  begin
    hash = parser.parse(line)
    status = hash["%>s"]
    uri = categorise_uri(hash["%r"])

    statistics[:status][status] += 1
    statistics[:uri][uri] += 1
  rescue ApacheLogRegex::ParseError
    # nil
  end

  if Time.now - last_write > 10
    File.write("/srv/www.openstreetmap.org/rails/tmp/statistics.json", statistics.to_json)
    last_write = Time.now
  end
end