stripectf3 level 3 solution

indexer.rb

#!/usr/bin/env ruby

exit if ARGV.shift != "--master"
ARGV.shift until ARGV.empty?

require 'sinatra'
require 'json'
require 'thread'
require 'set'

set :port, 9090
Thread.abort_on_exception = true

$indexed = false

get '/healthcheck' do
  content_type "application/json"
  {success: true}.to_json
end

get '/isIndexed' do
  content_type "application/json"
  {success: $indexed}.to_json
end

get '/' do
  content_type "application/json"
  {
    success: true,
    results: lookup(params[:q]),
  }.to_json
end

get '/index' do
  Thread.new {
    index(params[:path])
  }
  content_type "application/json"
  "OK"
end

def index(dir)
  Dir.chdir(dir)
  $word_locations = {}
  $word_str = ","

  files = Dir["**/*"].select { |f| File.stat(f).file? }
  files.each do |f|
    File.open(f).each_line.with_index { |l,i|
      l.scan(/\w+/).each { |w|
        unless $word_locations[w]
          $word_str << w << ","
          $word_locations[w] = []
        end
        $word_locations[w] << f.to_sym << i + 1
      }
    }
  end
  $indexed = true
end

def matches(q)
  offset = 0
  words = []
  while offset = $word_str.index(q, offset)
    r = $word_str.index(",", offset) - 1
    l = $word_str.rindex(",", offset) + 1
    words << $word_str[l..r]
    offset += 1
  end
  words
end

def lookup(q)
  matches(q).flat_map { |w|
    $word_locations[w].each_slice(2).map { |f, i|
      "#{f}:#{i}"
    }
  }.uniq
end