#! /usr/bin/env ruby

require 'yaml'
require 'fileutils'
require 'digest'

abort 'Error: Ruby >= 1.9.3 required.' if RUBY_VERSION < '1.9.3'

# Initialize config settings from config.yml
config = YAML.load_file('config.yml')

# ============================================================
# Add dynamically chosen config settings. These settings should
# be suitable for any installation.

# Any _PW/_SECRET config settings represent passwords/secrets. If they
# are blank, choose a password. Make sure the generated password
# doesn't change if config.yml doesn't change. Otherwise, keys won't
# match any more if (say) keep's files get regenerated but apiserver's
# don't.
config.sort.map do |var,val|
  if (var.end_with?('_PW') || var.end_with?('_SECRET')) && (config[var].nil? || config[var].empty?)
    config[var] = Digest::SHA1.hexdigest(`hostname` + var + config.to_yaml)
  end
end

# ============================================================
# For each *.in file in the docker directories, substitute any
# @@variables@@ found in the file with the appropriate config
# variable. Support up to 10 levels of nesting.
#
# TODO(twp): add the *.in files directory to the source tree, and
# when expanding them, add them to the "generated" directory with
# the same tree structure as in the original source. Then all
# the files can be added to the docker container with a single ADD.

if ARGV[0] and ARGV[0].length > 0
  globdir = ARGV[0]
else
  globdir = '*'
end

FileUtils.rm_r Dir.glob(globdir + '/generated/*')

File.umask(022)
Dir.glob(globdir + '/*.in') do |template_file|
  generated_dir = File.join(File.dirname(template_file), 'generated')
  Dir.mkdir(generated_dir) unless Dir.exists? generated_dir
  output_path = File.join(generated_dir, File.basename(template_file, '.in'))
  output_mode = (File.stat(template_file).mode & 0100) ? 0755 : 0644
  File.open(output_path, "w", output_mode) do |output|
    File.open(template_file) do |input|
      input.each_line do |line|

        # This count is used to short-circuit potential
        # infinite loops of variable substitution.
        @count = 0
        while @count < 10
          @out = line.gsub!(/@@(.*?)@@/) do |var|
            if config.key?(Regexp.last_match[1])
              config[Regexp.last_match[1]]
            else
              var.gsub!(/@@/, '@_NOT_FOUND_@')
            end
          end
          break if @out.nil?
          @count += 1
        end

        output.write(line)
      end
    end
  end
end