#! /usr/bin/env ruby

require 'optparse'
require 'xml-write-stream'
require 'yaml'

$options = {}

option_parser = OptionParser.new do |opts|
  opts.banner = "Usage: yaml2tmx [options]"

  opts.on('-s', '--source [file]', 'YAML file containing phrases in the source locale.') do |source|
    $options[:source] = source
  end

  opts.on('-t', '--target [file]', 'YAML file containing translations in the target locale.') do |target|
    $options[:target] = target
  end

  opts.on('-o', '--output [file]', 'The TMX output file to write. If not specified, output is printed to stdout.') do |output|
    $options[:output] = output
  end

  opts.on('-h', '--help', 'Prints this help message.') do
    puts opts
    exit
  end
end

option_parser.parse!

# load source and target phrases
source_phrases = YAML.load_file($options[:source])
target_phrases = YAML.load_file($options[:target])

source_locale = source_phrases.keys.first
target_locale = target_phrases.keys.first

source_phrases = source_phrases[source_locale]
target_phrases = target_phrases[target_locale]

def each_phrase(phrases, path, &block)
  case phrases
    when Hash
      phrases.each_pair do |key, value|
        each_phrase(value, path + [key], &block)
      end

    when Array
      phrases.each_with_index do |element, idx|
        each_phrase(element, path + [idx], &block)
      end

    when String
      yield phrases, path
  end
end

# correlate source and target phrases
trans_map = {}

phrase_count = 0

each_phrase(source_phrases, []) do |phrase, path|
  phrase_count += 1

  translation = path.inject(:start) do |ret, seg|
    if ret == :start
      target_phrases[seg]
    elsif ret
      if seg.is_a?(Numeric) && ret.is_a?(Array)
        ret[seg]  # array index case
      elsif seg.is_a?(String) && ret.is_a?(Hash)
        ret[seg]  # hash key case
      end
    end
  end

  trans_map[phrase] = translation if translation
end

STDERR.write("Matched #{trans_map.size} of #{phrase_count} source phrases\n")

stream = if $options[:output]
  File.open($options[:output], 'w+')
else
  STDOUT
end

writer = XmlWriteStream.from_stream(stream)
writer.open_tag('tmx', version: '1.4')
writer.open_single_line_tag('header', srclang: source_locale, datatype: 'plaintext', segtype: 'paragraph')
writer.close_tag

writer.open_tag('body')

trans_map.each_pair do |source_phrase, target_phrase|
  writer.open_tag('tu')
  writer.open_tag('tuv', 'xml:lang' => source_locale)
  writer.open_single_line_tag('seg')
  writer.write_text(source_phrase)
  writer.close_tag  # seg
  writer.close_tag  # tuv

  writer.open_tag('tuv', 'xml:lang' => target_locale)
  writer.open_single_line_tag('seg')
  writer.write_text(target_phrase)
  writer.close_tag  # seg
  writer.close_tag  # tuv
  writer.close_tag  # tu
end

writer.close

if $options[:output]
  STDERR.write("Wrote #{$options[:output]}\n")
end