require 'cgi'
require 'rexml/document'

module Twine
  module Formatters
    class Android < Abstract
      include Twine::Placeholders

      LANG_CODES = Hash[
        'zh' => 'zh-Hans',
        'zh-CN' => 'zh-Hans',
        'zh-HK' => 'zh-Hant',
        'en-GB' => 'en-GB',
        'in' => 'id'
      ]

      def format_name
        'android'
      end

      def extension
        '.xml'
      end

      def can_handle_directory?(path)
        Dir.entries(path).any? { |item| /^values.*$/.match(item) }
      end

      def default_file_name
        'strings.xml'
      end

      def determine_language_given_path(path)
        path_arr = path.split(File::SEPARATOR)
        path_arr.each do |segment|
          if segment == 'values'
            return @twine_file.language_codes[0]
          else
            # The language is defined by a two-letter ISO 639-1 language code, optionally followed by a two letter ISO 3166-1-alpha-2 region code (preceded by lowercase "r").
            # see http://developer.android.com/guide/topics/resources/providing-resources.html#AlternativeResources
            match = /^values-([a-z]{2}(-r[a-z]{2})?)$/i.match(segment)
            
            if match
              lang = match[1].sub('-r', '-')
              return LANG_CODES.fetch(lang, lang)
            end
          end
        end

        return
      end

      def output_path_for_language(lang)
        "values-#{lang}"
      end

      def set_translation_for_key(key, lang, value)
        value = CGI.unescapeHTML(value)
        value.gsub!('\\\'', '\'')
        value.gsub!('\\"', '"')
        value = convert_placeholders_from_android_to_twine(value)
        value.gsub!('\@', '@')
        value.gsub!(/(\\u0020)*|(\\u0020)*\z/) { |spaces| ' ' * (spaces.length / 6) }
        super(key, lang, value)
      end

      def read(io, lang)
        document = REXML::Document.new io, :compress_whitespace => %w{ string }

        comment = nil
        document.root.children.each do |child|
          if child.is_a? REXML::Comment
            content = child.string.strip
            comment = content if content.length > 0 and not content.start_with?("SECTION:")
          elsif child.is_a? REXML::Element
            next unless child.name == 'string'

            key = child.attributes['name']

            set_translation_for_key(key, lang, child.text)
            set_comment_for_key(key, comment) if comment

            comment = nil
          end 
        end
      end

      def format_header(lang)
        "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n<!-- Android Strings File -->\n<!-- Generated by Twine #{Twine::VERSION} -->\n<!-- Language: #{lang} -->"
      end

      def format_sections(twine_file, lang)
        result = '<resources>'
        
        result += super + "\n"

        result += "</resources>\n"
      end

      def format_section_header(section)
        "\t<!-- SECTION: #{section.name} -->"
      end

      def format_comment(definition, lang)
        "\t<!-- #{definition.comment.gsub('--', '—')} -->\n" if definition.comment
      end

      def key_value_pattern
        "\t<string name=\"%{key}\">%{value}</string>"
      end

      def escape_value(value)
        # escape double and single quotes, & signs and tags
        value = escape_quotes(value)
        value.gsub!("'", "\\\\'")
        value.gsub!(/&/, '&amp;')
        value.gsub!('<', '&lt;')

        # escape non resource identifier @ signs (http://developer.android.com/guide/topics/resources/accessing-resources.html#ResourcesFromXml)
        resource_identifier_regex = /@(?!([a-z\.]+:)?[a-z+]+\/[a-zA-Z_]+)/   # @[<package_name>:]<resource_type>/<resource_name>
        value.gsub(resource_identifier_regex, '\@')
      end

      # see http://developer.android.com/guide/topics/resources/string-resource.html#FormattingAndStyling
      # however unescaped HTML markup like in "Welcome to <b>Android</b>!" is stripped when retrieved with getString() (http://stackoverflow.com/questions/9891996/)
      def format_value(value)
        value = value.dup

        # convert placeholders (e.g. %@ -> %s)
        value = convert_placeholders_from_twine_to_android(value)

        # capture xliff tags and replace them with a placeholder
        xliff_tags = []
        value.gsub! /<xliff:g.+?<\/xliff:g>/ do
          xliff_tags << $&
          'TWINE_XLIFF_TAG_PLACEHOLDER'
        end

        # escape everything outside xliff tags
        value = escape_value(value)

        # put xliff tags back into place
        xliff_tags.each do |xliff_tag|
          # escape content of xliff tags
          xliff_tag.gsub! /(<xliff:g.*?>)(.*)(<\/xliff:g>)/ do "#{$1}#{escape_value($2)}#{$3}" end
          value.sub! 'TWINE_XLIFF_TAG_PLACEHOLDER', xliff_tag
        end
        
        # replace beginning and end spaces with \u0020. Otherwise Android strips them.
        value.gsub(/\A *| *\z/) { |spaces| '\u0020' * spaces.length }
      end

    end
  end
end

Twine::Formatters.formatters << Twine::Formatters::Android.new
