class String
  def message_quote
    quote = split("\n")
    body_quote = ''
    quote.each do |line|
      body_quote = body_quote + '> ' + line + "\n"
    end
    body_quote
  end

  def word_wrap(*args)
    options = args.extract_options!
    unless args.blank?
      options[:line_width] = args[0] || 82
    end
    options.reverse_merge!(line_width: 82)

    lines = self
    lines.split("\n").collect do |line|
      line.length > options[:line_width] ? line.gsub(/(.{1,#{options[:line_width]}})(\s+|$)/, "\\1\n").strip : line
    end * "\n"
  end

=begin

  filename = 'Some::Module'.to_filename

  returns
    'some/module'

=end

  def to_filename
    camel_cased_word = "#{self}" # rubocop:disable Style/UnneededInterpolation
    camel_cased_word.gsub(/::/, '/')
                    .gsub(/([A-Z]+)([A-Z][a-z])/, '\1_\2')
                    .gsub(/([a-z\d])([A-Z])/, '\1_\2')
                    .tr('-', '_').downcase
  end

=begin

  filename = 'some/module.rb'.to_classname

  returns
    'Some::Module'

=end

  def to_classname
    camel_cased_word = "#{self}" # rubocop:disable Style/UnneededInterpolation
    camel_cased_word.gsub!(/\.rb$/, '')
    camel_cased_word.split('/').map(&:camelize).join('::')
  end

  # because of mysql inno_db limitations, strip 4 bytes utf8 chars (e. g. emojis)
  # unfortunaly UTF8mb4 will raise other limitaions of max varchar and lower index sizes
  # More details: http://pjambet.github.io/blog/emojis-and-mysql/
  def utf8_to_3bytesutf8
    return self if Rails.application.config.db_4bytes_utf8
    each_char.select { |c|
      if c.bytes.count > 3
        Rails.logger.warn "strip out 4 bytes utf8 chars '#{c}' of '#{self}'"
        next
      end
      c
    }
             .join('')
  end

=begin

  text = html_string.html2text

  returns

    'string with text only'

=end

  def html2text(string_only = false, strict = false)
    string = "#{self}" # rubocop:disable Style/UnneededInterpolation

    # in case of invalid encodeing, strip invalid chars
    # see also test/fixtures/mail21.box
    # note: string.encode!('UTF-8', 'UTF-8', :invalid => :replace, :replace => '?') was not detecting invalid chars
    if !string.valid_encoding?
      string = string.chars.select(&:valid_encoding?).join
    end

    # remove html comments
    string.gsub!(/<!--.+?-->/m, '')

    # find <a href=....> and replace it with [x]
    link_list = ''
    counter   = 0
    if !string_only
      string.gsub!(/<a[[:space:]].*?href=("|')(.+?)("|').*?>/ix) {
        link = $2
        counter = counter + 1
        link_list += "[#{counter}] #{link}\n"
        "[#{counter}] "
      }
    else
      string.gsub!(%r{<a[[:space:]]+(|\S+[[:space:]]+)href=("|')(.+?)("|')([[:space:]]*|[[:space:]]+[^>]*)>(.+?)<[[:space:]]*/a[[:space:]]*>}mxi) { |_placeholder|
        link = $3
        text = $6
        text.gsub!(/\<.+?\>/, '')

        link_compare = link.dup
        if !link_compare.empty?
          link.strip!
          link_compare.strip!
          link_compare.downcase!
          link_compare.sub!(%r{/$}, '')
        end
        text_compare = text.dup
        if !text_compare.empty?
          text.strip!
          text_compare.strip!
          text_compare.downcase!
          text_compare.sub!(%r{/$}, '')
        end
        placeholder = if !link_compare.empty? && text_compare.empty?
                        link
                      elsif link_compare.empty? && !text_compare.empty?
                        text
                      elsif link_compare && link_compare =~ /^mailto/i
                        text
                      elsif !link_compare.empty? && !text_compare.empty? && (link_compare == text_compare || link_compare == "mailto:#{text}".downcase || link_compare == "http://#{text}".downcase)
                        "######LINKEXT:#{link}/TEXT:#{text}######"
                      elsif text !~ /^http/
                        "#{text} (######LINKRAW:#{link}######)"
                      else
                        "#{link} (######LINKRAW:#{text}######)"
                      end
      }
    end

    # remove style tags with content
    string.gsub!(%r{<style(|[[:space:]].+?)>(.+?)</style>}im, '')

    # remove empty lines
    string.gsub!(/^[[:space:]]*/m, '')
    if strict
      string.gsub!(%r{< [[:space:]]* (/*) [[:space:]]* (b|i|ul|ol|li|u|h1|h2|h3|hr) ([[:space:]]*|[[:space:]]+[^>]*) >}mxi, '######\1\2######')
    end

    # pre/code handling 1/2
    string.gsub!(%r{<pre>(.+?)</pre>}m) { |placeholder|
      placeholder = placeholder.gsub(/\n/, '###BR###')
    }
    string.gsub!(%r{<code>(.+?)</code>}m) { |placeholder|
      placeholder = placeholder.gsub(/\n/, '###BR###')
    }

    # insert spaces on [A-z]\n[A-z]
    string.gsub!(/([A-z])[[:space:]]([A-z])/m, '\1 \2')

    # remove all new lines
    string.gsub!(/(\n\r|\r\r\n|\r\n|\n)/, '')

    # blockquote handling
    string.gsub!(%r{<blockquote(| [^>]*)>(.+?)</blockquote>}m) {
      "\n" + $2.html2text(true).gsub(/^(.*)$/, '&gt; \1') + "\n"
    }

    # pre/code handling 2/2
    string.gsub!(/###BR###/, "\n")

    # add counting
    string.gsub!(/<li(| [^>]*)>/i, "\n* ")

    # add hr
    string.gsub!(%r{<hr(|/| [^>]*)>}i, "\n___\n")

    # add h\d
    string.gsub!(%r{</h\d>}i, "\n")

    # add new lines
    string.gsub!(%r{</div><div(|[[:space:]].+?)>}im, "\n")
    string.gsub!(%r{</p><p(|[[:space:]].+?)>}im, "\n")
    string.gsub!(%r{<(div|p|pre|br|table|tr|h)(|/| [^>]*)>}i, "\n")
    string.gsub!(%r{</(p|br|div)(|[[:space:]].+?)>}i, "\n")
    string.gsub!(%r{</td>}i, ' ')

    # strip all other tags
    string.gsub!(/\<.+?\>/, '')

    # replace multiple spaces with one
    string.gsub!(/  /, ' ')

    # add hyperlinks
    if strict
      string.gsub!(%r{([[:space:]])((http|https|ftp|tel)://.+?|(www..+?))([[:space:]]|\.[[:space:]]|,[[:space:]])}mxi) { |_placeholder|
        pre = $1
        content = $2
        post = $5
        if content =~ /^www/i
          content = "http://#{content}"
        end
        placeholder = if content =~ /^(http|https|ftp|tel)/i
                        "#{pre}######LINKRAW:#{content}#######{post}"
                      else
                        "#{pre}#{content}#{post}"
                      end
      }
    end

    # try HTMLEntities, if it fails on invalid signes, use manual way
    begin
      coder = HTMLEntities.new
      string = coder.decode(string)
    rescue

      # strip all &amp; &lt; &gt; &quot;
      string.gsub!('&amp;', '&')
      string.gsub!('&lt;', '<')
      string.gsub!('&gt;', '>')
      string.gsub!('&quot;', '"')
      string.gsub!('&nbsp;', ' ')

      # encode html entities like "&#8211;"
      string.gsub!(/(&\#(\d+);?)/x) {
        $2.chr
      }

      # encode html entities like "&#3d;"
      string.gsub!(/(&\#[xX]([0-9a-fA-F]+);?)/x) {
        chr_orig = $1
        hex      = $2.hex
        if hex
          chr = hex.chr
          if chr
            chr_orig = chr
          else
            chr_orig
          end
        else
          chr_orig
        end

        # check valid encoding
        begin
          if !chr_orig.encode('UTF-8').valid_encoding?
            chr_orig = '?'
          end
        rescue
          chr_orig = '?'
        end
        chr_orig
      }
    end

    # remove tailing empty spaces
    string.gsub!(/[[:blank:]]+$/, '')

    # remove double multiple empty lines
    string.gsub!(/\n\n\n+/, "\n\n")

    # add extracted links
    if link_list != ''
      string += "\n\n\n" + link_list
    end

    # remove double multiple empty lines
    string.gsub!(/\n\n\n+/, "\n\n")

    string.strip
  end

=begin

  html = text_string.text2html

=end

  def text2html
    text = CGI.escapeHTML(self)
    text.gsub!(/\n/, '<br>')
    text.chomp
  end

=begin

  html = text_string.text2html

=end

  def html2html_strict(force = false)
    string = html2text(true, true)
    string.signature_identify(force)
    string = string.text2html
    string.gsub!(%r{######LINKEXT:(.+?)/TEXT:(.+?)######}, '<a href="\1" target="_blank">\2</a>')
    string.gsub!(/######LINKRAW:(.+?)######/, '<a href="\1" target="_blank">\1</a>')
    marker_template = '<span class="js-signatureMarker"></span>'
    string.sub!(/######SIGNATURE_MARKER######/, marker_template)
    string.gsub!(/######SIGNATURE_MARKER######/, '')
    string.gsub!(/######(.+?)######/, '<\1>')
    string.chomp
  end

  def signature_identify(force = false)
    string = self

    # if we do have less then 10 lines and less then 300 chars ignore this
    if !force
      lines = string.split("\n")
      return if lines.count < 10 && string.length < 300
    end

    marker = '######SIGNATURE_MARKER######'

    # search for signature separator "--\n"
    string.sub!(/^\s{0,2}--\s{0,2}$/) { |placeholder|
      placeholder = "#{marker}#{placeholder}"
    }

    map = {}
    # Apple Mail
    # On 01/04/15 10:55, Bob Smith wrote:
    map['apple-en'] = '^(On)[[:space:]].{6,20}[[:space:]].{3,10}[[:space:]].{1,250}[[:space:]](wrote):'

    # Am 03.04.2015 um 20:58 schrieb Martin Edenhofer <me@znuny.ink>:
    map['apple-de'] = '^(Am)[[:space:]].{6,20}[[:space:]](um)[[:space:]].{3,10}[[:space:]](schrieb)[[:space:]].{1,250}:'

    # Thunderbird
    # Am 04.03.2015 um 12:47 schrieb Alf Aardvark:
    map['thunderbird-de'] = '^(Am)[[:space:]].{6,20}[[:space:]](um)[[:space:]].{3,10}[[:space:]](schrieb)[[:space:]].{1,250}:'

    # Thunderbird default - http://kb.mozillazine.org/Reply_header_settings
    # On 01-01-2007 11:00 AM, Alf Aardvark wrote:
    map['thunderbird-en-default'] = '^(On)[[:space:]].{6,20}[[:space:]].{3,10},[[:space:]].{1,250}(wrote):'

    # http://kb.mozillazine.org/Reply_header_settings
    # Alf Aardvark wrote, on 01-01-2007 11:00 AM:
    map['thunderbird-en'] = '^.{1,250}[[:space:]](wrote),[[:space:]]on[[:space:]].{3,20}:'

    # otrs
    # 25.02.2015 10:26 - edv hotline wrote:
    # 25.02.2015 10:26 - edv hotline schrieb:
    map['otrs-en-de'] = '^.{6,10}[[:space:]].{3,10}[[:space:]]-[[:space:]].{1,250}[[:space:]](wrote|schrieb):'

    # Ms
    # rubocop:disable Style/AsciiComments
    # From: Martin Edenhofer via Znuny Support [mailto:support@znuny.inc]
    # Send: Donnerstag, 2. April 2015 10:00
    # To/Cc/Bcc: xxx
    # Subject: xxx
    # - or -
    # From: xxx
    # To/Cc/Bcc: xxx
    # Date: 01.04.2015 12:41
    # Subject: xxx
    # - or -
    # De : xxx
    # À/?/?: xxx
    # Envoyé : mercredi 29 avril 2015 17:31
    # Objet : xxx
    # rubocop:enable Style/AsciiComments

    # en/de/fr | sometimes ms adds a space to "xx : value"
    map['ms-en-de-fr_from'] = '^(From|Von|De)( ?):[[:space:]].+?'
    map['ms-en-de-fr_from_html'] = "\n######b######(From|Von|De)([[:space:]]?):([[:space:]]?)(######\/b######)[[:space:]].+?"

    # word 14
    # edv hotline wrote:
    # edv hotline schrieb:
    #map['word-en-de'] = "[^#{marker}].{1,250}\s(wrote|schrieb):"

    map.each { |_key, regexp|
      string.sub!(/#{regexp}/) { |placeholder|
        placeholder = "#{marker}#{placeholder}"
      }
    }

    string
  end
end