class MTLite

# File lib/mtlite.rb, line 10
def initialize(raw_msg, debug: false)

  @debug = debug
  
  # reveal the expanded URL from a shortened URL
  raw_msg.gsub!(/https?:\/\/[^ ]+/) do |url|      
    
    puts 'url: ' + url.inspect if @debug
    
    Embiggen::URI(url).expand.to_s
  end
  
  puts 'raw_msg: ' + raw_msg.inspect if @debug
  
  # make the smartlinks into Markdown links
  @raw_msg = smartlink(raw_msg)
  
  puts '@raw_msg: '  + @raw_msg.inspect if @debug
  
end

# File lib/mtlite.rb, line 116
def length
  @msg.gsub(/<\/?.[^>]*>/,'').length
end

# File lib/mtlite.rb, line 31
def to_html(para: false, ignore_domainlabel: false)

  raw_msg = @raw_msg.clone    
  # if it looks like an MtLite list make it an MtLite list
  # e.g. "a todo list:\n* line 1\n* line 2" =>
  #                                       a todo list: [* line 1 * line 2]
  raw_msg.sub!(/^(?:[\*#][^\n]+\n?)+/,'[\0]') if raw_msg =~ /\n/
  raw_msg.gsub!(/\n/,' ')


  # add br tags to checklist items
  # todo list: [[x] line 1 [] line 2] =>
  #                         todo list: <br/>[x] line 1 <br/>[] line 2
  raw_msg.sub!(/\[\[.*\]/){|x| x[0..-2].gsub(/[^\n](\[[x\s]?\])/,'<br/>\1') }

  # convert square brackets to unicode check boxes
  # replaces a [] with a unicode checkbox,
  #                         and [x] with a unicode checked checkbox
  raw_msg = raw_msg.gsub(/\[\s*\](?= )/,'&#9744;').gsub(/\[x\]/,'&#9745;')

  # convert fractions using their associated unicode character
  # i.e. 1/4, 1/2, 3/4
  raw_msg = raw_msg.gsub('\b1/4\b','&#188;').gsub('\b1/2\b','&#189;')\
                  .gsub('\b3/4\b','&#190;')

  # add strikethru to completed items
  # e.g. -milk cow- becomes <del>milk cow</del>
  raw_msg.gsub!(/\s-[^-]+-?[^-]+-[\s\]]/) do |x|
    x.sub(/-([&\w]+.*\w+)-/,'<del>\1</del>')
  end
    
  unless ignore_domainlabel then
    
    # append a domain label after the URL
    raw_msg.gsub!(/(?:^\[|\s\[)[^\]]+\]\((https?:\/\/[^\s]+)/) do |x|
      s2 = x[/https?:\/\/([^\/]+)/,1].split(/\./)
      r = s2.length >= 3 ? s2[1..-1] :  s2
      "%s [%s]" % [x, r.join('.')]
    end
    
  end
  
  # generate html lists from mtlite 1-liner lists
  raw_msg.gsub!(/\[[\*#][^\]]+\]/) do |list|

    if not list[/\n/] then

      symbol = list[1]
      symbol.prepend '\\' if symbol == '*'
      tag = {'#' => 'ol', '\*' => 'ul'}[symbol]

      "<#{tag}>%s</#{tag}>" % list.strip[1..-2].split(/#{symbol}/)[1..-1].
        map{|x| "<li>%s</li>" % x.strip}.join
    else
      list
    end

  end

  msg = RDiscount.new(raw_msg).to_html
  msg.gsub!(/<\/?p[^>]*>/,'') unless para

  regex = %r([^ <]+)
  # generate anchor tags for URLs which don't have anchor tags
  msg.gsub!(/(?:^(https?:#{regex})|\s(https?:#{regex}))/,' <a href="\2">\2</a>')    
  
  msg.gsub!(/(?<=\>)https?:#{regex}/) do |x|
    
    # unescapeHTML will transform &amp; to &
    url = CGI.unescapeHTML x
    url2 = url.sub(/^https?:\/\//,'').sub(/^www\./,'')
    url3 = url2.length > 33 ? url2[0..33] + '...' : url2
    #" <a href='#{url}'>#{url3}</a>"
  end

  # add the target attribute to make all hyperlinks open in a new browser tab
  msg.gsub!(/<a /,'<a target="_blank" ')
  
  # undecorate h1 headings
  msg.gsub!(/<h1/,'<h1 style="font-size: 0.95em; font-weight: 600"')
      
  @msg = msg
  
end

# File lib/mtlite.rb, line 120
def to_s

  msg = @raw_msg.clone
  
  # remove markdown hyperlink markings
  msg.gsub!(/\[([^\]]+)\]\(([^\)]+)\)/, '\1 \2')

  # generate html lists from mtlite 1-liner lists
  msg.gsub!(/\[[\*#][^\]]+\]/) do |list|

    if not list[/\n/] then

      symbol = list[1]
      symbol.prepend '\\' if symbol == '*'

      list.strip[1..-2].split(/#{symbol}/)[1..-1]\
        .map{|x| "\n* %s" % x.strip}.join + "\n"
    else
      list
    end

  end

  @msg = msg.gsub('<br/>',"\n").gsub(/<\/?.[^>]*>/,'')
end

# File lib/mtlite.rb, line 148
def smartlink(s)
  
  s.gsub(/\B\?([^\n]+) +(https?:\/\/.*\?)(?=\B)/) do
    "[%s](%s)" % [$1, ($2).chop]
  end

end