module Wraptools
  # unwrap format=flowed text
  def self.unwrap(s)
    s.gsub(/ \n/, " ")
  end
  
  # unwrap a format=flowed text; preserves quoting information
  def self.unwrap_quoted(s)
    level = nil # the quoting level
    ff = nil # does the line end with " "?
    
    text = ''
    
    s.split(/\r*\n/).each do |t|

      old_level = level
      old_ff = ff
      # detect the quoting level of the line
      if t =~ /^(>+)/
        level = $1.size
      else
        level = 0
      end
      
      # trailing space?
      ff = (t[-1,1] == " ")

      if old_ff and level == old_level
        result = t.sub(/^>{#{level}}\s/, "")
      else
        result = t
      end
      
      if old_ff == false or (old_ff == true and level != old_level)
        text += "\n"
      end
      
      text += result
    end
    
    text.gsub(/ \n/, "\n")
  end
  
  # wrap a text with format=flowed
  def self.wrap_ff(s, n)
    wrap(s, n, " \n")
  end
  
  # wrap a text
  def self.wrap(s, n, break_string="\n")
    s.split("\n").map do |t|
      if t =~ /^[>|]/
        t + "\n"
      elsif t.strip == ""
        t = "\n"
      else
        t.gsub(/(.{0,#{n-1}}\S)(\s+|\Z)/,"\\1" + break_string).gsub(/\s+\n$/,"\n")
      end
    end.join('').chop
  end
  
  # split words that are longer than n characters
  def self.break_long_words(s, n)
    s.gsub(/(\S{#{n}})(?=\S)/, "\\1 \\2")
  end

  # add one level of indentation to a text
  def self.quote(s)
    s.split(/\r*\n/).each do |line|
      if line =~ /^>/
        line.replace '>' + line
      else
        line.replace '> ' + line
      end
    end.join("\n")
  end
end