# lib/string_wrap.rb

require 'io/console'

# This is a monkey patch to the String class which is
# okay in this context since this program is a
# stand-alone terminal utility.  Otherwise we would
# use a refinement or a namespace to keep this from
# impact other code.

class String
  def wrap(line_width: nil, indent: 0)
    # If line_width is not given, try to detect the terminal width
    line_width ||= IO.console ? IO.console.winsize[1] : 80

    # Prepare the prefix based on the type of the indent parameter
    prefix = indent.is_a?(String) ? indent : ' ' * indent.to_i

    # Split the string into paragraphs first, preserve paragraph breaks
    paragraphs = self.split(/\n{2,}/)

    # Create an empty array that will hold all wrapped paragraphs
    wrapped_paragraphs = []

    # Process each paragraph separately
    paragraphs.each do |paragraph|
      wrapped_lines = [] # Create an empty array for wrapped lines of the current paragraph
      
      # Split the paragraph into lines first, in case there are single newlines
      lines = paragraph.split(/(?<=\n)/)

      # Process each line separately to maintain single newlines
      lines.each do |line|
        words         = line.split
        current_line  = ""

        words.each do |word|
          if word.include?("\n") && !word.strip.empty?
            # If the word contains a newline, split and process as separate lines
            parts = word.split(/(?<=\n)/)

            parts.each_with_index do |part, index|
              if part == "\n"
                wrapped_lines << prefix + current_line
                current_line = ""
              else
                current_line << " " unless current_line.empty? or index == 0
                current_line << part.strip
              end
            end

          elsif current_line.length + word.length + 1 > line_width - prefix.length
            wrapped_lines << prefix + current_line.rstrip
            current_line  = word

          else
            current_line << " " unless current_line.empty?
            current_line << word
          end
        end

        # Don't forget to add the last line unless it's empty
        wrapped_lines << prefix + current_line unless current_line.empty?
      end

      # Preserve the paragraph structure by joining the wrapped lines and append to the wrapped_paragraphs array
      wrapped_paragraphs << wrapped_lines.join("\n")
    end

    # Join wrapped paragraphs with double newlines into a single string
    wrapped_paragraphs.join("\n\n")
  end
end