# == Annotate Routes
#
# Based on:
#
#
#
# Prepends the output of "rake routes" to the top of your routes.rb file.
# Yes, it's simple but I'm thick and often need a reminder of what my routes
# mean.
#
# Running this task will replace any exising route comment generated by the
# task. Best to back up your routes file before running:
#
# Author:
#  Gavin Montague
#  gavin@leftbrained.co.uk
#
# Released under the same license as Ruby. No Support. No Warranty.
#
module AnnotateRoutes
  PREFIX = '# == Route Map'

  def self.do_annotations(options={})
    return unless routes_exists?

    routes_map = AnnotateRoutes.app_routes_map(options)

    header = [
        "#{PREFIX}" + (options[:timestamp] ? " (Updated #{Time.now.strftime('%Y-%m-%d %H:%M')})" : ''), '#'
    ] + routes_map.map { |line| "# #{line}".rstrip }

    existing_text = File.read(routes_file)

    if write_contents(existing_text, header, options)
      puts "#{routes_file} annotated."
    end
  end

  def self.remove_annotations(options={})
    return unless routes_exists?
    existing_text = File.read(routes_file)
    content, where_header_found = strip_annotations(existing_text)

    content = strip_on_removal(content, where_header_found)

    if write_contents(existing_text, content, options)
      puts "Removed annotations from #{routes_file}."
    end
  end

  private

  def self.app_routes_map(options)
    routes_map = `rake routes`.split(/\n/, -1)

    # In old versions of Rake, the first line of output was the cwd.  Not so
    # much in newer ones.  We ditch that line if it exists, and if not, we
    # keep the line around.
    routes_map.shift if routes_map.first =~ /^\(in \//

    # Skip routes which match given regex
    # Note: it matches the complete line (route_name, path, controller/action)
    if options[:ignore_routes]
      routes_map.reject! { |line| line =~ /#{options[:ignore_routes]}/ }
    end

    routes_map
  end

  def self.routes_file
    @routes_rb ||= File.join('config', 'routes.rb')
  end

  def self.routes_exists?
    routes_exists = File.exists?(routes_file)
    puts "Can't find routes.rb" unless routes_exists

    routes_exists
  end

  def self.write_contents(existing_text, header, options = {})
    content, where_header_found = strip_annotations(existing_text)
    new_content = annotate_routes(header, content, where_header_found, options)

    # Make sure we end on a trailing newline.
    new_content << '' unless new_content.last == ''
    new_text = new_content.join("\n")

    if existing_text == new_text
      puts "#{routes_file} unchanged."
      false
    else
      File.open(routes_file, 'wb') { |f| f.puts(new_text) }
      true
    end
  end

  def self.annotate_routes(header, content, where_header_found, options = {})
    if %w(before top).include?(options[:position_in_routes])
      header = header << '' if content.first != ''
      new_content = header + content
    else
      # Ensure we have adequate trailing newlines at the end of the file to
      # ensure a blank line separating the content from the annotation.
      content << '' unless content.last == ''

      # We're moving something from the top of the file to the bottom, so ditch
      # the spacer we put in the first time around.
      content.shift if where_header_found == :before && content.first == ''

      new_content = content + header
    end

    new_content
  end

  # TODO: write the method doc using ruby rdoc formats
  # where_header_found => This will either be :before, :after, or
  # a number.  If the number is > 0, the
  # annotation was found somewhere in the
  # middle of the file.  If the number is
  # zero, no annotation was found.
  def self.strip_annotations(content)
    real_content = []
    mode = :content
    header_found_at = 0

    content.split(/\n/, -1).each_with_index do |line, line_number|
      if mode == :header && line !~ /\s*#/
        mode = :content
        next unless line == ''
      elsif mode == :content
        if line =~ /^\s*#\s*== Route.*$/
          header_found_at = line_number + 1 # index start's at 0
          mode = :header
        else
          real_content << line
        end
      end
    end

    where_header_found(real_content, header_found_at)
  end

  def self.where_header_found(real_content, header_found_at)
    # By default assume the annotation was found in the middle of the file

    # ... unless we have evidence it was at the beginning ...
    return real_content, :before if header_found_at == 1

    # ... or that it was at the end.
    return real_content, :after if header_found_at >= real_content.count

    # and the default
    return real_content, header_found_at
  end

  def self.strip_on_removal(content, where_header_found)
    if where_header_found == :before
      content.shift while content.first == ''
    elsif where_header_found == :after
      content.pop while content.last == ''
    end

    # TODO: If the user buried it in the middle, we should probably see about
    # TODO: preserving a single line of space between the content above and
    # TODO: below...
    content
  end
end