# frozen_string_literal: true
##
# A comment holds the text comment for a RDoc::CodeObject and provides a
# unified way of cleaning it up and parsing it into an RDoc::Markup::Document.
#
# Each comment may have a different markup format set by #format=.  By default
# 'rdoc' is used.  The :markup: directive tells RDoc which format to use.
#
# See {RDoc Markup Reference}[rdoc-ref:doc/markup_reference/rdoc.rdoc@Directive+for+Specifying+RDoc+Source+Format].


class RDoc::Comment

  include RDoc::Text

  ##
  # The format of this comment.  Defaults to RDoc::Markup

  attr_reader :format

  ##
  # The RDoc::TopLevel this comment was found in

  attr_accessor :location

  ##
  # Line where this Comment was written

  attr_accessor :line

  ##
  # For duck-typing when merging classes at load time

  alias file location # :nodoc:

  ##
  # The text for this comment

  attr_reader :text

  ##
  # Alias for text

  alias to_s text

  ##
  # Overrides the content returned by #parse.  Use when there is no #text
  # source for this comment

  attr_writer   :document

  ##
  # Creates a new comment with +text+ that is found in the RDoc::TopLevel
  # +location+.

  def initialize(text = nil, location = nil, language = nil)
    @location = location
    @text     = text.nil? ? nil : text.dup
    @language = language

    @document   = nil
    @format     = 'rdoc'
    @normalized = false
  end

  ##
  #--
  # TODO deep copy @document

  def initialize_copy(copy) # :nodoc:
    @text = copy.text.dup
  end

  def ==(other) # :nodoc:
    self.class === other and
      other.text == @text and other.location == @location
  end

  ##
  # Look for a 'call-seq' in the comment to override the normal parameter
  # handling.  The :call-seq: is indented from the baseline.  All lines of the
  # same indentation level and prefix are consumed.
  #
  # For example, all of the following will be used as the :call-seq:
  #
  #   # :call-seq:
  #   #   ARGF.readlines(sep=$/)     -> array
  #   #   ARGF.readlines(limit)      -> array
  #   #   ARGF.readlines(sep, limit) -> array
  #   #
  #   #   ARGF.to_a(sep=$/)     -> array
  #   #   ARGF.to_a(limit)      -> array
  #   #   ARGF.to_a(sep, limit) -> array

  def extract_call_seq
    # we must handle situations like the above followed by an unindented first
    # comment.  The difficulty is to make sure not to match lines starting
    # with ARGF at the same indent, but that are after the first description
    # paragraph.
    if /^(?<S> ((?!\n)\s)*+        (?# whitespaces except newline))
         :?call-seq:
           (?<B> \g<S>(?<N>\n|\z)  (?# trailing spaces))?
         (?<seq>
           (\g<S>(?!\w)\S.*\g<N>)*
           (?>
             (?<H> \g<S>\w+        (?# ' #   ARGF' in the example above))
             .*\g<N>)?
           (\g<S>\S.*\g<N>         (?# other non-blank line))*+
           (\g<B>+(\k<H>.*\g<N>    (?# ARGF.to_a lines))++)*+
         )
         (?m:^\s*$|\z)
        /x =~ @text
      seq = $~[:seq]

      all_start, all_stop = $~.offset(0)
      @text.slice! all_start...all_stop

      seq.gsub!(/^\s*/, '')
    end
  end

  ##
  # A comment is empty if its text String is empty.

  def empty?
    @text.empty? && (@document.nil? || @document.empty?)
  end

  ##
  # HACK dubious

  def encode!(encoding)
    @text = String.new @text, encoding: encoding
    self
  end

  ##
  # Sets the format of this comment and resets any parsed document

  def format=(format)
    @format = format
    @document = nil
  end

  def inspect # :nodoc:
    location = @location ? @location.relative_name : '(unknown)'

    "#<%s:%x %s %p>" % [self.class, object_id, location, @text]
  end

  ##
  # Normalizes the text.  See RDoc::Text#normalize_comment for details

  def normalize
    return self unless @text
    return self if @normalized # TODO eliminate duplicate normalization

    @text = normalize_comment @text

    @normalized = true

    self
  end

  # Change normalized, when creating already normalized comment.

  def normalized=(value)
    @normalized = value
  end

  ##
  # Was this text normalized?

  def normalized? # :nodoc:
    @normalized
  end

  ##
  # Parses the comment into an RDoc::Markup::Document.  The parsed document is
  # cached until the text is changed.

  def parse
    return @document if @document

    @document = super @text, @format
    @document.file = @location
    @document
  end

  ##
  # Removes private sections from this comment.  Private sections are flush to
  # the comment marker and start with <tt>--</tt> and end with <tt>++</tt>.
  # For C-style comments, a private marker may not start at the opening of the
  # comment.
  #
  #   /*
  #    *--
  #    * private
  #    *++
  #    * public
  #    */

  def remove_private
    # Workaround for gsub encoding for Ruby 1.9.2 and earlier
    empty = ''
    empty = RDoc::Encoding.change_encoding empty, @text.encoding

    @text = @text.gsub(%r%^\s*([#*]?)--.*?^\s*(\1)\+\+\n?%m, empty)
    @text = @text.sub(%r%^\s*[#*]?--.*%m, '')
  end

  ##
  # Replaces this comment's text with +text+ and resets the parsed document.
  #
  # An error is raised if the comment contains a document but no text.

  def text=(text)
    raise RDoc::Error, 'replacing document-only comment is not allowed' if
      @text.nil? and @document

    @document = nil
    @text = text.nil? ? nil : text.dup
  end

  ##
  # Returns true if this comment is in TomDoc format.

  def tomdoc?
    @format == 'tomdoc'
  end

  MULTILINE_DIRECTIVES = %w[call-seq].freeze # :nodoc:

  # There are more, but already handled by RDoc::Parser::C
  COLON_LESS_DIRECTIVES = %w[call-seq Document-method].freeze # :nodoc:

  DIRECTIVE_OR_ESCAPED_DIRECTIV_REGEXP = /\A(?<colon>\\?:|:?)(?<directive>[\w-]+):(?<param>.*)/

  private_constant :MULTILINE_DIRECTIVES, :COLON_LESS_DIRECTIVES, :DIRECTIVE_OR_ESCAPED_DIRECTIV_REGEXP

  class << self

    ##
    # Create a new parsed comment from a document

    def from_document(document) # :nodoc:
      comment = RDoc::Comment.new('')
      comment.document = document
      comment.location = RDoc::TopLevel.new(document.file) if document.file
      comment
    end

    # Parse comment, collect directives as an attribute and return [normalized_comment_text, directives_hash]
    # This method expands include and removes everything not needed in the document text, such as
    # private section, directive line, comment characters `# /* * */` and indent spaces.
    #
    # RDoc comment consists of include, directive, multiline directive, private section and comment text.
    #
    # Include
    #   # :include: filename
    #
    # Directive
    #   # :directive-without-value:
    #   # :directive-with-value: value
    #
    # Multiline directive (only :call-seq:)
    #   # :multiline-directive:
    #   #   value1
    #   #   value2
    #
    # Private section
    #   #--
    #   # private comment
    #   #++

    def parse(text, filename, line_no, type, &include_callback)
      case type
      when :ruby
        text = text.gsub(/^#+/, '') if text.start_with?('#')
        private_start_regexp = /^-{2,}$/
        private_end_regexp = /^\+{2}$/
        indent_regexp = /^\s*/
      when :c
        private_start_regexp = /^(\s*\*)?-{2,}$/
        private_end_regexp = /^(\s*\*)?\+{2}$/
        indent_regexp = /^\s*(\/\*+|\*)?\s*/
        text = text.gsub(/\s*\*+\/\s*\z/, '')
      when :simple
        # Unlike other types, this implementation only looks for two dashes at
        # the beginning of the line. Three or more dashes are considered to be
        # a rule and ignored.
        private_start_regexp = /^-{2}$/
        private_end_regexp = /^\+{2}$/
        indent_regexp = /^\s*/
      end

      directives = {}
      lines = text.split("\n")
      in_private = false
      comment_lines = []
      until lines.empty?
        line = lines.shift
        read_lines = 1
        if in_private
          # If `++` appears in a private section that starts with `--`, private section ends.
          in_private = false if line.match?(private_end_regexp)
          line_no += read_lines
          next
        elsif line.match?(private_start_regexp)
          # If `--` appears in a line, private section starts.
          in_private = true
          line_no += read_lines
          next
        end

        prefix = line[indent_regexp]
        prefix_indent = ' ' * prefix.size
        line = line.byteslice(prefix.bytesize..)

        if (directive_match = DIRECTIVE_OR_ESCAPED_DIRECTIV_REGEXP.match(line))
          colon = directive_match[:colon]
          directive = directive_match[:directive]
          raw_param = directive_match[:param]
          param = raw_param.strip
        else
          colon = directive = raw_param = param = nil
        end

        if !directive
          comment_lines << prefix_indent + line
        elsif colon == '\\:'
          # If directive is escaped, unescape it
          comment_lines << prefix_indent + line.sub('\\:', ':')
        elsif raw_param.start_with?(':') || (colon.empty? && !COLON_LESS_DIRECTIVES.include?(directive))
          # Something like `:toto::` is not a directive
          # Only few directives allows to start without a colon
          comment_lines << prefix_indent + line
        elsif directive == 'include'
          filename_to_include = param
          include_callback.call(filename_to_include, prefix_indent).lines.each { |l| comment_lines << l.chomp }
        elsif MULTILINE_DIRECTIVES.include?(directive)
          value_lines = take_multiline_directive_value_lines(directive, filename, line_no, lines, prefix_indent.size, indent_regexp, !param.empty?)
          read_lines += value_lines.size
          lines.shift(value_lines.size)
          unless param.empty?
            # Accept `:call-seq: first-line\n  second-line` for now
            value_lines.unshift(param)
          end
          value = value_lines.join("\n")
          directives[directive] = [value.empty? ? nil : value, line_no]
        else
          directives[directive] = [param.empty? ? nil : param, line_no]
        end
        line_no += read_lines
      end

      normalized_comment = String.new(encoding: text.encoding) << normalize_comment_lines(comment_lines).join("\n")
      [normalized_comment, directives]
    end

    # Remove preceding indent spaces and blank lines from the comment lines

    private def normalize_comment_lines(lines)
      blank_line_regexp = /\A\s*\z/
      lines = lines.dup
      lines.shift while lines.first&.match?(blank_line_regexp)
      lines.pop while lines.last&.match?(blank_line_regexp)

      min_spaces = lines.map do |l|
        l.match(/\A *(?=\S)/)&.end(0)
      end.compact.min
      if min_spaces && min_spaces > 0
        lines.map { |l| l[min_spaces..] || '' }
      else
        lines
      end
    end

    # Take value lines of multiline directive

    private def take_multiline_directive_value_lines(directive, filename, line_no, lines, base_indent_size, indent_regexp, has_param)
      return [] if lines.empty?

      first_indent_size = lines.first.match(indent_regexp).end(0)

      # Blank line or unindented line is not part of multiline-directive value
      return [] if first_indent_size <= base_indent_size

      if has_param
        # :multiline-directive: line1
        #   line2
        #   line3
        #
        value_lines = lines.take_while do |l|
          l.rstrip.match(indent_regexp).end(0) > base_indent_size
        end
        min_indent = value_lines.map { |l| l.match(indent_regexp).end(0) }.min
        value_lines.map { |l| l[min_indent..] }
      else
        # Take indented lines accepting blank lines between them
        value_lines = lines.take_while do |l|
          l = l.rstrip
          indent = l[indent_regexp]
          if indent == l || indent.size >= first_indent_size
            true
          end
        end
        value_lines.map! { |l| (l[first_indent_size..] || '').chomp }

        if value_lines.size != lines.size && !value_lines.last.empty?
          warn "#{filename}:#{line_no} Multiline directive :#{directive}: should end with a blank line."
        end
        value_lines.pop while value_lines.last&.empty?
        value_lines
      end
    end
  end
end