class Psych::Comments::Emitter

# File lib/psych/comments/emitter.rb, line 76
def initialize
  @out = ""
  @state = :init
  @indent = 0
  @flow = false
  @comment_lookahead = []
  @tagmap = DEFAULT_TAGMAP
end

# File lib/psych/comments/emitter.rb, line 283
def decompose_tag(tag)
  @tagmap.each do |handle, prefix|
    if tag.start_with?(prefix)
      suffix = tag.delete_prefix(prefix)
      if /\A(?:%[0-9a-fA-F]{2}|[-0-9a-z#;\/?:@&=+$_.~*'()])*\z/.match?(suffix)
        return [handle, suffix]
      end
    end
  end
  [nil, nil]
end

# File lib/psych/comments/emitter.rb, line 106
def emit(node)
  if node.equal?(@comment_lookahead[0])
    @comment_lookahead.shift
  else
    node.leading_comments.each do |comment|
      emit_comment(comment)
    end
  end
  if has_anchor(node)
    print "&#{node.anchor}"
    space!
  end
  if node.tag
    handle, suffix = decompose_tag(node.tag)
    if suffix
      print "#{handle}#{suffix}"
    else
      print "!<#{node.tag}>"
    end
    space!
  end
  case node
  when Psych::Nodes::Scalar, Psych::Nodes::Alias
    if node.is_a?(Psych::Nodes::Alias)
      print "*#{node.anchor}"
    else
      print stringify_adjust_scalar(node, INDENT * @indent)
    end
  when Psych::Nodes::Mapping
    set_flow(flow?(node)) do
      if @flow
        print "{"
        cont = false
        node.children.each_slice(2) do |(key, value)|
          if cont
            print ","
            space!
          end
          emit(key)
          print ":"
          space!
          emit(value)
          cont = true
        end
        print "}"
      else
        newline!
        node.children.each_slice(2) do |(key, value)|
          emit(key)
          print ":"
          space!
          if single_line?(value) || has_bullet(value)
            emit(value)
          else
            indented do
              emit(value)
            end
          end
          newline!
        end
      end
    end
  when Psych::Nodes::Sequence
    set_flow(flow?(node)) do
      if @flow
        print "["
        cont = false
        node.children.each do |subnode|
          if cont
            print ","
            space!
          end
          emit(subnode)
          cont = true
        end
        print "]"
      else
        newline!
        node.children.each do |subnode|
          emit_lookahead_comments(subnode) unless @flow
          print "- "
          @state = :pseudo_indent
          if single_line?(subnode)
            emit(subnode)
          else
            indented do
              emit(subnode)
            end
          end
          newline!
        end
      end
    end
  when Psych::Nodes::Document
    node.tag_directives.each do |(handle, prefix)|
      newline!
      print "%TAG #{handle} #{prefix}"
      newline!
    end
    unless node.implicit
      newline!
      print "---"
      space!
    end
    set_tagmap(node) do
      emit(node.root)
    end
    unless node.implicit_end
      newline!
      print "..."
    end
    newline!
  when Psych::Nodes::Stream
    node.children.each do |subnode|
      emit(subnode)
    end
  else
    raise TypeError, node
  end
  node.trailing_comments.each do |comment|
    emit_comment(comment)
  end
end

# File lib/psych/comments/emitter.rb, line 239
def emit_comment(comment)
  unless /\A#[^\r\n]*\z/.match?(comment)
    raise ArgumentError, "Invalid comment: #{comment.inspect}"
  end
  print comment
  newline!
end

# File lib/psych/comments/emitter.rb, line 230
def emit_lookahead_comments(node)
  return if node.equal?(@comment_lookahead[0])

  node.leading_comments.each do |comment|
    emit_comment(comment)
  end
  @comment_lookahead.push(node)
end

# File lib/psych/comments/emitter.rb, line 269
def flow?(node)
  case node
  when Psych::Nodes::Scalar, Psych::Nodes::Alias
    true
  when Psych::Nodes::Mapping
    @flow || node.style == Psych::Nodes::Mapping::FLOW || node.children.empty?
  when Psych::Nodes::Sequence
    @flow || node.style == Psych::Nodes::Sequence::FLOW || node.children.empty?
  else
    false
  end
end

# File lib/psych/comments/emitter.rb, line 247
def indented(&block)
  @indent += 1
  begin
    block.()
  ensure
    @indent -= 1
  end
end

# File lib/psych/comments/emitter.rb, line 100
def newline!
  return if @state == :init || @state == :line_start || @state == :pseudo_indent
  @out << "\n"
  @state = :line_start
end

# File lib/psych/comments/emitter.rb, line 85
def print(text)
  case @state
  when :word_end
    @out << " "
  when :line_start
    @out << INDENT * @indent
  end
  @state = :in_line
  @out << text
end

# File lib/psych/comments/emitter.rb, line 256
def set_flow(new_flow, &block)
  old_flow, @flow = @flow, new_flow
  begin
    block.()
  ensure
    @flow = old_flow
  end
end

# File lib/psych/comments/emitter.rb, line 296
def set_tagmap(node, &block)
  new_tagmap = DEFAULT_TAGMAP.dup
  node.tag_directives.each do |(handle, prefix)|
    new_tagmap[handle] = prefix
  end
  old_tagmap, @tagmap = @tagmap, new_tagmap
  begin
    block.()
  ensure
    @tagmap = old_tagmap
  end
end

# File lib/psych/comments/emitter.rb, line 265
def single_line?(node)
  flow?(node) && node.leading_comments.empty? && node.trailing_comments.empty?
end

# File lib/psych/comments/emitter.rb, line 96
def space!
  @state = :word_end
end