class Haml::Parser

def self.parse_class_and_id(list)
  attributes = {}
  return attributes if list.empty?
  list.scan(/([#.])([-:_a-zA-Z0-9\@]+)/) do |type, property|
    case type
    when '.'
      if attributes[CLASS_KEY]
        attributes[CLASS_KEY] += " "
      else
        attributes[CLASS_KEY] = ""
      end
      attributes[CLASS_KEY] += property
    when '#'; attributes[ID_KEY] = property
    end
  end
  attributes
end

def balance(*args)
  Haml::Util.balance(*args) or raise(SyntaxError.new(Error.message(:unbalanced_brackets)))
end

def balance_tokens(buf, start, finish, count: 0)
  text = ''.dup
  Ripper.lex(buf).each do |_, token, str|
    text << str
    case token
    when start
      count += 1
    when finish
      count -= 1
    end
    if count == 0
      return text, buf.sub(text, '')
    end
  end
  raise SyntaxError.new(Error.message(:unbalanced_brackets))
end

def block_keyword(text)
  return unless (keyword = text.scan(BLOCK_KEYWORD_REGEX)[0])
  keyword[0] || keyword[1]
end

def block_opened?
  @next_line.tabs > @line.tabs
end

def call(template)
  template = Haml::Util.check_haml_encoding(template) do |msg, line|
    raise Haml::Error.new(msg, line)
  end
  match = template.rstrip.scan(/(([ \t]+)?(.*?))(?:\Z|\r\n|\r|\n)/m)
  # discard the last match which is always blank
  match.pop
  @template = match.each_with_index.map do |(full, whitespace, text), index|
    Line.new(whitespace, text.rstrip, full, index, self, false)
  end
  # Append special end-of-document marker
  @template << Line.new(nil, '-#', '-#', @template.size, self, true)
  @root = @parent = ParseNode.new(:root)
  @flat = false
  @filter_buffer = nil
  @indentation = nil
  @line = next_line
  raise SyntaxError.new(Error.message(:indenting_at_start), @line.index) if @line.tabs != 0
  loop do
    next_line
    process_indent(@line) unless @line.text.empty?
    if flat?
      text = @line.full.dup
      text = "" unless text.gsub!(/^#{@flat_spaces}/, '')
      @filter_buffer << "#{text}\n"
      @line = @next_line
      next
    end
    @tab_up = nil
    process_line(@line) unless @line.text.empty?
    if block_opened? || @tab_up
      @template_tabs += 1
      @parent = @parent.children.last
    end
    if !flat? && @next_line.tabs - @line.tabs > 1
      raise SyntaxError.new(Error.message(:deeper_indenting, @next_line.tabs - @line.tabs), @next_line.index)
    end
    @line = @next_line
  end
  # Close all the open tags
  close until @parent.type == :root
  @root
rescue Haml::Error => e
  e.backtrace.unshift "#{@options.filename}:#{(e.line ? e.line + 1 : @line.index + 1) + @options.line - 1}"
  raise if @raise_error
  error_with_lineno(e)
end

def check_push_script_stack(keyword)
  if ["if", "case", "unless"].include?(keyword)
    # @script_level_stack contents are arrays of form
    # [:keyword, stack_level, other_info]
    @script_level_stack.push([keyword.to_sym, @line.tabs])
    @script_level_stack.last << false if keyword == 'case'
    @tab_up = true
  end
end

def close
  node, @parent = @parent, @parent.parent
  @template_tabs -= 1
  send("close_#{node.type}", node) if respond_to?("close_#{node.type}", :include_private)
end

def close_filter(_)
  close_flat_section
end

def close_flat_section
  @flat = false
  @flat_spaces = nil
  @filter_buffer = nil
end

def close_haml_comment(_)
  close_flat_section
end

def close_silent_script(node)
  @script_level_stack.pop if ["if", "case", "unless"].include? node.value[:keyword]
  # Post-process case statements to normalize the nesting of "when" clauses
  return unless node.value[:keyword] == "case"
  return unless (first = node.children.first)
  return unless first.type == :silent_script && first.value[:keyword] == "when"
  return if first.children.empty?
  # If the case node has a "when" child with children, it's the
  # only child. Then we want to put everything nested beneath it
  # beneath the case itself (just like "if").
  node.children = [first, *first.children]
  first.children = []
end

def closes_flat?(line)
  line && !line.text.empty? && line.full !~ /^#{@flat_spaces}/
end

def comment(text)
  if text[0..1] == '!['
    revealed = true
    text = text[1..-1]
  else
    revealed = false
  end
  conditional, text = balance(text, ?[, ?]) if text[0] == ?[
  text.strip!
  if Util.contains_interpolation?(text)
    parse = true
    text = Util.unescape_interpolation(text)
  else
    parse = false
  end
  if block_opened? && !text.empty?
    raise SyntaxError.new(Haml::Error.message(:illegal_nesting_content), @next_line.index)
  end
  ParseNode.new(:comment, @line.index + 1, :conditional => conditional, :text => text, :revealed => revealed, :parse => parse)
end

def compute_tabs(line)
  return 0 if line.text.empty? || !line.whitespace
  if @indentation.nil?
    @indentation = line.whitespace
    if @indentation.include?(?\s) && @indentation.include?(?\t)
      raise SyntaxError.new(Error.message(:cant_use_tabs_and_spaces), line.index)
    end
    @flat_spaces = @indentation * (@template_tabs+1) if flat?
    return 1
  end
  tabs = line.whitespace.length / @indentation.length
  return tabs if line.whitespace == @indentation * tabs
  return @template_tabs + 1 if flat? && line.whitespace =~ /^#{@flat_spaces}/
  message = Error.message(:inconsistent_indentation,
    human_indentation(line.whitespace),
    human_indentation(@indentation)
  )
  raise SyntaxError.new(message, line.index)
end

def continuation_script?(text)
  text[0] == SILENT_SCRIPT && mid_block_keyword?(text)
end

def div(line)
  line.text = "%div#{line.text}"
  tag(line)
end

def doctype(text)
  raise SyntaxError.new(Error.message(:illegal_nesting_header), @next_line.index) if block_opened?
  version, type, encoding = text[3..-1].strip.downcase.scan(DOCTYPE_REGEX)[0]
  ParseNode.new(:doctype, @line.index + 1, :version => version, :type => type, :encoding => encoding)
end

def error_with_lineno(error)
  return error if error.line
  trace = error.backtrace.first
  return error unless trace
  line = trace.match(/\d+\z/).to_s.to_i
  SyntaxError.new(error.message, line)
end

def filter(name)
  raise Error.new(Error.message(:invalid_filter_name, name)) unless name =~ /^\w+$/
  if filter_opened?
    @flat = true
    @filter_buffer = String.new
    # If we don't know the indentation by now, it'll be set in Line#tabs
    @flat_spaces = @indentation * (@template_tabs+1) if @indentation
  end
  ParseNode.new(:filter, @line.index + 1, :name => name, :text => @filter_buffer)
end

def filter_and_join(value, separator)
  return '' if (value.respond_to?(:empty?) && value.empty?)
  if value.is_a?(Array)
    value = value.flatten
    value.map! {|item| item ? item.to_s : nil}
    value.compact!
    value = value.join(separator)
  else
    value = value ? value.to_s : nil
  end
  !value.nil? && !value.empty? && value
end

def filter_opened?
  @next_line.full =~ (@indentation ? /^#{@indentation * (@template_tabs + 1)}/ : /^\s/)
end

def flat?
  @flat
end

def flat_script(line, escape_html = nil)
  raise SyntaxError.new(Error.message(:no_ruby_code, '~')) if line.text.empty?
  script(line, escape_html, :preserve)
end

def haml_comment(text)
  if filter_opened?
    @flat = true
    @filter_buffer = String.new
    @filter_buffer << "#{text}\n" unless text.empty?
    text = @filter_buffer
    # If we don't know the indentation by now, it'll be set in Line#tabs
    @flat_spaces = @indentation * (@template_tabs+1) if @indentation
  end
  ParseNode.new(:haml_comment, @line.index + 1, :text => text)
end

def handle_multiline(line)
  return unless is_multiline?(line.text)
  line.text.slice!(-1)
  loop do
    new_line = @template.first
    break if new_line.eod?
    next @template.shift if new_line.text.strip.empty?
    break unless is_multiline?(new_line.text.strip)
    line.text << new_line.text.strip[0...-1]
    @template.shift
  end
end

def handle_ruby_multiline(line)
  line.text.rstrip!
  return line unless is_ruby_multiline?(line.text)
  begin
    # Use already fetched @next_line in the first loop. Otherwise, fetch next
    new_line = new_line.nil? ? @next_line : @template.shift
    break if new_line.eod?
    next if new_line.text.empty?
    line.text << " #{new_line.text.rstrip}"
  end while is_ruby_multiline?(new_line.text)
  next_line
  line
end

def initialize(options)
  @options = ParserOptions.new(options)
  # Record the indent levels of "if" statements to validate the subsequent
  # elsif and else statements are indented at the appropriate level.
  @script_level_stack = []
  @template_index     = 0
  @template_tabs      = 0
  # When used in Haml::Engine, which gives options[:generator] to every filter
  # in the engine, including Haml::Parser, we don't want to throw exceptions.
  # However, when Haml::Parser is used as a library, we want to throw exceptions.
  @raise_error = !options.key?(:generator)
end

def is_multiline?(text)
  text && text.length > 1 && text[-1] == MULTILINE_CHAR_VALUE && text[-2] == ?\s && text !~ BLOCK_WITH_SPACES
end

def is_ruby_multiline?(text)
  text && text.length > 1 && text[-1] == ?, &&
    !((text[-3, 2] =~ /\W\?/) || text[-3, 2] == "?\\")
end

def merge_attributes!(to, from)
  from.keys.each do |key|
    to[key] = merge_value(key, to[key], from[key])
  end
  to
end

def merge_value(key, to, from)
  if from.kind_of?(Hash) || to.kind_of?(Hash)
    from = { nil => from } if !from.is_a?(Hash)
    to   = { nil => to }   if !to.is_a?(Hash)
    to.merge(from)
  elsif key == 'id'
    merged_id = filter_and_join(from, '_')
    if to && merged_id
      merged_id = "#{to}_#{merged_id}"
    elsif to || merged_id
      merged_id ||= to
    end
    merged_id
  elsif key == 'class'
    merged_class = filter_and_join(from, ' ')
    if to && merged_class
      merged_class = (to.split(' ') | merged_class.split(' ')).join(' ')
    elsif to || merged_class
      merged_class ||= to
    end
    merged_class
  else
    from
  end
end

def mid_block_keyword?(text)
  MID_BLOCK_KEYWORDS.include?(block_keyword(text))
end

def next_line
  line = @template.shift || raise(StopIteration)
  # `flat?' here is a little outdated,
  # so we have to manually check if either the previous or current line
  # closes the flat block, as well as whether a new block is opened.
  line_defined = instance_variable_defined?(:@line)
  @line.tabs if line_defined
  unless (flat? && !closes_flat?(line) && !closes_flat?(@line)) ||
      (line_defined && @line.text[0] == ?: && line.full =~ %r[^#{@line.full[/^\s+/]}\s])
    return next_line if line.text.empty?
    handle_multiline(line)
  end
  @next_line = line
end

def parse_new_attribute(scanner)
  unless (name = scanner.scan(/[-:\w]+/))
    return if scanner.scan(/\)/)
    return false
  end
  scanner.scan(/\s*/)
  return name, [:static, true] unless scanner.scan(/=/) #/end
  scanner.scan(/\s*/)
  unless (quote = scanner.scan(/["']/))
    return false unless (var = scanner.scan(/(@@?|\$)?\w+/))
    return name, [:dynamic, var]
  end
  re = /((?:\\.|\#(?!\{)|[^#{quote}\\#])*)(#{quote}|#\{)/
  content = []
  loop do
    return false unless scanner.scan(re)
    content << [:str, scanner[1].gsub(/\\(.)/, '\1')]
    break if scanner[2] == quote
    content << [:ruby, balance(scanner, ?{, ?}, 1).first[0...-1]]
  end
  return name, [:static, content.first[1]] if content.size == 1
  return name, [:dynamic,
    %!"#{content.each_with_object(''.dup) {|(t, v), s| s << (t == :str ? Util.inspect_obj(v)[1...-1] : "\#{#{v}}")}}"!]
end

def parse_new_attributes(text)
  scanner = StringScanner.new(text)
  last_line = @line.index + 1
  attributes = {}
  scanner.scan(/\(\s*/)
  loop do
    name, value = parse_new_attribute(scanner)
    break if name.nil?
    if name == false
      scanned = Haml::Util.balance(text, ?(, ?))
      text = scanned ? scanned.first : text
      raise Haml::SyntaxError.new(Error.message(:invalid_attribute_list, text.inspect), last_line - 1)
    end
    attributes[name] = value
    scanner.scan(/\s*/)
    if scanner.eos?
      text << " #{@next_line.text}"
      last_line += 1
      next_line
      scanner.scan(/\s*/)
    end
  end
  static_attributes = {}
  dynamic_attributes = "{".dup
  attributes.each do |name, (type, val)|
    if type == :static
      static_attributes[name] = val
    else
      dynamic_attributes << "#{Util.inspect_obj(name)} => #{val},"
    end
  end
  dynamic_attributes << "}"
  dynamic_attributes = nil if dynamic_attributes == "{}"
  return [static_attributes, dynamic_attributes], scanner.rest, last_line
end

def parse_old_attributes(text)
  last_line = @line.index + 1
  begin
    # Old attributes often look like a valid Hash literal, but it sometimes allow code like
    # `{ hash, foo: bar }`, which is compiled to `_hamlout.attributes({}, nil, hash, foo: bar)`.
    #
    # To scan such code correctly, this scans `a( hash, foo: bar }` instead, stops when there is
    # 1 more :on_embexpr_end (the last '}') than :on_embexpr_beg, and resurrects '{' afterwards.
    balanced, rest = balance_tokens(text.sub(?{, METHOD_CALL_PREFIX), :on_embexpr_beg, :on_embexpr_end, count: 1)
    attributes_hash = balanced.sub(METHOD_CALL_PREFIX, ?{)
  rescue SyntaxError => e
    if e.message == Error.message(:unbalanced_brackets) && !@template.empty?
      text << "\n#{@next_line.text}"
      last_line += 1
      next_line
      retry
    end
    raise e
  end
  return attributes_hash, rest, last_line
end

def parse_static_hash(text)
  attributes = {}
  return attributes if text.empty?
  text = text[1...-1] # strip brackets
  scanner = StringScanner.new(text)
  scanner.scan(/\s+/)
  until scanner.eos?
    return unless (key = scanner.scan(LITERAL_VALUE_REGEX))
    return unless scanner.scan(/\s*=>\s*/)
    return unless (value = scanner.scan(LITERAL_VALUE_REGEX))
    return unless scanner.scan(/\s*(?:,|$)\s*/)
    attributes[eval(key).to_s] = eval(value).to_s
  end
  attributes
end

def parse_tag(text)
  match = text.scan(/%([-:\w]+)([-:\w.#\@]*)(.+)?/)[0]
  raise SyntaxError.new(Error.message(:invalid_tag, text)) unless match
  tag_name, attributes, rest = match
  if !attributes.empty? && (attributes =~ /[.#](\.|#|\z)/)
    raise SyntaxError.new(Error.message(:illegal_element))
  end
  new_attributes_hash = old_attributes_hash = last_line = nil
  object_ref = :nil
  attributes_hashes = {}
  while rest && !rest.empty?
    case rest[0]
    when ?{
      break if old_attributes_hash
      old_attributes_hash, rest, last_line = parse_old_attributes(rest)
      attributes_hashes[:old] = old_attributes_hash
    when ?(
      break if new_attributes_hash
      new_attributes_hash, rest, last_line = parse_new_attributes(rest)
      attributes_hashes[:new] = new_attributes_hash
    when ?[
      break unless object_ref == :nil
      object_ref, rest = balance(rest, ?[, ?])
    else; break
    end
  end
  if rest && !rest.empty?
    nuke_whitespace, action, value = rest.scan(/(<>|><|[><])?([=\/\~&!])?(.*)?/)[0]
    if nuke_whitespace
      nuke_outer_whitespace = nuke_whitespace.include? '>'
      nuke_inner_whitespace = nuke_whitespace.include? '<'
    end
  end
  if @options.remove_whitespace
    nuke_outer_whitespace = true
    nuke_inner_whitespace = true
  end
  if value.nil?
    value = ''
  else
    value.strip!
  end
  [tag_name, attributes, attributes_hashes, object_ref, nuke_outer_whitespace,
   nuke_inner_whitespace, action, value, last_line || @line.index + 1]
end

def plain(line, escape_html = nil)
  if block_opened?
    raise SyntaxError.new(Error.message(:illegal_nesting_plain), @next_line.index)
  end
  unless Util.contains_interpolation?(line.text)
    return ParseNode.new(:plain, line.index + 1, :text => line.text)
  end
  escape_html = @options.escape_html && @options.mime_type != 'text/plain' if escape_html.nil?
  line.text = Util.unescape_interpolation(line.text)
  script(line, false).tap { |n| n.value[:escape_interpolation] = true if escape_html }
end

def process_indent(line)
  return unless line.tabs <= @template_tabs && @template_tabs > 0
  to_close = @template_tabs - line.tabs
  to_close.times {|i| close unless to_close - 1 - i == 0 && continuation_script?(line.text)}
end

def process_line(line)
  case line.text[0]
  when DIV_CLASS; push div(line)
  when DIV_ID
    return push plain(line) if %w[{ @ $].include?(line.text[1])
    push div(line)
  when ELEMENT; push tag(line)
  when COMMENT; push comment(line.text[1..-1].lstrip)
  when SANITIZE
    return push plain(line.strip!(3), :escape_html) if line.text[1, 2] == '=='
    return push script(line.strip!(2), :escape_html) if line.text[1] == SCRIPT
    return push flat_script(line.strip!(2), :escape_html) if line.text[1] == FLAT_SCRIPT
    return push plain(line.strip!(1), :escape_html) if line.text[1] == ?\s || line.text[1..2] == '#{'
    push plain(line)
  when SCRIPT
    return push plain(line.strip!(2)) if line.text[1] == SCRIPT
    line.text = line.text[1..-1]
    push script(line)
  when FLAT_SCRIPT; push flat_script(line.strip!(1))
  when SILENT_SCRIPT
    return push haml_comment(line.text[2..-1]) if line.text[1] == SILENT_COMMENT
    push silent_script(line)
  when FILTER; push filter(line.text[1..-1].downcase)
  when DOCTYPE
    return push doctype(line.text) if line.text[0, 3] == '!!!'
    return push plain(line.strip!(3), false) if line.text[1, 2] == '=='
    return push script(line.strip!(2), false) if line.text[1] == SCRIPT
    return push flat_script(line.strip!(2), false) if line.text[1] == FLAT_SCRIPT
    return push plain(line.strip!(1), false) if line.text[1] == ?\s || line.text[1..2] == '#{'
    push plain(line)
  when ESCAPE
    line.text = line.text[1..-1]
    push plain(line)
  else; push plain(line)
  end
end

def push(node)
  @parent.children << node
  node.parent = @parent
end

def script(line, escape_html = nil, preserve = false)
  raise SyntaxError.new(Error.message(:no_ruby_code, '=')) if line.text.empty?
  line = handle_ruby_multiline(line)
  escape_html = @options.escape_html if escape_html.nil?
  keyword = block_keyword(line.text)
  check_push_script_stack(keyword)
  ParseNode.new(:script, line.index + 1, :text => line.text, :escape_html => escape_html,
    :preserve => preserve, :keyword => keyword)
end

def silent_script(line)
  raise SyntaxError.new(Error.message(:no_end), line.index) if line.text[1..-1].strip == 'end'
  line = handle_ruby_multiline(line)
  keyword = block_keyword(line.text)
  check_push_script_stack(keyword)
  if ["else", "elsif", "when"].include?(keyword)
    if @script_level_stack.empty?
      raise Haml::SyntaxError.new(Error.message(:missing_if, keyword), @line.index)
    end
    if keyword == 'when' and !@script_level_stack.last[2]
      if @script_level_stack.last[1] + 1 == @line.tabs
        @script_level_stack.last[1] += 1
      end
      @script_level_stack.last[2] = true
    end
    if @script_level_stack.last[1] != @line.tabs
      message = Error.message(:bad_script_indent, keyword, @script_level_stack.last[1], @line.tabs)
      raise Haml::SyntaxError.new(message, @line.index)
    end
  end
  ParseNode.new(:silent_script, @line.index + 1,
    :text => line.text[1..-1], :keyword => keyword)
end

def tag(line)
  tag_name, attributes, attributes_hashes, object_ref, nuke_outer_whitespace,
    nuke_inner_whitespace, action, value, last_line = parse_tag(line.text)
  preserve_tag = @options.preserve.include?(tag_name)
  nuke_inner_whitespace ||= preserve_tag
  escape_html = (action == '&' || (action != '!' && @options.escape_html))
  case action
  when '/'; self_closing = true
  when '~'; parse = preserve_script = true
  when '='
    parse = true
    if value[0] == ?=
      value = Util.unescape_interpolation(value[1..-1].strip)
      escape_interpolation = true if escape_html
      escape_html = false
    end
  when '&', '!'
    if value[0] == ?= || value[0] == ?~
      parse = true
      preserve_script = (value[0] == ?~)
      if value[1] == ?=
        value = Util.unescape_interpolation(value[2..-1].strip)
        escape_interpolation = true if escape_html
        escape_html = false
      else
        value = value[1..-1].strip
      end
    elsif Util.contains_interpolation?(value)
      value = Util.unescape_interpolation(value)
      escape_interpolation = true if escape_html
      parse = true
      escape_html = false
    end
  else
    if Util.contains_interpolation?(value)
      value = Util.unescape_interpolation(value, escape_html)
      parse = true
      escape_html = false
    end
  end
  attributes = Parser.parse_class_and_id(attributes)
  dynamic_attributes = DynamicAttributes.new
  if attributes_hashes[:new]
    static_attributes, attributes_hash = attributes_hashes[:new]
    AttributeMerger.merge_attributes!(attributes, static_attributes) if static_attributes
    dynamic_attributes.new = attributes_hash
  end
  if attributes_hashes[:old]
    static_attributes = parse_static_hash(attributes_hashes[:old])
    AttributeMerger.merge_attributes!(attributes, static_attributes) if static_attributes
    dynamic_attributes.old = attributes_hashes[:old] unless static_attributes || @options.suppress_eval
  end
  raise SyntaxError.new(Error.message(:illegal_nesting_self_closing), @next_line.index) if block_opened? && self_closing
  raise SyntaxError.new(Error.message(:no_ruby_code, action), last_line - 1) if parse && value.empty?
  raise SyntaxError.new(Error.message(:self_closing_content), last_line - 1) if self_closing && !value.empty?
  if block_opened? && !value.empty? && !is_ruby_multiline?(value)
    raise SyntaxError.new(Error.message(:illegal_nesting_line, tag_name), @next_line.index)
  end
  self_closing ||= !!(!block_opened? && value.empty? && @options.autoclose.any? {|t| t === tag_name})
  value = nil if value.empty? && (block_opened? || self_closing)
  line.text = value
  line = handle_ruby_multiline(line) if parse
  ParseNode.new(:tag, line.index + 1, :name => tag_name, :attributes => attributes,
    :dynamic_attributes => dynamic_attributes, :self_closing => self_closing,
    :nuke_inner_whitespace => nuke_inner_whitespace,
    :nuke_outer_whitespace => nuke_outer_whitespace, :object_ref => object_ref,
    :escape_html => escape_html, :preserve_tag => preserve_tag,
    :preserve_script => preserve_script, :parse => parse, :value => line.text,
    :escape_interpolation => escape_interpolation)
end