class Haml::Parser

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

def balance(*args)
  res = Haml::Util.balance(*args)
  return res if res
  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 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(_)
  @flat = false
  @flat_spaces = nil
  @filter_buffer = nil
end

def close_haml_comment(_)
  @haml_comment = false
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(line)
  conditional, line = balance(line, ?[, ?]) if line[0] == ?[
  line.strip!
  conditional << ">" if conditional
  if block_opened? && !line.empty?
    raise SyntaxError.new(Haml::Error.message(:illegal_nesting_content), @next_line.index)
  end
  ParseNode.new(:comment, @index, :conditional => conditional, :text => line)
end

def div(line)
  tag('%div' + line)
end

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

def filter(name)
  raise Error.new(Error.message(:invalid_filter_name, name)) unless name =~ /^\w+$/
  @filter_buffer = String.new
  if filter_opened?
    @flat = true
    # 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, @index, :name => name, :text => @filter_buffer)
end

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

def flat?
  @flat
end

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

def haml_comment(text)
  @haml_comment = block_opened?
  ParseNode.new(:haml_comment, @index, :text => text)
end

def handle_multiline(line)
  return unless is_multiline?(line.text)
  line.text.slice!(-1)
  while new_line = raw_next_line.first
    break if new_line == :eod
    next if new_line.strip.empty?
    break unless is_multiline?(new_line.strip)
    line.text << new_line.strip[0...-1]
  end
  un_next_line new_line
end

def handle_ruby_multiline(text)
  text = text.rstrip
  return text unless is_ruby_multiline?(text)
  un_next_line @next_line.full
  begin
    new_line = raw_next_line.first
    break if new_line == :eod
    next if new_line.strip.empty?
    text << " " << new_line.strip
  end while is_ruby_multiline?(new_line.strip)
  next_line
  text
end

def initialize(template, options)
  # :eod is a special end-of-document marker
  @template           = (template.rstrip).split(/\r\n|\r|\n/) + [:eod, :eod]
  @options            = options
  @flat               = false
  @index              = 0
  # 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
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 mid_block_keyword?(text)
  MID_BLOCK_KEYWORDS.include?(block_keyword(text))
end

def next_line
  text, index = raw_next_line
  return unless text
  # :eod is a special end-of-document marker
  line =
    if text == :eod
      Line.new '-#', '-#', '-#', index, self, true
    else
      Line.new text.strip, text.lstrip.chomp, text, index, self, false
    end
  # `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
  @root = @parent = ParseNode.new(:root)
  @haml_comment = false
  @indentation = nil
  @line = next_line
  raise SyntaxError.new(Error.message(:indenting_at_start), @line.index) if @line.tabs != 0
  while 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.text, @line.index) unless @line.text.empty? || @haml_comment
    if @parent.type != :haml_comment && (block_opened? || @tab_up)
      @template_tabs += 1
      @parent = @parent.children.last
    end
    if !@haml_comment && !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 : @index) + @options[:line] - 1}"
  raise
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.map {|(t, v)| t == :str ? inspect_obj(v)[1...-1] : "\#{#{v}}"}.join + '"']
end

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

def parse_static_hash(text)
  attributes = {}
  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(line)
  match = line.scan(/%([-:\w]+)([-:\w\.\#]*)(.*)/)[0]
  raise SyntaxError.new(Error.message(:invalid_tag, line)) unless match
  tag_name, attributes, rest = match
  if 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
    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
    nuke_whitespace, action, value = rest.scan(/(<>|><|[><])?([=\/\~&!])?(.*)?/)[0]
    nuke_whitespace ||= ''
    nuke_outer_whitespace = nuke_whitespace.include? '>'
    nuke_inner_whitespace = nuke_whitespace.include? '<'
  end
  if @options[:remove_whitespace]
    nuke_outer_whitespace = true
    nuke_inner_whitespace = true
  end
  value = value.to_s.strip
  [tag_name, attributes, attributes_hashes, object_ref, nuke_outer_whitespace,
   nuke_inner_whitespace, action, value, last_line || @index]
end

def plain(text, escape_html = nil)
  if block_opened?
    raise SyntaxError.new(Error.message(:illegal_nesting_plain), @next_line.index)
  end
  unless contains_interpolation?(text)
    return ParseNode.new(:plain, @index, :text => text)
  end
  escape_html = @options[:escape_html] if escape_html.nil?
  script(unescape_interpolation(text, escape_html), false)
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 && mid_block_keyword?(line.text)}
end

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

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

def raw_next_line
  text = @template.shift
  return unless text
  index = @template_index
  @template_index += 1
  return text, index
end

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

def silent_script(text)
  return haml_comment(text[2..-1]) if text[1] == SILENT_COMMENT
  raise SyntaxError.new(Error.message(:no_end), @index - 1) if text[1..-1].strip == "end"
  text = handle_ruby_multiline(text)
  keyword = block_keyword(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, @index,
    :text => 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)
  preserve_tag = @options[:preserve].include?(tag_name)
  nuke_inner_whitespace ||= preserve_tag
  preserve_tag = false if @options[:ugly]
  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 = unescape_interpolation(value[1..-1].strip, escape_html)
      escape_html = false
    end
  when '&', '!'
    if value[0] == ?= || value[0] == ?~
      parse = true
      preserve_script = (value[0] == ?~)
      if value[1] == ?=
        value = unescape_interpolation(value[2..-1].strip, escape_html)
        escape_html = false
      else
        value = value[1..-1].strip
      end
    elsif contains_interpolation?(value)
      value = unescape_interpolation(value, escape_html)
      parse = true
      escape_html = false
    end
  else
    if contains_interpolation?(value)
      value = unescape_interpolation(value, escape_html)
      parse = true
      escape_html = false
    end
  end
  attributes = Parser.parse_class_and_id(attributes)
  attributes_list = []
  if attributes_hashes[:new]
    static_attributes, attributes_hash = attributes_hashes[:new]
    Buffer.merge_attrs(attributes, static_attributes) if static_attributes
    attributes_list << attributes_hash
  end
  if attributes_hashes[:old]
    static_attributes = parse_static_hash(attributes_hashes[:old])
    Buffer.merge_attrs(attributes, static_attributes) if static_attributes
    attributes_list << attributes_hashes[:old] unless static_attributes || @options[:suppress_eval]
  end
  attributes_list.compact!
  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)
  value = handle_ruby_multiline(value) if parse
  ParseNode.new(:tag, @index, :name => tag_name, :attributes => attributes,
    :attributes_hashes => attributes_list, :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 => value)
end

def un_next_line(line)
  @template.unshift line
  @template_index -= 1
end