class Solargraph::Source::SourceChainer

def chain source, position
  new(source, Solargraph::Position.normalize(position)).chain
end

def chain
  # Special handling for files that end with an integer and a period

  return Chain.new([Chain::Literal.new('Integer'), Chain::UNDEFINED_CALL]) if phrase =~ /^[0-9]+\.$/
  return Chain.new([Chain::Literal.new('Symbol')]) if phrase.start_with?(':') && !phrase.start_with?('::')
  return SourceChainer.chain(source, Position.new(position.line, position.character + 1)) if end_of_phrase.strip == '::' && source.code[Position.to_offset(source.code, position)].to_s.match?(/[a-z]/i)
  begin
    return Chain.new([]) if phrase.end_with?('..')
    node = nil
    parent = nil
    if !source.repaired? && source.parsed? && source.synchronized?
      tree = source.tree_at(position.line, position.column)
      node, parent = tree[0..2]
    elsif source.parsed? && source.repaired? && end_of_phrase == '.'
      node, parent = source.tree_at(fixed_position.line, fixed_position.column)[0..2]
      node = Parser.parse(fixed_phrase) if node.nil?
    elsif source.repaired?
      node = Parser.parse(fixed_phrase)
    else
      node, parent = source.tree_at(fixed_position.line, fixed_position.column)[0..2] unless source.error_ranges.any?{|r| r.nil? || r.include?(fixed_position)}
      # Exception for positions that chain literal nodes in unsynchronized sources

      node = nil unless source.synchronized? || !Parser.infer_literal_node_type(node).nil?
      node = Parser.parse(fixed_phrase) if node.nil?
    end
  rescue Parser::SyntaxError
    return Chain.new([Chain::UNDEFINED_CALL])
  end
  return Chain.new([Chain::UNDEFINED_CALL]) if node.nil? || (node.type == :sym && !phrase.start_with?(':'))
  # chain = NodeChainer.chain(node, source.filename, parent && parent.type == :block)

  chain = Parser.chain(node, source.filename, parent)
  if source.repaired? || !source.parsed? || !source.synchronized?
    if end_of_phrase.strip == '.'
      chain.links.push Chain::UNDEFINED_CALL
    elsif end_of_phrase.strip == '::'
      chain.links.push Chain::UNDEFINED_CONSTANT
    end
  elsif chain.links.last.is_a?(Source::Chain::Constant) && end_of_phrase.strip == '::'
    chain.links.push Source::Chain::UNDEFINED_CONSTANT
  end
  chain
end

def end_of_phrase
  @end_of_phrase ||= begin
    match = phrase.match(/[\s]*(\.{1}|::)[\s]*$/)
    if match
      match[0]
    else
      ''
    end
  end
end

def fixed_phrase
  @fixed_phrase ||= phrase[0..-(end_of_phrase.length+1)]
end

def fixed_position
  @fixed_position ||= Position.from_offset(source.code, offset - end_of_phrase.length)
end

def get_offset line, column
  Position.line_char_to_offset(@source.code, line, column)
end

def get_signature_data_at index
  brackets = 0
  squares = 0
  parens = 0
  index -=1
  in_whitespace = false
  while index >= 0
    pos = Position.from_offset(@source.code, index)
    break if index > 0 and @source.comment_at?(pos)
    break if brackets > 0 or parens > 0 or squares > 0
    char = @source.code[index, 1]
    break if char.nil? # @todo Is this the right way to handle this?

    if brackets.zero? and parens.zero? and squares.zero? and [' ', "\r", "\n", "\t"].include?(char)
      in_whitespace = true
    else
      if brackets.zero? and parens.zero? and squares.zero? and in_whitespace
        unless char == '.' or @source.code[index+1..-1].strip.start_with?('.')
          old = @source.code[index+1..-1]
          nxt = @source.code[index+1..-1].lstrip
          index += (@source.code[index+1..-1].length - @source.code[index+1..-1].lstrip.length)
          break
        end
      end
      if char == ')'
        parens -=1
      elsif char == ']'
        squares -=1
      elsif char == '}'
        brackets -= 1
      elsif char == '('
        parens += 1
      elsif char == '{'
        brackets += 1
      elsif char == '['
        squares += 1
      end
      if brackets.zero? and parens.zero? and squares.zero?
        break if ['"', "'", ',', ';', '%'].include?(char)
        break if ['!', '?'].include?(char) && index < offset - 1
        break if char == '$'
        if char == '@'
          index -= 1
          if @source.code[index, 1] == '@'
            index -= 1
          end
          break
        end
      elsif parens == 1 || brackets == 1 || squares == 1
        break
      end
      in_whitespace = false
    end
    index -= 1
  end
  index + 1
end

def initialize source, position
  @source = source
  @position = position
  @calculated_literal = false
end

def offset
  @offset ||= get_offset(position.line, position.column)
end

def phrase
  @phrase ||= source.code[signature_data..offset-1]
end

def signature_data
  @signature_data ||= get_signature_data_at(offset)
end

def string?
  # @string ||= (node.type == :str or node.type == :dstr)

  @string ||= @source.string_at?(position)
end