class Prism::ParseResult::Errors

# File lib/prism/parse_result/errors.rb, line 14
def initialize(parse_result)
  @parse_result = parse_result
end

# File lib/prism/parse_result/errors.rb, line 19
def format
  error_lines = {} #: Hash[Integer, Array[ParseError]]
  parse_result.errors.each do |error|
    location = error.location
    (location.start_line..location.end_line).each do |line|
      error_lines[line] ||= []
      error_lines[line] << error
    end
  end

  source_lines = parse_result.source.source.lines
  source_lines << "" if error_lines.key?(source_lines.size + 1)

  io = StringIO.new
  source_lines.each.with_index(1) do |line, line_number|
    io.puts(line)

    (error_lines.delete(line_number) || []).each do |error|
      location = error.location

      case line_number
      when location.start_line
        io.print(" " * location.start_column + "^")

        if location.start_line == location.end_line
          if location.start_column != location.end_column
            io.print("~" * (location.end_column - location.start_column - 1))
          end

          io.puts(" " + error.message)
        else
          io.puts("~" * (line.bytesize - location.start_column))
        end
      when location.end_line
        io.puts("~" * location.end_column + " " + error.message)
      else
        io.puts("~" * line.bytesize)
      end
    end
  end

  io.puts
  io.string
end