class SimpleConfig

def default_options
  {
    quotes: '',
    multiline: false,
    comment_char: '#',
    line_separator: nil, # uses this char to seperate lines before parsing
    assignment_re: /^\s*([^=]*?)\s*=\s*(.*?)\s*$/,
    group_re: /\[([^\]]+)\]\s*$/,
    key_vals: 1, # default for key=value, may require for 'key val1 val2 val3'
    standalone_comments: false,
    multiple_values: false,
  }
end

def initialize(raw_data, opts = {})
  parse(raw_data, opts)
end

def is_empty_line(l)
  l =~ /^\s*$/
end

def parse(raw_data, opts = nil)
  @params = {}
  @groups = []
  @vals = @params
  options = default_options.merge(opts || {})
  return if raw_data.nil?
  # prepare raw data if required
  if !options[:line_separator].nil?
    raw_data = raw_data.tr(options[:line_separator], "\n")
  end
  rest = raw_data
  rest = parse_rest(rest, options) while rest.length > 0
end

def parse_group_line(line, opts)
  return nil if opts[:group_re].nil?
  m = opts[:group_re].match(line)
  return nil if m.nil?
  @groups.push(m[1])
  @vals = @params[m[1]] = {}
end

def parse_implicit_assignment_line(line, opts)
  return nil if is_empty_line(line)
  if opts[:multiple_values]
    @vals[line.strip] ||= []
  else
    @vals[line.strip] = ''
  end
end

def parse_params_line(line, opts)
  # now line contains what we are interested in parsing
  # check if it is an assignment
  m = opts[:assignment_re].match(line)
  return nil if m.nil?
  if opts[:multiple_values]
    @vals[m[1]] ||= []
    @vals[m[1]].push(parse_values(m, opts[:key_vals]))
  else
    @vals[m[1]] = parse_values(m, opts[:key_vals])
  end
end

def parse_rest(rest, opts)
  line, idx_nl = parse_comment_line(rest, opts)
  parse_params_line(line, opts) or
    parse_group_line(line, opts) or
    parse_implicit_assignment_line(line, opts)
  # return whatever is left
  rest[(idx_nl + 1)..-1] || ''
end

def parse_values(match, values)
  start_idx = 2
  i = 0
  count = values - 1
  return match[start_idx] if values == 1
  # iterate over expected parameters
  values = []
  loop do
    values.push(match[start_idx + i])
    i += 1
    break if i > count
  end
  values
end