class TomlRB::Dumper

def bare_key?(key)
  !!key.to_s.match(/^[a-zA-Z0-9_-]*$/)
end

def dump_nested_pairs(nested_pairs, prefix)
  nested_pairs.each do |key, val|
    key = quote_key(key) unless bare_key? key
    visit val, prefix + [key], false
  end
end

def dump_pairs(simple, nested, table_array, prefix = [])
  # First add simple pairs, under the prefix
  dump_simple_pairs simple
  dump_nested_pairs nested, prefix
  dump_table_array_pairs table_array, prefix
end

def dump_simple_pairs(simple_pairs)
  simple_pairs.each do |key, val|
    key = quote_key(key) unless bare_key? key
    @toml_str << "#{key} = #{to_toml(val)}\n"
  end
end

def dump_table_array_pairs(table_array_pairs, prefix)
  table_array_pairs.each do |key, val|
    key = quote_key(key) unless bare_key? key
    aux_prefix = prefix + [key]
    val.each do |child|
      print_prefix aux_prefix, true
      args = sort_pairs(child) << aux_prefix
      dump_pairs(*args)
    end
  end
end

def initialize(hash)
  @toml_str = ''
  visit(hash, [])
end

def print_prefix(prefix, extra_brackets = false)
  new_prefix = prefix.join('.')
  new_prefix = '[' + new_prefix + ']' if extra_brackets
  @toml_str += "[" + new_prefix + "]\n"
end

def quote_key(key)
  '"' + key.gsub('"', '\\"') + '"'
end

def sort_pairs(hash)
  nested_pairs = []
  simple_pairs = []
  table_array_pairs = []
  hash.keys.sort.each do |key|
    val = hash[key]
    element = [key, val]
    if val.is_a? Hash
      nested_pairs << element
    elsif val.is_a?(Array) && val.first.is_a?(Hash)
      table_array_pairs << element
    else
      simple_pairs << element
    end
  end
  [simple_pairs, nested_pairs, table_array_pairs]
end

def to_toml(obj)
  if obj.is_a?(Time) || obj.is_a?(DateTime)
    obj.strftime('%Y-%m-%dT%H:%M:%SZ')
  elsif obj.is_a?(Date)
    obj.strftime('%Y-%m-%d')
  elsif obj.is_a? Regexp
    obj.inspect.inspect
  elsif obj.is_a? String
    obj.inspect.gsub(/\\(#[$@{])/, '\1')
  else
    obj.inspect
  end
end

def visit(hash, prefix, extra_brackets = false)
  simple_pairs, nested_pairs, table_array_pairs = sort_pairs hash
  if prefix.any? && (simple_pairs.any? || hash.empty?)
    print_prefix prefix, extra_brackets
  end
  dump_pairs simple_pairs, nested_pairs, table_array_pairs, prefix
end