class DatabaseCleaner::Cleaner

def self.available_strategies(orm_module)
  # introspect publically available constants for descendents of Strategy to get list of strategies
  # ignore classes named Base, because its a common name for a shared base class that adds ORM access stuff to Strategy before being inherited by final concrete class
  # if you're writing an adapter and this method is falsely returning an internal constant that isn't a valid strategy, consider making it private with Module#private_constant.
  orm_module.constants.select do |constant_name|
    ancestors = orm_module.const_get(constant_name).ancestors rescue []
    ancestors.include?(DatabaseCleaner::Strategy)
  end.map do |constant_name|
    underscore(constant_name).to_sym
  end - [:base]
end

def self.underscore(camel_cased_word)
  return camel_cased_word unless /[A-Z-]|::/.match?(camel_cased_word)
  word = camel_cased_word.to_s.gsub("::", "/")
  word.gsub!(/([A-Z\d]+)([A-Z][a-z])/, '\1_\2')
  word.gsub!(/([a-z\d])([A-Z])/, '\1_\2')
  word.tr!("-", "_")
  word.downcase!
  word
end

def <=>(other)
  [orm, db] <=> [other.orm, other.db]
end

def camelize(term)
  string = term.to_s
  string = string.sub(/^[a-z\d]*/) { |match| match.capitalize }
  string.gsub!(/(?:_|(\/))([a-z\d]*)/i) { "#{$1}#{$2.capitalize}" }
  string.gsub!("/", "::")
  string
end

def clean_with(*args)
  strategy = create_strategy(*args)
  set_strategy_db strategy, db
  strategy.clean
  strategy
end

def create_strategy(*args)
  strategy, *strategy_args = args
  orm_strategy(strategy).new(*strategy_args)
end

def db
  @db ||= :default
end

def db=(desired_db)
  @db = self.strategy_db = desired_db
end

def initialize(orm, db: nil)
  @orm = orm
  self.db = db
end

def orm_module
  orm_module_name = camelize(orm)
  DatabaseCleaner.const_get(orm_module_name)
end

def orm_strategy(strategy)
  strategy_module_name = strategy.to_s.capitalize
  orm_module.const_get(strategy_module_name)
rescue NameError
  available_strategies = self.class.available_strategies(orm_module)
  raise UnknownStrategySpecified, "The '#{strategy}' strategy does not exist for the #{orm} ORM!  Available strategies: #{available_strategies.join(', ')}"
end

def set_strategy_db(strategy, desired_db)
  if strategy.respond_to? :db=
    strategy.db = desired_db
  elsif desired_db != :default
    raise ArgumentError, "You must provide a strategy object that supports non default databases when you specify a database"
  end
end

def strategy
  @strategy ||= NullStrategy.new
end

def strategy=(args)
  strategy, *strategy_args = args
  @strategy = if strategy.is_a?(Symbol)
    create_strategy(*args)
  elsif strategy_args.empty?
    strategy
  else
    raise ArgumentError, "You must provide a strategy object, or a symbol for a known strategy along with initialization params."
  end
  set_strategy_db @strategy, db
end

def strategy_db=(desired_db)
  set_strategy_db(strategy, desired_db)
end