require 'set'

module SqliteExt

  module DbMethodPrepends

    # Adds functions registered with SqliteExt to each new
    # instance before it is returned from `.new` or `.open`or is
    # passed to the given block.
    def initialize(file, *other_init_args)
      if block_given?
        super file, *other_init_args do
          SqliteExt.enhance_db_session self
          yield self
        end
      else
        super
        SqliteExt.enhance_db_session self
      end
    end

    def create_function(name, arity, *other_args, &block)
      super
      created_function_names << name_key_from(name)
    end

    # Given a name, returns true if a function of that hane has
    # been created on the target instance. The name lookup is
    # case-insensitive, and either a string or a symbol may be
    # supplied.
    def function_created?(name)
      name_key = name_key_from(name)
      created_function_names.include?(name_key)
    end

    private

    def name_key_from(name)
      "#{name}".upcase
    end

    def created_function_names
      @created_function_names ||= Set.new
    end

  end

end