class
	ACCOUNT

create
	make

feature -- Access

	balance: REAL_64
			-- Kontostand

	creditline: REAL_64 assign set_creditline
			-- Kreditrahmen

	interest_deposit: REAL_64 assign set_interest_deposit
			-- Habenverzinsung

	interest_debit: REAL_64 assign set_interest_debit
			-- Sollverzinsung

	transfer_minamount: REAL_64 assign set_transfer_minamount
			-- Mindestbetrag fuer jede Einzahlung, Auszahlung und Ueberweisung

feature {NONE} -- Implementation

	range: detachable TUPLE [min: REAL_64; max: REAL_64]

	creditline_range: attached like range
			-- min/max for creditline

	interest_deposit_range: attached like range
			-- min/max for interest_deposit

	interest_debit_range: attached like range
			-- min/max for interest_debit

	authorized_signers: ARRAYED_SET [PERSON]
			-- Zeichnungsberechtigte

feature {NONE} -- Initialization

	make (an_authorized_signer: PERSON;
		  an_interest_deposit: like interest_deposit;
		  an_interest_debit: like interest_debit;
		  a_credit_line: like creditline;
		  an_interest_deposit_range: like interest_deposit_range;
		  an_interest_debit_range: like interest_debit_range;
		  a_credit_line_range: like creditline_range)
		require
			a_credit_line_range.min < a_credit_line_range.max
			an_interest_debit_range.min < an_interest_debit_range.max
			an_interest_deposit_range.min < an_interest_deposit_range.max
		do
			create authorized_signers.make(1)
			add_authorized_signer (an_authorized_signer)
			creditline := a_credit_line
			interest_debit := an_interest_debit
			interest_deposit := an_interest_deposit
			interest_deposit_range := an_interest_deposit_range
			interest_debit_range := an_interest_debit_range
			creditline_range := a_credit_line_range

			set_default_transfer_minamount
			balance := 0.0
		end

feature -- Basic operations

	deposit (an_amount: like transfer_minamount; an_authorized_signer: PERSON)
		require
			an_authorized_signer_authorized: get_authorized_signers.has (an_authorized_signer)
			transfer_minamount_ok: an_amount >= transfer_minamount
		do
			balance := balance + an_amount
		ensure
			balance_increased: balance > old balance
			deposited: balance = old balance + an_amount
		end

	withdraw (an_amount: like transfer_minamount; an_authorized_signer: PERSON)
		require
			an_authorized_signer_authorized: get_authorized_signers.has (an_authorized_signer)
			transfer_minamount_ok: an_amount >= transfer_minamount
			balance_beneath_creditline: balance - an_amount >= creditline
		do
			balance := balance - an_amount
		ensure
			balance_beneath_creditline: balance >= creditline
			balance_decreased: balance < old balance
			withdrawed: balance = old balance - an_amount
		end

	transfer(an_amount: like transfer_minamount; an_authorized_signer: PERSON;
			 an_account: like Current; another_authorized_signer: PERSON)
		require
			recipient_account_not_same: Current /= an_account
		do
			withdraw (an_amount, an_authorized_signer)
			an_account.deposit (an_amount, another_authorized_signer)
		end

	add_authorized_signer (an_authorized_signer: PERSON)
		do
			if not authorized_signers.has (an_authorized_signer) then
				authorized_signers.put (an_authorized_signer)
			end
		ensure
			authorized_signers_assigned: authorized_signers.has (an_authorized_signer)
		end

	remove_authorized_signer (an_authorized_signer: PERSON)
		require
			authorized_signer_exists: (get_authorized_signers.has (an_authorized_signer))
			authorized_signers_not_empty: get_authorized_signers.count >= 2
		do
			authorized_signers.prune (an_authorized_signer)
		ensure
			authorized_signers_assigned: not authorized_signers.has (an_authorized_signer)
		end

	get_authorized_signers: FINITE [PERSON]
		do
			Result := authorized_signers
		end

	advance
		do
			if balance < 0.0 then
				-- debit
				balance := balance + (balance * interest_debit)
			else
				-- deposit
				balance := balance + (balance * interest_deposit)
			end
		end

feature {NONE} -- Implementation

	set_transfer_minamount (a_transfer_minamount: like transfer_minamount)
		require
			a_transfer_minamount_positive: a_transfer_minamount > 0.0
		do
			transfer_minamount := a_transfer_minamount
		ensure
			transfer_minamount_assigned: transfer_minamount = a_transfer_minamount
		end

	set_default_transfer_minamount
		do
			set_transfer_minamount (2.0)
		end

	set_creditline (a_creditline: like creditline)
		require
			a_creditline_within_bounds: a_creditline >= creditline_range.min
				and a_creditline <= creditline_range.max
		do
			creditline := a_creditline
		ensure
			creditline_assigned: creditline = a_creditline
		end

	set_interest_deposit (an_interest_deposit: like interest_deposit)
		require
			an_interest_deposit_within_bounds: interest_deposit >= interest_deposit_range.min
				and interest_deposit <= interest_deposit_range.max
		do
			interest_deposit := an_interest_deposit
		ensure
			interest_deposit_assigned: interest_deposit = an_interest_deposit
		end

	set_interest_debit (an_interest_debit: like interest_debit)
		require
			an_interest_deposit_within_bounds: interest_debit >= interest_debit_range.min
				and interest_debit <= interest_debit_range.max
		do
			interest_debit := an_interest_debit
		ensure
			interest_debit_assigned: interest_debit = an_interest_debit
		end

invariant
	authorized_signers_not_empty: authorized_signers.count > 0
	transfer_minamount_positive: transfer_minamount > 0.0
	creditline_within_bounds: creditline >= creditline_range.min
		and creditline <= creditline_range.max
	interest_debit_within_bounds: interest_debit >= interest_debit_range.min
		and interest_debit <= interest_debit_range.max
	interest_deposit_within_bounds: interest_deposit >= interest_deposit_range.min
		and interest_deposit <= interest_deposit_range.max
end