;;
;; bank-account.scm
;;
;; Generic bank account records.
;;
;; ISC License
;;
;; Copyright 2023 Brmlab, z.s.
;; Dominik Pantůček <dominik.pantucek@trustica.cz>
;;
;; Permission to use, copy, modify, and/or distribute this software
;; for any purpose with or without fee is hereby granted, provided
;; that the above copyright notice and this permission notice appear
;; in all copies.
;; 
;; THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
;; WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
;; WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
;; AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
;; CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
;; OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
;; NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
;; CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
;;

(declare (unit bank-account))

(module
 bank-account
 (
  make-bank-account
  bank-account-transactions
  bank-account-number
  bank-account-bank
  bank-account-insert

  make-bank-transaction
  bank-transaction-varsym
  bank-transaction-amount
  bank-transaction-currency
  )

 (import scheme
	 (chicken base))

 ;; Bank account is represented as a list with list with the following
 ;; elements: list of transactions, account number, bank code. This
 ;; allows cheap transaction prepending.
 (define (make-bank-account number bank . maybe-transactions)
   (let ((transactions (if (null? maybe-transactions)
			   '()
			   (car maybe-transactions))))
     (list transactions number bank)))

 ;; Trivial accessors
 (define bank-account-transactions car)
 (define bank-account-number cadr)
 (define bank-account-bank caddr)

 ;; Prepends given transaction to given bank account. It expects the
 ;; transactions list to be the first element of the bank account
 ;; list.
 (define (bank-account-insert account transaction)
   (cons (cons transaction (car account))
	 (cdr account)))

 ;; Creates a new bank transaction. The order of elements is
 ;; well-suited for fast access to commonly used fields.
 (define (make-bank-transaction id date amount currency varsym)
   (list varsym amount currency date id))

 ;; Accessors for the fields actually used
 (define bank-transaction-varsym car)
 (define bank-transaction-amount cadr)
 (define bank-transaction-currency caddr)

 )