#! /usr/bin/env racket
#lang racket

(module+ main
  (displayln total-cost))

(struct item (description quantity unit-cost max-lead-days where-to-get))

(define bill-of-materials
  (list
   (item "Arduino(tm) board"
         1 21 8 (string-append "http://store.mp3car.com/"
                               "Genuine_Arduino_Uno_R3_SMD_p/OPN-013B.htm"
                               "?gclid=CKizyYOKsrkCFap7Qgod9kgAOQ"))
   (item "USB a to b" 1 4 7 "https://www.sparkfun.com/products/512")
   (item "wheel" 2 3 7 "http://www.pololu.com/catalog/product/184")
   (item "motor" 2 6 7 "http://www.pololu.com/catalog/product/181")
   (item "half BreadBoard" 1 5 3 "http://www.adafruit.com/products/64")
   (item "jumper wire male/male assorted lengths"
         1 6 3 "http://www.adafruit.com/products/153")
   (item "jumper wire female/male" 1/5 6 2
         (string-append "http://www.nexuscyber.com/"
                        "7-premium-40-pin-male-to-female-jumper-wires"))
   (item "small squares of double sided tape"
         1/30 12 1
         (string-append
          "http://www.officedepot.com/"
          "a/products/495242/Scotch-Permanent-Double-Sided-Foam-Tape/"))
   (item "#4-40 Phillips 1/2 inch flat-head screws"
         3 .1 1 "home depot, lowes")
   (item "#4-40 hex nuts"
         6 .1 1 "home depot, lowes")
   (item "#4 lock washers"
         3 .1 1 "home depot, lowes")
   (item "Red LEDs"
         2 .1 1 "evil mad science?")
   (item "Yellow LEDs"
         2 .1 1 "evil mad science?")
   (item "Green LEDs"
         2 .1 1 "evil mad science?")
   (item "330 Ohm Resistors"
         6 .1 1 "evil mad science?")))

(define total-cost
  (apply + (for/list ([thing bill-of-materials])
             (* (item-quantity thing) (item-unit-cost thing)))))