# L-24 MCS 260 Mon 8 Mar 2010 : library manager

# A library management system with classes

from classcatalog import *
from classpeople import *

def show_menu(p,c,w):
   "Shows the menu to the user."
   if w == -1:  # no one logged on
      print 'Please log on'
      return 0
   else: # w == 0 is patron
      print 'choose from the menu :'
      print '  1. log off'
      print '  2. show the collection'
      print '  3. check out a book'
      print '  4. return a book'   
      if w == +1: # librarian
         print '  5. add a new book'
         print '  6. delete a book'
         print '  7. add a new user'
         print '  8. delete a user'
         print '  9. shut down'
      a = input('Make your choice : ')
      return a

def act(p,c,a,w):
   "Performs the requested action."
   r = w
   if a == 0:
      r = p.logon()
   elif a == 1:
      p.logoff()
      r = -1
   elif a == 2: c.show()
   elif a == 3: c.checkout()
   elif a == 4: c.checkin()
   elif a == 5: c.add()
   elif a == 6: c.delete()
   elif a == 7: p.add()
   elif a == 8: p.delete()
   return r 

def main():
   "Main library management program."
   c = Catalog()
   p = People()
   w = -1
   print 'Welcome to our library!'
   while True:
      a = show_menu(p,c,w)
      if a == 9: break
      w = act(p,c,a,w)

main()