# MVC_model.py
#
# Version 1 (archived as MVC_model_1.py)
#
# Changes:
#
# - Changed "from Quote_0 import *" to "import quote"
#   and then updated references to quote methods in test block,
#   e.g. Quote becomes quote.Quote.
#
# - Moved "import quote" down into the test block because that is the
#   only place it is needed.
#
# - Rewrote listall so it returns a list of all the objects,
#   but leaves rendering them up to the controller.
#
# Version 0 (archived as MVC_model_0.py)
#
# - Initial roughing out.

import shelve

class Model:
    def __init__(self, location):
        self.location = location
        self.datastore = shelve.open(location)

    def create(self, item):
        self.datastore[item.uid] = item

    def retrieve(self, uid):
        if self.datastore.has_key(uid):
            return self.datastore[uid]
        else:
            return False
    
    def update(self, uid):
        #
        # Your Assignment 6 code here.
        #
        pass
        
    def delete(self, uid):
        if self.datastore.has_key(uid):
            del self.datastore[uid]
            return True
        else:
            return False

    def listall(self):
        return_set = []
        for key in self.datastore:
            return_set.append( self.datastore[key] )
        return return_set

    def close(self):
        self.datastore.close()

if __name__ == '__main__':   
    import quote
    model = 'test_model'
    print 'Opening the model %s.' % (model)
    m = Model('test_model')
    print
    print 'Creating two Quotes.'
    q = quote.Quote( 'Kent Beck', 'Optimism is an occupational hazard of programming: testing is the treatment.')
    r = quote.Quote( 'Brian Kernighan', 'Controlling complexity is the essence of computer programming.')
    print
    print 'Adding them to the model.'
    m.create(q)
    m.create(r)
    print
    print 'Displaying all objects in the model.'
    for obj in m.listall():
        print obj
    print
    print 'Deleting one of the objects from the model.'
    m.delete(q.uid)
    print
    print 'Displaying all objects in the model for verification.'
    for obj in m.listall():
        print obj
    print
    print 'Closing the model.'
    m.close()
    print
    print 'Done.'