# fdemo.py
# Lillian Lee (LJL2), Steve Marschner (srm2)
# The idea to have an if-statement based on "he loves me",
# which was the inspiration for this demo,  is due to J. Kleinberg
# Feb 19, 2014

"""Module that when run, simulates the 'he loves me' flower ritual.

This demo was developed for the purposes of demonstrating if-statements
and conditional expressions; see the functions pluck(f), pluck1(f) and
pluck2(f). You can put any of these plucking functions into
run_flower() and see what happens.

It also happens to demonstrate primitive versions of useful stuff
that we haven't talked about (yet): defining your own class of objects,
prompting a user for input, and doing something repeatedly via
while-loops.

A number of design choices were made in writing this code, simple
as it may seem, and several alternatives are possible."""

import random


class Flower(object):
    """An instance is a flower.  Flowers have two attributes.
    We describe these below by giving the 'class invariants' in
    comments. Programmers are assumed to write code that maintains
    the class invariants; they are constraints that are assumed
    to hold before and after code is executed.

    num_petals [int]: the number of petals.  >= 0.

    loves_me_not: True if and only if the next petal
    to pluck corresponds to "he loves me" (vs. "he loves me not"),
    assuming there is at least one more petal.
    BUT, if there are no more petals, the value of loves_me_not
    is None."""

    # max number of petals a flower can have (since lecture is short)
    MAX_PETALS = 5  

   # METHODS
    def __init__(self):
        """Initializer: A new flower() with num_petals set
        to a random int in [1,MAX_PETALS], and he_loves_me
        set to True."""
        self.num_petals = random.randrange(1, Flower.MAX_PETALS+1)
        self.he_loves_me = True

    def print_petals(self):
        """Returns: String showing all the flower's petals as vertical bars.
        Sample outputs are:
            '|||'
            '||'
            ''
        """

        return '|' * self.num_petals 


def pluck(f):
    """Pluck a petal in the 'he loves me' ritual

    Prints out the appropriate 'he loves me' or 'he loves me not'
    message, and then removes a petal. An exclamation point is added
    to the printout if this was the last petal.

    Precondition: f is a Flower with at least one petal.
    Prints out a warning and exits if f has no petals"""

    # This implementation uses if-statements with complex booleans.

    if f.num_petals == 0:
        print 'no more petals'
        return # execution stops here

    # print out the right thing
    if f.he_loves_me and f.num_petals > 1:
        print "he loves me"
    elif f.he_loves_me and f.num_petals == 1:
        print "he loves me!"
    elif not f.he_loves_me and f.num_petals > 1:
        print "he loves me not"
    else:
        print "he loves me not!"

    # reduce the number of petals
    f.num_petals = f.num_petals - 1

    # "flip" the he_loves_me "bool"
    if f.num_petals > 0:
        f.he_loves_me = not f.he_loves_me
    else: # no more petals left
        f.he_loves_me =  None


def pluck1(f):
    """Pluck a petal in the 'he loves me' ritual

    Prints out the appropriate 'he loves me' or 'he loves me not'
    message, and then removes a petal. An exclamation point is added
    to the printout if this was the last petal.

    Precondition: f is a Flower with at least one petal.
    Prints out a warning and exits if f has no petals"""

    #This implementation uses nested if-statements.

    if f.num_petals == 0:
        print 'no more petals'
        return

    if f.he_loves_me:
        if f.num_petals > 1:
            print "he loves me"
        else:
            print "he loves me!"
    else:  # he doesn't love me OR he_loves_me is None
        if f.num_petals > 1:
            print "he loves me not"
        else:
            print "he loves me not!"

    # maintain class invariants on f.he_loves_me and f.num_petals
    f.num_petals = f.num_petals - 1
    f.he_loves_me = not f.he_loves_me if f.num_petals > 0 else None


def pluck2(f):
    """Pluck a petal in the 'he loves me' ritual

    Prints out the appropriate 'he loves me' or 'he loves me not'
    message, and then removes a petal. An exclamation point is added
    to the printout if this was the last petal.

    Precondition: f is a Flower with at least one petal.
    Prints out a warning and exits if f has no petals"""
    #this implementation uses conditional expressions

    if f.num_petals == 0:
        print 'no more petals'
        return

    if f.he_loves_me:
        print "he loves me" + ('' if f.num_petals > 1 else '!')
    else:
        print "he loves me not" + ('' if f.num_petals > 1 else '!')

    # maintain class invariants on f.he_loves_me and f.num_petals
    f.num_petals = f.num_petals - 1
    f.he_loves_me = not f.he_loves_me if f.num_petals > 0 else None


def pluck3(f):
    """Pluck a petal in the 'he loves me' ritual

    Prints out the appropriate 'he loves me' or 'he loves me not'
    message, and then removes a petal. An exclamation point is added
    to the printout if this was the last petal.

    Precondition: f is a Flower with at least one petal.
    Prints out a warning and exits if f has no petals"""
    #this implementation uses a "one-liner" conditional expressions 


    if f.num_petals == 0:
        print 'no more petals'
        return # execution halts here if this if clause were entered

    print ("he loves me" +
            ("" if f.he_loves_me else " not") +
            ("" if f.num_petals > 1 else "!"))
    

    # maintain class invariants on f.he_loves_me and f.num_petals
    f.num_petals = f.num_petals - 1
    f.he_loves_me = not f.he_loves_me if f.num_petals > 0 else None


if __name__ == '__main__':
    """Simulate the 'he loves me' ritual with the user."""

    # Uses a while loop.
    print "\nHope you had a happy Valentine's Day!"
    raw_input("Press 'return' to pick a flower. ")
    f = Flower()  # don't need flower.Flower() because inside flower.py

    print "New flower picked. " # omit for more surprise: + f.print_petals()

    while f.num_petals > 0:
        raw_input('Press "return" to pluck a petal. ')
        pluck(f)
    
        # omitting the line below so as to not spoil the surprise        
        #nprint f.print_petals()