#Future Value
#It is difficult to make a budget that spans several years,
#because prices are not stable. If your company needs 200 pencils
#per year, you cannot simply use this year's price as the cost of
#pencils two years from now. Because of inflation the cost is likely
#to be higher than it is today. 
#
#Write a program to gauge the expected cost of an item in a specified
#number of years. The program asks for the cost of the item,
#the number of years from now that the item will be purchased,
# and the rate of inflation. The program then outputs the estimated
#cost of the item after the specified period. 

#Have the user enter the inflation rate as a percentage, like 5.6 (%).
#Your program should then convert the percent to a fraction, like 0.056,
#and should use a loop to estimate the price adjusted for inflation.

from graphics import *

def main():
    print "This program calculates the expected price of an item"
    price = input("Please, input the today's price of an item: ")
    years = input("Please, input the number of years from now that the item will be purchased: ")
    inflation = input("Please, input the inflation rate: ")

    print "Now let's do it in graphics!"

    window=GraphWin('Predicting item\'s price.',320,240)
    window.setBackground("white")

    # let's draw the scale (you may skip this part till
    # drawing bars:
    starting_price=price
    
    inflation = inflation/100.0
    for i in range(years):
        price=price+price*inflation
        print "price=%f" %(price)

    print "start price=%f, price=%f" %(starting_price,price)
    diff=price-starting_price
    scale=diff/4.
    print "difference=%f, scale=%f" %(diff,scale)
    
    l1=str(starting_price)
    l1=l1[:4]
    print "label 1=%s" %(l1)

    label2=starting_price+scale
    l2=str(label2)
    l2=l2[:4]
    print "label 2=%s" %(l2)
  
    label3=starting_price+2*scale
    l3=str(label3)
    l3=l3[:4]
    print "label 3=%s" %(l3)

    label4=starting_price+3*scale
    l4=str(label4)
    l4=l4[:4]
    print "label 4=%s" %(l4)

    label5=starting_price+4*scale
    l5=str(label5)
    l5=l5[:4]
    print "label 5=%s" %(l5)

    Text(Point(20,30), l5).draw(window)
    Text(Point(20,80), l4).draw(window)
    Text(Point(20,130),l3).draw(window)
    Text(Point(20,180),l2).draw(window)
    Text(Point(20,230),l1).draw(window)

    # draw bars for successive years

    price=starting_price # I saved the initial price of the item
    # aside, and now I'm updating the price value to initial one
    
    # need variable pixels to find the bar height
    pixels=(50.)/scale
    print "pixels=%f" % (pixels)
    #inflation = inflation/100.0
    for i in range(years):
        price=price+price*inflation
        print "price=%f" % (price)
        # draw bar for this value
        x=i * 25 + 60
        height=(price-starting_price)*pixels
        print "height=%f" % (height)
        bar=Rectangle(Point(x,230),Point(x+25,230-height))
#       bar=Rectangle(Point(x,230),Point(x+25,30))
        bar.setFill('green')
        bar.setWidth(2)
        bar.draw(window)
        

    print "In ", years, "years the price of the item will be ", price
    print "Have a good day!"

    flag=raw_input("Please input any symbol to close the window:")
    window.close()

main()