# AreaCalculator_3_1171.py - version 3
#
# This program allows us to compute the area of
# a triangle, a circle, a rectangle, a square and an ellipse.
#
# Anne Lavergne:
# Created June 2015 - Modified March 2017
#
# Liaqat Ali:
# Modified July 2018
#
# Demonstrating "Incremental Development"
# ( For 1) and 2) , see version 1. )
# 3) We continue incrementally implementing the steps of this algorithm: (Step 4)
#    In this version of our AreaCalculator, we add the code that deal with computing the area of a "square".
#    NOTE: This code does not correlate with exactly 1 specific step of our low-level algorithm, as in version 1,
#          but span across a few steps of our algorithm, namely:
#      # if "square" is selected, then ask for one side
#      # If "square" is selected, then compute area = side squared
#      # Display result
#          # Print the shape, the input data and the area
# 
# 4) We make sure our partial program executes (it has no syntax/runtime errors). (Step 5)
# 5) Then, we create test plans for it and test it (make sure it has no semantic errors). (Step 5)



# Set variables
exitProgram  = 'X'

          
def printMenu( ) :
    """
       Print description of program and menu displaying selection of shapes.
       Parameters: none.
       Returned value: none.
    """
    print("Welcome to my Area Calculator.\n")
    print("""This AreaCalculator allows us to compute the area of:\n
      \ta triangle\tEnter T
      \ta circle\tEnter C
      \ta rectangle\tEnter R
      \ta square\tEnter S
      \tan ellipse\tEnter E
      \tto exit\t\tEnter X""")
    return


def getSelection( ) :
    """
       Print input instruction to user, read user input (selection) then validate user input.
       Parameter: "notASelectionCode" - a letter indicating that the user has entered an invalid input.
       Returned value: "selectedShape" - either contains a valid selection or the value of parameter "notASelectionCode".
    """
    # Print input instruction to user and read user input
    selectedShape = input("\nPlease, enter your selection: ")
    # Validate input
    # Transform the user's input into an upper case letter in case
    # the user has entered a lower case letter as an selection
    selectedShape = selectedShape.upper( )
    return selectedShape

def rectangle( ):
    """
       Get width and height of rectangle from user, then compute and display the area of such rectangle. 
       Parameter: none.
       Returned value: none.
    """
    # Echo selection to user
    print("You have selected 'rectangle'.")
    # Ask for the width and height
    width = input("\nPlease, enter the width of the rectangle as a positive integer number: ")
    
    # Make sure the user has entered positive integer number (valid input)
    if not width.isalpha() and int(width) > 0:
        height = input("Please, enter the height of the rectangle as a positive integer number: ")
        if not height.isalpha() and int(height) > 0:
            # Compute area = width * height
            width = int(width)
            height = int(height)
            area = width * height
            # Print the shape, the input data and the area
            print("\nThe area of the rectangle with a width of %d and a height of %d is %d.\n" %(width, height, area))
        else:
            print("\nThe height you entered for the rectangle (%s) is invalid.\n" %height)
    else:
        print("\nThe width you entered for the rectangle (%s) is invalid.\n" %width)
    return


def square( ):
    """
       Get side of square from user, then compute and display the area of such square. 
       Parameter: none.
       Returned value: none.
    """
    # Echo selection to user
    print("You have selected 'square'.")
    # Ask for the length of the side of the square
    side = input("\nPlease, enter the length of the side of the square as a positive integer number: ")
        
    # Make sure the user has entered positive integer number (valid input)
    if not side.isalpha() and int(side) > 0:
        # Compute area = side ** 2
        side = int(side)
        area = side ** 2
        # Print the shape, the input data and the area
        print("\nThe area of the square with a side length of %d is %d.\n" %(side, area))
    else:
        print("\nThe side you entered for the square (%s) is invalid.\n" %side)
    return


# Main part of the program - top level (of execution)
# Print description of program and menu displaying selection of shapes
printMenu( )

# Get selection from user (+ validate input)
selectedShape = getSelection( )

# As long as the user enters a valid selection ...
while selectedShape != exitProgram: 
    # If "triangle" is selected?
    if selectedShape == "T":
        print("triangle")
    # If "circle" is selected?
    elif selectedShape == "C":
        print("circle")
    # If "rectangle" is selected?
    elif selectedShape == "R":
         rectangle()
    # If "square" is selected?
    elif selectedShape == "S":
        square()
    # If "ellipse" is selected?
    elif selectedShape == "E" :
        print("elipse")
    elif len(selectedShape) == 0 :
        print("You have not entered anything. Please, try again!")
    # Has the user entered valid input (1 letter either T, C, R, S or E)
    elif not (selectedShape in ["T", "C", "R", "S", "E"] ) :  
        print("You have not entered valid input. Please, try again!")
    selectedShape = getSelection( )
# For testing purposes:
# print("Exiting Main: selectedShape = ", selectedShape)
print("---")


# NOT YET IMPLEMENTED
# Based on selection selected by user, get appropriate input from user (validate input)
    # If "triangle" is selected, then ask for the base and height
    # If "circle" is selected, then ask for the radius
    # If "elipse" is selected, then ask for both radii
    # Validate input
    
# Compute desired area
    # If "triangle" is selected, then compute area = 0.5 ( base * height )
    # If "circle" is selected, then compute area = pi * radius squared
    # If "elipse" is selected, then compute area = pi * radius1 * radius2
    
# Display result
    # Print the shape, the input data and the area