# Week 8 - Lab: Python Program
# Assignment Value: 10 points
# Description:

#     Create a Python program that demonstrates exception handling.  
#     Your program should include at least three custom-defined exceptions and handle them appropriately.
#     Implement try-except blocks to handle exceptions and provide meaningful error messages.
#     Test your program with various scenarios to ensure proper exception handling.

# Instructions:

#     Create a Python script named exception_handling.py. 
#     Define three custom exceptions: CustomError1, CustomError2, and CustomError3.
#     Implement a function divide_numbers() that takes two numbers as input and returns the result of dividing the first number by the second number.
#         Handle the ZeroDivisionError exception. If the second number is zero, raise CustomError1.
#     Implement a function open_file() that takes a filename as input and tries to open the file.
#         Handle the FileNotFoundError exception. If the file does not exist, raise CustomError2.
#     Implement a function process_data() that takes a list as input and tries to access an element at a specific index.
#         Handle the IndexError exception. If the index is out of range, raise CustomError3.
#     In the main part of your script, demonstrate the usage of all the implemented functions by invoking them and handling exceptions appropriately.  
#     Take a screenshot of Thonny showing both the code and output at the end of the exercise.
#     Upload the screenshot. 

# Directions for submitting your written assignment as an attachment:

#     When you have completed the assignment, save the file on your computer with your name as part of the file name, for example, a_student_assignment1.docx [using your first initial and last name]
#     Click on the title of the assignment above.
#     Click on "Upload Files".
#     Click on the "Browse Local Files" button to attach your file to this assignment.
#     Once you have attached your file, click on the "Submit" button to send your file to your instructor.

# Note: This assignment is due 11:59 PM ET, Sunday of Week 8.

import os

def divide_numbers(num1, num2):
    try:
        print(f"Dividing numbers {num1} / {num2}")
        if num2 == 0:
            raise CustomError1
        return num1 / num2
    except CustomError1:
        print("CustomError1: Cannot divide by zero.")

def open_file(input_file):
    try:
        print(f"Trying to open the {input_file}")
        with open(input_file, 'r') as f:
            print(f"{input_file} has been opened successfully.")
            pass
    except FileNotFoundError:
        raise CustomError2

def process_data(data, index):
    try:
        print(f"Trying to return the data for each index.")
        return data[index]
    
    except IndexError:
        raise CustomError3
    
class CustomError1(Exception):
    pass

class CustomError2(Exception):
    pass

class CustomError3(Exception):
    pass

def __main__():
    script_directory = os.path.dirname(os.path.abspath(__file__)) # get the directory of the script
    input_file = os.path.join(script_directory, "input.txt") #had to use os.path.join to get the correct path. Wasn't working with just the file name
    fail_input_file = os.path.join(script_directory, "doesnotexist.txt")
    try:
        print("\n\n----------Division Function-------------")
        print("----------------------------------------")
        print(f"Failure case: {divide_numbers(10, 0)}")
        print(f"Success case: {divide_numbers(100, 10)}")
        
    except CustomError1:
        print("CustomError1 handled.")

    print("----------End Division Function---------\n\n")


    try:
        print("---------Open File Function-------------")
        print("----------------------------------------")
        print(f"Success Case: Trying to open {input_file}")
        open_file(input_file)
        
        print(f"Fail Case: Trying to open {fail_input_file}")
        open_file(fail_input_file)
    
    except CustomError2:
        print("CustomError2 handled.")

    print("---------End Open File Function---------\n\n")


    try:
        print("-------Process List Input Function------")
        print("----------------------------------------")
        print(f"Failure case: {process_data([1, 2, 3], 3)}")
        print(process_data([1, 2, 3], 2))
        
    except CustomError3:
        print("CustomError3 handled.")

    try:
        print("-------Process List Input Function------")
        print("----------------------------------------")
        print(f"Success case: {process_data([1, 2, 3], 2)}")
        
    except CustomError3:
        print("CustomError3 handled.")
   
    print("----End Process List Input Function-----\n\n")

if __name__ == "__main__":
    
    __main__()