contact_book.py

import json #it is a built-in module in Python that provides functions for working with JSON data. It allows you to convert Python objects to JSON format and vice versa.
import os # os is a built-in module in Python that provides a way to interact with the operating system. It allows you to perform various tasks such as file and directory manipulation, environment variable access, and process management.

FILE_NAME = "contacts.json"


# ---------------------------
# Load Contacts
# ---------------------------
def load_contacts(): #it is a function that loads the contacts from a JSON file named "contacts.json". It checks if the file exists using os.path.exists(). If the file exists, it opens the file in read mode and uses json.load() to load the JSON data into a Python dictionary. If the file does not exist, it returns an empty dictionary.
    if os.path.exists(FILE_NAME): #the os.path.exists() function checks if the specified file or directory exists in the file system. In this case, it checks if the "contacts.json" file exists.
        with open(FILE_NAME, "r") as file: #the with statement is used to ensure that the file is properly closed after it is no longer needed.
            return json.load(file)  #when the file is opened in read mode, the json.load() function is used to parse the JSON data from the file and convert it into a Python dictionary. The resulting dictionary is then returned by the load_contacts() function.
    return {}

#this function checks if the file "contacts.json" exists. If it does, it opens the file in read mode and loads the JSON data into a Python dictionary using json.load(). If the file does not exist, it returns an empty dictionary.
# ---------------------------
# Save Contacts
# ---------------------------
def save_contacts():
    with open(FILE_NAME, "w") as file:
        json.dump(contacts, file, indent=4)


contacts = load_contacts()


# ---------------------------
# Add Contact
# ---------------------------
def add_contact():
    name = input("Enter Name: ").strip()

    if name in contacts:
        print("❌ Contact already exists!")
        return

    phone = input("Enter Phone Number: ")
    email = input("Enter Email: ")

    contacts[name] = {
        "Phone": phone,
        "Email": email
    }

    save_contacts()

    print("✅ Contact Added Successfully!")


# ---------------------------
# View Contacts
# ---------------------------
def view_contacts():
    if not contacts:
        print("\nNo Contacts Found.\n")
        return

    print("\n========== CONTACT LIST ==========")

    for name in sorted(contacts):
        print(f"\nName  : {name}")
        print(f"Phone : {contacts[name]['Phone']}")
        print(f"Email : {contacts[name]['Email']}")


# ---------------------------
# Search Contact
# ---------------------------
def search_contact():
    name = input("Enter Name: ")

    if name in contacts:
        print("\nContact Found")
        print("----------------------")
        print("Name :", name)
        print("Phone:", contacts[name]["Phone"])
        print("Email:", contacts[name]["Email"])
    else:
        print("❌ Contact Not Found.")


# ---------------------------
# Update Contact
# ---------------------------
def update_contact():
    name = input("Enter Name to Update: ")

    if name not in contacts:
        print("❌ Contact Not Found.")
        return

    phone = input("New Phone: ")
    email = input("New Email: ")

    contacts[name]["Phone"] = phone
    contacts[name]["Email"] = email

    save_contacts()

    print("✅ Contact Updated Successfully.")


# ---------------------------
# Delete Contact
# ---------------------------
def delete_contact():
    name = input("Enter Name to Delete: ")

    if name in contacts:
        del contacts[name]
        save_contacts()
        print("🗑 Contact Deleted Successfully.")
    else:
        print("❌ Contact Not Found.")


# ---------------------------
# Main Menu
# ---------------------------
while True:

    print("\n==============================")
    print("      CONTACT BOOK")
    print("==============================")
    print("1. Add Contact")
    print("2. View Contacts")
    print("3. Search Contact")
    print("4. Update Contact")
    print("5. Delete Contact")
    print("6. Exit")

    choice = input("\nEnter Choice: ")

    if choice == "1":
        add_contact()

    elif choice == "2":
        view_contacts()

    elif choice == "3":
        search_contact()

    elif choice == "4":
        update_contact()

    elif choice == "5":
        delete_contact()

    elif choice == "6":
        print("\nThank You For Using Contact Book ❤️")
        break

    else:
        print("❌ Invalid Choice.")