User.py

from Post import TextPost, ImagePost, SalePost


class Notification:
    def __init__(self, message, notification_type):
        self.message = message
        self.notification_type = notification_type


# User class behaves as the subject in the observer design pattern.
class User:

    def __init__(self, username, password):
        if not (4 <= len(password) <= 8):
            raise ValueError("Password must be between 4 and 8 characters.")
        self.username = username
        self.password = password
        self.status = True
        self.followers = []  # represents the observers
        self.following = []
        self.posts = []
        self.notifications = []

    def __str__(self):
        return f"User name: {self.username}, Number of posts: {len(self.posts)}, Number of followers: {len(self.followers) or ' '}"

    def disconnect(self):
        self.status = False

    def connect(self):
        self.status = True

    def notifications_manager(self):
        pass

    def notify(self, message):
        self.notifications.append(message)

    def follow(self, user):
        if user not in self.following:
            self.following.append(user)
            user.followers.append(self)
            print(f"{self.username} started following {user.username}")

    def unfollow(self, user):
        if user in self.following:
            if self.status:
                self.following.remove(user)
                user.followers.remove(self)
                print(f"{self.username} unfollowed {user.username}")
            else:
                print("User is not connected.")

    def publish_post(self, post_type, *args):
        post = None
        if not self.status:
            print("User is not connected. Cannot publish post.")
            return None

        if post_type == "Text":
            post = TextPost(*args)
        elif post_type == "Image":
            print(f"{self.username} posted a picture")
            print()
            post = ImagePost(*args)
        elif post_type == "Sale":
            post = SalePost(*args)

        if post:
            post._author = self
            self.posts.append(post)
            self.update(post)
            return post
        else:
            print(f"Invalid post type: {post_type}")
            return None

    def update(self, post):
        for follower in self.followers:
            follower.notify(f"{self.username} has a new post")
        if post.post_type != "Image":
            post.display()
            if post.post_type == "Text":
                print()

    def print_notifications(self):
        if self.status:
            print(f"{self.username}'s notifications:")
            for notification in self.notifications:
                if notification is not None:
                    print(f"{notification}")