adds login generator as OOP and MVC

learning_python3.md

@@ -2760,7 +2760,339 @@ if __name__ == "__main__":
 
 ### Improve the login generator
 
-TODO convert the login generator to a class
+First the library...
+
+```python
+Oimport string
+import random
+import json
+
+
+def load_file(filepath):
+    words = []
+    with open(filepath, "r") as fp:
+        data = fp.readlines()
+    for line in data:
+        word = line.strip()
+        words.append(word)
+    return words
+
+
+class Login(object):
+    ADJECTIVES = load_file("adjectives.txt")
+    ANIMALS = load_file("subjects.txt")
+
+    def __init__(self, site=None):
+        self.site = site
+        self.generate_password()
+        self.generate_username()
+
+    def __str__(self):
+        msg = "site: {} - username: {} with password: {}".format(self.site, self.username, self.password)
+        return msg
+
+    def generate_password(self, length=16, complex=False):
+        if complex:
+            db = list(string.ascii_letters + string.digits + string.punctuation)
+        else:
+            db = list(string.ascii_letters)
+        password = []
+        for i in range(0, length):
+            char = random.choice(db)
+            password.append(char)
+        password = "".join(password)
+        self.password = password
+
+    def generate_username(self):
+        """generates a random username from a list of animals and adjectives"""
+        adj = random.choice(self.__class__.ADJECTIVES)
+        sbj = random.choice(self.__class__.ANIMALS)
+        username = f"{adj.capitalize()}{sbj.capitalize()}"
+        self.username = username
+
+    def set_password(self, password):
+        self.password = password
+
+    def set_username(self, username):
+        self.username = username
+
+    def verify_password(self, password):
+        if password == self.password:
+            return True
+        return False
+
+    def verify_username(self, username):
+        if username == self.username:
+            return True
+        return False
+
+    def verify_login(self, username, password):
+        # if password == self.password and username == self.username:
+        if self.verify_password(password) and self.verify_username(username):
+            return True
+        return False
+
+
+class Database(object):
+    def __init__(self, path="db.json"):
+        self.path = path
+        self.data = []
+
+    def add(self, login):
+        if isinstance(login, Login):
+            self.data.append(login)
+
+    def get_all(self):
+        return self.data
+
+    def get_by_index(self, index):
+        if index in range(0, len(self.data)):
+            return self.data[index]
+
+    def save_to_disk(self):
+        with open(self.path, "w") as fp:
+            json.dump(self.data, fp , default=vars)
+
+    def load_from_disk(self):
+        with open(self.path, "r") as fp:
+            data = json.load(fp)
+        for item in data:
+            l = Login(item["site"])
+            l.set_password(item["password"])
+            l.set_username(item["username"])
+            self.data.append(l)
+
+
+if __name__ == "__main__":
+    db = Database()
+    db.load_from_disk()
+    for login in db.data:
+        print(login)
+        login.generate_password()
+    db.save_to_disk()
+```
+
+Now the command line interface with a **bad** separation of responsibilities.
+
+```python
+from login_lib_OOP import Login, Database
+
+
+class CommandLineInterface(object):
+    def __init__(self, db):
+        self.db = db
+
+    def ask_for_int(self, msg):
+        while True:
+            result = input(msg)
+            if result.isdigit():
+                number = int(result)
+                break
+            print("only intergers please...")
+        return number
+
+    def ask_for_bool(self, msg):
+        while True:
+            result = input(msg).lower()
+            if result.startswith("y"):
+                status = True
+                break
+            elif result.startswith("n"):
+                status = False
+                break
+            print("answer with y(es)/n(o) please...")
+        return status
+
+    def ask_for_view(self):
+        msg = "do you want to view your logins?"
+        status = self.ask_for_bool(msg)
+
+    def ask_for_add_logins(self):
+        msg = "how many logins do you want to add?"
+        number = self.ask_for_int(msg)
+        for i in range(0, number):
+            l = Login("undefined")
+            self.db.add(l)
+
+    def view_logins(self):
+        for login in self.db.data:
+            print("\t{}: {}".format(self.db.data.index(login), login))
+
+    def main_menu(self):
+        actions = ["show logins", "add logins", "save to disk","load from disk", "quit"]
+        for action in actions:
+            print("{}: {}".format(actions.index(action), action))
+        msg = "what do you want to do?"
+        action = self.ask_for_int(msg)
+        if action == 0:
+            self.view_logins()
+        elif action == 1:
+            self.ask_for_add_logins()
+        elif action == 2:
+            self.db.save_to_disk()
+        elif action == 3:
+            self.db.load_from_disk()
+        elif action == 4:
+            return False
+        return True
+
+    def run(self):
+        while True:
+            status = self.main_menu()
+            if not status:
+                break
+
+
+if __name__ == "__main__":
+    db = Database()
+    app = CommandLineInterface(db)
+    app.run()
+```
+
+Now a minimal **MVC** version...
+
+```python
+from login_lib_OOP import Login, Database
+
+
+class Controller(object):
+    def __init__(self, model):
+        self.model = model
+
+    def set_view(self, view):
+        self.view = view
+
+    def add_multiple_logins(self, number):
+        for i in range(0, number):
+            l = Login()
+            self.model.add(l)
+            self.view.show_message("added {}".format(l))
+
+    def get_all_logins(self):
+        data = self.model.get_all()
+        self.view.show_message("there are {} logins in your database".format(len(data)))
+        for login in data:
+            msg = "{}: {}".format(data.index(login), login)
+            self.view.show_data(msg)
+
+    def get_one_login(self, index):
+        login = self.model.get_all()[index]
+        return login
+
+    def load(self):
+        self.model.load_from_disk()
+        number = len(self.model.get_all())
+        self.view.show_message("loaded {} logins from disk".format(number))
+
+    def save(self):
+        self.model.save_to_disk()
+        number = len(self.model.get_all())
+        self.view.show_message("saved {} logins to disk".format(number))
+
+
+class CommandLineInterface(object):
+    def __init__(self, controller):
+        self.controller = controller
+
+    def ask_for_int(self, msg):
+        while True:
+            result = input(msg)
+            if result.isdigit():
+                number = int(result)
+                break
+            print("only intergers please...")
+        return number
+
+    def ask_for_bool(self, msg):
+        while True:
+            result = input(msg).lower()
+            if result.startswith("y"):
+                status = True
+                break
+            elif result.startswith("n"):
+                status = False
+                break
+            print("answer with y(es)/n(o) please...")
+        return status
+
+    def ask_for_login_index(self):
+        msg = "which login do you want to modify?"
+        number = self.ask_for_int(msg)
+        return number
+
+    def show_data(self, msg):
+        print("\t{}".format(msg))
+
+    def show_message(self, msg):
+        print("MSG: {}".format(msg))
+
+    def show_header(self, msg):
+        print(msg)
+        print(len(msg) * "-")
+
+    def main_menu(self):
+        self.show_header("main menu:")
+        actions = ["show logins", "add logins", "save to disk", "load from disk", "modify a login", "quit"]
+        for action in actions:
+            print("{}: {}".format(actions.index(action), action))
+        msg = "what do you want to do?"
+        action = self.ask_for_int(msg)
+        if action == 0:
+            self.controller.get_all_logins()
+        elif action == 1:
+            msg = "how many logins do you want?"
+            number = self.ask_for_int(msg)
+            self.controller.add_multiple_logins(number) 
+        elif action == 2:
+            self.controller.save()
+        elif action == 3:
+            self.controller.load()
+        elif action == 4:
+            self.sub_menu_modify()
+        elif action == 5:
+            return False
+        return True
+
+    def sub_menu_modify(self):
+        self.show_header("modify entry:")
+        msg = "which login do you want to modify?"
+        number = self.ask_for_int(msg)
+        login = self.controller.get_one_login(number)
+        msg = "do you want to change the site name?"
+        status = self.ask_for_bool(msg)
+        if status:
+            login.site = input("for which site is this login?")
+            self.show_message("set site to: {}".format(login.site))
+        msg = "do you want to renew the username?"
+        status = self.ask_for_bool(msg)
+        if status:
+            login.generate_username()
+            self.show_message("set username to: {}".format(login.username))
+        msg = "do you want to renew the password?"
+        status = self.ask_for_bool(msg)
+        if status:
+            login.generate_password()
+            self.show_message("set password to: {}".format(login.password))
+        msg = "save changes?"
+        status = self.ask_for_bool(msg)
+        if status:
+            self.controller.save()
+
+    def run(self):
+        while True:
+            status = self.main_menu()
+            if not status:
+                break
+
+
+if __name__ == "__main__":
+    model = Database()
+    controller = Controller(model)
+    view = CommandLineInterface(controller)
+    controller.set_view(view)
+    view.run()
+
+```
 
 ### Improve the task manager