SignIn Screen
=============

The SignIn screen is the first point of user interaction for authentication in the SailPilot app. It provides users with a form to enter their credentials and access the application.

Layout and Widgets
------------------

- **Text Fields**: Includes email and password fields with respective `TextEditingController`s for user input.
- **PrimaryButton**: A custom button widget used for the sign-in action. It is wrapped inside a `ShakeWidget` to provide a shake animation on certain conditions (like invalid credentials).
- **Social Sign-In Options**: Offers alternative sign-in methods using social media accounts (Google, Facebook, Apple).

Authentication Process
----------------------

Upon tapping the sign-in button, the app:
- Validates the input fields to ensure they are not empty.
- Calls the `login` method from `AuthService` to authenticate the user.
- If authentication is successful, updates the `AuthState` and navigates to the `LandingPage`.
- If there are issues (like invalid credentials), triggers a shake animation and clears the input fields.

Dark Mode Support
-----------------

The screen adjusts its background color and other UI elements based on the current theme (light or dark mode).

User Feedback
-------------

- Displays a loading indicator during the authentication process.
- Shows a `SnackBar` with an error message if the authentication fails or if the input fields are empty.

Navigation to SignUp Screen
---------------------------

Includes a text button that navigates users to the `SignUp` screen for new account creation.

.. note:: The SignIn screen is crucial for user experience, providing a straightforward and visually appealing interface for users to access their accounts in SailPilot.