from typing import Optional, Dict, List, Tuple, Any
from html import escape
import uuid
from itsdangerous import URLSafeTimedSerializer, BadSignature
from micropie import App, HttpMiddleware, Request

class CSRFMiddleware(HttpMiddleware):
    """Middleware for CSRF protection using itsdangerous-signed tokens."""
    def __init__(self, app: App, secret_key: str, max_age: int = 8 * 3600):
        self.app = app  # Store the App instance
        self.serializer = URLSafeTimedSerializer(secret_key, salt="csrf-token")
        self.max_age = max_age

    async def before_request(self, request: Request) -> Optional[Dict]:
        """Verify CSRF token for POST/PUT/PATCH requests and generate a new token if needed."""
        # Extract session ID from cookies or generate a new one
        session_id = request.headers.get("cookie", "").split("session_id=")[-1].split(";")[0] if "session_id=" in request.headers.get("cookie", "") else str(uuid.uuid4())

        if request.method in ("POST", "PUT", "PATCH"):
            print(f"Request body_params: {request.body_params}")  # Debugging
            submitted_token = request.body_params.get("csrf_token", [""])[0]
            print(f"Submitted CSRF token: {submitted_token}")  # Debugging
            if not submitted_token:
                return {"status_code": 403, "body": "Missing CSRF token"}
            try:
                # Verify the submitted token's signature
                self.serializer.loads(submitted_token, max_age=self.max_age)
            except BadSignature:
                return {"status_code": 403, "body": "Invalid or expired CSRF token"}

        # Generate a new CSRF token if one doesn't exist in the session
        if "csrf_token" not in request.session:
            csrf_token = str(uuid.uuid4())
            signed_token = self.serializer.dumps(csrf_token)
            request.session["csrf_token"] = signed_token
            # Save the session
            print(f"Saving session with CSRF token: {signed_token}")  # Debugging
            await self.app.session_backend.save(session_id, request.session, self.max_age)

        return None

    async def after_request(
        self, request: Request, status_code: int, response_body: Any, extra_headers: List[Tuple[str, str]]
    ) -> Optional[Dict]:
        """Include CSRF token in response headers for client-side use."""
        if request.session.get("csrf_token"):
            extra_headers.append(("X-CSRF-Token", request.session["csrf_token"]))
        return None
        
# Define the Sub-App
class ApiApp(App):
    async def index(self):
        return {"message": "Welcome to the API!"}

    async def users(self, user_id: str):
        return {"user_id": user_id, "message": f"User {user_id} from API"}

    async def visits(self):
        if "visits" not in self.request.session:
            self.request.session["visits"] = 1
        else:
            self.request.session["visits"] += 1
        visits = self.request.session["visits"]
        return f"You have visited {visits} times."

    async def login(self):
        csrf_token = self.request.session.get("csrf_token", "")
        return f"""<form method="POST" action="/api/plogin">
            <input type="hidden" name="csrf_token" value="{escape(csrf_token)}">
            <input type="text" name="name">
            <button type="submit">Submit</button>
            </form>"""
        
    async def plogin(self, name):
        return f"Hello {name}"

class UserApp(App):
    async def index(self):
        return {"msg": "Hello world"}
    
    async def hello(self, name="world"):
        return f"hello {name}"

# Define a Middleware to Mount the Sub-App
class SubAppMiddleware(HttpMiddleware):
    def __init__(self, mount_path: str, subapp: App):
        self.mount_path = mount_path.lstrip("/")
        self.subapp = subapp

    async def before_request(self, request):
        path = request.scope["path"].lstrip("/")
        if path.startswith(self.mount_path):
            # Set the subapp and the remaining path
            request._subapp = self.subapp
            request._subapp_path = path[len(self.mount_path):].lstrip("/") or "/"
            return None  # Continue processing
        return None  # Not a subapp path, continue with main app

    async def after_request(
        self, request, status_code, response_body, extra_headers):
        return None  # No changes to response

# Define the Main App
class MainApp(App):
    async def index(self):
        return {"message": "Welcome to the Main App!"}

    async def hello(self, name: str):
        return {"message": f"Hello, {name} from Main App!"}

# Create and Configure the Apps
app = MainApp()
api_app = ApiApp()
api_app.middlewares.append(CSRFMiddleware(app=app, secret_key="my-secret-key"))
user_app = UserApp()

apiapp_middleware = SubAppMiddleware(mount_path="/api", subapp=api_app)
userapp_middleware = SubAppMiddleware(mount_path="/user", subapp=user_app)

app.middlewares.append(apiapp_middleware)
app.middlewares.append(userapp_middleware)
