strong base for payment handling

backend/src/payments/payment_handler.py

@@ -1,149 +1,336 @@
 from typing import Literal
+from datetime import datetime, timedelta
 import logging
 import json
 
-from pydantic import BaseModel
-from fastapi import HTTPException
+from pydantic import BaseModel, Field, field_validator
 import requests
 
 from ..configuration.environment import Environment
 
 
-# Model for payment request body
-class OrderDetails():
-    
+# Define the base URL, might move that to toml file
+BASE_URL = 'https://api-m.sandbox.paypal.com'
+
+# Intialize the logger
+logger = logging.getLogger(__name__)
+
+
+class BasketItem(BaseModel):
+    """
+    Represents a single item in the user's basket.
+
+    Attributes:
+        id (str): The unique identifier for the item.
+        quantity (int): The number of units of the item.
+    """
+    id: str
+    quantity: int
+
+
+class Item(BaseModel):
+    """
+    Represents an item available in the shop.
+
+    Attributes:
+        id (str): The unique identifier for the item.
+        name (str): The name of the item.
+        description (str): The description of the item.
+        unit_price (str): The unit price of the item.
+    """
+    id: str
+    name: str
+    description: str
+    unit_price: str
+
+
+def item_from_sql(item_id: str):
+    """
+    Fetches an item from the database by its ID.
+
+    Args:
+        item_id (str): The unique identifier for the item.
+
+    Returns:
+        Item: The item object retrieved from the database.
+    """
+    # TODO: Replace with actual SQL fetch logic
+    return Item(
+        id = '12345678',
+        name = 'test_item',
+        description = 'lorem ipsum',
+        unit_price = 420
+    )
+
+
+class OrderRequest(BaseModel):
+    """
+    Represents an order request from the frontend.
+
+    Attributes:
+        user_id (str): The ID of the user placing the order.
+        basket (list[BasketItem]): List of basket items.
+        currency (str): The currency code for the order.
+        created_at (datetime): Timestamp when the order was created.
+        updated_at (datetime): Timestamp when the order was last updated.
+        items (list[Item]): List of item details loaded from the database.
+        total_price (float): Total price of the order.
+    """
     user_id: str
-    number_of_credits: Literal[10, 50, 100]
-    unit_price: float
-    amount: int
-    currency: Literal['USD', 'EUR', 'CHF']
+    basket: list[BasketItem]
+    currency: Literal['CHF', 'EUR', 'USD']
+    created_at: datetime = Field(default_factory=datetime.now)
+    updated_at: datetime = Field(default_factory=datetime.now)
+    items: list[Item] = Field(default_factory=list)
+    total_price: float = 0
+
+    @field_validator('basket')
+    def validate_basket(cls, v):
+        """Validates the basket items.
+
+        Args:
+            v (list): List of basket items.
+
+        Raises:
+            ValueError: If basket does not contain valid BasketItem objects.
+
+        Returns:
+            list: The validated basket.
+        """
+        if not v or not all(isinstance(i, BasketItem) for i in v):
+            raise ValueError('Basket must contain BasketItem objects')
+        return
+    
+    def load_items_and_price(self):
+        """
+        Loads item details from database and calculates the total price.
+        """
+        self.items = []
+        self.total_price = 0
+        for basket_item in self.basket:
+            item = item_from_sql(basket_item.id)
+            self.items.append(item)
+            self.total_price += item.unit_price * basket_item.quantity
 
 
+    def to_paypal_items(self): 
+        """
+        Converts items to the PayPal API item format.
+
+        Returns:
+            list: List of items formatted for PayPal API.
+        """
+        item_list = []
+
+        for basket_item, item in zip(self.basket, self.items):
+            item_list.append({
+                'id': item.id,
+                'name': item.name,
+                'description': item.description,
+                'quantity': str(basket_item.quantity),
+                'unit_amount': {
+                    'currency_code': self.currency,
+                    'value': str(item.unit_price)
+                }
+            })
+        return item_list
+
+
+
+ 
 
 # Payment handler class for managing PayPal payments
 class PaypalHandler:
+    """
+    Handles PayPal payment operations.
 
-    # PayPal secrets
-    username = Environment.paypal_id_sandbox
-    password = Environment.paypal_key_sandbox
+    Attributes:
+        sandbox (bool): Whether to use the sandbox environment.
+        id (str): PayPal client ID.
+        key (str): PayPal client secret.
+        base_url (str): Base URL for PayPal API.
+        _token_cache (dict): Cache for the PayPal OAuth access token.
+    """
 
+    _token_cache = {
+        "access_token": None,
+        "expires_at": 0
+    }
+
+    order_request = None
 
     def __init__(
             self,
-            order_details: OrderDetails,
             sandbox_mode: bool = False
             ):
-        # Initialize the logger
-        self.logger = logging.getLogger(__name__)
+        """
+        Initializes the handler.
 
-        # Payment request parameters
-        self.order_details = order_details
+        Args:
+            sandbox_mode (bool): Whether to use sandbox credentials.
+        """
+        self.logger = logging.getLogger(__name__)
         self.sandbox = sandbox_mode
 
-    # Only support purchase of credit 'bundles': 10, 50 or 100 credits worth of trip generation
-    # def fetch_price(self) -> float:
-    #     '''
-    #     Fetches the price of credits in the specified currency.
-    #     '''
-    #     result = self.supabase.table('prices').select('credit_amount').eq('currency', self.details.currency).single().execute()
-    #     if result.data:
-    #         return result.data.get('price')
-    #     else:
-    #         self.logger.error(f'Unsupported currency: {self.details.currency}')
-    #         return None
-
-
-    def validate(self):
-
-        if self.sandbox :
-            validation_url = 'https://api-m.sandbox.paypal.com/v1/oauth2/token'
+        # PayPal keys
+        if sandbox_mode :
+            self.id = Environment.paypal_id_sandbox
+            self.key = Environment.paypal_key_sandbox
+            self.base_url = BASE_URL
         else :
-            validation_url = 'https://api-m.paypal.com/v1/oauth2/token'
+            self.id = Environment.paypal_id_prod
+            self.key = Environment.paypal_key_prod
+            self.base_url = 'https://api-m.paypal.com'
 
-        # payload for the validation request
+
+
+    def _get_access_token(self) -> str | None:
+        """
+        Gets (and caches) a PayPal access token.
+
+        Returns:
+            str | None: The access token if successful, None otherwise.
+        """
+        now = datetime.now()
+        # Check if token is still valid
+        if (
+            self._token_cache["access_token"] is not None
+            and self._token_cache["expires_at"] > now
+        ):
+            self.logger.info('Returning (cached) access token.')
+            return self._token_cache["access_token"]
+
+        # Request new token
         validation_data = {'grant_type': 'client_credentials'}
 
         try: 
             # pass the request
             validation_response = requests.post(
-                url=validation_url,
-                data=validation_data,
-                auth=(self.username, self.password)
+                url  = f'{self.base_url}/v1/oauth2/token',
+                data = validation_data,
+                auth =(self.id, self.key)
             )
 
         except Exception as exc:
             self.logger.error(f'Error while requesting access token: {exc}')
             return None
-        
-        if validation_response.status_code == 201 :
-            access_token = json.loads(validation_response.text)['access_token']
-            self.logger.info('Validation step successful. Returning access token.')
-            return access_token
-        
-        self.logger.error(f'Error {validation_response.status_code} while requesting access token: {validation_response.text}')
-        return None        
+    
+        data = validation_response.json()
+        access_token = data.get("access_token")
+        expires_in = int(data.get("expires_in", 3600)) # seconds, default 1 hour
+
+        # Cache the token and its expiry
+        self._token_cache["access_token"] = access_token
+        self._token_cache["expires_at"] = now + timedelta(seconds=expires_in - 60)  # buffer 1 min
+
+        self.logger.info('Returning (new) access token.')
+        return access_token
 
 
-    def order(
-        self,
-        access_token: int
-    ):
+    def order(self, order_request: OrderRequest):
+        """
+        Creates a new PayPal order.
 
-        if self.sandbox :
-            order_url = 'https://api-m.sandbox.paypal.com/v2/checkout/orders'
-        else :
-            order_url = 'https://api-m.paypal.com/v2/checkout/orders'
+        Args:
+            order_request (OrderRequest): The order request.
 
-        # payload for the order equest
+        Returns:
+            dict | None: PayPal order response JSON, or None if failed.
+        """
         order_data = {
             'intent': 'CAPTURE',
             'purchase_units': [
                 {
-                    'items': [
-                        {
-                            'name': f'{self.order_details.number_of_credits} Credits Pack',
-                            'description': f'Credits for {self.order_details.number_of_credits} trip generations on AnyWay.',
-                            'quantity': self.order_details.amount,
-                            'unit_amount': {
-                                'currency_code': self.order_details.currency,
-                                'value': self.order_details.unit_price
-                            }
-
-                        }
-                    ],
+                    'items': order_request.to_paypal_items(),
                     'amount': {
-                        'currency_code': self.order_details.currency,
-                        'value': self.order_details.amount*self.order_details.unit_price,
-                        # 'breakdown': {
-                        #     'item_total': {
-                        #         'currency_code': 'CHF',
-                        #         'value': '5.00'
-                        #     }
-                        # }
-                        ## what is that for ?
+                        'currency_code': order_request.currency,
+                        'value': str(order_request.total_price),
+                        'breakdown': {
+                            'item_total': {
+                                'currency_code': order_request.currency,
+                                'value': str(order_request.total_price)
+                            }
+                        }
                     }
                 }
             ],
-            # TODO: add these to anydev website somehow
+            # TODO: add these to anydev website
             'application_context': {
                 'return_url': 'https://anydev.info',
                 'cancel_url': 'https://anydev.info'
             }
         }
 
-        # TODO continue here
+        # Get the access_token:
+        access_token = self._get_access_token()
+
+        try: 
+            order_response = requests.post(
+                url     = f'{self.base_url}/v2/checkout/orders',
+                headers = {'Authorization': f'Bearer {access_token}'},
+                json    = order_data,
+            )
+
+        # Raise HTTP Exception if request was unsuccessful.
+        except Exception as exc:
+            self.logger.error(f'Error creating PayPal order: {exc}')
+            return None
+
+        order_response.raise_for_status()
+
+        # TODO Now that we have the order ID, we can inscribe the details in sql database using the order id given by paypal
+        # DB for storing the transactions:
+
+        # order_id (key): json.loads(order_response.text)["id"]
+        # user_id       : order_request.user_id
+        # created_at    : order_request.created_at
+        # status        : order_request.status
+        # basket (json) : OrderDetails.jsonify()
+        # total_price   : order_request.total_price
+        # currency      : order_request.currency
+        # updated_at    : order_request.created_at
+
+        return order_response.json()
 
 
-        pass
+    # Standalone function to capture a payment
+    def capture(self, order_id: str):
+        """
+        Captures payment for a PayPal order.
 
-    def capture(self):
-
-
-
-
-        pass
+        Args:
+            order_id (str): The PayPal order ID.
+
+        Returns:
+            dict | None: PayPal capture response JSON, or None if failed.
+        """
+        # Get the access_token:
+        access_token = self._get_access_token()
+
+        try: 
+            capture_response = requests.post(
+                url  = f'{BASE_URL}/v2/checkout/orders/{order_id}/capture',
+                headers = {'Authorization': f'Bearer {access_token}'},
+                json = {},
+            )
+        except Exception as exc:
+            logger.error(f'Error while requesting access token: {exc}')
+            return None
+
+        capture_response.raise_for_status()
+
+        # todo check status code + try except
+        print(capture_response.text)
+        # order_id = json.loads(response.text)["id"]
+
+        # TODO: update status to PAID in sql database
+
+        # where order_id (key) = order_id
+        # status        : 'PAID'
+        # updated_at    : datetime.now()
 
 
+    # Not sure yet if/how to implement that
     def cancel(self):
                
         pass

backend/src/payments/payment_router.py

@@ -1,79 +1,136 @@
-import logging
-import paypalrestsdk
-from fastapi import HTTPException, APIRouter
+from typing import Literal
 
-from ..supabase.supabase import SupabaseClient
-from .payment_handler import PaymentRequest, PaymentHandler
+from fastapi import FastAPI, HTTPException
+from ..payments import PaypalHandler, OrderRequest
 
-# Set up logging and supabase
-logger = logging.getLogger(__name__)
-supabase = SupabaseClient()
+app = FastAPI()
 
-# Configure PayPal SDK
-paypalrestsdk.configure({
-    "mode": "sandbox",  # Use 'live' for production
-    "client_id": "YOUR_PAYPAL_CLIENT_ID",
-    "client_secret": "YOUR_PAYPAL_SECRET"
-})
+# Initialize PayPal handler
+paypal_handler = PaypalHandler(sandbox_mode=True)
 
-
-# Define the API router
-router = APIRouter()
-
-@router.post("/purchase/credits")
-def purchase_credits(payment_request: PaymentRequest):
+@app.post("/orders/new")
+def create_order(
+        user_id: str,
+        basket: list,
+        currency: Literal['CHF', 'EUR', 'USD']
+    ):
     """
-    Handles token purchases. Calculates the number of tokens based on the amount paid,
-    updates the user's balance, and processes PayPal payment.
+    Creates a new PayPal order.
+
+    Args:
+        user_id (str): The ID of the user placing the order.
+        basket (list): The basket items.
+        currency (str): The currency code.
+
+    Returns:
+        dict: The PayPal order details.
     """
-    payment_handler = PaymentHandler(payment_request)
 
-    # Create PayPal payment and get the approval URL
-    approval_url = payment_handler.create_paypal_payment()
+    # Create order :
+    order = OrderRequest(
+        user_id = user_id,
+        basket=basket,
+        currency=currency
+    )
 
-    return {
-        "message": "Purchase initiated successfully",
-        "payment_id": payment_handler.payment_id,
-        "credits": payment_request.credit_amount,
-        "approval_url": approval_url,
-    }
+    # Process the order and return the details
+    return paypal_handler.order(order_request = order)
 
 
-@router.get("/payment/success")
-def payment_success(paymentId: str, PayerID: str):
+
+@app.post("/orders/{order_id}/capture")
+def capture_order(order_id: str):
     """
-    Handles successful PayPal payment.
+    Captures payment for an existing PayPal order.
+
+    Args:
+        order_id (str): The PayPal order ID.
+
+    Returns:
+        dict: The PayPal capture response.
     """
-    payment = paypalrestsdk.Payment.find(paymentId)
-
-    if payment.execute({"payer_id": PayerID}):
-        logger.info("Payment executed successfully")
-
-        # Retrieve transaction details from the database
-        result = supabase.table("pending_payments").select("*").eq("payment_id", paymentId).single().execute()
-        if not result.data:
-            raise HTTPException(status_code=404, detail="Transaction not found")
-
-        # Extract the necessary information
-        user_id = result.data["user_id"]
-        credit_amount = result.data["credit_amount"]
-
-        # Update the user's balance
-        supabase.increment_credit_balance(user_id, amount=credit_amount)
-
-        # Optionally, delete the pending payment entry since the transaction is completed
-        supabase.table("pending_payments").delete().eq("payment_id", paymentId).execute()
-
-        return {"message": "Payment completed successfully"}
-    else:
-        logger.error(f"Payment execution failed: {payment.error}")
-        raise HTTPException(status_code=500, detail="Payment execution failed")
+    result = paypal_handler.capture(order_id)
+    return result
 
 
-@router.get("/payment/cancel")
-def payment_cancel():
-    """
-    Handles PayPal payment cancellation.
-    """
-    return {"message": "Payment was cancelled"}
+
+
+# import logging
+# import paypalrestsdk
+# from fastapi import HTTPException, APIRouter
+
+# from ..supabase.supabase import SupabaseClient
+# from .payment_handler import PaymentRequest, PaymentHandler
+
+# # Set up logging and supabase
+# logger = logging.getLogger(__name__)
+# supabase = SupabaseClient()
+
+# # Configure PayPal SDK
+# paypalrestsdk.configure({
+#     "mode": "sandbox",  # Use 'live' for production
+#     "client_id": "YOUR_PAYPAL_CLIENT_ID",
+#     "client_secret": "YOUR_PAYPAL_SECRET"
+# })
+
+
+# # Define the API router
+# router = APIRouter()
+
+# @router.post("/purchase/credits")
+# def purchase_credits(payment_request: PaymentRequest):
+#     """
+#     Handles token purchases. Calculates the number of tokens based on the amount paid,
+#     updates the user's balance, and processes PayPal payment.
+#     """
+#     payment_handler = PaymentHandler(payment_request)
+
+#     # Create PayPal payment and get the approval URL
+#     approval_url = payment_handler.create_paypal_payment()
+
+#     return {
+#         "message": "Purchase initiated successfully",
+#         "payment_id": payment_handler.payment_id,
+#         "credits": payment_request.credit_amount,
+#         "approval_url": approval_url,
+#     }
+
+
+# @router.get("/payment/success")
+# def payment_success(paymentId: str, PayerID: str):
+#     """
+#     Handles successful PayPal payment.
+#     """
+#     payment = paypalrestsdk.Payment.find(paymentId)
+
+#     if payment.execute({"payer_id": PayerID}):
+#         logger.info("Payment executed successfully")
+
+#         # Retrieve transaction details from the database
+#         result = supabase.table("pending_payments").select("*").eq("payment_id", paymentId).single().execute()
+#         if not result.data:
+#             raise HTTPException(status_code=404, detail="Transaction not found")
+
+#         # Extract the necessary information
+#         user_id = result.data["user_id"]
+#         credit_amount = result.data["credit_amount"]
+
+#         # Update the user's balance
+#         supabase.increment_credit_balance(user_id, amount=credit_amount)
+
+#         # Optionally, delete the pending payment entry since the transaction is completed
+#         supabase.table("pending_payments").delete().eq("payment_id", paymentId).execute()
+
+#         return {"message": "Payment completed successfully"}
+#     else:
+#         logger.error(f"Payment execution failed: {payment.error}")
+#         raise HTTPException(status_code=500, detail="Payment execution failed")
+
+
+# @router.get("/payment/cancel")
+# def payment_cancel():
+#     """
+#     Handles PayPal payment cancellation.
+#     """
+#     return {"message": "Payment was cancelled"}
 

backend/src/payments/test.py

@@ -74,6 +74,7 @@ order_data = {
 
 order_response = requests.post(
     url=order_url,
+    headers={"Authorization": f"Bearer {access_token}"},        ## need access token here? 
     json=order_data,
     auth=(username, password)
 )