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payment_service.py

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+"""
+Payment service for Stripe integration.
+Handles subscription creation, checkout sessions, and webhook processing.
+"""
+
+import stripe
+import os
+from dotenv import load_dotenv
+from datetime import datetime, timezone, timedelta
+
+# Load environment variables
+load_dotenv()
+
+# Initialize Stripe with secret key
+stripe.api_key = os.getenv("STRIPE_SECRET_KEY")
+
+# Stripe webhook secret for signature verification
+STRIPE_WEBHOOK_SECRET = os.getenv("STRIPE_WEBHOOK_SECRET")
+
+def create_checkout_session(
+    user_id: str,
+    user_email: str,
+    plan_id: str,
+    stripe_price_id: str,
+    success_url: str,
+    cancel_url: str
+):
+    """
+    Create a Stripe Checkout session for subscription payment.
+
+    Args:
+        user_id: User's UUID
+        user_email: User's email address
+        plan_id: SubscriptionPlan UUID
+        stripe_price_id: Stripe Price ID for the plan
+        success_url: URL to redirect after successful payment
+        cancel_url: URL to redirect if user cancels
+
+    Returns:
+        dict: Checkout session object with session ID and URL
+    """
+    try:
+        # Create Checkout Session
+        checkout_session = stripe.checkout.Session.create(
+            customer_email=user_email,
+            payment_method_types=["card"],
+            line_items=[
+                {
+                    "price": stripe_price_id,
+                    "quantity": 1,
+                }
+            ],
+            mode="subscription",
+            success_url=success_url,
+            cancel_url=cancel_url,
+            metadata={
+                "user_id": str(user_id),
+                "plan_id": str(plan_id),
+            },
+            subscription_data={
+                "metadata": {
+                    "user_id": str(user_id),
+                    "plan_id": str(plan_id),
+                }
+            }
+        )
+
+        return {
+            "session_id": checkout_session.id,
+            "url": checkout_session.url
+        }
+
+    except stripe.error.StripeError as e:
+        raise Exception(f"Stripe error: {str(e)}")
+
+
+def verify_webhook_signature(payload: bytes, sig_header: str) -> dict:
+    """
+    Verify Stripe webhook signature and construct event.
+
+    Args:
+        payload: Raw webhook payload bytes
+        sig_header: Stripe signature header
+
+    Returns:
+        dict: Verified webhook event
+
+    Raises:
+        ValueError: If signature verification fails
+    """
+    try:
+        event = stripe.Webhook.construct_event(
+            payload, sig_header, STRIPE_WEBHOOK_SECRET
+        )
+        return event
+    except ValueError as e:
+        raise ValueError(f"Invalid payload: {str(e)}")
+    except stripe.error.SignatureVerificationError as e:
+        raise ValueError(f"Invalid signature: {str(e)}")
+
+
+def get_subscription_end_date(billing_cycle: str = "yearly") -> datetime:
+    """
+    Calculate subscription end date based on billing cycle.
+
+    Args:
+        billing_cycle: "yearly" or "monthly"
+
+    Returns:
+        datetime: End date for the subscription
+    """
+    now = datetime.now(timezone.utc)
+
+    if billing_cycle == "yearly":
+        # Add 1 year
+        return now + timedelta(days=365)
+    elif billing_cycle == "monthly":
+        # Add 1 month (approximation)
+        return now + timedelta(days=30)
+    else:
+        # Default to yearly
+        return now + timedelta(days=365)
+
+
+def create_stripe_price(
+    product_name: str,
+    price_cents: int,
+    billing_cycle: str = "yearly"
+) -> str:
+    """
+    Create a Stripe Price object for a subscription plan.
+
+    Args:
+        product_name: Name of the product/plan
+        price_cents: Price in cents
+        billing_cycle: "yearly" or "monthly"
+
+    Returns:
+        str: Stripe Price ID
+    """
+    try:
+        # Create a product first
+        product = stripe.Product.create(name=product_name)
+
+        # Determine recurring interval
+        interval = "year" if billing_cycle == "yearly" else "month"
+
+        # Create price
+        price = stripe.Price.create(
+            product=product.id,
+            unit_amount=price_cents,
+            currency="usd",
+            recurring={"interval": interval},
+        )
+
+        return price.id
+
+    except stripe.error.StripeError as e:
+        raise Exception(f"Stripe error creating price: {str(e)}")
+
+
+def get_customer_portal_url(stripe_customer_id: str, return_url: str) -> str:
+    """
+    Create a Stripe Customer Portal session for subscription management.
+
+    Args:
+        stripe_customer_id: Stripe Customer ID
+        return_url: URL to return to after portal session
+
+    Returns:
+        str: Customer portal URL
+    """
+    try:
+        session = stripe.billing_portal.Session.create(
+            customer=stripe_customer_id,
+            return_url=return_url,
+        )
+        return session.url
+    except stripe.error.StripeError as e:
+        raise Exception(f"Stripe error creating portal session: {str(e)}")