"""
Stripe payment provider — checkout sessions, webhook handling, subscription management.

Exports the same interface as paddle.py so billing/routes.py can dispatch:
- build_checkout_payload()
- build_multi_item_checkout_payload()
- cancel_subscription()
- get_management_url()
- verify_webhook()
- parse_webhook()

Stripe Tax add-on handles EU VAT collection (must be enabled in Stripe Dashboard).
"""

import json
import logging

import stripe as stripe_sdk

from ..core import config

logger = logging.getLogger(__name__)


def _stripe_client():
    """Configure and return the stripe module with our API key."""
    stripe_sdk.api_key = config.STRIPE_SECRET_KEY
    stripe_sdk.max_network_retries = 2
    return stripe_sdk


def build_checkout_payload(
    price_id: str, custom_data: dict, success_url: str,
) -> dict:
    """Create a Stripe Checkout Session for a single item.

    Returns {checkout_url: "https://checkout.stripe.com/..."} — the client
    JS redirects the browser there (no overlay SDK needed).
    """
    s = _stripe_client()
    session = s.checkout.Session.create(
        mode=_mode_for_price(s, price_id),
        line_items=[{"price": price_id, "quantity": 1}],
        metadata=custom_data,
        success_url=success_url + "?session_id={CHECKOUT_SESSION_ID}",
        cancel_url=success_url.rsplit("/success", 1)[0] + "/pricing",
        automatic_tax={"enabled": True},
        tax_id_collection={"enabled": True},


    )
    return {"checkout_url": session.url}


def build_multi_item_checkout_payload(
    items: list[dict], custom_data: dict, success_url: str,
) -> dict:
    """Create a Stripe Checkout Session for multiple line items.

    items: list of {"priceId": "price_xxx", "quantity": 1}
    """
    s = _stripe_client()

    line_items = [{"price": i["priceId"], "quantity": i.get("quantity", 1)} for i in items]

    # Determine mode: if any item is recurring, use "subscription".
    # Otherwise use "payment" for one-time purchases.
    has_recurring = any(_is_recurring_price(s, i["priceId"]) for i in items)
    mode = "subscription" if has_recurring else "payment"

    session = s.checkout.Session.create(
        mode=mode,
        line_items=line_items,
        metadata=custom_data,
        success_url=success_url + "?session_id={CHECKOUT_SESSION_ID}",
        cancel_url=success_url.rsplit("/success", 1)[0],
        automatic_tax={"enabled": True},
        tax_id_collection={"enabled": True},


    )
    return {"checkout_url": session.url}


def _mode_for_price(s, price_id: str) -> str:
    """Determine Checkout Session mode from price type."""
    try:
        price = s.Price.retrieve(price_id)
        return "subscription" if price.type == "recurring" else "payment"
    except Exception:
        # Default to payment if we can't determine
        return "payment"


def _is_recurring_price(s, price_id: str) -> bool:
    """Check if a Stripe price is recurring (subscription)."""
    try:
        price = s.Price.retrieve(price_id)
        return price.type == "recurring"
    except Exception:
        return False


def cancel_subscription(provider_subscription_id: str) -> None:
    """Cancel a Stripe subscription at end of current billing period."""
    s = _stripe_client()
    s.Subscription.modify(
        provider_subscription_id,
        cancel_at_period_end=True,


    )


def get_management_url(provider_subscription_id: str) -> str:
    """Create a Stripe Billing Portal session and return its URL."""
    s = _stripe_client()

    # Get customer_id from the subscription
    sub = s.Subscription.retrieve(
        provider_subscription_id,


    )
    portal = s.billing_portal.Session.create(
        customer=sub.customer,
        return_url=f"{config.BASE_URL}/billing/success",


    )
    return portal.url


def verify_webhook(payload: bytes, headers) -> bool:
    """Verify Stripe webhook signature using the Stripe-Signature header."""
    if not config.STRIPE_WEBHOOK_SECRET:
        return True
    sig_header = headers.get("Stripe-Signature", "")
    if not sig_header:
        return False
    try:
        stripe_sdk.Webhook.construct_event(
            payload, sig_header, config.STRIPE_WEBHOOK_SECRET,
        )
        return True
    except (stripe_sdk.SignatureVerificationError, ValueError):
        return False


def parse_webhook(payload: bytes) -> dict:
    """Parse a Stripe webhook payload into a normalized event dict.

    Maps Stripe event types to the shared format used by _handle_webhook_event():
    - checkout.session.completed (mode=subscription) → subscription.activated
    - customer.subscription.created → subscription.activated
    - customer.subscription.updated → subscription.updated
    - customer.subscription.deleted → subscription.canceled
    - invoice.payment_failed → subscription.past_due
    - checkout.session.completed (mode=payment) → transaction.completed
    """
    raw = json.loads(payload)
    stripe_type = raw.get("type", "")
    obj = raw.get("data", {}).get("object", {})

    # Extract metadata — Stripe stores custom data in session/subscription metadata
    metadata = obj.get("metadata") or {}

    # Common fields
    customer_id = obj.get("customer", "")
    user_id = metadata.get("user_id")
    supplier_id = metadata.get("supplier_id")
    plan = metadata.get("plan", "")

    # Map Stripe events to our shared event types
    if stripe_type == "checkout.session.completed":
        mode = obj.get("mode", "")
        if mode == "subscription":
            subscription_id = obj.get("subscription", "")
            # Fetch subscription details for period end
            period_end = None
            if subscription_id:
                try:
                    s = _stripe_client()
                    sub = s.Subscription.retrieve(
                        subscription_id,
                

                    )
                    # Stripe API 2026-02+ moved period_end to items
                    ts = sub.current_period_end
                    if not ts and sub.get("items", {}).get("data"):
                        ts = sub["items"]["data"][0].get("current_period_end")
                    period_end = _unix_to_iso(ts)
                except Exception:
                    logger.warning("Failed to fetch subscription %s for period_end", subscription_id)

            return {
                "event_type": "subscription.activated",
                "subscription_id": subscription_id,
                "customer_id": str(customer_id),
                "user_id": user_id,
                "supplier_id": supplier_id,
                "plan": plan,
                "status": "active",
                "current_period_end": period_end,
                "data": obj,
                "items": _extract_line_items(obj),
                "custom_data": metadata,
            }
        else:
            # One-time payment
            return {
                "event_type": "transaction.completed",
                "subscription_id": "",
                "customer_id": str(customer_id),
                "user_id": user_id,
                "supplier_id": supplier_id,
                "plan": plan,
                "status": "completed",
                "current_period_end": None,
                "data": obj,
                "items": _extract_line_items(obj),
                "custom_data": metadata,
            }

    elif stripe_type == "customer.subscription.created":
        # New subscription — map to subscription.activated so the handler creates the DB row
        status = _map_stripe_status(obj.get("status", ""))
        return {
            "event_type": "subscription.activated",
            "subscription_id": obj.get("id", ""),
            "customer_id": str(customer_id),
            "user_id": user_id,
            "supplier_id": supplier_id,
            "plan": plan,
            "status": status,
            "current_period_end": _get_period_end(obj),
            "data": obj,
            "items": _extract_sub_items(obj),
            "custom_data": metadata,
        }

    elif stripe_type == "customer.subscription.updated":
        status = _map_stripe_status(obj.get("status", ""))
        return {
            "event_type": "subscription.updated",
            "subscription_id": obj.get("id", ""),
            "customer_id": str(customer_id),
            "user_id": user_id,
            "supplier_id": supplier_id,
            "plan": plan,
            "status": status,
            "current_period_end": _get_period_end(obj),
            "data": obj,
            "items": _extract_sub_items(obj),
            "custom_data": metadata,
        }

    elif stripe_type == "customer.subscription.deleted":
        return {
            "event_type": "subscription.canceled",
            "subscription_id": obj.get("id", ""),
            "customer_id": str(customer_id),
            "user_id": user_id,
            "supplier_id": supplier_id,
            "plan": plan,
            "status": "cancelled",
            "current_period_end": _get_period_end(obj),
            "data": obj,
            "items": _extract_sub_items(obj),
            "custom_data": metadata,
        }

    elif stripe_type == "invoice.payment_failed":
        sub_id = obj.get("subscription", "")
        return {
            "event_type": "subscription.past_due",
            "subscription_id": sub_id,
            "customer_id": str(customer_id),
            "user_id": user_id,
            "supplier_id": supplier_id,
            "plan": plan,
            "status": "past_due",
            "current_period_end": None,
            "data": obj,
            "items": [],
            "custom_data": metadata,
        }

    # Unknown event — return a no-op
    return {
        "event_type": "",
        "subscription_id": "",
        "customer_id": str(customer_id),
        "user_id": user_id,
        "supplier_id": supplier_id,
        "plan": plan,
        "status": "",
        "current_period_end": None,
        "data": obj,
        "items": [],
        "custom_data": metadata,
    }


# =============================================================================
# Helpers
# =============================================================================

def _map_stripe_status(stripe_status: str) -> str:
    """Map Stripe subscription status to our internal status."""
    mapping = {
        "active": "active",
        "trialing": "on_trial",
        "past_due": "past_due",
        "canceled": "cancelled",
        "unpaid": "past_due",
        "incomplete": "past_due",
        "incomplete_expired": "expired",
        "paused": "paused",
    }
    return mapping.get(stripe_status, stripe_status)


def _unix_to_iso(ts) -> str | None:
    """Convert Unix timestamp to ISO string, or None."""
    if not ts:
        return None
    from datetime import UTC, datetime
    return datetime.fromtimestamp(int(ts), tz=UTC).strftime("%Y-%m-%dT%H:%M:%S.000000Z")


def _get_period_end(obj: dict) -> str | None:
    """Extract current_period_end from subscription or its first item.

    Stripe API 2026-02+ moved period fields from subscription to subscription items.
    """
    ts = obj.get("current_period_end")
    if not ts:
        items = obj.get("items", {}).get("data", [])
        if items:
            ts = items[0].get("current_period_end")
    return _unix_to_iso(ts)


def _extract_line_items(session_obj: dict) -> list[dict]:
    """Extract line items from a Checkout Session in Paddle-compatible format.

    Stripe doesn't embed line_items in checkout.session.completed webhooks,
    so we fetch them via the API. Returns [{"price": {"id": "price_xxx"}}].
    """
    session_id = session_obj.get("id", "")
    if not session_id or not session_id.startswith("cs_"):
        return []

    try:
        s = _stripe_client()
        line_items = s.checkout.Session.list_line_items(session_id, limit=20)
        return [
            {"price": {"id": item["price"]["id"]}}
            for item in line_items.get("data", [])
            if item.get("price", {}).get("id")
        ]
    except Exception:
        logger.warning("Failed to fetch line_items for session %s", session_id)
        # Fallback: check if line_items were embedded in the payload (e.g. tests)
        embedded = session_obj.get("line_items", {}).get("data", [])
        return [
            {"price": {"id": item["price"]["id"]}}
            for item in embedded
            if item.get("price", {}).get("id")
        ]


def _extract_sub_items(sub_obj: dict) -> list[dict]:
    """Extract items from a Stripe Subscription object in Paddle-compatible format."""
    items = sub_obj.get("items", {}).get("data", [])
    return [{"price": {"id": item.get("price", {}).get("id", "")}} for item in items]