"""Billing routes: Stripe checkout, webhook, subscription management.

Business logic lives in ``app.billing.stripe_service.StripeService``.
The route layer handles HTTP concerns (request parsing, response shaping)
and delegates everything else to the service singleton.
"""

from __future__ import annotations

from typing import Any

from fastapi import APIRouter, Depends, Header, HTTPException, Request, status
from pydantic import BaseModel
from sqlalchemy.ext.asyncio import AsyncSession

from app.api.deps import get_current_user
from app.billing.stripe_service import stripe_service
from app.db import get_session
from app.schemas import BillingTier, UserProfile

router = APIRouter(prefix="/billing", tags=["billing"])


# ── Request bodies ─────────────────────────────────────────────────────

class _CheckoutRequest(BaseModel):
    tier: BillingTier


# ── Routes ─────────────────────────────────────────────────────────────

@router.post("/checkout", response_model=dict)
async def create_checkout(
    body: _CheckoutRequest,
    current_user: UserProfile = Depends(get_current_user),
) -> dict[str, str]:
    """Create a Stripe checkout session for a tier upgrade.

    Returns a stub URL when ``STRIPE_SECRET_KEY`` is not configured.
    """
    url = stripe_service.create_checkout_session(current_user.id, body.tier)
    return {"checkout_url": url}


@router.post("/webhook", response_model=dict)
async def stripe_webhook(
    request: Request,
    stripe_signature: str = Header(default="", alias="Stripe-Signature"),
    db: AsyncSession = Depends(get_session),
) -> dict[str, bool]:
    """Handle Stripe webhook events.

    No JWT auth — authenticated via Stripe signature verification instead.
    Returns 200 immediately when Stripe is not configured (local dev).
    """
    payload = await request.body()
    await stripe_service.handle_webhook(payload, stripe_signature, db)
    return {"ok": True}


@router.get("/subscription", response_model=dict)
async def get_subscription(
    current_user: UserProfile = Depends(get_current_user),
    db: AsyncSession = Depends(get_session),
) -> dict[str, Any]:
    """Return the current subscription info for the authenticated user."""
    sub = await stripe_service.get_subscription(current_user.id, db)
    if sub is None:
        return {
            "tier": current_user.tier,
            "status": "free",
            "stripe_subscription_id": None,
            "current_period_end": None,
        }
    return sub


@router.delete("/subscription", response_model=dict, status_code=status.HTTP_200_OK)
async def cancel_subscription(
    current_user: UserProfile = Depends(get_current_user),
    db: AsyncSession = Depends(get_session),
) -> dict[str, bool]:
    """Cancel the active subscription."""
    await stripe_service.cancel_subscription(current_user.id, db)
    return {"ok": True}


@router.get("/invoices", response_model=list[dict])
async def list_invoices(
    current_user: UserProfile = Depends(get_current_user),
    db: AsyncSession = Depends(get_session),
) -> list[dict[str, Any]]:
    """Return billing history (invoices) from Stripe.

    Returns an empty list when Stripe is not configured.
    """
    invoices = await stripe_service.list_invoices(current_user.id, db)
    return invoices


# ── Quota check ────────────────────────────────────────────────────────

from app.billing.quota import check_folder_quota, QuotaExceeded  # noqa: E402


class QuotaCheckRequest(BaseModel):
    feature: str
    estimated_files: int


@router.post("/quota/check")
async def quota_check(
    payload: QuotaCheckRequest,
    current_user: UserProfile = Depends(get_current_user),
    db: AsyncSession = Depends(get_session),
) -> dict:
    """Pre-flight folder quota check. 402 if tier limits would be exceeded."""
    if payload.feature != "folder_index":
        raise HTTPException(status_code=400, detail="Unknown feature")
    try:
        await check_folder_quota(
            user_id=current_user.id,
            tier=current_user.tier,
            estimated_files=payload.estimated_files,
            db=db,
        )
    except QuotaExceeded as exc:
        raise HTTPException(
            status_code=402,
            detail={"reason": exc.reason, "message": str(exc)},
        )
    return {"ok": True}