"""Billing routes: Stripe checkout, webhook, subscription, tier query.

Adapted for the Billing microservice:
  - Authenticated routes use Traefik-injected headers (X-User-Id, X-User-Tier)
  - Webhook route has NO auth (Stripe signature verification only)
  - Added /tier/{user_id} for internal service-to-service tier lookups
  - Added /features/{tier} for feature matrix queries
"""

from __future__ import annotations

from typing import Any

from fastapi import APIRouter, Header, HTTPException, Request, status
from pydantic import BaseModel

from shared.db import async_session
from shared.schemas import BillingTier

from app.stripe_service import stripe_service
from app.tier_manager import tier_manager, FEATURES, RATE_LIMITS

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


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

class _CheckoutRequest(BaseModel):
    tier: BillingTier


# ── Checkout ───────────────────────────────────────────────────────────

@router.post("/checkout")
async def create_checkout(
    body: _CheckoutRequest,
    x_user_id: str = Header(..., alias="X-User-Id"),
) -> dict[str, str]:
    """Create a Stripe checkout session for a tier upgrade."""
    url = stripe_service.create_checkout_session(x_user_id, body.tier)
    return {"checkout_url": url}


# ── Webhook (NO auth — Stripe signature only) ─────────────────────────

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

    This endpoint is exposed without ForwardAuth in Traefik config
    so Stripe can reach it directly.
    """
    payload = await request.body()
    async with async_session() as db:
        await stripe_service.handle_webhook(payload, stripe_signature, db)
    return {"ok": True}


# ── Subscription CRUD ─────────────────────────────────────────────────

@router.get("/subscription")
async def get_subscription(
    x_user_id: str = Header(..., alias="X-User-Id"),
    x_user_tier: str = Header("free", alias="X-User-Tier"),
) -> dict[str, Any]:
    """Return the current subscription info for the authenticated user."""
    async with async_session() as db:
        sub = await stripe_service.get_subscription(x_user_id, db)
    if sub is None:
        return {
            "tier": x_user_tier,
            "status": "free",
            "stripe_subscription_id": None,
            "current_period_end": None,
        }
    return sub


@router.delete("/subscription")
async def cancel_subscription(
    x_user_id: str = Header(..., alias="X-User-Id"),
) -> dict[str, bool]:
    """Cancel the active subscription."""
    async with async_session() as db:
        await stripe_service.cancel_subscription(x_user_id, db)
    return {"ok": True}


# ── Tier query (internal, service-to-service) ─────────────────────────

@router.get("/tier/{user_id}")
async def get_user_tier(user_id: str) -> dict[str, str]:
    """Return the billing tier for a given user_id.

    Used by other services for tier lookups. Protected by Traefik
    ForwardAuth — only internal services should call this.
    """
    async with async_session() as db:
        tier = await tier_manager.get_tier(user_id, db)
    return {"user_id": user_id, "tier": tier}


# ── Feature matrix (public, cacheable) ────────────────────────────────

@router.get("/features/{tier}")
async def get_tier_features(tier: str) -> dict[str, Any]:
    """Return the feature matrix for a tier."""
    if tier not in FEATURES:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail=f"Unknown tier: {tier}",
        )
    return {
        "tier": tier,
        "features": FEATURES[tier],
        "rate_limit_rpm": RATE_LIMITS.get(tier, RATE_LIMITS["free"]),
    }


@router.get("/features")
async def get_all_features() -> dict[str, Any]:
    """Return the full feature matrix for all tiers."""
    return {
        "tiers": {
            tier: {
                "features": features,
                "rate_limit_rpm": RATE_LIMITS.get(tier, RATE_LIMITS["free"]),
            }
            for tier, features in FEATURES.items()
        },
    }