import json

from fastapi import APIRouter, Depends, HTTPException
from pydantic import BaseModel
from sqlalchemy.orm import Session

from core.db import get_db
from core.di import get_service
from core.events import event_bus
from core.redis_client import redis_client
from core.security import get_current_user_id

from apps.cart.models import Cart, CartItem

router = APIRouter()


class AddressIn(BaseModel):
    name: str
    street: str
    zip: str
    city: str
    country: str = "DE"


class CheckoutIn(BaseModel):
    address: AddressIn
    payment_method: str = "dummy"


class CheckoutPreview(BaseModel):
    items: list[dict]
    subtotal: float
    total: float


@router.post("/preview", response_model=CheckoutPreview)
def preview(user_id: int = Depends(get_current_user_id), db: Session = Depends(get_db)):
    cart = db.query(Cart).filter_by(user_id=user_id).first()
    if not cart or not cart.items:
        raise HTTPException(400, "Cart is empty")
    items = []
    subtotal = 0.0
    for it in cart.items:
        raw = redis_client.get(f"product:{it.product_id}")
        if not raw:
            raise HTTPException(400, f"Product {it.product_id} no longer available")
        p = json.loads(raw)
        line = round(float(p["price"]) * it.qty, 2)
        subtotal += line
        items.append({"product_id": it.product_id, "name": p["name"], "qty": it.qty, "price": float(p["price"]), "line_total": line})
    return CheckoutPreview(items=items, subtotal=round(subtotal, 2), total=round(subtotal, 2))


@router.post("/confirm")
def confirm(body: CheckoutIn, user_id: int = Depends(get_current_user_id), db: Session = Depends(get_db)):
    cart = db.query(Cart).filter_by(user_id=user_id).first()
    if not cart or not cart.items:
        raise HTTPException(400, "Cart is empty")

    # Snapshot items
    snapshot_items = []
    subtotal = 0.0
    for it in cart.items:
        raw = redis_client.get(f"product:{it.product_id}")
        if not raw:
            raise HTTPException(400, f"Product {it.product_id} not available")
        p = json.loads(raw)
        line = round(float(p["price"]) * it.qty, 2)
        subtotal += line
        snapshot_items.append(
            {
                "product_id": it.product_id,
                "sku": p.get("sku", ""),
                "name": p.get("name", {}),
                "price": float(p["price"]),
                "qty": it.qty,
                "line_total": line,
            }
        )
    total = round(subtotal, 2)

    payment = get_service("PaymentProvider").charge(total, "EUR", body.payment_method)
    if payment["status"] != "paid":
        raise HTTPException(402, "Payment failed")

    event_payload = {
        "user_id": user_id,
        "items": snapshot_items,
        "subtotal": round(subtotal, 2),
        "total": total,
        "currency": "EUR",
        "address": body.address.model_dump(),
        "payment": payment,
    }
    event_bus.publish("checkout.confirmed", event_payload, db=db)

    # Clear cart
    for it in list(cart.items):
        db.delete(it)
    db.commit()

    # Find order id from events handler (orders-app) — pull via redis key or return event_payload
    # Since the orders handler sets 'last_order_id' for this user in redis for convenience:
    last = redis_client.get(f"user:{user_id}:last_order_id")
    return {"ok": True, "order_id": int(last) if last else None, "payment": payment}