import json
from fastapi import APIRouter, Depends, HTTPException, Query
from pydantic import BaseModel
from typing import Optional
from sqlalchemy.ext.asyncio import AsyncSession
from app.database import get_db
from app.api.v1.deps import get_current_user_id
from app.services.credit import CreditService
from app.services.payment import PaymentService

router = APIRouter()


class PurchaseRequest(BaseModel):
    package_id: str
    pay_type: str = "alipay"


class StripePurchaseRequest(BaseModel):
    package_id: str
    gateway: str = "stripe"
    success_url: str = "https://trade.yuzhiran.com/workspace/credits?pay=success"
    cancel_url: str = "https://trade.yuzhiran.com/workspace/credits?pay=cancel"


class SubscribeRequest(BaseModel):
    plan_id: str
    pay_type: str = "alipay"


@router.get("/balance")
async def get_balance(
    user_id: str = Depends(get_current_user_id),
    db: AsyncSession = Depends(get_db),
):
    svc = CreditService(db)
    return await svc.get_balance(user_id)


@router.get("/history")
async def get_history(
    page: int = Query(1, ge=1),
    size: int = Query(20, ge=1, le=100),
    user_id: str = Depends(get_current_user_id),
    db: AsyncSession = Depends(get_db),
):
    svc = CreditService(db)
    return await svc.get_history(user_id, page, size)


@router.get("/packages")
async def list_packages(
    db: AsyncSession = Depends(get_db),
):
    svc = CreditService(db)
    return await svc.get_packages()


@router.get("/subscription-plans")
async def list_subscription_plans(
    user_id: str = Depends(get_current_user_id),
    db: AsyncSession = Depends(get_db),
):
    svc = CreditService(db)
    return await svc.get_subscription_plans()


@router.post("/purchase")
async def purchase_package(
    req: PurchaseRequest,
    user_id: str = Depends(get_current_user_id),
    db: AsyncSession = Depends(get_db),
):
    svc = CreditService(db)
    packages = await svc.get_packages()
    pkg = next((p for p in packages if p["id"] == req.package_id), None)
    if not pkg:
        raise HTTPException(status_code=404, detail="次数包不存在")

    pay_svc = PaymentService(db)
    order = await pay_svc.create_credit_order(
        user_id=user_id,
        amount=pkg["price"],
        description=f"购买 {pkg['name']} ({pkg['credits']}次)",
        pay_type=req.pay_type,
        metadata={"credit_package_id": req.package_id, "credits": pkg["credits"]},
    )
    return order


@router.post("/subscribe")
async def subscribe_plan(
    req: SubscribeRequest,
    user_id: str = Depends(get_current_user_id),
    db: AsyncSession = Depends(get_db),
):
    svc = CreditService(db)
    plans = await svc.get_subscription_plans()
    plan = next((p for p in plans if p["id"] == req.plan_id), None)
    if not plan:
        raise HTTPException(status_code=404, detail="订阅套餐不存在")

    pay_svc = PaymentService(db)
    order = await pay_svc.create_credit_order(
        user_id=user_id,
        amount=plan["price"],
        description=f"开通 {plan['name']} (每月{plan['credits_per_month']}次)",
        pay_type=req.pay_type,
        metadata={"subscription_plan_id": req.plan_id, "credits_per_month": plan["credits_per_month"]},
    )
    return order


@router.post("/stripe-purchase")
async def stripe_purchase(
    req: StripePurchaseRequest,
    user_id: str = Depends(get_current_user_id),
    db: AsyncSession = Depends(get_db),
):
    svc = CreditService(db)
    packages = await svc.get_packages()
    pkg = next((p for p in packages if p["id"] == req.package_id), None)
    if not pkg:
        raise HTTPException(status_code=404, detail="次数包不存在")

    from app.services.payment import get_gateway, gen_order_no

    price_usd = pkg.get("price_usd") or round(pkg["price"] / 7, 2)
    amount_cents = int(price_usd * 100)

    order_no = gen_order_no(user_id)
    gw = get_gateway(req.gateway)
    sep = '&' if '?' in req.success_url else '?'
    success_url = f"{req.success_url}{sep}order_id={order_no}"
    gw_result = await gw.create_order(
        order_no, amount_cents, f"{pkg['name_en']} ({pkg['credits']} credits)",
        pay_type=req.gateway,
        success_url=success_url,
        cancel_url=req.cancel_url,
    )

    from app.models.payment_transaction import PaymentTransaction
    txn = PaymentTransaction(
        user_id=user_id, order_no=order_no, plan="credit_purchase",
        amount=price_usd, gateway=req.gateway, pay_type=req.gateway,
        status="pending", description=json.dumps({"credits": pkg["credits"]}),
        gateway_order_no=gw_result.get("session_id", ""),
    )
    db.add(txn)
    await db.flush()

    return {
        "status": "pending",
        "order_id": order_no,
        "session_url": gw_result.get("session_url"),
        "session_id": gw_result.get("session_id"),
        "amount": price_usd,
        "currency": "USD",
        "gateway": req.gateway,
    }


@router.post("/cancel-subscription")
async def cancel_subscription(
    user_id: str = Depends(get_current_user_id),
    db: AsyncSession = Depends(get_db),
):
    from app.models.user_credit import UserCredit
    from sqlalchemy import select

    result = await db.execute(select(UserCredit).where(UserCredit.user_id == user_id))
    uc = result.scalar_one_or_none()
    if not uc or not uc.subscription_plan_id:
        raise HTTPException(status_code=400, detail="没有有效的订阅")

    uc.subscription_auto_renew = False
    await db.flush()
    return {"success": True, "message": "已取消自动续费，当前订阅到期后不再续费"}