/**
 * 订阅开通 / 升级 / 续费 / 取消 / 到期扫描 / 支付确认
 */
const baseModel = require("../../middleware/baseModel");
const { op } = baseModel;

async function assertUserActive(userId) {
  const u = await baseModel.biz_user.findByPk(userId);
  if (!u) throw new Error("用户不存在");
  if (u.status !== "active") throw new Error("用户已禁用");
  return u;
}

async function assertPlanActive(planId) {
  const p = await baseModel.biz_plan.findByPk(planId);
  if (!p) throw new Error("套餐不存在");
  if (p.status !== "active") throw new Error("套餐未上线");
  return p;
}

async function openSubscription(body) {
  const {
    user_id,
    plan_id,
    start_time,
    end_time,
    status = "pending",
    renew_mode = "manual",
    payment_channel,
    payment_ref,
  } = body;
  await assertUserActive(user_id);
  await assertPlanActive(plan_id);
  const row = await baseModel.biz_subscription.create({
    user_id,
    plan_id,
    status,
    start_time,
    end_time,
    renew_mode,
    payment_channel: payment_channel || null,
    payment_ref: payment_ref || null,
  });
  return row;
}

async function upgradeSubscription(body) {
  const { subscription_id, new_plan_id, start_time, end_time } = body;
  const sub = await baseModel.biz_subscription.findByPk(subscription_id);
  if (!sub) throw new Error("订阅不存在");
  await assertPlanActive(new_plan_id);
  await sub.update({
    plan_id: new_plan_id,
    start_time: start_time || sub.start_time,
    end_time: end_time || sub.end_time,
  });
  return sub;
}

async function renewSubscription(body) {
  const { subscription_id, end_time } = body;
  const sub = await baseModel.biz_subscription.findByPk(subscription_id);
  if (!sub) throw new Error("订阅不存在");
  await sub.update({
    end_time,
    status: "active",
  });
  return sub;
}

async function cancelSubscription(body) {
  const { subscription_id } = body;
  const sub = await baseModel.biz_subscription.findByPk(subscription_id);
  if (!sub) throw new Error("订阅不存在");
  await sub.update({ status: "cancelled" });
  return sub;
}

/** 每天扫描：将已过期且仍为 active 的订阅置为 expired */
async function expireDueSubscriptions() {
  const now = new Date();
  const [n] = await baseModel.biz_subscription.update(
    { status: "expired" },
    {
      where: {
        status: "active",
        end_time: { [op.lt]: now },
      },
    }
  );
  return n;
}

/** 线下确认：pending -> active，写入 payment_ref */
async function confirmOfflinePayment(body) {
  const { subscription_id, payment_ref } = body;
  if (!subscription_id) throw new Error("缺少 subscription_id");
  const sub = await baseModel.biz_subscription.findByPk(subscription_id);
  if (!sub) throw new Error("订阅不存在");
  await sub.update({
    status: "active",
    payment_channel: "offline",
    payment_ref: payment_ref || sub.payment_ref,
  });
  return sub;
}

/** 链接支付确认（MVP：与线下类似，仅标记渠道） */
async function confirmLinkPayment(body) {
  const { subscription_id, payment_ref } = body;
  if (!subscription_id) throw new Error("缺少 subscription_id");
  const sub = await baseModel.biz_subscription.findByPk(subscription_id);
  if (!sub) throw new Error("订阅不存在");
  await sub.update({
    status: "active",
    payment_channel: "pay_link",
    payment_ref: payment_ref || sub.payment_ref,
  });
  return sub;
}

module.exports = {
  openSubscription,
  upgradeSubscription,
  renewSubscription,
  cancelSubscription,
  expireDueSubscriptions,
  confirmOfflinePayment,
  confirmLinkPayment,
};