"use client";

import { Copy, Loader2, QrCode } from "lucide-react";
import { useRouter } from "next/navigation";
import { useSession } from "next-auth/react";
import { useEffect, useMemo, useState } from "react";
import { cn } from "@/lib/utils";
import {
  Dialog,
  DialogContent,
  DialogDescription,
  DialogHeader,
  DialogTitle,
} from "@/components/ui/dialog";

export function WechatPricingButton({
  planId,
  planName,
  enabled,
}: {
  planId: string;
  planName: string;
  enabled: boolean;
}) {
  const { data: session } = useSession();
  const router = useRouter();

  const [isPending, setIsPending] = useState(false);
  const [open, setOpen] = useState(false);
  const [outTradeNo, setOutTradeNo] = useState<string | null>(null);
  const [qrCodeImageUrl, setQrCodeImageUrl] = useState<string | null>(null);
  const [codeUrl, setCodeUrl] = useState<string | null>(null);
  const [statusText, setStatusText] = useState("请使用微信扫码完成支付");

  const canPoll = useMemo(() => open && Boolean(outTradeNo), [open, outTradeNo]);

  useEffect(() => {
    if (!canPoll || !outTradeNo) {
      return;
    }

    let timer: number | undefined;
    let stopped = false;

    const poll = async () => {
      try {
        const response = await fetch(`/api/billing/wechat/order-status?outTradeNo=${encodeURIComponent(outTradeNo)}`);
        if (!response.ok) {
          return;
        }

        const data = (await response.json()) as { status?: string };
        if (stopped || !data.status) {
          return;
        }

        if (data.status === "paid") {
          setStatusText("支付成功，正在跳转...");
          stopped = true;
          setTimeout(() => {
            router.push(`/lovart/pricing?checkout=success&plan=${encodeURIComponent(planId)}`);
          }, 800);
          return;
        }

        if (data.status !== "created" && data.status !== "processing") {
          setStatusText(`当前状态：${data.status}`);
        }
      } catch {
        // ignore polling failure
      }

      if (!stopped) {
        timer = window.setTimeout(poll, 3000);
      }
    };

    void poll();

    return () => {
      stopped = true;
      if (timer) {
        window.clearTimeout(timer);
      }
    };
  }, [canPoll, outTradeNo, planId, router]);

  async function handleCheckout() {
    if (isPending) {
      return;
    }

    if (!enabled) {
      window.alert("微信支付尚未配置，请先配置微信支付环境变量。");
      return;
    }

    if (!session?.user || session.user.type === "guest") {
      router.push("/login?callbackUrl=/lovart/pricing");
      return;
    }

    setIsPending(true);

    try {
      const response = await fetch("/api/billing/wechat/checkout", {
        method: "POST",
        headers: {
          "Content-Type": "application/json",
        },
        body: JSON.stringify({ planId }),
      });

      const data = (await response.json()) as {
        error?: string;
        outTradeNo?: string;
        qrCodeImageUrl?: string;
        codeUrl?: string;
      };

      if (!response.ok || !data.outTradeNo || !data.qrCodeImageUrl || !data.codeUrl) {
        window.alert(data.error || "创建微信支付订单失败，请稍后重试。");
        return;
      }

      setOutTradeNo(data.outTradeNo);
      setQrCodeImageUrl(data.qrCodeImageUrl);
      setCodeUrl(data.codeUrl);
      setStatusText("请使用微信扫码完成支付");
      setOpen(true);
    } catch (error) {
      console.error("[WechatPricingButton] checkout error", error);
      window.alert("创建微信支付订单失败，请稍后重试。");
    } finally {
      setIsPending(false);
    }
  }

  async function handleCopyLink() {
    if (!codeUrl) {
      return;
    }

    try {
      await navigator.clipboard.writeText(codeUrl);
      window.alert("支付链接已复制");
    } catch {
      window.alert("复制失败，请手动复制");
    }
  }

  return (
    <>
      <button
        className={cn(
          "inline-flex w-full items-center justify-center gap-2 rounded-xl border border-emerald-300/30 bg-emerald-500/10 px-4 py-2 text-sm font-semibold text-emerald-100 hover:border-emerald-300/60",
          isPending && "cursor-not-allowed opacity-75"
        )}
        disabled={isPending}
        onClick={handleCheckout}
        type="button"
      >
        {isPending ? <Loader2 className="h-4 w-4 animate-spin" /> : <QrCode className="h-4 w-4" />}
        微信支付 {planName}
      </button>

      <Dialog open={open} onOpenChange={setOpen}>
        <DialogContent className="max-w-sm border-white/10 bg-[#0a1120] text-zinc-100">
          <DialogHeader>
            <DialogTitle>微信扫码支付</DialogTitle>
            <DialogDescription className="text-zinc-300">{statusText}</DialogDescription>
          </DialogHeader>

          <div className="space-y-3">
            {qrCodeImageUrl ? (
              <div className="mx-auto w-fit rounded-xl bg-white p-2">
                <img alt="wechat pay qrcode" className="h-56 w-56" src={qrCodeImageUrl} />
              </div>
            ) : (
              <div className="mx-auto flex h-56 w-56 items-center justify-center rounded-xl border border-dashed border-white/20 text-sm text-zinc-400">
                正在生成二维码...
              </div>
            )}

            <div className="rounded-lg border border-white/10 bg-white/[0.03] px-3 py-2 text-xs text-zinc-300">
              <p>订单号：{outTradeNo || "-"}</p>
            </div>

            <button
              className="inline-flex w-full items-center justify-center gap-2 rounded-lg border border-white/20 px-3 py-2 text-xs text-zinc-100 hover:border-white/40"
              onClick={handleCopyLink}
              type="button"
            >
              <Copy className="h-3.5 w-3.5" />
              复制支付链接
            </button>
          </div>
        </DialogContent>
      </Dialog>
    </>
  );
}