import type { PiOAuthMode, PiOAuthStartResult, PiOAuthState, PiProviderInfo, PiUpstream } from "@umt/contracts";
import { Check, Copy, ExternalLink, LoaderCircle } from "lucide-react";
import { useEffect, useRef, useState } from "react";
import { toast } from "sonner";
import { completePiOAuth, useInvalidatePi, useStartPiOAuth } from "~/api/pi.ts";
import { FormField } from "~/components/console/form-field.tsx";
import { StatusBadge } from "~/components/console/status-badge.tsx";
import { Button } from "~/components/ui/button.tsx";
import { Input } from "~/components/ui/input.tsx";
import { errorMessage } from "~/lib/api.ts";
import { cn } from "~/lib/utils.ts";

// 订阅登录:start → browser 粘回地址栏 URL / device 前端轮询 complete → 终态。
// 登录会话只在服务端内存里,15 分钟过期;失败、过期、被取消都可以重新开始。

const MODE_LABEL: Record<PiOAuthMode, string> = { device: "验证码", browser: "浏览器授权" };

const END_LABEL: Record<
  Exclude<PiOAuthState, "pending">,
  { label: string; tone: "success" | "destructive" | "warning" }
> = {
  succeeded: { label: "已登录", tone: "success" },
  failed: { label: "登录失败", tone: "destructive" },
  expired: { label: "登录会话已过期", tone: "warning" },
  cancelled: { label: "登录已取消", tone: "warning" },
};

function CopyButton({ text, label }: { text: string; label: string }) {
  const [done, setDone] = useState(false);
  return (
    <Button
      type="button"
      variant="outline"
      size="icon-sm"
      aria-label={`复制${label}`}
      onClick={async () => {
        try {
          await navigator.clipboard.writeText(text);
          setDone(true);
          toast.success("已复制");
        } catch {
          toast.error("复制失败，手动选中复制");
        }
      }}
    >
      {done ? <Check /> : <Copy />}
    </Button>
  );
}

function useCountdown(expiresAt: string | null) {
  const [now, setNow] = useState(() => Date.now());
  useEffect(() => {
    if (!expiresAt) return;
    const t = setInterval(() => setNow(Date.now()), 1000);
    return () => clearInterval(t);
  }, [expiresAt]);
  if (!expiresAt) return null;
  const left = Math.max(0, Math.floor((new Date(expiresAt).getTime() - now) / 1000));
  return left;
}

export function PiOAuthLogin({
  upstream,
  provider,
  onSucceeded,
}: {
  upstream: PiUpstream;
  provider: PiProviderInfo | undefined;
  onSucceeded?: () => void;
}) {
  const start = useStartPiOAuth();
  const invalidate = useInvalidatePi();
  const modes = provider?.oauth?.modes ?? ["browser"];
  const [mode, setMode] = useState<PiOAuthMode>(modes[0] ?? "browser");
  const [session, setSession] = useState<PiOAuthStartResult | null>(null);
  const [state, setState] = useState<PiOAuthState | null>(null);
  const [message, setMessage] = useState<string | null>(null);
  const [progress, setProgress] = useState<string[]>([]);
  const [pasted, setPasted] = useState("");
  const [submitting, setSubmitting] = useState(false);
  const abortRef = useRef<AbortController | null>(null);
  const left = useCountdown(state === "pending" ? (session?.expiresAt ?? null) : null);
  const termsNote = provider?.oauth?.termsNote ?? provider?.termsNote ?? null;

  useEffect(() => () => abortRef.current?.abort(), []);

  const finish = (s: PiOAuthState, msg: string | null) => {
    setState(s);
    setMessage(msg);
    invalidate();
    if (s === "succeeded") {
      toast.success(`${upstream.name}已登录`);
      onSucceeded?.();
    }
  };

  // device:反复调 complete(每次服务端最多等 25 秒)直到终态或本地判定过期
  const poll = async (s: PiOAuthStartResult) => {
    abortRef.current?.abort();
    const ac = new AbortController();
    abortRef.current = ac;
    while (!ac.signal.aborted) {
      if (Date.now() > new Date(s.expiresAt).getTime()) {
        finish("expired", "授权已超时。");
        return;
      }
      try {
        const r = await completePiOAuth(upstream.id, { sessionId: s.sessionId, waitMs: 25_000 }, ac.signal);
        setProgress(r.progress);
        if (r.state !== "pending") {
          finish(r.state, r.message);
          return;
        }
      } catch (err) {
        if (ac.signal.aborted) return;
        finish("failed", errorMessage(err, "轮询登录状态失败"));
        return;
      }
    }
  };

  const begin = async () => {
    abortRef.current?.abort();
    setMessage(null);
    setProgress([]);
    setPasted("");
    try {
      const r = await start.mutateAsync({ id: upstream.id, body: { mode } });
      setSession(r);
      setState(r.state);
      setMessage(r.message);
      if (r.state === "pending" && r.mode === "device") void poll(r);
    } catch (err) {
      setSession(null);
      setState(null);
      toast.error(errorMessage(err, "无法开始登录"));
    }
  };

  const submitPasted = async (e: React.FormEvent) => {
    e.preventDefault();
    if (!session || !pasted.trim()) return;
    setSubmitting(true);
    try {
      const r = await completePiOAuth(upstream.id, {
        sessionId: session.sessionId,
        pastedUrlOrCode: pasted.trim(),
        waitMs: 25_000,
      });
      setProgress(r.progress);
      if (r.state === "pending") setMessage("还在处理，稍后再提交一次。");
      else finish(r.state, r.message);
    } catch (err) {
      toast.error(errorMessage(err, "提交失败"));
    } finally {
      setSubmitting(false);
    }
  };

  const pending = state === "pending" && !!session;
  const ended = state && state !== "pending" ? END_LABEL[state] : null;
  const mmss = left === null ? "" : `${Math.floor(left / 60)}:${String(left % 60).padStart(2, "0")}`;

  return (
    <div className="grid gap-3">
      {termsNote ? (
        <p className="rounded-lg border border-warning/40 bg-warning/10 px-3 py-2 text-caption text-foreground">
          {termsNote}
        </p>
      ) : null}

      {!pending ? (
        <div className="grid gap-3">
          {modes.length > 1 ? (
            <fieldset className="grid gap-1.5">
              <legend className="mb-1 text-caption font-medium">登录方式</legend>
              <div className="flex flex-wrap gap-2">
                {modes.map((m) => (
                  <button
                    key={m}
                    type="button"
                    aria-pressed={mode === m}
                    onClick={() => setMode(m)}
                    className={cn(
                      "rounded-full border px-3 py-1 text-caption transition-colors duration-micro",
                      mode === m
                        ? "border-foreground/30 bg-foreground/[0.08] text-foreground"
                        : "border-border text-muted-foreground hover:bg-foreground/[0.04]",
                    )}
                  >
                    {MODE_LABEL[m]}
                  </button>
                ))}
              </div>
            </fieldset>
          ) : null}
          {ended ? (
            <div className="flex flex-wrap items-center gap-2 text-caption">
              <StatusBadge tone={ended.tone}>{ended.label}</StatusBadge>
              {message ? <span className="text-muted-foreground">{message}</span> : null}
            </div>
          ) : null}
          {state !== "succeeded" ? (
            <div>
              <Button size="sm" onClick={begin} disabled={start.isPending}>
                {start.isPending ? <LoaderCircle className="animate-spin" /> : null}
                {ended ? "重新登录" : upstream.status === "expired" ? "重新登录" : "开始登录"}
              </Button>
            </div>
          ) : null}
        </div>
      ) : session.mode === "device" ? (
        <div className="grid gap-2 rounded-lg border border-border/60 p-3">
          <p className="text-caption text-muted-foreground">
            在任意设备打开验证地址，输入下面的验证码。授权后这里自动完成。
          </p>
          <div className="flex items-center gap-2">
            <code className="rounded-md bg-muted px-3 py-1.5 font-mono text-lead tracking-widest select-all">
              {session.userCode}
            </code>
            {session.userCode ? <CopyButton text={session.userCode} label="验证码" /> : null}
          </div>
          {session.verificationUrl ? (
            <a
              href={session.verificationUrl}
              target="_blank"
              rel="noreferrer noopener"
              className="inline-flex items-center gap-1 text-caption break-all underline"
            >
              {session.verificationUrl}
              <ExternalLink className="size-3.5 shrink-0" />
            </a>
          ) : null}
          {session.instructions ? <p className="text-meta text-muted-foreground">{session.instructions}</p> : null}
          <p className="flex items-center gap-2 text-meta text-muted-foreground">
            <LoaderCircle className="size-3.5 animate-spin" />
            等待授权 · 剩余 {mmss}
            {progress.length ? ` · ${progress[progress.length - 1]}` : ""}
          </p>
          <div>
            <Button
              type="button"
              variant="ghost"
              size="sm"
              onClick={() => {
                abortRef.current?.abort();
                setState(null);
                setSession(null);
              }}
            >
              取消
            </Button>
          </div>
        </div>
      ) : (
        <form onSubmit={submitPasted} noValidate className="grid gap-2 rounded-lg border border-border/60 p-3">
          <p className="text-caption text-muted-foreground">
            在浏览器打开授权链接。授权后会跳到 localhost 地址，页面打不开属正常，把地址栏里的完整 URL 粘贴到下面。
          </p>
          {session.authorizeUrl ? (
            <div className="flex min-w-0 items-center gap-2">
              <a
                href={session.authorizeUrl}
                target="_blank"
                rel="noreferrer noopener"
                className="inline-flex min-w-0 items-center gap-1 text-caption underline"
              >
                <span className="truncate">打开授权链接</span>
                <ExternalLink className="size-3.5 shrink-0" />
              </a>
              <CopyButton text={session.authorizeUrl} label="授权链接" />
            </div>
          ) : null}
          <FormField label="地址栏 URL" htmlFor={`oauth-paste-${upstream.id}`} hint={`剩余 ${mmss}`}>
            <Input
              id={`oauth-paste-${upstream.id}`}
              value={pasted}
              onChange={(e) => setPasted(e.target.value)}
              placeholder="http://localhost:…/callback?code=…&state=…"
              autoComplete="off"
              disabled={submitting}
            />
          </FormField>
          {message ? <p className="text-meta text-muted-foreground">{message}</p> : null}
          <div className="flex gap-2">
            <Button type="submit" size="sm" disabled={submitting || !pasted.trim()}>
              {submitting ? <LoaderCircle className="animate-spin" /> : null}
              完成登录
            </Button>
            <Button
              type="button"
              variant="ghost"
              size="sm"
              onClick={() => {
                setState(null);
                setSession(null);
              }}
            >
              取消
            </Button>
          </div>
        </form>
      )}
    </div>
  );
}