import { useQueryClient } from "@tanstack/react-query";
import type { Dashboard } from "@umt/contracts";
import {
  Activity,
  AlertTriangle,
  ArrowRight,
  Bot,
  CircleCheck,
  Download,
  Library as LibraryIcon,
  type LucideIcon,
  Pause,
  Play,
} from "lucide-react";
import type { ReactNode } from "react";
import { useRef } from "react";
import { Link } from "react-router";
import { toast } from "sonner";
import { useAttention } from "~/api/attention.ts";
import { useDashboard, useSitesWithAccounts } from "~/api/dashboard.ts";
import { useEngineRunsPage } from "~/api/engine.ts";
import { useUpdateSettings } from "~/api/settings.ts";
import { useSystemHealth } from "~/api/system.ts";
import { ConfirmDialog } from "~/components/console/confirm-dialog.tsx";
import { EmptyState, ErrorState, LoadingState } from "~/components/console/empty-state.tsx";
import { consolePath, settingsPath } from "~/components/console/nav.ts";
import { PageHeader } from "~/components/console/page-header.tsx";
import { AttentionList, attentionRows } from "~/components/dashboard/attention-summary.tsx";
import { HomeRuntime } from "~/components/dashboard/home-runtime.tsx";
import { runTitle } from "~/components/tasks/labels.ts";
import { useLiveTasks } from "~/components/tasks/live.ts";
import { Button } from "~/components/ui/button.tsx";
import { errorMessage } from "~/lib/api.ts";
import { formatRelative } from "~/lib/labels.ts";
import { qk } from "~/lib/query-keys.ts";
import { useSse } from "~/lib/sse.ts";
import { cn } from "~/lib/utils.ts";

// 首页概览:自动化、存储与下载器状态,以及当前工作、要我处理的汇总计数(整理需要处理 / 等你批准 / 系统健康)和最近整理。

/** 首页关心的事件:任意一个到达就(节流)刷新聚合 */
const DASHBOARD_EVENTS = [
  "task.created",
  "task.status_changed",
  "download.submitted",
  "download.status_changed",
  "download.threshold",
  "organization.changed",
  "agent.run_status",
  "decision.created",
  "decision.updated",
  "settings.changed",
];

function useLiveDashboard() {
  const qc = useQueryClient();
  const timer = useRef<ReturnType<typeof setTimeout> | null>(null);
  useSse(DASHBOARD_EVENTS, () => {
    if (timer.current) return;
    timer.current = setTimeout(() => {
      timer.current = null;
      qc.invalidateQueries({ queryKey: qk.dashboard });
    }, 1500);
  });
  return useDashboard();
}

function Section({
  title,
  icon: Icon,
  to,
  children,
  className,
}: {
  title: string;
  icon: LucideIcon;
  to?: string;
  children: ReactNode;
  className?: string;
}) {
  return (
    <section className={cn("pg-slab flex min-w-0 flex-col rounded-xl p-5", className)}>
      <div className="mb-3 flex items-center gap-2">
        <Icon className="h-4 w-4 text-muted-foreground" aria-hidden />
        <h2 className="text-body font-semibold text-foreground">{title}</h2>
        {to ? (
          <Link
            to={to}
            className="ml-auto inline-flex items-center gap-1 text-meta text-muted-foreground hover:text-foreground"
          >
            全部
            <ArrowRight className="h-3.5 w-3.5" />
          </Link>
        ) : null}
      </div>
      {children}
    </section>
  );
}

function Row({ children }: { children: ReactNode }) {
  return <li className="flex min-w-0 items-center justify-between gap-3 py-1.5 text-sm">{children}</li>;
}

/** 非零项拼一句:[[3, "个下载"], [0, "个整理中"]] → "3 个下载" */
function nonZero(parts: [number, string][]): string {
  return parts
    .filter(([n]) => n > 0)
    .map(([n, s]) => `${n} ${s}`)
    .join(" · ");
}

// ─── 顶部一行:自动化状态 + 需要知道的异常 ───
function StatusLine({ d }: { d: Dashboard }) {
  const a = d.automation;
  const update = useUpdateSettings();
  const health = useSystemHealth(60_000);
  const sites = useSitesWithAccounts();
  const setEnabled = async (enabled: boolean) => {
    try {
      await update.mutateAsync({ automation: { enabled } });
      toast.success(enabled ? "自动化已恢复" : "自动化已暂停");
    } catch (err) {
      toast.error(errorMessage(err, "切换失败"));
      throw err;
    }
  };

  // 只列不正常的:服务异常、下载盘到暂停线、站点账号失效、下载器离线
  const problems: { text: string; to: string }[] = [];
  const lv = health.data?.level;
  if (lv === "critical" || lv === "warn")
    problems.push({ text: lv === "critical" ? "服务异常" : "服务需要关注", to: consolePath("status") });
  for (const v of d.cache.volumes)
    if (v.usedPercent !== null && v.usedPercent >= v.hardThresholdPercent)
      problems.push({ text: `下载盘已用 ${Math.round(v.usedPercent)}%，新下载已暂停`, to: consolePath("downloads") });
  const badAccounts = (sites.data?.items ?? []).filter(
    (s) => s.enabled && s.accountStatus && ["invalid", "expired", "challenge"].includes(s.accountStatus),
  ).length;
  if (badAccounts) problems.push({ text: `${badAccounts} 个站点账号需要重新登录`, to: consolePath("sites") });
  const offline = d.sources.downloaders.filter((x) => x.enabled && ["offline", "failing"].includes(x.health)).length;
  if (offline) problems.push({ text: `${offline} 个下载器连不上`, to: settingsPath("downloaders") });

  const paused = !a.enabled;
  const warn = paused || a.readOnlyReconcile || problems.length > 0;
  return (
    <div
      className={cn(
        "pg-slab mb-4 flex flex-col gap-3 rounded-xl px-4 py-3 sm:flex-row sm:items-center sm:px-5",
        warn && "border border-warning/40",
      )}
    >
      <p className="min-w-0 flex-1 text-sm text-foreground">
        <span className={cn("mr-2 inline-block size-2 rounded-full", warn ? "bg-warning" : "bg-success")} aria-hidden />
        {paused ? (
          "自动化已暂停，手动操作仍可用"
        ) : a.readOnlyReconcile ? (
          <>
            只读模式：不会自动下载和整理。
            <Link to={settingsPath("system", "readonly")} className="underline underline-offset-4">
              去设置关闭
            </Link>
          </>
        ) : a.activeSubscriptions > 0 ? (
          `自动化已开启 · ${a.activeSubscriptions} 个订阅`
        ) : (
          <>
            自动化已开启 · 还没有订阅。
            <Link to={consolePath("search")} className="underline underline-offset-4">
              去搜索添加
            </Link>
          </>
        )}
        {problems.map((p) => (
          <span key={p.text}>
            {" · "}
            <Link to={p.to} className="text-warning underline-offset-4 hover:underline">
              {p.text}
            </Link>
          </span>
        ))}
      </p>
      {paused ? (
        <Button size="sm" disabled={update.isPending} onClick={() => setEnabled(true).catch(() => {})}>
          <Play />
          恢复
        </Button>
      ) : (
        <ConfirmDialog
          trigger={
            <Button variant="outline" size="sm" disabled={update.isPending}>
              <Pause />
              暂停
            </Button>
          }
          title="暂停全部自动化？"
          description="自动收录、下载、整理会停止，已提交的下载任务不受影响。可随时恢复。"
          confirmLabel="暂停自动化"
          onConfirm={() => setEnabled(false)}
        />
      )}
    </div>
  );
}

// ─── 在忙什么:下载中的任务 + 进行中的智能体会话 + 有业务对象的运行 ───
function Busy({ w }: { w: Dashboard["currentWork"] }) {
  const running = useEngineRunsPage({ status: "running" }, 10, 10_000);
  const runs = (running.data?.items ?? []).filter((r) => r.business);
  const downloads = w.items.slice(0, 4);
  const agents = w.agentRuns.slice(0, 2);
  const summary = nonZero([
    [w.downloading, "个下载中"],
    [w.importing, "个整理中"],
    [w.stalled, "个没有进展"],
    [w.paused, "个已暂停"],
  ]);
  const empty = !downloads.length && !agents.length && !runs.length;
  return (
    <Section title="在忙什么" icon={Activity} to="/console/logs?type=task&level=running">
      {running.isPending && !downloads.length ? (
        <LoadingState rows={3} />
      ) : empty ? (
        <EmptyState plain icon={CircleCheck} title="现在没有在跑的任务" className="py-6" />
      ) : (
        <ul className="divide-y divide-border/60">
          {downloads.map((t) => (
            <Row key={t.downloadTaskId}>
              <Link to={`/console/downloads/${t.downloadTaskId}`} className="min-w-0 flex-1 hover:underline">
                <span className="block truncate">{t.name}</span>
                {t.status === "stalled" ? <span className="block text-meta text-warning">没有进展</span> : null}
              </Link>
              <span className="shrink-0 text-meta text-muted-foreground tabular-nums">
                <Download className="mr-1 inline h-3 w-3" aria-hidden />
                {Math.round(t.progress * 100)}%
              </span>
            </Row>
          ))}
          {agents.map((r) => (
            <Row key={r.id}>
              <Link to={`/console/agent/${r.id}`} className="min-w-0 flex-1 hover:underline">
                <span className="block truncate">{r.goal}</span>
              </Link>
              <Bot className="h-3.5 w-3.5 shrink-0 text-muted-foreground" aria-label="智能体" />
            </Row>
          ))}
          {runs.slice(0, Math.max(0, 5 - downloads.length - agents.length)).map((r) => (
            <Row key={r.id}>
              <Link to={`/console/logs?run=${encodeURIComponent(r.id)}`} className="min-w-0 flex-1 hover:underline">
                <span className="block truncate">{runTitle(r)}</span>
              </Link>
            </Row>
          ))}
        </ul>
      )}
      {summary ? <p className="mt-auto pt-3 text-meta text-muted-foreground">{summary}</p> : null}
    </Section>
  );
}

// ─── 要我处理什么:汇总计数(整理需要处理、等你批准、系统健康),点进去到对应页面 ───
function NeedsMe() {
  const q = useAttention();
  const rows = attentionRows(q.data);
  return (
    <Section title="要我处理" icon={AlertTriangle}>
      {q.isPending ? (
        <LoadingState rows={2} />
      ) : rows.length === 0 ? (
        <EmptyState plain icon={CircleCheck} title="没有要你处理的事" className="py-6" />
      ) : (
        <AttentionList rows={rows} />
      )}
    </Section>
  );
}

// ─── 最近整理了什么:成功 / 部分成功的整理 ───
function RecentImports({ d }: { d: Dashboard }) {
  const rows = d.recentOutput.filter((r) => r.status === "succeeded" || r.status === "partial").slice(0, 6);
  const today = d.automation.today.filesImported;
  return (
    <Section title="最近整理" icon={LibraryIcon} to={consolePath("organize")}>
      {rows.length === 0 ? (
        <EmptyState plain icon={LibraryIcon} title="最近没有新整理的作品" className="py-6" />
      ) : (
        <ul className="divide-y divide-border/60">
          {rows.map((r) => (
            <Row key={r.recordId}>
              <Link
                to={r.mediaEntityId ? `/console/library/${r.mediaEntityId}` : `/console/organize/${r.recordId}`}
                className="min-w-0 flex-1 hover:underline"
              >
                <span className="block truncate">{r.title ?? r.targetPath?.split("/").pop() ?? "未关联作品"}</span>
                {r.status === "partial" ? (
                  <span className="block text-meta text-warning">
                    {r.counts.succeeded}/{r.counts.total} 个文件已整理
                  </span>
                ) : null}
              </Link>
              <span className="shrink-0 text-meta text-muted-foreground">{formatRelative(r.finishedAt)}</span>
            </Row>
          ))}
        </ul>
      )}
      {today ? <p className="mt-auto pt-3 text-meta text-muted-foreground">今天整理 {today} 个文件</p> : null}
    </Section>
  );
}

export default function Home() {
  const q = useLiveDashboard();
  useLiveTasks();
  return (
    <>
      <PageHeader
        title="首页"
        actions={
          q.data ? (
            <span className="text-meta text-muted-foreground">更新于 {formatRelative(q.data.generatedAt)}</span>
          ) : null
        }
      />
      {q.data ? <StatusLine d={q.data} /> : null}
      <HomeRuntime downloaders={q.data?.sources.downloaders} />
      {q.isPending ? (
        <div className="grid gap-4 md:grid-cols-2 xl:grid-cols-3">
          {["a", "b", "c"].map((k) => (
            <div key={k} className="pg-slab rounded-xl p-5">
              <LoadingState rows={3} />
            </div>
          ))}
        </div>
      ) : q.isError ? (
        <ErrorState title="首页加载失败" error={q.error} onRetry={() => q.refetch()} />
      ) : (
        <div className="grid gap-4 md:grid-cols-2 xl:grid-cols-3">
          <Busy w={q.data.currentWork} />
          <NeedsMe />
          <RecentImports d={q.data} />
        </div>
      )}
    </>
  );
}