import { useQueryClient } from "@tanstack/react-query";
import type { Dashboard } from "@umt/contracts";
import {
  Activity,
  AlertTriangle,
  ArrowRight,
  CircleCheck,
  HardDrive,
  ListTodo,
  type LucideIcon,
  Pause,
  Play,
  Radio,
  ShieldAlert,
  Sparkles,
} from "lucide-react";
import type { ReactNode } from "react";
import { useRef } from "react";
import { Link } from "react-router";
import { toast } from "sonner";
import { useDashboard } from "~/api/dashboard.ts";
import { useUpdateSettings } from "~/api/settings.ts";
import { ConfirmDialog } from "~/components/console/confirm-dialog.tsx";
import { EmptyState, ErrorState, LoadingState } from "~/components/console/empty-state.tsx";
import { consolePath } from "~/components/console/nav.ts";
import { PageHeader } from "~/components/console/page-header.tsx";
import { StatTile } from "~/components/console/stat-tile.tsx";
import { StatusBadge } from "~/components/console/status-badge.tsx";
import { Button } from "~/components/ui/button.tsx";
import { Switch } from "~/components/ui/switch.tsx";
import { errorMessage } from "~/lib/api.ts";
import {
  agentRunLabel,
  decisionKindLabel,
  downloadLabel,
  formatRelative,
  healthLabel,
  organizationActionLabel,
  organizationLabel,
} from "~/lib/labels.ts";
import { qk } from "~/lib/query-keys.ts";
import { useSse, useSseStatus } from "~/lib/sse.ts";
import { cn, formatBytes } from "~/lib/utils.ts";

/** 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",
  "feed.fetched",
  "feed.health_changed",
  "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" />
        <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"
          >
            查看
            <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>;
}

// ─── 自动化总开关:显眼状态 + 切换 ───
function AutomationBanner({ a }: { a: Dashboard["automation"] }) {
  const update = useUpdateSettings();
  const setAutomation = async (patch: { enabled?: boolean; readOnlyReconcile?: boolean }, ok: string) => {
    try {
      await update.mutateAsync({ automation: patch });
      toast.success(ok);
    } catch (err) {
      toast.error(errorMessage(err, "切换失败"));
      throw err;
    }
  };
  const paused = !a.enabled;
  const readOnly = a.readOnlyReconcile;

  return (
    <div
      className={cn(
        "pg-slab mb-4 flex flex-col gap-4 rounded-xl p-4 sm:flex-row sm:items-center sm:p-5",
        (paused || readOnly) && "border border-warning/40",
      )}
    >
      <div className="flex min-w-0 flex-1 items-start gap-3">
        <span
          className={cn(
            "grid h-10 w-10 shrink-0 place-items-center rounded-full",
            paused || readOnly ? "bg-warning/10 text-warning" : "bg-success/10 text-success",
          )}
        >
          {readOnly ? (
            <ShieldAlert className="h-5 w-5" />
          ) : paused ? (
            <Pause className="h-5 w-5" />
          ) : (
            <Play className="h-5 w-5" />
          )}
        </span>
        <div className="min-w-0">
          <div className="flex flex-wrap items-center gap-2">
            <p className="text-lead font-semibold text-foreground">
              {paused ? "自动化已暂停" : readOnly ? "只读对账中" : "自动化运行中"}
            </p>
            <StatusBadge tone={paused ? "warning" : "success"}>总开关{paused ? "关" : "开"}</StatusBadge>
            {readOnly ? <StatusBadge tone="warning">只读对账</StatusBadge> : null}
          </div>
          <p className="mt-0.5 text-caption text-muted-foreground">
            {paused
              ? "自动收录、下载、整理都已停下；查询与手动操作仍可用。"
              : readOnly
                ? "恢复后的只读对账：只核对不写入，确认无误后再关掉。"
                : `${a.activeSubscriptions} 个订阅在追踪，按规则自动收录、下载与入库。`}
          </p>
        </div>
      </div>
      <div className="flex flex-wrap items-center gap-x-5 gap-y-2">
        <div className="flex items-center gap-2 text-caption text-foreground">
          <label htmlFor="home-readonly">只读对账</label>
          <Switch
            id="home-readonly"
            checked={readOnly}
            disabled={update.isPending}
            onCheckedChange={(v) =>
              setAutomation({ readOnlyReconcile: v }, v ? "已进入只读对账模式" : "已退出只读对账模式").catch(() => {})
            }
            aria-label="只读对账模式"
          />
        </div>
        {paused ? (
          <Button
            size="sm"
            disabled={update.isPending}
            onClick={() => setAutomation({ enabled: true }, "自动化已恢复").catch(() => {})}
          >
            <Play />
            恢复自动化
          </Button>
        ) : (
          <ConfirmDialog
            trigger={
              <Button variant="outline" size="sm" disabled={update.isPending}>
                <Pause />
                暂停自动化
              </Button>
            }
            title="暂停全部自动化？"
            description="自动收录、下载、整理会停下，已提交的下载任务不受影响。随时可以恢复。"
            confirmLabel="暂停"
            onConfirm={() => setAutomation({ enabled: false }, "自动化已暂停")}
          />
        )}
      </div>
    </div>
  );
}

function Overview({ a }: { a: Dashboard["automation"] }) {
  const t = a.today;
  return (
    <Section title="自动化概览" icon={Sparkles} to={consolePath("subscriptions")}>
      <div className="grid grid-cols-2 gap-2">
        <StatTile plain label="今日新计划" value={t.plansCreated} />
        <StatTile plain label="今日提交下载" value={t.downloadsSubmitted} />
        <StatTile plain label="今日入库文件" value={t.filesImported} />
        <StatTile plain label="今日升级" value={t.upgrades} />
      </div>
      <p className="mt-3 text-meta text-muted-foreground">
        整理成功 {t.recordsSucceeded} · 失败 {t.recordsFailed} · 满足的版本目标 {a.slotCounts.satisfied} · 需关注{" "}
        {a.slotCounts.attention}
      </p>
    </Section>
  );
}

function CurrentWork({ w }: { w: Dashboard["currentWork"] }) {
  const counts = [
    { label: "下载中", v: w.downloading },
    { label: "已暂停", v: w.paused },
    { label: "无进展", v: w.stalled },
    { label: "入库中", v: w.importing },
  ];
  const idle = counts.every((c) => c.v === 0) && w.items.length === 0 && w.agentRuns.length === 0;
  return (
    <Section title="当前工作" icon={Activity} to={consolePath("tasks")}>
      <div className="mb-2 flex flex-wrap gap-x-4 gap-y-1 text-meta text-muted-foreground">
        {counts.map((c) => (
          <span key={c.label}>
            {c.label} <span className="font-medium text-foreground tabular-nums">{c.v}</span>
          </span>
        ))}
      </div>
      {idle ? (
        <EmptyState plain icon={CircleCheck} title="没有进行中的工作" className="py-6" />
      ) : (
        <ul className="divide-y divide-border/60">
          {w.items.slice(0, 5).map((it) => {
            const s = downloadLabel(it.status);
            return (
              <Row key={it.downloadTaskId}>
                <Link to={consolePath("tasks", it.downloadTaskId)} className="min-w-0 flex-1 truncate hover:underline">
                  {it.name}
                </Link>
                <span className="shrink-0 text-meta text-muted-foreground tabular-nums">
                  {Math.round(it.progress * 100)}%
                </span>
                <StatusBadge tone={s.tone}>{s.label}</StatusBadge>
              </Row>
            );
          })}
          {w.agentRuns.slice(0, 3).map((r) => {
            const s = agentRunLabel(r.status);
            return (
              <Row key={r.id}>
                <Link to={consolePath("agent", r.id)} className="min-w-0 flex-1 truncate hover:underline">
                  Agent：{r.goal}
                </Link>
                <StatusBadge tone={s.tone}>{s.label}</StatusBadge>
              </Row>
            );
          })}
        </ul>
      )}
    </Section>
  );
}

function NeedsAttention({ n }: { n: Dashboard["needsAttention"] }) {
  return (
    <Section title="需要我处理" icon={AlertTriangle} to={consolePath("inbox")}>
      {n.total === 0 ? (
        <EmptyState plain icon={CircleCheck} title="没有待你决定的事" className="py-6" />
      ) : (
        <>
          <p className="mb-2 text-title-sm font-semibold text-warning tabular-nums">
            {n.total}
            <span className="ml-1.5 text-caption font-normal text-muted-foreground">项待处理</span>
          </p>
          <ul className="divide-y divide-border/60">
            {n.byKind.map((k) => (
              <Row key={k.kind}>
                <span className="truncate">{decisionKindLabel(k.kind)}</span>
                <span className="text-meta text-muted-foreground tabular-nums">{k.count}</span>
              </Row>
            ))}
          </ul>
        </>
      )}
    </Section>
  );
}

function CacheSection({ c }: { c: Dashboard["cache"] }) {
  return (
    <Section title="缓存与保留" icon={HardDrive} to={consolePath("settings")}>
      {c.volumes.length === 0 ? (
        <EmptyState
          plain
          icon={HardDrive}
          title="尚未登记下载器"
          description="添加下载器实例后显示缓存卷水位。"
          className="py-6"
        />
      ) : (
        <ul className="space-y-4">
          {c.volumes.map((v) => {
            const pct = v.usedPercent;
            const over = pct !== null && pct >= v.hardThresholdPercent;
            const near = pct !== null && pct >= v.resumePercent;
            return (
              <li key={v.volumeKey} className="min-w-0">
                <div className="flex items-center justify-between gap-2 text-sm">
                  <span className="truncate font-medium">{v.volumeKey}</span>
                  <StatusBadge tone={pct === null ? "neutral" : over ? "destructive" : near ? "warning" : "success"}>
                    {pct === null ? "用量未知" : `${pct.toFixed(0)}%${over ? " 已达阈值" : ""}`}
                  </StatusBadge>
                </div>
                <div className="relative mt-2 h-1.5 overflow-hidden rounded-full bg-foreground/[0.08]" aria-hidden>
                  <div
                    className={cn(
                      "h-full rounded-full",
                      over ? "bg-destructive" : near ? "bg-warning" : "bg-foreground/60",
                    )}
                    style={{ width: `${pct ?? 0}%` }}
                  />
                  <span
                    aria-hidden
                    className="absolute inset-y-0 w-px bg-destructive"
                    style={{ left: `${v.hardThresholdPercent}%` }}
                  />
                </div>
                <p className="mt-1.5 text-meta text-muted-foreground">
                  阈值 {v.hardThresholdPercent}% / 恢复 {v.resumePercent}% · 在途 {formatBytes(v.pendingBytes)} · 可清理{" "}
                  {formatBytes(v.cleanableBytes)} · 保留期锁定 {formatBytes(v.retentionLockedBytes)}
                  {v.pausedByThreshold ? ` · 因阈值暂停 ${v.pausedByThreshold} 个` : ""}
                </p>
                {v.notes.map((n) => (
                  <p key={n} className="text-meta text-muted-foreground">
                    {n}
                  </p>
                ))}
              </li>
            );
          })}
        </ul>
      )}
    </Section>
  );
}

function SourcesSection({ s }: { s: Dashboard["sources"] }) {
  const rows = [
    ...s.sites.map((x) => ({
      id: x.id,
      kind: "站点",
      name: x.name,
      enabled: x.enabled,
      health: x.health,
      at: x.lastSnapshotAt,
      err: null as string | null,
    })),
    ...s.feeds.map((x) => ({
      id: x.id,
      kind: "Feed",
      name: x.name,
      enabled: x.enabled,
      health: x.health,
      at: x.lastSuccessAt,
      err: x.lastError,
    })),
    ...s.downloaders.map((x) => ({
      id: x.id,
      kind: "下载器",
      name: x.name,
      enabled: x.enabled,
      health: x.health,
      at: x.lastSeenAt,
      err: null,
    })),
    ...s.mediaServers.map((x) => ({
      id: x.id,
      kind: "媒体服务器",
      name: x.name,
      enabled: x.enabled,
      health: x.health,
      at: x.lastSeenAt,
      err: null,
    })),
  ];
  return (
    <Section title="来源健康" icon={Radio} to={consolePath("sources")}>
      {rows.length === 0 ? (
        <EmptyState
          plain
          icon={Radio}
          title="还没有来源"
          description="在系统设置或来源页登记站点、Feed 与实例。"
          className="py-6"
        />
      ) : (
        <ul className="divide-y divide-border/60">
          {rows.slice(0, 8).map((r) => {
            const h = r.enabled ? healthLabel(r.health) : healthLabel("disabled");
            return (
              <Row key={`${r.kind}-${r.id}`}>
                <div className="min-w-0 flex-1">
                  <p className="truncate">
                    <span className="mr-1.5 text-meta text-muted-foreground">{r.kind}</span>
                    {r.name}
                  </p>
                  {r.err ? <p className="truncate text-meta text-destructive">{r.err}</p> : null}
                </div>
                <span className="hidden shrink-0 text-meta text-muted-foreground sm:inline">
                  {formatRelative(r.at)}
                </span>
                <StatusBadge tone={h.tone}>{h.label}</StatusBadge>
              </Row>
            );
          })}
        </ul>
      )}
    </Section>
  );
}

function RecentOutput({ items }: { items: Dashboard["recentOutput"] }) {
  return (
    <Section title="最近产出" icon={ListTodo} to={consolePath("organize")}>
      {items.length === 0 ? (
        <EmptyState plain icon={ListTodo} title="还没有入库记录" className="py-6" />
      ) : (
        <ul className="divide-y divide-border/60">
          {items.slice(0, 6).map((r) => {
            const s = organizationLabel(r.status);
            return (
              <li key={r.recordId} className="min-w-0 py-2">
                <div className="flex items-center justify-between gap-3 text-sm">
                  <Link to={consolePath("organize", r.recordId)} className="min-w-0 truncate hover:underline">
                    {r.title ?? "未命名"}
                  </Link>
                  <StatusBadge tone={s.tone}>{s.label}</StatusBadge>
                </div>
                <p className="truncate text-meta text-muted-foreground">
                  {organizationActionLabel(r.action)} · {r.counts.succeeded}/{r.counts.total} 个文件 ·{" "}
                  {formatRelative(r.finishedAt)}
                  {r.targetPath ? ` · ${r.targetPath}` : ""}
                </p>
              </li>
            );
          })}
        </ul>
      )}
    </Section>
  );
}

function LiveIndicator() {
  const s = useSseStatus();
  const tone = s === "open" ? "success" : s === "reconnecting" ? "warning" : "neutral";
  const label = s === "open" ? "实时" : s === "reconnecting" ? "重连中" : "连接中";
  return <StatusBadge tone={tone}>{label}</StatusBadge>;
}

export default function Home() {
  const q = useLiveDashboard();
  return (
    <>
      <PageHeader
        title="首页"
        description="系统是否在推进目标、完成了什么、还有什么缺口、是否需要你。"
        actions={
          <div className="flex items-center gap-2">
            <LiveIndicator />
            {q.data ? (
              <span className="hidden text-meta text-muted-foreground sm:inline">
                更新于 {formatRelative(q.data.generatedAt)}
              </span>
            ) : null}
          </div>
        }
      />
      {q.isPending ? (
        <div className="grid gap-4 md:grid-cols-2 xl:grid-cols-3">
          {["a", "b", "c", "d", "e", "f"].map((k) => (
            <div key={k} className="pg-slab rounded-xl p-5">
              <LoadingState rows={3} />
            </div>
          ))}
        </div>
      ) : q.isError ? (
        <ErrorState title="首页数据加载失败" error={q.error} onRetry={() => q.refetch()} />
      ) : (
        <>
          <AutomationBanner a={q.data.automation} />
          <div className="grid gap-4 md:grid-cols-2 xl:grid-cols-3">
            <Overview a={q.data.automation} />
            <CurrentWork w={q.data.currentWork} />
            <NeedsAttention n={q.data.needsAttention} />
            <CacheSection c={q.data.cache} />
            <SourcesSection s={q.data.sources} />
            <RecentOutput items={q.data.recentOutput} />
          </div>
        </>
      )}
    </>
  );
}