import { useQueryClient } from "@tanstack/react-query";
import type { EngineRun } from "@umt/contracts";
import { Ban, CheckCircle2, Clock, Cpu, LoaderCircle, RotateCw, XCircle } from "lucide-react";
import { useEffect, useRef, useState } from "react";
import { useNavigate, useSearchParams } from "react-router";
import { useEngineRuns, useEngineStats } from "~/api/engine.ts";
import { DataTable } from "~/components/console/data-table.tsx";
import { FilterBar, FilterSelect } from "~/components/console/filter-bar.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 { engineRunLabel, formatDuration, formatRelative, spanSec as runDurationSec } from "~/lib/labels.ts";
import { qk } from "~/lib/query-keys.ts";
import { useSse } from "~/lib/sse.ts";

export const meta = () => [{ title: "工作流引擎 · UHD 媒体自动化控制台" }];

const STAT_ORDER = [
  { status: "pending", label: "待执行", icon: Clock, tone: "neutral" },
  { status: "running", label: "运行中", icon: LoaderCircle, tone: "neutral" },
  { status: "completed", label: "完成", icon: CheckCircle2, tone: "success" },
  { status: "failed", label: "失败", icon: XCircle, tone: "destructive" },
  { status: "canceled", label: "已取消", icon: Ban, tone: "warning" },
] as const;

const STATUS_OPTIONS = ["pending", "running", "completed", "failed", "canceled", "sleeping", "succeeded"].map((s) => ({
  value: s,
  label: engineRunLabel(s).label,
}));

/** 持续任务事件到达时节流刷新引擎视图(引擎本身不发事件,业务任务事件足以代表它在动) */
const ENGINE_EVENTS = [
  "task.created",
  "task.status_changed",
  "download.status_changed",
  "organization.changed",
  "agent.run_status",
];

function useDebounced<T>(value: T, ms = 350): T {
  const [v, setV] = useState(value);
  useEffect(() => {
    const t = setTimeout(() => setV(value), ms);
    return () => clearTimeout(t);
  }, [value, ms]);
  return v;
}

export default function EnginePage() {
  const navigate = useNavigate();
  const qc = useQueryClient();
  const [params, setParams] = useSearchParams();
  const status = params.get("status") ?? "";
  const [name, setName] = useState(params.get("workflow") ?? "");
  const workflowName = useDebounced(name.trim());

  useEffect(() => {
    setParams(
      (p) => {
        if (workflowName) p.set("workflow", workflowName);
        else p.delete("workflow");
        return p;
      },
      { replace: true },
    );
  }, [workflowName, setParams]);

  const setStatus = (s: string) =>
    setParams(
      (p) => {
        if (s) p.set("status", s);
        else p.delete("status");
        return p;
      },
      { replace: true },
    );

  const runs = useEngineRuns({ status: status || undefined, workflowName: workflowName || undefined });
  const stats = useEngineStats();

  const timer = useRef<ReturnType<typeof setTimeout> | null>(null);
  useSse(ENGINE_EVENTS, () => {
    if (timer.current) return;
    timer.current = setTimeout(() => {
      timer.current = null;
      qc.invalidateQueries({ queryKey: qk.all("engine") });
    }, 2000);
  });

  const rows = runs.data?.pages.flatMap((p) => p.items);
  const s = stats.data;

  return (
    <>
      <PageHeader
        title="工作流引擎"
        description="持久任务引擎的运行记录，只读诊断用；业务进度请看「下载与任务」。"
        actions={
          <Button
            variant="outline"
            size="sm"
            onClick={() => qc.invalidateQueries({ queryKey: qk.all("engine") })}
            disabled={runs.isFetching}
          >
            <RotateCw className={runs.isFetching ? "animate-spin" : undefined} />
            刷新
          </Button>
        }
      />

      <div className="mb-3 grid grid-cols-2 gap-2 sm:grid-cols-3 lg:grid-cols-5">
        {STAT_ORDER.map((t) => (
          <StatTile
            key={t.status}
            label={t.label}
            icon={t.icon}
            tone={(s?.byStatus[t.status] ?? 0) > 0 ? t.tone : "neutral"}
            value={stats.isPending ? "…" : stats.isError ? "—" : (s?.byStatus[t.status] ?? 0)}
            active={status === t.status}
            onClick={() => setStatus(status === t.status ? "" : t.status)}
          />
        ))}
      </div>
      <div className="mb-5 flex flex-wrap gap-x-5 gap-y-1 text-meta text-muted-foreground">
        <span>
          最老待执行：
          {s?.oldestPending ? (
            <button
              type="button"
              className="cursor-pointer text-foreground underline-offset-2 hover:underline"
              onClick={() => navigate(consolePath("engine", s.oldestPending?.id ?? ""))}
            >
              {s.oldestPending.workflowName} · 已等 {formatDuration(s.oldestPending.ageSec)}
            </button>
          ) : (
            "无"
          )}
        </span>
        <span className="inline-flex items-center gap-1.5">
          <Cpu className="h-3.5 w-3.5" />
          持有租约的 worker：
          {s && s.activeWorkers.length > 0
            ? s.activeWorkers.map((w) => `${w.workerId}(${w.running})`).join("、")
            : "无"}
          <span className="text-muted-foreground/80">(快照，非权威注册表)</span>
        </span>
      </div>

      <FilterBar
        search={{ value: name, onChange: setName, placeholder: "按工作流名称筛选" }}
        onReset={
          status || name
            ? () => {
                setName("");
                setStatus("");
              }
            : undefined
        }
      >
        <FilterSelect label="状态" value={status} onChange={setStatus} options={STATUS_OPTIONS} />
      </FilterBar>

      <DataTable<EngineRun>
        rows={rows}
        rowKey={(r) => r.id}
        loading={runs.isPending}
        error={runs.error}
        onRetry={() => runs.refetch()}
        empty={{
          title: status || workflowName ? "没有符合条件的 run" : "引擎还没有运行记录",
          description: status || workflowName ? "换个筛选条件试试。" : "有任务入队后会出现在这里。",
        }}
        onRowClick={(r) => navigate(consolePath("engine", r.id))}
        hasMore={!!runs.hasNextPage}
        onLoadMore={() => runs.fetchNextPage()}
        loadingMore={runs.isFetchingNextPage}
        columns={[
          {
            key: "status",
            header: "状态",
            cell: (r) => {
              const l = engineRunLabel(r.status);
              return <StatusBadge tone={l.tone}>{l.label}</StatusBadge>;
            },
          },
          {
            key: "name",
            header: "工作流",
            cell: (r) => (
              <div className="min-w-0 max-w-[16rem] sm:max-w-none">
                <p className="truncate font-medium">
                  {r.workflowName}
                  {r.version ? <span className="ml-1.5 text-meta text-muted-foreground">{r.version}</span> : null}
                </p>
                <p className="truncate font-mono text-meta text-muted-foreground">{r.id}</p>
              </div>
            ),
          },
          { key: "attempts", header: "尝试", hideBelow: "md", align: "right", cell: (r) => r.attempts },
          {
            key: "dur",
            header: "耗时",
            hideBelow: "sm",
            cell: (r) => <span className="tabular-nums">{formatDuration(runDurationSec(r))}</span>,
          },
          {
            key: "created",
            header: "创建",
            hideBelow: "md",
            cell: (r) => <span className="whitespace-nowrap text-muted-foreground">{formatRelative(r.createdAt)}</span>,
          },
        ]}
      />
    </>
  );
}