/**
 * 治理台外壳 —— 自原型 `Governance.tsx` 第 389–514 行平移。
 *
 * 左轨(九功能)→ 顶栏 → 面包屑 → 区首页(页签 + 主视图)/ 整页下钻。
 * 「**不用抽屉、不用弹窗**:每一层内容都有自己的页面。」
 *
 * §9.2「路由状态即应用状态」:当前区 / 页签 / 下钻栈全部编码进 URL 的 hash,
 * 刷新与深链都能完整还原;前端零过程状态。
 */
import { useCallback, useEffect, useState } from 'react';
import { Ico } from '@web-shared/Ico.tsx';
import { TABS, ZM, ZONES, routeLabel } from '@web-shared/gov/gov-route.ts';
import type { GovZone, Nav, Route } from '@web-shared/gov/gov-route.ts';
import { useGovStaff, useGovTasks } from '@web-shared/gov/gov-api.ts';
import { TasksHome, TaskLogPage, TaskPage, WfPage } from '@features/gov-task';
import { EmpPage, PeopleHome, RolePage } from '@features/gov-staff';
import { EdgesPage, PkgPage, WorkflowsHome } from '@features/gov-process';
import { TriggerPage, TriggersHome } from '@features/gov-trigger';
import { ActPage, LibraryHome } from '@features/gov-activity';
import { ToolPage, ToolsHome } from '@features/gov-tool';
import { DataHome, ObjPage } from '@features/gov-data';
import { MemPage, MemoryHome } from '@features/gov-memory';
import { ChanPage, LlmPage, SystemHome } from '@features/gov-system';

/* ── URL 编解码:`#/gov/<zone>/<tab>[/<k>:<id>…]` ──────────────────────── */

type Place = { zone: GovZone; tab: string; stack: Route[] };

function readPlace(): Place {
  const raw = window.location.hash.replace(/^#\/?/, '');
  const parts = raw.split('/').filter((s) => s !== '');
  const zone = (ZONES.find((z) => z.key === parts[1])?.key ?? 'tasks') as GovZone;
  const tabs = TABS[zone];
  const tab = tabs.find((t) => t.key === parts[2])?.key ?? tabs[0]!.key;
  const stack: Route[] = [];
  for (const seg of parts.slice(3)) {
    const at = seg.indexOf(':');
    if (at <= 0) continue;
    stack.push({ k: seg.slice(0, at), id: decodeURIComponent(seg.slice(at + 1)) } as Route);
  }
  return { zone, tab, stack };
}

const writePlace = (p: Place): string =>
  ['#', 'gov', p.zone, p.tab, ...p.stack.map((r) => `${r.k}:${encodeURIComponent(r.id)}`)].join('/');

export function GovShell() {
  const [place, setPlace] = useState<Place>(readPlace);
  const staff = useGovStaff();
  const tasks = useGovTasks();

  // 浏览器前进 / 后退即导航 —— 路由状态就是应用状态
  useEffect(() => {
    const onHash = () => setPlace(readPlace());
    window.addEventListener('hashchange', onHash);
    return () => window.removeEventListener('hashchange', onHash);
  }, []);

  const go = useCallback((next: Place) => {
    window.location.hash = writePlace(next);
    setPlace(next);
  }, []);

  const push = useCallback(
    (r: Route) => go({ ...readPlace(), stack: [...readPlace().stack, r] }),
    [go],
  );
  const back = useCallback(() => {
    const p = readPlace();
    go({ ...p, stack: p.stack.slice(0, -1) });
  }, [go]);
  const goZone = useCallback((z: GovZone) => go({ zone: z, tab: TABS[z][0]!.key, stack: [] }), [go]);
  const jump = useCallback((z: GovZone, tab: string, r?: Route) => go({ zone: z, tab, stack: r ? [r] : [] }), [go]);
  const nav: Nav = { push, jump };

  // Esc 退一级 —— 与面包屑同义
  useEffect(() => {
    const h = (e: KeyboardEvent) => {
      if (e.key === 'Escape') back();
    };
    window.addEventListener('keydown', h);
    return () => window.removeEventListener('keydown', h);
  }, [back]);

  const { zone, tab, stack } = place;
  const meta = ZM[zone];
  const top = stack[stack.length - 1];
  const me = staff.data?.staff.find((s) => s.account === 'fengbing');

  /** 告警计数:异常工作流 + 非放行终态的任务 */
  const alerts =
    (tasks.data?.workflows ?? []).filter((w) => w.state === 'abnormal').length +
    (tasks.data?.tasks ?? []).filter((t) => t.terminal !== undefined && t.terminal !== 'released').length;

  /* 面包屑:治理台 › 区 › 页签 › 下钻各级 */
  const crumbs: Array<{ label: string; go?: () => void }> = [{ label: '治理台', go: () => goZone(zone) }];
  crumbs.push({ label: meta.title, go: () => go({ zone, tab, stack: [] }) });
  crumbs.push({ label: TABS[zone].find((t) => t.key === tab)?.label ?? '', go: () => go({ zone, tab, stack: [] }) });
  stack.forEach((r, i) =>
    crumbs.push({
      label: routeLabel(r),
      ...(i === stack.length - 1 ? {} : { go: () => go({ zone, tab, stack: stack.slice(0, i + 1) }) }),
    }),
  );

  return (
    <div className="g-shell gov-root">
      {/* ===== 深色左轨 ===== */}
      <nav className="g-nav">
        <div className="g-nav-mark">
          <Ico name="shield-alert" s={20} />
        </div>
        <div className="g-nav-brand">治理台</div>
        {ZONES.map((z) => (
          <button key={z.key} className={'g-nav-b' + (zone === z.key ? ' on' : '')} onClick={() => goZone(z.key)}>
            <span className="g-nav-ico">
              <Ico name={z.icon} s={18} />
            </span>
            <span>{z.label}</span>
          </button>
        ))}
        <div className="g-nav-foot">
          <span className="g-nav-ava">{(me?.name ?? '—').slice(0, 1)}</span>
          <span>{me?.name ?? '未登录'}</span>
        </div>
      </nav>

      <div className="g-body">
        {/* ===== 深色顶栏 ===== */}
        <header className="g-top">
          <span className="g-top-brand">
            JCAI 操作系统<em>单组织 · ≤50 人 · 生产环境</em>
          </span>
          <label className="g-search">
            <Ico name="search" s={14} />
            <input placeholder="跨对象检索:工作流 / 任务 / 活动 / 工具 / 触发器 / 对象…" />
            <kbd>⌘K</kbd>
          </label>
          <div className="g-top-r">
            <button className={'g-tbtn' + (alerts ? ' alert' : '')} onClick={() => jump('tasks', 'todo')}>
              <Ico name="alert-triangle" s={13} />
              告警<b>{alerts}</b>
            </button>
            <a className="g-tbtn" href="/">
              <Ico name="list-checks" s={13} />
              工作台
            </a>
          </div>
        </header>

        {/* ===== 工作面 ===== */}
        <div className="g-page">
          <div className="g-crumb">
            {stack.length > 0 && (
              <button className="g-back" onClick={back} title="返回上一级(Esc)">
                <Ico name="arrow-left" s={15} />
              </button>
            )}
            {crumbs.map((c, i) => (
              <span key={i} className="g-crumb-i">
                {i > 0 && <i className="sep">›</i>}
                {c.go ? <button onClick={c.go}>{c.label}</button> : <b>{c.label}</b>}
              </span>
            ))}
          </div>

          {top === undefined ? (
            <>
              <div className="g-head">
                <span className="g-head-i" style={{ background: meta.accent }}>
                  <Ico name={meta.icon} s={19} />
                </span>
                <div className="g-head-t">
                  <h1>{meta.title}</h1>
                  <p>{meta.desc}</p>
                </div>
              </div>
              <div className="g-tabs">
                {TABS[zone].map((t) => (
                  <button
                    key={t.key}
                    className={'g-tab' + (tab === t.key ? ' on' : '')}
                    onClick={() => go({ zone, tab: t.key, stack: [] })}
                  >
                    <Ico name={t.ico} s={13} />
                    {t.label}
                  </button>
                ))}
              </div>
              <ZoneHome zone={zone} tab={tab} nav={nav} />
            </>
          ) : (
            <div className="g-detail" key={`${stack.length}:${top.k}:${top.id}`}>
              <Detail route={top} nav={nav} />
            </div>
          )}
        </div>
      </div>
    </div>
  );
}

function ZoneHome({ zone, tab, nav }: { zone: GovZone; tab: string; nav: Nav }) {
  const P = {
    tasks: TasksHome,
    people: PeopleHome,
    workflows: WorkflowsHome,
    triggers: TriggersHome,
    library: LibraryHome,
    tools: ToolsHome,
    data: DataHome,
    memory: MemoryHome,
    system: SystemHome,
  }[zone];
  return <P tab={tab} nav={nav} />;
}

function Detail({ route, nav }: { route: Route; nav: Nav }) {
  switch (route.k) {
    case 'wf':
    case 'apr':
      return <WfPage id={route.id} nav={nav} />;
    case 'task':
      return <TaskPage id={route.id} nav={nav} />;
    case 'tasklog':
      return <TaskLogPage id={route.id} />;
    case 'emp':
      return <EmpPage id={route.id} nav={nav} />;
    case 'role':
      return <RolePage id={route.id} />;
    case 'pkg':
      return <PkgPage id={route.id} nav={nav} />;
    case 'edges':
      return <EdgesPage id={route.id} />;
    case 'trigger':
      return <TriggerPage id={route.id} />;
    case 'act':
      return <ActPage id={route.id} nav={nav} />;
    case 'tool':
      return <ToolPage id={route.id} />;
    case 'obj':
      return <ObjPage id={route.id} />;
    case 'mem':
      return <MemPage id={route.id} />;
    case 'llm':
      return <LlmPage id={route.id} />;
    case 'chan':
      return <ChanPage id={route.id} />;
  }
}