import { useEffect, useState } from "react";
import { applyTheme, readTheme, type ThemeMode } from "../lib/theme";
import { getAuthToken, getStoredRole, health } from "../lib/api";
import { useAppStore } from "../store/useAppStore";
import type { WsStatus } from "../lib/types";
import { UiModeSwitch } from "../design/UiModeSwitch";
import { ADMIN_GROUPS, ADMIN_SECTIONS } from "./sections";
import { navigateAdmin, navigateUserShell, type AdminSectionId } from "./router";
import { Button, Tag, type TagTone } from "../components/primitives";
import { Icon } from "../components/Icon";
import { DashboardModule } from "./modules/Dashboard";
import { PersonasModule } from "./modules/Personas";
import { SessionsModule } from "./modules/Sessions";
import { MemoriesModule } from "./modules/Memories";
import { PluginsModule } from "./modules/Plugins";
import { ChannelsModule } from "./modules/Channels";
import { ChannelEventsModule } from "./modules/ChannelEvents";
import { IoTModule } from "./modules/IoT";
import { RagModule } from "./modules/Rag";
import { LlmModule } from "./modules/Llm";
import { AutomationsModule } from "./modules/Automations";
import { AgentsModule } from "./modules/Agents";
import { FlowModule } from "./modules/Flow";
import { BackthinkModule } from "./modules/Backthink";
import { NotificationsModule } from "./modules/Notifications";
import { ObservabilityModule } from "./modules/Observability";
import { UsersModule } from "./modules/Users";
import { SystemModule } from "./modules/System";

function renderSection(section: AdminSectionId): React.ReactNode {
  switch (section) {
    case "dashboard": return <DashboardModule />;
    case "personas": return <PersonasModule />;
    case "sessions": return <SessionsModule />;
    case "memories": return <MemoriesModule />;
    case "plugins": return <PluginsModule />;
    case "channels": return <ChannelsModule />;
    case "channel-events": return <ChannelEventsModule />;
    case "iot": return <IoTModule />;
    case "rag": return <RagModule />;
    case "llm": return <LlmModule />;
    case "automations": return <AutomationsModule />;
    case "agents": return <AgentsModule />;
    case "flow": return <FlowModule />;
    case "backthink": return <BackthinkModule />;
    case "notifications": return <NotificationsModule />;
    case "observability": return <ObservabilityModule />;
    case "users": return <UsersModule />;
    case "system": return <SystemModule />;
    default: return <DashboardModule />;
  }
}

/**
 * Sidebar content shared by the desktop rail and the mobile drawer (design/10).
 * Both render ADMIN_GROUPS with the same `onNavigate` hook — the drawer passes
 * its close callback (tap an item → close), the desktop rail passes a no-op — so
 * desktop and mobile never diverge.
 */
function adminNavContent({ active, onNavigate }: { active: AdminSectionId; onNavigate: () => void }): React.ReactNode {
  return (
    <>
      {ADMIN_GROUPS.map((group) => (
        <div key={group} className="mb-1">
          <div className="px-2 py-2 text-xs font-semibold uppercase tracking-wider text-[var(--mu-text-lo)]">{group}</div>
          {ADMIN_SECTIONS.filter((s) => s.group === group).map((s) => (
            <button
              key={s.id}
              onClick={() => { navigateAdmin(s.id); onNavigate(); }}
              className={`flex w-full items-center gap-2.5 rounded-[var(--mu-radius)] px-3 py-2 text-sm text-left transition-all duration-200 ease-[var(--mu-spring)] active:scale-[0.98] ${
                s.id === active
                  ? "bg-[var(--mu-accent)]/15 font-medium text-[var(--mu-accent-hi)]"
                  : "text-[var(--mu-text-mid)] hover:bg-[var(--mu-surface-4)]"
              }`}
            >
              <Icon name={s.icon} size={18} />
              <span>{s.label}</span>
            </button>
          ))}
        </div>
      ))}
    </>
  );
}

/** Desktop left rail — fixed, `hidden md:flex`. */
function AdminSidebar({ active }: { active: AdminSectionId }): React.ReactNode {
  return (
    <nav className="glass hidden h-full w-[var(--mu-sidebar-w)] shrink-0 flex-col gap-1 overflow-y-auto border-r border-[var(--mu-glass-border)] p-3 md:flex">
      {adminNavContent({ active, onNavigate: () => {} })}
    </nav>
  );
}

/** Mobile drawer — scrim + spring slide-in panel (reuses mu-drawer-in). */
function AdminMobileNav({ open, active, onClose }: { open: boolean; active: AdminSectionId; onClose: () => void }): React.ReactNode {
  if (!open) return null;
  return (
    <div className="fixed inset-0 z-40 md:hidden" role="dialog" aria-modal="true">
      <div
        className="absolute inset-0 bg-black/50 backdrop-blur-[2px]"
        onClick={onClose}
        aria-label="关闭侧边栏"
      />
      <nav
        className="glass absolute inset-y-0 left-0 flex w-[var(--mu-sidebar-w)] max-w-[80vw] flex-col gap-1 overflow-y-auto border-r border-[var(--mu-glass-border)] p-3"
        style={{ animation: "mu-drawer-in 0.3s var(--mu-spring) both" }}
      >
        <div className="flex items-center justify-between px-2 pb-1">
          <span className="text-xs font-medium text-[var(--mu-text-lo)]">菜单</span>
          <button
            onClick={onClose}
            aria-label="关闭"
            className="inline-flex h-8 w-8 items-center justify-center rounded-[var(--mu-radius)] text-[var(--mu-text-mid)] transition-all duration-200 hover:bg-[var(--mu-surface-4)] active:scale-95"
          >
            <Icon name="close" size={18} />
          </button>
        </div>
        {adminNavContent({ active, onNavigate: onClose })}
      </nav>
    </div>
  );
}

/** Poll interval for the backend liveness probe (GET /api/v1/health). */
const HEALTH_POLL_MS = 15_000;

type BackendState = "checking" | "online" | "offline";

const BACKEND_META: Record<BackendState, { label: string; tone: TagTone; dot: string }> = {
  checking: { label: "后端检测中", tone: "neutral", dot: "mu-blink" },
  online: { label: "后端在线", tone: "ok", dot: "bg-[var(--mu-ok)]" },
  offline: { label: "后端失联", tone: "err", dot: "bg-[var(--mu-err)]" },
};

const WS_META: Record<WsStatus, { label: string; tone: TagTone; dot: string }> = {
  idle: { label: "未连接", tone: "neutral", dot: "bg-[var(--mu-text-lo)]" },
  connecting: { label: "连接中", tone: "warn", dot: "mu-blink" },
  connected: { label: "实时", tone: "ok", dot: "bg-[var(--mu-ok)]" },
  reconnecting: { label: "重连中", tone: "warn", dot: "mu-blink" },
  disconnected: { label: "已断开", tone: "err", dot: "bg-[var(--mu-err)]" },
  expired: { label: "登录过期", tone: "err", dot: "bg-[var(--mu-err)]" },
};

/** Real liveness probe — the tag must never claim 在线 before /health has actually
 *  answered, so it starts as "检测中" (which is a state of its own, not a guess).
 *  The realtime channel is a separate signal from the store: it can be down while
 *  REST is fine (and vice versa), so it is shown as its own tag. */
function useBackendHealth(): BackendState {
  const [state, setState] = useState<BackendState>("checking");
  useEffect(() => {
    let cancelled = false;
    const probe = () => {
      health()
        .then(() => {
          if (!cancelled) setState("online");
        })
        .catch(() => {
          if (!cancelled) setState("offline");
        });
    };
    probe();
    const id = window.setInterval(probe, HEALTH_POLL_MS);
    return () => {
      cancelled = true;
      window.clearInterval(id);
    };
  }, []);
  return state;
}

/** 后端在线 / 失联 + 实时通道状态, both from real signals. */
function BackendStatusTag(): React.ReactNode {
  const backend = useBackendHealth();
  const wsStatus = useAppStore((s) => s.wsStatus);
  const meta = BACKEND_META[backend];
  const ws = WS_META[wsStatus];
  return (
    <>
      <span className="inline-flex shrink-0" title={`GET /api/v1/health · 每 ${HEALTH_POLL_MS / 1000}s 探测一次`}>
        <Tag tone={meta.tone}>
          <span className={`inline-block h-1.5 w-1.5 rounded-full ${meta.dot}`} />
          {meta.label}
        </Tag>
      </span>
      <span className="hidden shrink-0 sm:inline-flex" title="实时通道（/ws）状态">
        <Tag tone={ws.tone}>
          <span className={`inline-block h-1.5 w-1.5 rounded-full ${ws.dot}`} />
          实时通道 · {ws.label}
        </Tag>
      </span>
    </>
  );
}

function AdminTopBar({ section, onMenu }: { section: AdminSectionId; onMenu?: () => void }): React.ReactNode {
  const role = getStoredRole();
  const [theme, setTheme] = useState<ThemeMode>(readTheme);
  const meta = ADMIN_SECTIONS.find((s) => s.id === section);
  const toggleTheme = () => {
    const next: ThemeMode = theme === "dark" ? "light" : "dark";
    applyTheme(next);
    setTheme(next);
  };

  return (
    <header className="glass sticky top-0 z-30 flex h-[var(--mu-topbar-h)] items-center gap-2 border-b border-[var(--mu-glass-border)] px-3 sm:px-4">
      {onMenu ? (
        <button
          onClick={onMenu}
          aria-label="打开菜单"
          title="菜单"
          className="inline-flex h-8 w-8 shrink-0 items-center justify-center rounded-[var(--mu-radius)] text-[var(--mu-text-mid)] transition-all duration-200 ease-[var(--mu-spring)] hover:bg-[var(--mu-surface-4)] active:scale-95 md:hidden"
        >
          <Icon name="menu" size={20} />
        </button>
      ) : null}
      <div className="flex min-w-0 items-center gap-2">
        <img src="/images/Cyrene_Avatar/3rd_Form/Cyrene-3F-Q-Happy-1.png" alt="Cyrene" className="h-7 w-7 shrink-0 rounded-full object-cover" />
        <div className="min-w-0 leading-tight">
          <div className="truncate whitespace-nowrap text-sm font-semibold">Cyrene · 管理面板</div>
          <div className="truncate whitespace-nowrap text-[11px] text-[var(--mu-text-lo)]">{meta?.label ?? "仪表盘"}</div>
        </div>
      </div>
      <div className="flex-1" />
      {role ? (
        <Tag tone={role === "owner" ? "accent" : role === "admin" ? "ok" : "neutral"} className="hidden shrink-0 sm:inline-flex">
          {role}
        </Tag>
      ) : null}
      <BackendStatusTag />
      {/* 双档 UI 档位（裁决 16.4.4）：面板顶栏也吃档位，胶囊形态对齐其余 h-8 按钮。
          与用户端顶栏同理：窄屏收起（<sm），避免与「返回用户端」等既有控件争宽。 */}
      <span className="hidden shrink-0 sm:inline-flex">
        <UiModeSwitch variant="compact" />
      </span>
      <button
        onClick={toggleTheme}
        aria-label="切换主题"
        className="inline-flex h-8 w-8 shrink-0 items-center justify-center rounded-[var(--mu-radius)] bg-[var(--mu-surface-4)] text-sm transition-all duration-200 ease-[var(--mu-spring)] hover:bg-[var(--mu-surface-5)] active:scale-95"
      >
        <Icon name={theme === "dark" ? "sun" : "moon"} size={18} />
      </button>
      <Button size="sm" variant="ghost" className="shrink-0" onClick={() => { navigateUserShell(); }}>
        返回用户端
      </Button>
    </header>
  );
}

function LoginGate(): React.ReactNode {
  return (
    <div className="flex h-full flex-col items-center justify-center gap-4 p-8 text-center">
      <div className="flex h-12 w-12 items-center justify-center rounded-[var(--mu-radius-lg)] bg-[var(--mu-surface-4)] text-[var(--mu-accent)]">
        <Icon name="lock" size={32} />
      </div>
      <div className="text-lg font-semibold">需要登录</div>
      <p className="max-w-md text-sm text-[var(--mu-text-lo)]">
        管理面板需持有 JWT。请先在用户端 <span className="text-[var(--mu-text-hi)]">登录页</span> 完成登录后，再返回本页。
      </p>
      <Button variant="primary" onClick={() => { navigateUserShell(); }}>前往用户端登录</Button>
    </div>
  );
}

function Forbidden403(): React.ReactNode {
  const role = getStoredRole();
  return (
    <div className="flex h-full flex-col items-center justify-center gap-4 p-8 text-center">
      <div className="flex h-12 w-12 items-center justify-center rounded-[var(--mu-radius-lg)] bg-[var(--mu-err)]/15 text-[var(--mu-err)]">
        <Icon name="block" size={32} />
      </div>
      <div className="text-lg font-semibold">403 · 权限不足</div>
      <p className="max-w-md text-sm text-[var(--mu-text-lo)]">
        当前角色 <Tag tone="neutral">{role ?? "?"}</Tag>（viewer 只读）。管理面板需 <Tag tone="accent">owner</Tag> 或 <Tag tone="ok">admin</Tag> 角色；管理端写操作仅 owner。
      </p>
      <div className="flex gap-2">
        <Button variant="primary" onClick={() => { navigateUserShell(); }}>返回用户端</Button>
      </div>
    </div>
  );
}

export function AdminApp({ section }: { section: AdminSectionId }): React.ReactNode {
  // Mobile nav drawer — only surfaced on the admin shell (md+ keeps the fixed
  // sidebar); the login/403 guards never render it but still hold the hook.
  const [adminMenuOpen, setAdminMenuOpen] = useState(false);

  // RBAC guard (design/10 §2 + design/11 §7). A logged-in viewer or an
  // unauthenticated user never sees the admin module; the gateway would also
  // reject them with 401/403.
  if (!getAuthToken() || !getStoredRole()) {
    return (
      <div className="flex h-full flex-col">
        <AdminTopBar section={section} />
        <LoginGate />
      </div>
    );
  }
  if (getStoredRole() === "viewer") {
    return (
      <div className="flex h-full flex-col">
        <AdminTopBar section={section} />
        <Forbidden403 />
      </div>
    );
  }

  return (
    <div className="flex h-full flex-col">
      <AdminTopBar section={section} onMenu={() => setAdminMenuOpen(true)} />
      <div className="flex min-h-0 flex-1">
        <AdminSidebar active={section} />
        <main className="relative flex-1 overflow-y-auto p-4 md:p-6">
          <div className="mx-auto max-w-6xl">{renderSection(section)}</div>
        </main>
      </div>
      <AdminMobileNav open={adminMenuOpen} active={section} onClose={() => setAdminMenuOpen(false)} />
    </div>
  );
}