import { useCallback, useEffect, useState } from 'react';
import * as api from '../api/client';
import type { AdminScopes, User } from '../types';
import { CheckIcon, LockIcon, UsersIcon, ChevronRightIcon, KeyIcon, BotIcon, CpuIcon } from './icons';
import KeyPanel from './KeyPanel';
import QuotaPanel from './QuotaPanel';
import ModelScopePanel from './ModelScopePanel';

type Tab = 'users' | 'keys' | 'quotas' | 'models';

export default function AdminUsersPage() {
  const [tab, setTab] = useState<Tab>('users');
  const [users, setUsers] = useState<User[]>([]);
  const [scopes, setScopes] = useState<AdminScopes>({ agents: [], paths: [] });
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const [notice, setNotice] = useState<string | null>(null);
  const [creating, setCreating] = useState(false);
  const [editing, setEditing] = useState<string | null>(null);

  // Agent 密钥面板
  const [keys, setKeys] = useState<api.AgentKey[]>([]);
  const [keyBusy, setKeyBusy] = useState(false);
  const [keyError, setKeyError] = useState<string | null>(null);
  const [newToken, setNewToken] = useState<string | null>(null);

  const load = async () => {
    setLoading(true);
    setError(null);
    try {
      const [u, s] = await Promise.all([api.adminListUsers(), api.adminListScopes()]);
      setUsers(u.users || []);
      setScopes(s);
    } catch (err) {
      setError(err instanceof Error ? err.message : String(err));
    } finally {
      setLoading(false);
    }
  };

  useEffect(() => { load(); }, []);

  const loadKeys = useCallback(async () => {
    try {
      const r = await api.adminListAgentKeys();
      setKeys(r.keys);
      setKeyError(null);
    } catch (err) {
      setKeyError(err instanceof Error ? err.message : String(err));
    }
  }, []);

  useEffect(() => {
    if (tab === 'keys') loadKeys();
  }, [tab, loadKeys]);

  const createKey = async (payload: api.CreateKeyPayload) => {
    setKeyBusy(true);
    setKeyError(null);
    try {
      const r = await api.adminCreateAgentKey(payload);
      // 登记客户端已有密钥时对方已经持有全文，无需再弹一次
      setNewToken(payload.key_token ? null : r.key.key_token ?? null);
      await loadKeys();
    } catch (err) {
      setKeyError(err instanceof Error ? err.message : String(err));
    } finally {
      setKeyBusy(false);
    }
  };

  const deleteKey = async (id: string) => {
    setKeyError(null);
    try {
      await api.adminDeleteAgentKey(id);
      await loadKeys();
    } catch (err) {
      setKeyError(err instanceof Error ? err.message : String(err));
    }
  };

  const bindKey = async (id: string, agentName: string) => {
    setKeyError(null);
    try {
      await api.adminBindAgentKey(id, agentName);
      await loadKeys();
    } catch (err) {
      setKeyError(err instanceof Error ? err.message : String(err));
    }
  };

  const flash = (msg: string) => {
    setNotice(msg);
    setTimeout(() => setNotice(null), 2500);
  };

  return (
    <div className="flex-1 min-w-0 flex flex-col bg-white">
      <div className="px-4 md:px-6 py-3 border-b border-gray-200 flex items-center gap-1 flex-wrap">
        <TabButton active={tab === 'users'} onClick={() => setTab('users')}>
          <UsersIcon className="w-4 h-4" />
          用户管理
          <span className="text-xs text-gray-400">{users.length}</span>
        </TabButton>
        <TabButton active={tab === 'keys'} onClick={() => setTab('keys')}>
          <KeyIcon className="w-4 h-4" />
          Agent 密钥
        </TabButton>
        <TabButton active={tab === 'quotas'} onClick={() => setTab('quotas')}>
          <BotIcon className="w-4 h-4" />
          Agent 管理
        </TabButton>
        <TabButton active={tab === 'models'} onClick={() => setTab('models')}>
          <CpuIcon className="w-4 h-4" />
          模型范围
        </TabButton>
        <div className="flex-1" />
        {notice && <span className="text-xs text-green-600">{notice}</span>}
        {tab === 'users' && (
          <button onClick={() => setCreating(v => !v)} className="tap px-3 py-1.5 text-xs font-medium rounded-md bg-blue-600 text-white hover:bg-blue-700">
            {creating ? '收起' : '新建用户'}
          </button>
        )}
      </div>

      {error && <p className="mx-6 mt-3 text-xs text-red-600 bg-red-50 border border-red-100 rounded-md px-2.5 py-1.5">{error}</p>}

      {tab === 'models' ? (
        <div className="flex-1 overflow-y-auto px-4 md:px-6 py-4">
          <ModelScopeTab />
        </div>
      ) : tab === 'quotas' ? (
        <div className="flex-1 overflow-y-auto px-4 md:px-6 py-4">
          <QuotaPanel />
        </div>
      ) : tab === 'keys' ? (
        <div className="flex-1 overflow-y-auto px-4 md:px-6 py-4">
          <KeyPanel
            variant="agent"
            keys={keys}
            loading={keyBusy}
            error={keyError}
            newToken={newToken}
            onCreate={createKey}
            onDelete={deleteKey}
            onBind={bindKey}
            onDismissToken={() => setNewToken(null)}
          />
        </div>
      ) : (
        <>
          {creating && <CreateUserForm scopes={scopes} onDone={() => { setCreating(false); flash('用户已创建'); load(); }} onError={setError} />}

          <div className="flex-1 overflow-y-auto px-4 md:px-6 py-4 space-y-2">
            {users.map(u => (
              <UserCard key={u.user_id} user={u} scopes={scopes}
                expanded={editing === u.user_id}
                onToggle={() => setEditing(editing === u.user_id ? null : u.user_id)}
                onSaved={flash} onReload={load} setError={setError} />
            ))}
            {loading && users.length === 0 && <p className="text-xs text-gray-400 text-center py-6">加载中</p>}
          </div>
        </>
      )}
    </div>
  );
}

function TabButton({ active, onClick, children }: {
  active: boolean; onClick: () => void; children: React.ReactNode;
}) {
  return (
    <button
      onClick={onClick}
      className={`tap flex items-center gap-1.5 px-3 py-1.5 text-sm rounded-md ${
        active ? 'bg-blue-600 text-white' : 'text-gray-600 hover:bg-gray-100'
      }`}
    >
      {children}
    </button>
  );
}

/* ── UserCard ── */

function UserCard({ user, scopes, expanded, onToggle, onSaved, onReload, setError }: {
  user: User; scopes: AdminScopes; expanded: boolean; onToggle: () => void;
  onSaved: (msg: string) => void; onReload: () => void; setError: (msg: string) => void;
}) {
  return (
    <div className="rounded-lg border border-gray-200">
      <div className="px-4 py-2.5 flex items-center gap-x-3 gap-y-1 flex-wrap">
        <button onClick={onToggle} className="tap flex items-center gap-1 text-xs text-gray-400 hover:text-gray-600">
          <ChevronRightIcon className={`w-3 h-3 transition-transform ${expanded ? 'rotate-90' : ''}`} />
        </button>
        <span className="font-mono text-sm text-gray-900 min-w-[100px]">{user.username}</span>
        <span className="tap text-2xs text-gray-500">{user.display_name}</span>
        <span className={`text-3xs px-1.5 py-0.5 rounded ${user.role === 'admin' ? 'bg-blue-100 text-blue-700' : 'bg-gray-100 text-gray-600'}`}>
          {user.role === 'admin' ? '管理员' : '用户'}
        </span>
        <span className={`text-3xs px-1.5 py-0.5 rounded ${user.status === 'active' ? 'bg-green-100 text-green-700' : 'bg-gray-200 text-gray-500'}`}>
          {user.status === 'active' ? '启用' : '禁用'}
        </span>
        {user.role !== 'admin' && (user.allowed_agents.length > 0 || user.allowed_paths.length > 0) && (
          <span className="text-3xs text-gray-400">受限</span>
        )}
        <div className="flex-1" />
        <span className="text-3xs text-gray-400">{user.last_login || '从未登录'}</span>
      </div>
      {expanded && <UserEditor user={user} scopes={scopes} onSaved={onSaved} onReload={onReload} setError={setError} />}
    </div>
  );
}

/* ── UserEditor ── */

function UserEditor({ user, scopes, onSaved, onReload, setError }: {
  user: User; scopes: AdminScopes; onSaved: (msg: string) => void; onReload: () => void; setError: (msg: string) => void;
}) {
  const [displayName, setDisplayName] = useState(user.display_name);
  const [role, setRole] = useState<'admin' | 'user'>(user.role as 'admin' | 'user');
  const [agents, setAgents] = useState<string[]>(user.allowed_agents);
  const [paths, setPaths] = useState<string[]>(user.allowed_paths);
  const [pw, setPw] = useState('');
  const [busy, setBusy] = useState(false);

  const toggleAgent = (a: string) => setAgents(p => p.includes(a) ? p.filter(x => x !== a) : [...p, a]);
  const togglePath = (p: string) => setPaths(prev => prev.includes(p) ? prev.filter(x => x !== p) : [...prev, p]);

  const save = async () => {
    setBusy(true);
    try {
      await api.adminUpdateUser(user.user_id, { display_name: displayName, role, allowed_agents: agents, allowed_paths: paths });
      onSaved('用户已更新'); await onReload();
    } catch (err) { setError(err instanceof Error ? err.message : String(err)); }
    finally { setBusy(false); }
  };

  const disableUser = async () => {
    try { await api.adminDisableUser(user.user_id); onSaved('用户已禁用'); await onReload(); }
    catch (err) { setError(err instanceof Error ? err.message : String(err)); }
  };

  const enableUser = async () => {
    try { await api.adminUpdateUser(user.user_id, { status: 'active' }); onSaved('用户已启用'); await onReload(); }
    catch (err) { setError(err instanceof Error ? err.message : String(err)); }
  };

  const resetPassword = async () => {
    if (pw.length < 8) return;
    setBusy(true);
    try { await api.adminResetPassword(user.user_id, pw); onSaved('密码已重置'); setPw(''); }
    catch (err) { setError(err instanceof Error ? err.message : String(err)); }
    finally { setBusy(false); }
  };

  return (
    <div className="border-t border-gray-100 bg-gray-50 px-4 py-3 space-y-4">
      <div className="grid grid-cols-1 sm:grid-cols-3 gap-3 text-sm">
        <div>
          <label className="block text-2xs font-medium text-gray-500 mb-1">显示名</label>
          <input value={displayName} onChange={e => setDisplayName(e.target.value)}
            className="w-full text-sm border border-gray-300 rounded-md px-2.5 py-1.5 focus:outline-none focus:ring-2 focus:ring-blue-100 focus:border-blue-400" />
        </div>
        <div>
          <label className="block text-2xs font-medium text-gray-500 mb-1">角色</label>
          <select value={role} onChange={e => setRole(e.target.value as 'admin' | 'user')}
            className="w-full text-sm border border-gray-300 rounded-md px-2 py-1.5 focus:outline-none focus:ring-2 focus:ring-blue-100 focus:border-blue-400">
            <option value="user">普通用户</option>
            <option value="admin">管理员</option>
          </select>
        </div>
        <div>
          <label className="block text-2xs font-medium text-gray-500 mb-1">状态</label>
          {user.status === 'active' ? (
            <button onClick={disableUser} className="px-3 py-1.5 text-xs rounded-md border border-red-300 text-red-600 hover:bg-red-50 w-full">禁用</button>
          ) : (
            <button onClick={enableUser} className="px-3 py-1.5 text-xs rounded-md border border-green-300 text-green-700 hover:bg-green-50 w-full">启用</button>
          )}
        </div>
      </div>

      {user.role !== 'admin' && (
        <>
          <div>
            <label className="block text-2xs font-medium text-gray-500 mb-1.5">
              可调用 Agent {agents.length > 0 && <span className="text-gray-400">（{agents.length} 项）</span>}
              <span className="ml-2 font-normal text-gray-400">未勾选 = 不限</span>
            </label>
            <div className="flex flex-wrap gap-1.5">
              {scopes.agents.map(a => (
                <button key={a} onClick={() => toggleAgent(a)}
                  className={`px-2.5 py-1 text-xs font-mono rounded-md border transition-colors ${
                    agents.includes(a) ? 'bg-blue-50 border-blue-300 text-blue-700' : 'border-gray-200 text-gray-500 hover:bg-gray-100'
                  }`}>{a}</button>
              ))}
            </div>
          </div>
          <div>
            <label className="block text-2xs font-medium text-gray-500 mb-1.5">
              可访问目录 {paths.length > 0 && <span className="text-gray-400">（{paths.length} 项）</span>}
              <span className="ml-2 font-normal text-gray-400">未勾选 = 不限；按目录前缀匹配</span>
            </label>
            <div className="flex flex-wrap gap-1.5">
              {scopes.paths.map(p => (
                <button key={p} onClick={() => togglePath(p)}
                  className={`px-2.5 py-1 text-xs font-mono rounded-md border transition-colors ${
                    paths.includes(p) ? 'bg-green-50 border-green-300 text-green-700' : 'border-gray-200 text-gray-500 hover:bg-gray-100'
                  }`}>{p}</button>
              ))}
            </div>
          </div>
        </>
      )}

      <div className="flex items-center gap-x-3 gap-y-1 flex-wrap">
        <button onClick={save} disabled={busy} className="tap px-4 py-1.5 text-xs font-medium rounded-md bg-blue-600 text-white hover:bg-blue-700 disabled:opacity-40 transition-colors">
          {busy ? '保存中' : '保存更改'}
        </button>
        <div className="flex items-center gap-1.5 ml-auto flex-wrap">
          <LockIcon className="w-3 h-3 text-gray-400" />
          <input type="password" value={pw} onChange={e => setPw(e.target.value)} placeholder="新密码（至少 8 位）"
            className="w-40 text-xs border border-gray-300 rounded-md px-2 py-1 focus:outline-none focus:ring-2 focus:ring-blue-100 focus:border-blue-400" />
          <button onClick={resetPassword} disabled={pw.length < 8 || busy}
            className="tap inline-flex items-center gap-1 px-2 py-1 text-2xs rounded bg-chrome-700 text-white hover:bg-chrome-800 disabled:opacity-40">
            <CheckIcon className="w-3 h-3" /> 重置
          </button>
        </div>
      </div>
    </div>
  );
}

/* ── CreateUserForm ── */

function CreateUserForm({ scopes, onDone, onError }: {
  scopes: AdminScopes; onDone: () => void; onError: (msg: string) => void;
}) {
  const [username, setUsername] = useState('');
  const [displayName, setDisplayName] = useState('');
  const [password, setPassword] = useState('');
  const [role, setRole] = useState<'admin' | 'user'>('user');
  const [agents, setAgents] = useState<string[]>([]);
  const [paths, setPaths] = useState<string[]>([]);
  const [busy, setBusy] = useState(false);

  const ok = username.trim().length >= 2 && password.length >= 8 && !busy;

  const submit = async () => {
    if (!ok) return;
    setBusy(true);
    try {
      await api.adminCreateUser({
        username: username.trim().toLowerCase(), password, display_name: displayName.trim(), role: role,
        allowed_agents: role === 'admin' ? [] : agents, allowed_paths: role === 'admin' ? [] : paths,
      });
      setUsername(''); setDisplayName(''); setPassword(''); setRole('user'); setAgents([]); setPaths([]);
      onDone();
    } catch (err) { onError(err instanceof Error ? err.message : String(err)); }
    finally { setBusy(false); }
  };

  return (
    <div className="mx-6 mt-3 p-4 rounded-lg border border-gray-200 bg-gray-50 space-y-3">
      <div className="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-4 gap-3">
        <Field label="用户名" hint="小写字母数字 . _ -">
          <input value={username} onChange={e => setUsername(e.target.value)} placeholder="alice" spellCheck={false}
            className="w-full text-sm font-mono border border-gray-300 rounded-md px-2.5 py-1.5 focus:outline-none focus:ring-2 focus:ring-blue-100 focus:border-blue-400" />
        </Field>
        <Field label="显示名"><input value={displayName} onChange={e => setDisplayName(e.target.value)} placeholder="Alice"
          className="w-full text-sm border border-gray-300 rounded-md px-2.5 py-1.5 focus:outline-none focus:ring-2 focus:ring-blue-100 focus:border-blue-400" /></Field>
        <Field label="初始密码" hint="至少 8 位"><input type="password" value={password} onChange={e => setPassword(e.target.value)}
          className="w-full text-sm border border-gray-300 rounded-md px-2.5 py-1.5 focus:outline-none focus:ring-2 focus:ring-blue-100 focus:border-blue-400" /></Field>
        <Field label="角色">
          <select value={role} onChange={e => setRole(e.target.value as 'admin' | 'user')}
            className="w-full text-sm border border-gray-300 rounded-md px-2 py-1.5 focus:outline-none focus:ring-2 focus:ring-blue-100 focus:border-blue-400">
            <option value="user">普通用户</option>
            <option value="admin">管理员</option>
          </select>
        </Field>
      </div>

      {role !== 'admin' && (
        <>
          <ScopePick label="可调用 Agent" items={scopes.agents} selected={agents} onToggle={a => setAgents(p => p.includes(a) ? p.filter(x => x !== a) : [...p, a])} color="blue" />
          <ScopePick label="可访问目录" items={scopes.paths} selected={paths} onToggle={p => setPaths(prev => prev.includes(p) ? prev.filter(x => x !== p) : [...prev, p])} color="green" />
        </>
      )}

      <div className="flex justify-end">
        <button onClick={submit} disabled={!ok} className="tap px-4 py-1.5 text-xs font-medium rounded-md bg-blue-600 text-white hover:bg-blue-700 disabled:opacity-40">
          {busy ? '创建中' : '创建'}
        </button>
      </div>
    </div>
  );
}

function ScopePick({ label, items, selected, onToggle, color }: {
  label: string; items: string[]; selected: string[]; onToggle: (item: string) => void; color: 'blue' | 'green';
}) {
  const active = color === 'blue' ? 'bg-blue-50 border-blue-300 text-blue-700' : 'bg-green-50 border-green-300 text-green-700';
  return (
    <div>
      <label className="block text-2xs font-medium text-gray-500 mb-1">
        {label} <span className="font-normal text-gray-400">未勾选 = 不限</span>
      </label>
      <div className="flex flex-wrap gap-1.5">
        {items.map(i => (
          <button key={i} onClick={() => onToggle(i)}
            className={`px-2.5 py-1 text-xs font-mono rounded-md border transition-colors ${
              selected.includes(i) ? active : 'border-gray-200 text-gray-500 hover:bg-gray-100'
            }`}>{i}</button>
        ))}
      </div>
    </div>
  );
}

function Field({ label, hint, children }: { label: string; hint?: string; children: React.ReactNode }) {
  return (
    <div>
      <div className="flex items-baseline gap-1.5 mb-1">
        <label className="text-2xs font-medium text-gray-500">{label}</label>
        {hint && <span className="text-3xs text-gray-400">{hint}</span>}
      </div>
      {children}
    </div>
  );
}

/**
 * 模型范围页。
 *
 * Agent 列表复用 `/admin/quotas` —— 它返回的就是全部已注册 Agent。
 * 另开一个「列出 Agent」接口只会多一条做同一件事的路径。
 */
function ModelScopeTab() {
  const [agents, setAgents] = useState<api.AgentStats[]>([]);
  const [err, setErr] = useState('');

  useEffect(() => {
    api
      .adminListAgentStats()
      .then(res => setAgents(res.quotas))
      .catch(e => setErr(e instanceof Error ? e.message : String(e)));
  }, []);

  if (err) return <p className="text-xs text-red-600">{err}</p>;
  return <ModelScopePanel agents={agents} />;
}