import { useState } from 'react';
import { useNavigate, useParams } from 'react-router';
import { useTranslation } from 'react-i18next';
import {
  Window,
  Card,
  Button,
  TextField,
  SegmentedControl,
  Dialog,
  AlertDialog,
  Menu,
  MenuTrigger,
  MenuContent,
  MenuItem,
  IconButton,
  Badge,
  Callout,
} from '@olly/modern-sk';
import { Icon } from '../../components/common/Icon';
import { LoadingSkeleton } from '../../components/common/LoadingSkeleton';
import { EmptyState } from '../../components/common/EmptyState';
import { ErrorState } from '../../components/common/ErrorState';
import { usePermissions } from '../../hooks/usePermissions';
import {
  useGetUsersQuery,
  useGetUserQuery,
  useCreateUserMutation,
  useUpdateUserMutation,
  useDeleteUserMutation,
  useResetPasswordMutation,
  useGetServicesQuery,
  useGetSourcesQuery,
  useReindexMutation,
} from '../../api/endpoints/admin';
import type { User, ServiceStatus } from '../../api/types';

function StubPanel({ title }: { title: string }) {
  const { t } = useTranslation();
  return (
    <Window title={title}>
      <p style={{ color: 'var(--color-text-2)', margin: 0 }}>
        {t('common.comingSoon')}
      </p>
    </Window>
  );
}

/** Role + active-status badges shared by the list and the detail view. */
function UserBadges({ user }: { user: User }) {
  const { t } = useTranslation();
  return (
    <div style={{ display: 'flex', gap: '0.375rem', alignItems: 'center' }}>
      <Badge variant={user.role === 'admin' ? 'lime' : 'neutral'}>
        {t(`admin.users.role.${user.role}`)}
      </Badge>
      {!user.isActive && (
        <Badge variant="ember">{t('admin.users.status.blocked')}</Badge>
      )}
    </div>
  );
}

/** `/admin/users` — user list with add / role toggle / (de)activate / reset password. */
export function AdminUsers() {
  const { t } = useTranslation();
  const { data: users, isLoading, isError, refetch } = useGetUsersQuery();
  const [createUser, { isLoading: isCreating }] = useCreateUserMutation();

  const [createOpen, setCreateOpen] = useState(false);
  const [username, setUsername] = useState('');
  const [password, setPassword] = useState('');
  const [role, setRole] = useState<'admin' | 'user'>('user');
  const [createError, setCreateError] = useState(false);

  const resetForm = () => {
    setUsername('');
    setPassword('');
    setRole('user');
    setCreateError(false);
  };

  const handleCreate = async (e: React.FormEvent) => {
    e.preventDefault();
    const name = username.trim();
    if (!name || !password) return;
    setCreateError(false);
    try {
      await createUser({ username: name, password, role }).unwrap();
      setCreateOpen(false);
      resetForm();
    } catch {
      setCreateError(true);
    }
  };

  return (
    <Window title={t('admin.tabs.users')}>
      <div
        style={{
          display: 'flex',
          justifyContent: 'flex-end',
          marginBottom: '1rem',
        }}
      >
        <Dialog
          open={createOpen}
          onOpenChange={(open) => {
            setCreateOpen(open);
            if (!open) resetForm();
          }}
          title={t('admin.users.newDialog.title')}
          trigger={
            <Button variant="primary">
              <Icon name="plus" /> {t('admin.users.add')}
            </Button>
          }
          footer={
            <div
              style={{
                display: 'flex',
                justifyContent: 'flex-end',
                gap: '0.5rem',
              }}
            >
              <Button variant="ghost" onClick={() => setCreateOpen(false)}>
                {t('admin.users.newDialog.cancel')}
              </Button>
              <Button
                variant="primary"
                disabled={!username.trim() || !password || isCreating}
                onClick={(e) => void handleCreate(e)}
              >
                {t('admin.users.newDialog.create')}
              </Button>
            </div>
          }
        >
          <form
            onSubmit={(e) => void handleCreate(e)}
            style={{ display: 'flex', flexDirection: 'column', gap: '0.75rem' }}
          >
            <TextField
              autoFocus
              value={username}
              onChange={(e) => setUsername(e.target.value)}
              placeholder={t('admin.users.newDialog.username')}
              autoComplete="off"
            />
            <TextField
              type="password"
              value={password}
              onChange={(e) => setPassword(e.target.value)}
              placeholder={t('admin.users.newDialog.password')}
              autoComplete="new-password"
            />
            <SegmentedControl
              value={role}
              onValueChange={(v) => setRole(v === 'admin' ? 'admin' : 'user')}
              items={[
                { value: 'user', label: t('admin.users.role.user') },
                { value: 'admin', label: t('admin.users.role.admin') },
              ]}
            />
            {createError && (
              <Callout variant="danger">
                {t('admin.users.newDialog.error')}
              </Callout>
            )}
          </form>
        </Dialog>
      </div>

      {isLoading && <LoadingSkeleton rows={5} height={56} />}
      {isError && <ErrorState onRetry={refetch} />}
      {!isLoading && !isError && (users?.length ?? 0) === 0 && (
        <EmptyState icon="☺" title={t('admin.users.empty')} />
      )}
      {!isLoading && !isError && users && users.length > 0 && (
        <div style={{ display: 'flex', flexDirection: 'column', gap: '0.5rem' }}>
          {users.map((user) => (
            <UserRow key={user.id} user={user} />
          ))}
        </div>
      )}
    </Window>
  );
}

/** One row in the user list: identity + badges + actions menu. */
function UserRow({ user }: { user: User }) {
  const { t } = useTranslation();
  const navigate = useNavigate();
  const { user: currentUser } = usePermissions();
  const isSelf = currentUser?.id === user.id;

  const [updateUser] = useUpdateUserMutation();
  const [deleteUser] = useDeleteUserMutation();

  const [resetOpen, setResetOpen] = useState(false);
  const [deactivateOpen, setDeactivateOpen] = useState(false);

  const toggleRole = () =>
    void updateUser({
      id: user.id,
      role: user.role === 'admin' ? 'user' : 'admin',
    });
  const toggleActive = () =>
    void updateUser({ id: user.id, isActive: !user.isActive });

  return (
    <Card
      style={{
        padding: '0.75rem 1rem',
        display: 'flex',
        alignItems: 'center',
        gap: '1rem',
      }}
    >
      <button
        type="button"
        onClick={() => void navigate(`/admin/users/${user.id}`)}
        style={{
          flex: 1,
          minWidth: 0,
          textAlign: 'left',
          background: 'none',
          border: 'none',
          cursor: 'pointer',
          padding: 0,
          font: 'inherit',
          color: 'inherit',
        }}
      >
        <div
          style={{
            fontWeight: 600,
            overflow: 'hidden',
            textOverflow: 'ellipsis',
            whiteSpace: 'nowrap',
          }}
        >
          {user.username}
          {isSelf && (
            <span
              style={{
                marginLeft: '0.5rem',
                fontSize: '0.75rem',
                color: 'var(--color-text-3)',
                fontWeight: 400,
              }}
            >
              {t('admin.users.you')}
            </span>
          )}
        </div>
        <div style={{ fontSize: '0.8125rem', color: 'var(--color-text-3)' }}>
          {t('admin.users.added', {
            date: new Date(user.createdAt).toLocaleDateString(),
          })}
        </div>
      </button>

      <UserBadges user={user} />

      <Menu>
        <MenuTrigger asChild>
          <IconButton
            variant="ghost"
            size="sm"
            aria-label={t('admin.users.menu.options')}
          >
            ⋯
          </IconButton>
        </MenuTrigger>
        <MenuContent>
          <MenuItem onSelect={toggleRole}>
            {user.role === 'admin'
              ? t('admin.users.menu.makeUser')
              : t('admin.users.menu.makeAdmin')}
          </MenuItem>
          <MenuItem onSelect={() => setResetOpen(true)}>
            {t('admin.users.menu.resetPassword')}
          </MenuItem>
          {/* Guard against locking yourself out of the instance. */}
          {!isSelf && (
            <MenuItem
              onSelect={() =>
                user.isActive ? setDeactivateOpen(true) : toggleActive()
              }
            >
              {user.isActive
                ? t('admin.users.menu.deactivate')
                : t('admin.users.menu.activate')}
            </MenuItem>
          )}
        </MenuContent>
      </Menu>

      <ResetPasswordDialog
        user={user}
        open={resetOpen}
        onOpenChange={setResetOpen}
      />

      <AlertDialog
        open={deactivateOpen}
        onOpenChange={setDeactivateOpen}
        title={t('admin.users.deactivateDialog.title')}
        description={t('admin.users.deactivateDialog.description', {
          name: user.username,
        })}
        cancelLabel={t('admin.users.deactivateDialog.cancel')}
        actionLabel={t('admin.users.deactivateDialog.confirm')}
        destructive
        onAction={() => void deleteUser(user.id)}
      />
    </Card>
  );
}

/** Reset-password dialog: admin sets a new password for the account. */
function ResetPasswordDialog({
  user,
  open,
  onOpenChange,
}: {
  user: User;
  open: boolean;
  onOpenChange: (open: boolean) => void;
}) {
  const { t } = useTranslation();
  const [resetPassword, { isLoading }] = useResetPasswordMutation();
  const [value, setValue] = useState('');
  const [done, setDone] = useState(false);

  const handleSubmit = async (e: React.FormEvent) => {
    e.preventDefault();
    if (!value) return;
    await resetPassword({ id: user.id, newPassword: value }).unwrap();
    setValue('');
    setDone(true);
  };

  return (
    <Dialog
      open={open}
      onOpenChange={(o) => {
        onOpenChange(o);
        if (!o) {
          setValue('');
          setDone(false);
        }
      }}
      title={t('admin.users.resetDialog.title', { name: user.username })}
      footer={
        <div
          style={{ display: 'flex', justifyContent: 'flex-end', gap: '0.5rem' }}
        >
          <Button variant="ghost" onClick={() => onOpenChange(false)}>
            {t('admin.users.resetDialog.cancel')}
          </Button>
          <Button
            variant="primary"
            disabled={!value || isLoading}
            onClick={(e) => void handleSubmit(e)}
          >
            {t('admin.users.resetDialog.submit')}
          </Button>
        </div>
      }
    >
      {done ? (
        <Callout variant="success">{t('admin.users.resetDialog.done')}</Callout>
      ) : (
        <form onSubmit={(e) => void handleSubmit(e)}>
          <TextField
            autoFocus
            type="password"
            value={value}
            onChange={(e) => setValue(e.target.value)}
            placeholder={t('admin.users.resetDialog.newPassword')}
            autoComplete="new-password"
          />
        </form>
      )}
    </Dialog>
  );
}

/** `/admin/users/:userId` — per-user detail: identity, role toggle, reset, status. */
export function AdminUserDetail() {
  const { t } = useTranslation();
  const navigate = useNavigate();
  const { userId = '' } = useParams();
  const { user: currentUser } = usePermissions();

  const { data: user, isLoading, isError, refetch } = useGetUserQuery(userId, {
    skip: !userId,
  });
  const [updateUser] = useUpdateUserMutation();
  const [resetOpen, setResetOpen] = useState(false);

  const isSelf = currentUser?.id === user?.id;

  return (
    <Window title={t('admin.userDetail')}>
      <Button variant="ghost" size="sm" onClick={() => void navigate('/admin/users')}>
        ← {t('common.back')}
      </Button>

      <div style={{ marginTop: '1rem' }}>
        {isLoading && <LoadingSkeleton rows={3} height={40} />}
        {isError && <ErrorState onRetry={refetch} />}
        {user && (
          <div
            style={{ display: 'flex', flexDirection: 'column', gap: '1.25rem' }}
          >
            <div
              style={{ display: 'flex', alignItems: 'center', gap: '0.75rem' }}
            >
              <h2 style={{ margin: 0, fontSize: '1.25rem' }}>{user.username}</h2>
              <UserBadges user={user} />
            </div>

            <div style={{ fontSize: '0.8125rem', color: 'var(--color-text-3)' }}>
              {t('admin.users.added', {
                date: new Date(user.createdAt).toLocaleDateString(),
              })}
            </div>

            <div style={{ display: 'flex', gap: '0.5rem', flexWrap: 'wrap' }}>
              <Button
                variant="ghost"
                onClick={() =>
                  void updateUser({
                    id: user.id,
                    role: user.role === 'admin' ? 'user' : 'admin',
                  })
                }
              >
                {user.role === 'admin'
                  ? t('admin.users.menu.makeUser')
                  : t('admin.users.menu.makeAdmin')}
              </Button>
              <Button variant="ghost" onClick={() => setResetOpen(true)}>
                {t('admin.users.menu.resetPassword')}
              </Button>
              {!isSelf && (
                <Button
                  variant={user.isActive ? 'ember' : 'ghost'}
                  onClick={() =>
                    void updateUser({ id: user.id, isActive: !user.isActive })
                  }
                >
                  {user.isActive
                    ? t('admin.users.menu.deactivate')
                    : t('admin.users.menu.activate')}
                </Button>
              )}
            </div>

            <ResetPasswordDialog
              user={user}
              open={resetOpen}
              onOpenChange={setResetOpen}
            />
          </div>
        )}
      </div>
    </Window>
  );
}

/** `/admin/sources` — pluggable source management (creds/cookies/status). Scaffold. */
export function AdminSources() {
  const { t } = useTranslation();
  return <StubPanel title={t('admin.tabs.sources')} />;
}

const SERVICE_VARIANT: Record<ServiceStatus, 'lime' | 'ember' | 'neutral'> = {
  ok: 'lime',
  down: 'ember',
  skipped: 'neutral',
};

/** `/admin/instance` — backing-service health, source status, library reindex. */
export function AdminInstance() {
  const { t } = useTranslation();
  const {
    data: servicesData,
    isLoading: servicesLoading,
    isError: servicesError,
    refetch: refetchServices,
  } = useGetServicesQuery();
  const {
    data: sourcesData,
    isLoading: sourcesLoading,
    isError: sourcesError,
    refetch: refetchSources,
  } = useGetSourcesQuery();
  const [reindex, { isLoading: isReindexing }] = useReindexMutation();
  const [reindexMsg, setReindexMsg] = useState<
    { kind: 'success' | 'danger'; text: string } | null
  >(null);

  const handleReindex = async () => {
    setReindexMsg(null);
    try {
      const jobs = await reindex().unwrap();
      setReindexMsg({
        kind: 'success',
        text: t('admin.instance.reindex.enqueued', { count: jobs.length }),
      });
    } catch {
      // 400 when no indexable source is configured (see admin.py::trigger_reindex).
      setReindexMsg({
        kind: 'danger',
        text: t('admin.instance.reindex.noSource'),
      });
    }
  };

  return (
    <Window title={t('admin.tabs.instance')}>
      <div style={{ display: 'flex', flexDirection: 'column', gap: '1.5rem' }}>
        {/* ── Services ─────────────────────────────────────────────── */}
        <section>
          <h3 style={{ margin: '0 0 0.5rem', fontSize: '0.95rem' }}>
            {t('admin.instance.services.title')}
          </h3>
          {servicesLoading && <LoadingSkeleton rows={3} height={40} />}
          {servicesError && <ErrorState onRetry={refetchServices} />}
          {servicesData && (
            <div
              style={{ display: 'flex', flexDirection: 'column', gap: '0.5rem' }}
            >
              {(['database', 'redis', 'ml'] as const).map((key) => {
                const status = servicesData[key];
                return (
                  <Card
                    key={key}
                    style={{
                      padding: '0.625rem 1rem',
                      display: 'flex',
                      alignItems: 'center',
                      gap: '1rem',
                    }}
                  >
                    <span style={{ flex: 1 }}>
                      {t(`admin.instance.services.${key}`)}
                    </span>
                    <Badge variant={SERVICE_VARIANT[status]} dot>
                      {t(`admin.instance.status.${status}`)}
                    </Badge>
                  </Card>
                );
              })}
            </div>
          )}
        </section>

        {/* ── Sources (read-only; configured via env) ──────────────── */}
        <section>
          <h3 style={{ margin: '0 0 0.25rem', fontSize: '0.95rem' }}>
            {t('admin.instance.sources.title')}
          </h3>
          <p
            style={{
              margin: '0 0 0.5rem',
              fontSize: '0.8125rem',
              color: 'var(--color-text-3)',
            }}
          >
            {t('admin.instance.sources.envNote')}
          </p>
          {sourcesLoading && <LoadingSkeleton rows={2} height={40} />}
          {sourcesError && <ErrorState onRetry={refetchSources} />}
          {sourcesData && sourcesData.length === 0 && (
            <EmptyState icon="⊘" title={t('admin.instance.sources.empty')} />
          )}
          {sourcesData && sourcesData.length > 0 && (
            <div
              style={{ display: 'flex', flexDirection: 'column', gap: '0.5rem' }}
            >
              {sourcesData.map((s) => (
                <Card
                  key={s.name}
                  style={{
                    padding: '0.625rem 1rem',
                    display: 'flex',
                    alignItems: 'center',
                    gap: '1rem',
                  }}
                >
                  <span style={{ flex: 1 }}>
                    {s.label}
                    <span
                      style={{
                        marginLeft: '0.5rem',
                        fontSize: '0.75rem',
                        color: 'var(--color-text-3)',
                      }}
                    >
                      {s.kind}
                    </span>
                  </span>
                  <Badge variant={s.available ? 'lime' : 'ember'} dot>
                    {t(
                      s.available
                        ? 'admin.instance.sources.available'
                        : 'admin.instance.sources.unavailable',
                    )}
                  </Badge>
                </Card>
              ))}
            </div>
          )}
        </section>

        {/* ── Reindex ──────────────────────────────────────────────── */}
        <section>
          <h3 style={{ margin: '0 0 0.25rem', fontSize: '0.95rem' }}>
            {t('admin.instance.reindex.title')}
          </h3>
          <p
            style={{
              margin: '0 0 0.75rem',
              fontSize: '0.8125rem',
              color: 'var(--color-text-3)',
            }}
          >
            {t('admin.instance.reindex.description')}
          </p>
          {reindexMsg && (
            <div style={{ marginBottom: '0.75rem' }}>
              <Callout variant={reindexMsg.kind}>{reindexMsg.text}</Callout>
            </div>
          )}
          <Button
            variant="primary"
            disabled={isReindexing}
            onClick={() => void handleReindex()}
          >
            {t('admin.instance.reindex.button')}
          </Button>
        </section>
      </div>
    </Window>
  );
}