/**
 * API Tokens settings page — Bearer tokens for programmatic access
 * (UI-Backlog module 3/16).
 *
 * Backend: /api/v1/tokens (create, list, revoke). The plaintext token is
 * returned ONCE at creation — shown once with copy button, never again.
 * Permissions: mcp:read (list) / mcp:write (create, revoke).
 */

import React, { useState } from 'react';
import { useTranslation } from 'react-i18next';
import {
  KeyRound,
  Plus,
  Trash2,
  Copy,
  Check,
  Inbox,
  AlertTriangle,
} from 'lucide-react';
import {
  useApiTokens,
  useCreateApiToken,
  useRevokeApiToken,
  type ApiTokenInfo,
} from '@/api/apiTokens';
import { usePermission } from '@/hooks/usePermission';
import { Card } from '@/components/ui/Card';
import { Button } from '@/components/ui/Button';
import { Modal } from '@/components/ui/Modal';
import { Input } from '@/components/ui/Input';
import { Badge } from '@/components/ui/Badge';

function formatDateTime(iso: string | null): string {
  if (!iso) return '—';
  try {
    return new Date(iso).toLocaleString();
  } catch {
    return iso;
  }
}

function TokenCard({
  token,
  canWrite,
  onRevoke,
  isMutating,
}: {
  token: ApiTokenInfo;
  canWrite: boolean;
  onRevoke: (token: ApiTokenInfo) => void;
  isMutating: boolean;
}) {
  const { t } = useTranslation();
  const expired =
    token.expires_at !== null && new Date(token.expires_at) < new Date();

  return (
    <Card className="p-4" data-testid={`api-token-card-${token.id}`}>
      <div className="flex flex-col gap-3 sm:flex-row sm:items-center sm:justify-between">
        <div className="min-w-0 flex-1">
          <div className="flex items-center gap-2 flex-wrap">
            <KeyRound className="w-4 h-4 text-primary-600 flex-shrink-0" aria-hidden="true" />
            <span className="text-sm font-medium text-secondary-900 dark:text-secondary-100">
              {token.name}
            </span>
            {expired && (
              <span data-testid={`api-token-expired-${token.id}`}>
                <Badge variant="danger">{t('apiTokens.expiredBadge')}</Badge>
              </span>
            )}
          </div>
          <div className="mt-1 flex flex-wrap gap-1">
            {token.scopes.map((scope) => (
              <Badge key={scope} variant="secondary">{scope}</Badge>
            ))}
          </div>
          <div className="mt-2 text-xs text-secondary-500 dark:text-secondary-400">
            {t('apiTokens.created')} {formatDateTime(token.created_at)} ·{' '}
            {t('apiTokens.expires')} {formatDateTime(token.expires_at)} ·{' '}
            {t('apiTokens.lastUsed')} {formatDateTime(token.last_used_at)}
          </div>
        </div>
        {canWrite && (
          <Button
            variant="ghost"
            size="sm"
            onClick={() => onRevoke(token)}
            disabled={isMutating}
            aria-label={t('apiTokens.revoke')}
            data-testid={`api-token-revoke-${token.id}`}
            className="text-danger-600 hover:text-danger-700"
          >
            <Trash2 className="w-4 h-4" aria-hidden="true" />
          </Button>
        )}
      </div>
    </Card>
  );
}

function CreateTokenDialog({
  open,
  onClose,
  onSubmit,
  isSubmitting,
}: {
  open: boolean;
  onClose: () => void;
  onSubmit: (payload: { name: string; scopes?: string[]; expires_in_days?: number | null }) => void;
  isSubmitting: boolean;
}) {
  const { t } = useTranslation();
  const [name, setName] = useState('');
  const [scopes, setScopes] = useState('');
  const [expiresInDays, setExpiresInDays] = useState('');

  const parsedScopes = scopes
    .split(',')
    .map((s) => s.trim())
    .filter(Boolean);
  const parsedDays = expiresInDays ? parseInt(expiresInDays, 10) : null;
  const valid = name.trim().length > 0 && (parsedDays === null || (!isNaN(parsedDays) && parsedDays > 0));

  const submit = () => {
    if (!valid) return;
    onSubmit({
      name: name.trim(),
      scopes: parsedScopes,
      expires_in_days: parsedDays,
    });
  };

  return (
    <Modal open={open} onClose={onClose} title={t('apiTokens.createTitle')}>
      <div className="space-y-4">
        <Input
          label={t('apiTokens.name')}
          value={name}
          onChange={(e) => setName(e.target.value)}
          required
          placeholder={t('apiTokens.namePlaceholder')}
        />
        <Input
          label={t('apiTokens.scopes')}
          value={scopes}
          onChange={(e) => setScopes(e.target.value)}
          placeholder={t('apiTokens.scopesPlaceholder')}
          helperText={t('apiTokens.scopesHelper')}
        />
        <Input
          label={t('apiTokens.expiresInDays')}
          type="number"
          min={1}
          value={expiresInDays}
          onChange={(e) => setExpiresInDays(e.target.value)}
          placeholder={t('apiTokens.expiresPlaceholder')}
        />
        <div className="flex justify-end gap-2 pt-2">
          <Button variant="ghost" onClick={onClose}>{t('common.cancel')}</Button>
          <Button onClick={submit} disabled={!valid || isSubmitting} data-testid="api-token-create-submit">
            {t('apiTokens.createSubmit')}
          </Button>
        </div>
      </div>
    </Modal>
  );
}

function TokenRevealDialog({
  token,
  onClose,
}: {
  token: string | null;
  onClose: () => void;
}) {
  const { t } = useTranslation();
  const [copied, setCopied] = useState(false);

  const copy = async () => {
    if (!token) return;
    try {
      await navigator.clipboard.writeText(token);
      setCopied(true);
      setTimeout(() => setCopied(false), 2000);
    } catch {
      // clipboard API unavailable — user can select manually
    }
  };

  return (
    <Modal open={!!token} onClose={onClose} title={t('apiTokens.revealTitle')}>
      <div className="space-y-4">
        <p className="text-sm text-warning-700 dark:text-warning-300" role="alert">
          {t('apiTokens.revealWarning')}
        </p>
        <div className="flex items-center gap-2">
          <code
            className="flex-1 block break-all rounded-md bg-secondary-100 dark:bg-secondary-800 px-3 py-2 text-xs font-mono"
            data-testid="api-token-plaintext"
          >
            {token}
          </code>
          <Button variant="ghost" size="sm" onClick={copy} aria-label={t('apiTokens.copy')} data-testid="api-token-copy">
            {copied
              ? <Check className="w-4 h-4 text-success-600" aria-hidden="true" />
              : <Copy className="w-4 h-4" aria-hidden="true" />}
          </Button>
        </div>
        <div className="flex justify-end">
          <Button onClick={onClose} data-testid="api-token-reveal-done">{t('apiTokens.done')}</Button>
        </div>
      </div>
    </Modal>
  );
}

export function ApiTokensPage() {
  const { t } = useTranslation();
  const [showCreate, setShowCreate] = useState(false);
  const [revealedToken, setRevealedToken] = useState<string | null>(null);
  const { data, isLoading, isError } = useApiTokens();
  const createMut = useCreateApiToken();
  const revokeMut = useRevokeApiToken();
  const { hasPermission } = usePermission();

  const canWrite = hasPermission('mcp:write');
  const isMutating = createMut.isPending || revokeMut.isPending;

  const handleSubmit = (payload: { name: string; scopes?: string[]; expires_in_days?: number | null }) => {
    createMut.mutate(payload, {
      onSuccess: (result) => {
        setShowCreate(false);
        setRevealedToken(result.token);
      },
    });
  };

  const handleRevoke = (token: ApiTokenInfo) => {
    if (window.confirm(t('apiTokens.revokeConfirm', { name: token.name }))) {
      revokeMut.mutate(token.id);
    }
  };

  const items = data?.items ?? [];

  return (
    <div className="max-w-3xl mx-auto p-4 sm:p-6 space-y-4" data-testid="api-tokens-page">
      <div className="flex flex-col gap-3 sm:flex-row sm:items-center sm:justify-between">
        <h1 className="text-2xl font-bold text-secondary-900 dark:text-secondary-100">
          {t('apiTokens.title')}
        </h1>
        {canWrite && (
          <Button onClick={() => setShowCreate(true)} data-testid="api-token-create-open">
            <Plus className="w-4 h-4 mr-2" aria-hidden="true" />
            {t('apiTokens.create')}
          </Button>
        )}
      </div>

      {isLoading && (
        <div className="flex items-center justify-center min-h-[30vh]" role="status" data-testid="api-tokens-loading">
          <div className="animate-spin rounded-full h-8 w-8 border-b-2 border-primary-500" aria-hidden="true" />
        </div>
      )}

      {isError && (
        <Card className="p-6 flex items-center gap-3 text-danger-600" data-testid="api-tokens-error">
          <AlertTriangle className="w-5 h-5" aria-hidden="true" />
          <span>{t('apiTokens.loadError')}</span>
        </Card>
      )}

      {!isLoading && !isError && items.length === 0 && (
        <Card className="p-8 flex flex-col items-center gap-3 text-secondary-500" data-testid="api-tokens-empty">
          <Inbox className="w-10 h-10" aria-hidden="true" />
          <p>{t('apiTokens.empty')}</p>
        </Card>
      )}

      <div className="space-y-3">
        {items.map((token) => (
          <TokenCard
            key={token.id}
            token={token}
            canWrite={canWrite}
            onRevoke={handleRevoke}
            isMutating={isMutating}
          />
        ))}
      </div>

      <CreateTokenDialog
        open={showCreate}
        onClose={() => setShowCreate(false)}
        onSubmit={handleSubmit}
        isSubmitting={createMut.isPending}
      />
      <TokenRevealDialog
        token={revealedToken}
        onClose={() => setRevealedToken(null)}
      />
    </div>
  );
}

export default ApiTokensPage;