import type { components } from '@pipu/api-client';
import { ApiError, unwrap } from '@pipu/core';
import { useMutation, useQuery } from '@tanstack/react-query';
import { Link } from '@tanstack/react-router';
import { useEffect, useState } from 'react';
import { useTranslation } from 'react-i18next';

import { useSession } from '../../app/session';
import { useErrorText } from '../../shared/lib/errors';
import { addIcon, arrowDownIcon, arrowUpIcon, deleteIcon } from '../../shared/ui/icons';
import { Button, cx, Field, FormError, Icon } from '../../shared/ui/ui';
import s from '../page.module.css';
import l from './library.module.css';
import { WriteTemplateSection } from './WriteTemplateSection';

type Pattern = components['schemas']['PathPattern'];
type Preview = components['schemas']['PatternPreview'];

/** Примеры из docs/library-and-storage.md — частые раскладки папок. */
const EXAMPLES = [
  String.raw`^(?P<artist>[^/]+)/(?P<year>\d{4}) - (?P<album>[^/]+)/(?:(?P<disc>\d)-)?(?P<track>\d{1,3}) - (?P<title>[^/]+)\.\w+$`,
  String.raw`^(?P<genre>[^/]+)/(?P<artist>[^/]+)/(?P<album>.+?) \((?P<year>\d{4})\)/(?P<track>\d+)\. (?P<title>[^/]+)\.\w+$`,
  String.raw`^Compilations/(?P<album>[^/]+)/(?P<track>\d+) - (?P<artist>.+?) - (?P<title>[^/]+)\.\w+$`,
];

/** Ошибка компиляции из 422: номер шаблона и причина. */
function patternError(err: unknown): { index: number; reason: string } | null {
  if (err instanceof ApiError && err.code === 'validation.pattern_invalid') {
    return { index: Number(err.params.index), reason: String(err.params.reason) };
  }
  return null;
}

export function PatternsPage({ id }: { id: string }) {
  const { t } = useTranslation(['admin', 'common']);
  const session = useSession();
  const errorText = useErrorText();
  const source = useQuery({
    queryKey: ['source', id],
    queryFn: async () => unwrap(await session.client.GET('/api/v1/admin/sources/{id}', { params: { path: { id } } })),
  });
  const saved = useQuery({
    queryKey: ['patterns', id],
    queryFn: async () =>
      unwrap(await session.client.GET('/api/v1/admin/sources/{id}/patterns', { params: { path: { id } } })).patterns,
  });
  const [rows, setRows] = useState<Pattern[]>([]);
  useEffect(() => {
    if (saved.data) setRows(saved.data);
  }, [saved.data]);

  const preview = useMutation({
    mutationFn: async () =>
      unwrap(
        await session.client.POST('/api/v1/admin/sources/{id}/patterns/preview', {
          params: { path: { id } },
          body: { patterns: rows, sample: 50 },
        }),
      ),
  });
  const save = useMutation({
    mutationFn: async () =>
      unwrap(
        await session.client.PUT('/api/v1/admin/sources/{id}/patterns', {
          params: { path: { id } },
          body: { patterns: rows },
        }),
      ),
    onSuccess: (r) => setRows(r.patterns),
  });

  const err = save.error ?? preview.error;
  const perr = patternError(err);
  const update = (i: number, p: Partial<Pattern>) => {
    save.reset();
    setRows((rs) => rs.map((r, k) => (k === i ? { ...r, ...p } : r)));
  };
  const move = (i: number, d: -1 | 1) =>
    setRows((rs) => {
      const next = [...rs];
      [next[i], next[i + d]] = [next[i + d]!, next[i]!];
      return next;
    });

  return (
    <div className={`${s.page} ${s.narrow}`} style={{ maxWidth: 1100 }}>
      <div className={s.head}>
        <div>
          <h1>{t('patterns.title', { name: source.data?.name ?? '…' })}</h1>
          <p className={s.subtitle}>
            <Link to="/admin/sources">{t('sources.title')}</Link>
          </p>
        </div>
      </div>
      <section className={s.section}>
        <p className={s.note}>{t('patterns.intro')}</p>
        <p className={l.groups}>{t('patterns.groups')}</p>
        {rows.map((r, i) => (
          <div key={i} className={l.patternRow}>
            <span className={l.patternNum}>{i + 1}</span>
            <Field
              label={t('patterns.regex', { n: i + 1 })}
              value={r.regex}
              onChange={(v) => update(i, { regex: v })}
              maxLength={1000}
              spellCheck={false}
              autoCapitalize="none"
              mono
              error={perr?.index === i ? t('patterns.error_at', { n: i + 1, reason: perr.reason }) : undefined}
            />
            <div className={l.patternTools} style={{ marginTop: 22 }}>
              <label className={l.check}>
                <input type="checkbox" checked={r.is_enabled} onChange={(e) => update(i, { is_enabled: e.target.checked })} />
                {t('patterns.enabled')}
              </label>
              <Button variant="ghost" aria-label={t('patterns.up')} disabled={i === 0} onClick={() => move(i, -1)}>
                <Icon src={arrowUpIcon} size={18} />
              </Button>
              <Button
                variant="ghost"
                aria-label={t('patterns.down')}
                disabled={i === rows.length - 1}
                onClick={() => move(i, 1)}
              >
                <Icon src={arrowDownIcon} size={18} />
              </Button>
              <Button
                variant="ghost"
                aria-label={t('patterns.remove')}
                onClick={() => setRows((rs) => rs.filter((_, k) => k !== i))}
              >
                <Icon src={deleteIcon} size={18} />
              </Button>
            </div>
          </div>
        ))}
        <div className={s.toolbar}>
          <Button icon={addIcon} onClick={() => setRows((rs) => [...rs, { regex: '', is_enabled: true }])}>
            {t('patterns.add')}
          </Button>
          <Button
            variant="ghost"
            onClick={() => setRows((rs) => [...rs, ...EXAMPLES.map((regex) => ({ regex, is_enabled: true }))])}
          >
            {t('patterns.examples')}
          </Button>
          <span style={{ flex: 1 }} />
          <Button busy={preview.isPending} onClick={() => preview.mutate()}>
            {t('patterns.preview')}
          </Button>
          <Button variant="primary" busy={save.isPending} onClick={() => save.mutate()}>
            {t('patterns.save')}
          </Button>
        </div>
        {save.isSuccess && <span className={s.ok}>{t('patterns.saved')}</span>}
        <FormError>{err && !perr ? errorText(err) : null}</FormError>
      </section>
      {preview.data && <PreviewTable preview={preview.data} />}
      {source.data && <WriteTemplateSection source={source.data} />}
    </div>
  );
}

function PreviewTable({ preview }: { preview: Preview }) {
  const { t } = useTranslation('admin');
  const fields = ['artist', 'album', 'title'] as const;
  return (
    <>
      <p className={s.note}>{t('patterns.unmatched', { count: preview.unmatched, total: preview.items.length })}</p>
      <div className={s.tableWrap} style={{ overflowX: 'auto' }}>
        <table className={s.table}>
          <thead>
            <tr>
              <th>{t('patterns.col_path')}</th>
              <th>{t('patterns.col_pattern')}</th>
              <th>{t('patterns.col_result')}</th>
            </tr>
          </thead>
          <tbody>
            {preview.items.map((it) => (
              <tr key={it.rel_path}>
                <td className={l.match}>{it.rel_path}</td>
                <td className={cx(l.match, it.pattern_index === null && l.noMatch)}>
                  {it.skipped
                    ? t('patterns.skipped')
                    : it.pattern_index === null
                      ? t('patterns.no_match')
                      : `#${it.pattern_index + 1}`}
                </td>
                <td>
                  <div className={l.result}>
                    {fields.map((f) => {
                      const fromPath = f in it.path_fields;
                      const fromTags = (f === 'artist' ? 'artist' : f) in it.tags;
                      return (
                        <span key={f}>
                          <b>{it.result[f]}</b>{' '}
                          {!fromPath && fromTags && <span className={l.fromTags}>{t('patterns.from_tags')}</span>}
                        </span>
                      );
                    })}
                    <span className={l.fromTags}>
                      {[it.result.year, it.result.track && `#${it.result.track}`, it.result.genres.join(', ')]
                        .filter(Boolean)
                        .join(' · ')}
                    </span>
                    {it.error && <span className={l.scanError}>{it.error}</span>}
                  </div>
                </td>
              </tr>
            ))}
          </tbody>
        </table>
      </div>
    </>
  );
}