import { useState, useEffect } from 'react';
import { useParams, useNavigate } from 'react-router-dom';
import { useSelector } from 'react-redux';
import { useGetArticleQuery, useUpdateArticleMutation, useDeleteArticleMutation } from '/src/api/apiArticle';
import { selectRegions } from '../store/slice/regionSlice';
import { TextEditor } from '../components/Editors/TextEditor';
import { LoadingComponent } from '../components/Placeholders/LoadingComponent';
import { ErrorComponent } from '../components/Placeholders/ErrorComponent';
import { NotFindElement } from '../components/Placeholders/NotFindElement';
import { EditElementForm } from '../components/Forms/EditElementForm';
import Modal from '../components/Modals/Modal';

export function EditArticlePage() {
  const { id } = useParams();
  const navigate = useNavigate();
  const navigateBack = () => navigate(`/article`);
  const regions = useSelector(selectRegions);
  const { data: item, isFetching, error } = useGetArticleQuery({ articleId: id });
  const [updateArticle] = useUpdateArticleMutation();
  const [deleteArticle] = useDeleteArticleMutation();
  const [isModalSuccess, setModalSuccess] = useState(false);
  const [errors, setErrors] = useState({ name: '', alias: '', regionId: '' });
  const [form, setForm] = useState({
    name: '',
    active: false,
    regionId: '',
    alias: '',
    previewPicture: '',
    doctors: '',
    services: '',
  });
  const [anons, setAnons] = useState('');
  const [content, setContent] = useState('');

  useEffect(() => {
    if (!item) return;
    setForm({
      name: item.name ?? '',
      active: Boolean(item.active),
      regionId: item.regionId ?? '',
      alias: item.alias ?? '',
      previewPicture: item.previewPicture ?? '',
      doctors: item.doctors == null ? '' : JSON.stringify(item.doctors, null, 2),
      services: item.services == null ? '' : JSON.stringify(item.services, null, 2),
    });
    setAnons(item.anons ?? '');
    setContent(item.content ?? '');
  }, [item]);

  const handleChange = (key) => (e) => {
    const value = e.target.type === 'checkbox' ? e.target.checked : e.target.value;
    setForm((f) => ({ ...f, [key]: value }));
    if (key === 'name' || key === 'alias' || key === 'regionId') setErrors((err) => ({ ...err, [key]: '' }));
  };

  const handleDelete = async () => {
    try {
      await deleteArticle({ articleId: id }).unwrap();
      setModalSuccess(true);
      window.setTimeout(() => navigateBack(), 2000);
    } catch (err) {
      console.error('Ошибка при удалении:', err);
    }
  };

  const handleSave = async () => {
    const newErrors = { name: '', alias: '', regionId: '' };
    let hasError = false;
    if (!String(form.name ?? '').trim()) { newErrors.name = 'Название не может быть пустым'; hasError = true; }
    if (!String(form.alias ?? '').trim()) { newErrors.alias = 'Alias не может быть пустым'; hasError = true; }
    if (form.regionId === '' || form.regionId == null) { newErrors.regionId = 'Укажите регион'; hasError = true; }
    if (hasError) { setErrors(newErrors); window.alert('Пожалуйста исправьте ошибки в форме.'); return; }
    const data = { anons, content };
    try {
      data.name = form.name === '' ? null : form.name;
      data.active = Boolean(form.active);
      data.regionId = form.regionId === '' ? null : Number(form.regionId);
      data.alias = form.alias === '' ? null : form.alias;
      data.previewPicture = form.previewPicture === '' ? null : form.previewPicture;
      data.doctors = !form.doctors || !String(form.doctors).trim() ? null : JSON.parse(form.doctors);
      data.services = !form.services || !String(form.services).trim() ? null : JSON.parse(form.services);
    } catch (e) { window.alert('Пожалуйста исправьте ошибки в форме.'); return; }
    try {
      await updateArticle({ articleId: id, data }).unwrap();
      setModalSuccess(true);
      window.setTimeout(() => window.location.reload(), 2000);
    } catch (err) {
      console.error('Ошибка сохранения:', err);
    }
  };

  if (isFetching) return <LoadingComponent />;
  if (error) return <ErrorComponent />;
  if (!item) return <NotFindElement message={`Статья с ID=${id} не найдена.`} navigateBack={navigateBack} />;

  return (
    <EditElementForm navigateBack={navigateBack} header={`Редактирование: статью #${id}`} handleSave={handleSave} handleDelete={handleDelete}>
      <div className="form-group"><label>Название</label><input type="text" className="form-control" value={form.name} onChange={handleChange('name')} />
        {errors.name && <small className="text-danger">{errors.name}</small>}</div>
      <div className="form-group form-check"><input type="checkbox" className="form-check-input" id="active" checked={Boolean(form.active)} onChange={handleChange('active')} /><label className="form-check-label" htmlFor="active">Активно</label></div>
      <div className="form-group"><label>Регион</label><select className="form-control" value={form.regionId === '' || form.regionId == null ? '' : String(form.regionId)} onChange={handleChange('regionId')}><option value="">—</option>{Object.entries(regions).map(([rid, name]) => (<option key={rid} value={rid}>{name}</option>))}</select>
        {errors.regionId && <small className="text-danger">{errors.regionId}</small>}</div>
      <div className="form-group"><label>Alias</label><input type="text" className="form-control" value={form.alias} onChange={handleChange('alias')} />
        {errors.alias && <small className="text-danger">{errors.alias}</small>}</div>
      <div className="form-group"><label>Анонс</label><TextEditor content={anons} setContent={setAnons} /></div>
      <div className="form-group"><label>Контент</label><TextEditor content={content} setContent={setContent} /></div>
      <div className="form-group"><label>previewPicture</label><input type="text" className="form-control" value={form.previewPicture} onChange={handleChange('previewPicture')} /></div>
      <div className="form-group"><label>doctors (JSON)</label><textarea className="form-control font-monospace" rows={4} value={form.doctors} onChange={handleChange('doctors')} /></div>
      <div className="form-group"><label>services (JSON)</label><textarea className="form-control font-monospace" rows={4} value={form.services} onChange={handleChange('services')} /></div>
      <Modal isOpen={isModalSuccess} title="Изменения внесены" hasButtons={false}><p className="mb-1">Изменения успешно внесены.</p></Modal>
    </EditElementForm>
  );
}