import { useEffect, useRef, useState } from 'react';

function ImportModal({
  show,
  title = 'Импорт',
  description = 'Вставьте текст или перетащите файл TXT/CSV. Формат: VALUE COMMUNITY',
  parseLine,
  validateItem,
  onConfirm,
  onClose,
  sampleHeader = ['value', 'community'],
  placeholder = 'value community\nvalue community',
}) {
  const [text, setText] = useState('');
  const [dragOver, setDragOver] = useState(false);
  const [parsed, setParsed] = useState({ items: [], invalid: [] });
  const [fileName, setFileName] = useState('');
  const textAreaRef = useRef(null);

  useEffect(() => {
    if (show) {
      setText('');
      setParsed({ items: [], invalid: [] });
      setFileName('');
      setDragOver(false);
      setTimeout(() => textAreaRef.current?.focus(), 0);
    }
  }, [show]);

  if (!show) return null;

  const parseText = (raw) => {
    const lines = String(raw || '')
      .split(/\r?\n/)
      .map(l => l.trim())
      .filter(Boolean);
    const items = [];
    const invalid = [];
    for (const line of lines) {
      const obj = parseLine(line);
      if (obj && validateItem(obj)) items.push(obj); else invalid.push(line);
    }
    setParsed({ items, invalid });
  };

  const handleDrop = async (e) => {
    e.preventDefault();
    setDragOver(false);
    const file = e.dataTransfer?.files?.[0];
    if (!file) return;
    setFileName(file.name);
    const content = await file.text();
    setText(content);
    parseText(content);
  };

  const handleChange = (value) => {
    setText(value);
    parseText(value);
  };

  const handleConfirm = () => {
    if (parsed.items.length === 0) return;
    onConfirm?.(parsed.items);
  };

  const downloadSample = () => {
    const csv = [sampleHeader, ['example', '65000:100']]
      .map(r => r.map(x => `"${String(x ?? '').replace(/"/g, '""')}"`).join(','))
      .join('\n');
    const blob = new Blob([csv], { type: 'text/csv;charset=utf-8;' });
    const url = URL.createObjectURL(blob);
    const a = document.createElement('a');
    a.href = url;
    a.download = 'sample.csv';
    a.click();
    URL.revokeObjectURL(url);
  };

  return (
    <div className="modal modal-blur fade show" style={{display: 'block'}} tabIndex="-1">
      <div className="modal-dialog modal-lg modal-dialog-centered" role="document">
        <div className="modal-content">
          <button type="button" className="btn-close" onClick={onClose}></button>
          <div className="modal-header">
            <h3 className="modal-title">{title}</h3>
          </div>
          <div className="modal-body">
            <div className="mb-2 text-muted">{description}</div>
            <div
              className={`mb-3 border-dashed rounded p-3 ${dragOver ? 'bg-blue-lt' : ''}`}
              onDragOver={(e) => { e.preventDefault(); setDragOver(true); }}
              onDragLeave={() => setDragOver(false)}
              onDrop={handleDrop}
            >
              <div className="d-flex align-items-center justify-content-between">
                <div className="me-3 text-muted">
                  {fileName ? `Файл: ${fileName}` : 'Перетащите TXT/CSV сюда или вставьте текст ниже'}
                </div>
                <label className="btn btn-outline-primary mb-0">
                  Выбрать файл
                  <input type="file" accept=".txt,.csv,.log" hidden onChange={async (e) => {
                    const f = e.target.files?.[0];
                    if (!f) return;
                    setFileName(f.name);
                    const t = await f.text();
                    setText(t);
                    parseText(t);
                  }} />
                </label>
              </div>
            </div>
            <textarea
              ref={textAreaRef}
              className="form-control"
              rows={8}
              value={text}
              onChange={(e) => handleChange(e.target.value)}
              placeholder={placeholder}
            />
            <div className="row mt-3 g-3">
              <div className="col-md-6">
                <div className="card"><div className="card-body">
                  <div className="text-muted">Готово к импорту</div>
                  <div className="h2 m-0">{parsed.items.length}</div>
                </div></div>
              </div>
              <div className="col-md-6">
                <div className="card"><div className="card-body">
                  <div className="text-muted">Пропущено (ошибки)</div>
                  <div className="h2 m-0">{parsed.invalid.length}</div>
                </div></div>
              </div>
            </div>
            <div className="form-text mt-2">Проверьте предпросмотр и нажмите «Импортировать».</div>
          </div>
          <div className="modal-footer">
            <button className="btn btn-outline-secondary" onClick={downloadSample}>Шаблон CSV</button>
            <button className="btn" onClick={onClose}>Отмена</button>
            <button className="btn btn-primary" disabled={parsed.items.length === 0} onClick={handleConfirm}>Импортировать</button>
          </div>
        </div>
      </div>
    </div>
  );
}

export default ImportModal;