import { useEffect, useRef, useState } from 'react';
import { IconUpload, IconFileText, IconAlertCircle, IconCheck, IconX } from '@tabler/icons-react';

/**
 * ImportModal - модальное окно импорта данных
 * Простой подход со встроенным backdrop (как в HistoryModal)
 */
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(), 100);
    }
  }, [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);
  };

  const handleBackdropClick = (e) => {
    if (e.target === e.currentTarget) {
      onClose?.();
    }
  };

  return (
    <>
      {/* Modal Backdrop */}
      <div className="modal-backdrop show" onClick={handleBackdropClick} />
      
      {/* Modal */}
      <div 
        className="modal show d-block" 
        role="dialog" 
        aria-modal="true"
        tabIndex={-1}
        onKeyDown={(e) => { if (e.key === 'Escape') onClose?.(); }}
      >
        <div className="modal-dialog modal-lg modal-dialog-centered" role="document">
          <div className="modal-content" tabIndex={-1}>
            <div className="modal-header">
              <h5 className="modal-title d-flex align-items-center">
                <IconUpload className="me-2" size={24} />
                {title}
              </h5>
              <button type="button" className="btn-close" onClick={onClose} aria-label="Закрыть" />
            </div>
          
          <div className="modal-body">
            {/* Description */}
            <div className="alert alert-info mb-3">
              <div className="d-flex">
                <IconAlertCircle className="me-2 flex-shrink-0" size={20} />
                <div className="text-muted small">{description}</div>
              </div>
            </div>

            {/* Drop zone */}
            <div
              className={`card mb-3 ${dragOver ? 'border-primary bg-blue-lt' : 'border-dashed'}`}
              onDragOver={(e) => { e.preventDefault(); setDragOver(true); }}
              onDragLeave={() => setDragOver(false)}
              onDrop={handleDrop}
            >
              <div className="card-body">
                <div className="d-flex align-items-center justify-content-between">
                  <div className="text-muted">
                    {fileName ? (
                      <div className="d-flex align-items-center">
                        <IconFileText size={20} className="me-2 text-primary" />
                        <strong>Файл:</strong> {fileName}
                      </div>
                    ) : (
                      'Перетащите TXT/CSV сюда или вставьте текст ниже'
                    )}
                  </div>
                  <label className="btn btn-outline-primary mb-0">
                    <IconUpload size={16} className="me-1" />
                    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>
            </div>

            {/* Textarea */}
            <div className="mb-3">
              <textarea
                ref={textAreaRef}
                className="form-control font-monospace"
                rows={8}
                value={text}
                onChange={(e) => handleChange(e.target.value)}
                placeholder={placeholder}
              />
            </div>

            {/* Stats */}
            <div className="row g-2">
              <div className="col-md-6">
                <div className="card bg-green-lt">
                  <div className="card-body py-2">
                    <div className="d-flex align-items-center">
                      <IconCheck size={20} className="text-green me-2" />
                      <div>
                        <div className="text-muted small">Готово к импорту</div>
                        <div className="h3 m-0 text-green">{parsed.items.length}</div>
                      </div>
                    </div>
                  </div>
                </div>
              </div>
              <div className="col-md-6">
                <div className="card bg-red-lt">
                  <div className="card-body py-2">
                    <div className="d-flex align-items-center">
                      <IconX size={20} className="text-red me-2" />
                      <div>
                        <div className="text-muted small">Пропущено (ошибки)</div>
                        <div className="h3 m-0 text-red">{parsed.invalid.length}</div>
                      </div>
                    </div>
                  </div>
                </div>
              </div>
            </div>

            {parsed.invalid.length > 0 && (
              <div className="alert alert-warning mt-3">
                <div className="text-muted small">
                  <strong>Некорректные строки (показаны первые 5):</strong>
                  <ul className="mb-0 mt-1">
                    {parsed.invalid.slice(0, 5).map((line, i) => (
                      <li key={i}><code>{line}</code></li>
                    ))}
                  </ul>
                </div>
              </div>
            )}
          </div>
          
          <div className="modal-footer">
            <button className="btn btn-outline-secondary" onClick={downloadSample}>
              <IconFileText size={16} className="me-1" />
              Скачать шаблон
            </button>
            <button className="btn" onClick={onClose}>
              Отмена
            </button>
            <button 
              className="btn btn-primary" 
              disabled={parsed.items.length === 0} 
              onClick={handleConfirm}
            >
              <IconCheck size={16} className="me-1" />
              Импортировать ({parsed.items.length})
            </button>
          </div>
        </div>
      </div>
    </div>
    </>
  );
}

export default ImportModal;