frontend/src/components/upload.tsx

import { useCallback, useRef, useState } from 'preact/hooks';

interface UploadProps {
  onFile: (file: File) => void;
  disabled?: boolean;
}

export function Upload({ onFile, disabled }: UploadProps) {
  const [dragOver, setDragOver] = useState(false);
  const inputRef = useRef<HTMLInputElement>(null);

  const handleFile = useCallback(
    (file: File | undefined) => {
      if (file && (file.type === 'image/jpeg' || file.type === 'image/png')) {
        onFile(file);
      }
    },
    [onFile]
  );

  const onDrop = useCallback(
    (e: DragEvent) => {
      e.preventDefault();
      setDragOver(false);
      handleFile(e.dataTransfer?.files[0]);
    },
    [handleFile]
  );

  const onDragOver = useCallback((e: DragEvent) => {
    e.preventDefault();
    setDragOver(true);
  }, []);

  const onDragLeave = useCallback(() => setDragOver(false), []);

  const onChange = useCallback(
    (e: Event) => {
      const input = e.target as HTMLInputElement;
      handleFile(input.files?.[0]);
    },
    [handleFile]
  );

  return (
    <div
      class={`upload-zone ${dragOver ? 'drag-over' : ''} ${disabled ? 'disabled' : ''}`}
      onDrop={onDrop}
      onDragOver={onDragOver}
      onDragLeave={onDragLeave}
      onClick={() => !disabled && inputRef.current?.click()}
    >
      <input
        ref={inputRef}
        type="file"
        accept="image/jpeg,image/png"
        onChange={onChange}
        hidden
      />
      <p class="upload-icon">+</p>
      <p>Drag & drop an aerial image here, or click to browse</p>
      <p class="upload-hint">JPEG or PNG</p>
    </div>
  );
}