'use client';

import { useRef, useState } from 'react';

interface FileDropAreaProps {
  onFile: (file: File) => void;
  onClear: () => void;
  accept: string;
  file: File | null;
  /** Text in der leeren Flaeche. */
  placeholder: string;
  /** Zweite Zeile (erlaubte Formate). */
  hint?: string;
  /** Beschriftung des Entfernen-Knopfs (fuer Screenreader). */
  clearLabel: string;
  disabled?: boolean;
}

/**
 * Ablageflaeche fuer eine einzelne Datei (Finanzbuchhaltungs-Module,
 * quick-261002-fm5). Eigenstaendig, ohne Texte aus einem anderen Modul —
 * Bauform wie die Ablage des Zertifikat-Managers: echte Schaltflaeche fuer
 * Klick UND Ziehen, Entfernen als Geschwister daneben.
 */
export function FileDropArea({
  onFile,
  onClear,
  accept,
  file,
  placeholder,
  hint,
  clearLabel,
  disabled = false,
}: FileDropAreaProps) {
  const inputRef = useRef<HTMLInputElement>(null);
  const [isDragOver, setIsDragOver] = useState(false);

  return (
    <div>
      <input
        ref={inputRef}
        type="file"
        accept={accept}
        className="hidden"
        data-testid="file-drop-input"
        onChange={(e) => {
          const picked = e.target.files?.[0];
          if (picked) onFile(picked);
          e.target.value = '';
        }}
      />
      <div className="relative">
        <button
          type="button"
          disabled={disabled}
          onClick={() => inputRef.current?.click()}
          onDragOver={(e) => {
            e.preventDefault();
            setIsDragOver(true);
          }}
          onDragLeave={() => setIsDragOver(false)}
          onDrop={(e) => {
            e.preventDefault();
            setIsDragOver(false);
            const dropped = e.dataTransfer.files?.[0];
            if (dropped && !disabled) onFile(dropped);
          }}
          className={`block w-full cursor-pointer rounded-lg border-2 border-dashed p-8 text-center transition-colors disabled:cursor-not-allowed disabled:opacity-60 ${
            isDragOver ? 'border-primary bg-primary/5' : 'border-border hover:border-primary/50'
          }`}
        >
          {file ? (
            <span className="text-sm text-foreground">
              {file.name}{' '}
              <span className="text-muted-foreground">({(file.size / 1024).toFixed(1)} KB)</span>
            </span>
          ) : (
            <span className="block space-y-1">
              <span className="block text-sm text-muted-foreground">{placeholder}</span>
              {hint && <span className="block text-xs text-muted-foreground">{hint}</span>}
            </span>
          )}
        </button>
        {file && (
          <button
            type="button"
            aria-label={clearLabel}
            onClick={onClear}
            className="absolute right-2 top-2 rounded border border-border bg-card px-2 py-0.5 text-xs text-muted-foreground hover:text-foreground"
          >
            &#x2715;
          </button>
        )}
      </div>
    </div>
  );
}