'use client';

import { useEffect, useState } from 'react';
import { FileText } from 'lucide-react';
import type { LabCaseAttachmentMeta } from '@/types/cases';

interface LabCaseAttachmentPreviewProps {
  caseId: string;
  attachment: LabCaseAttachmentMeta;
  loadBlob: (caseId: string, attachmentId: string) => Promise<Blob>;
  className?: string;
}

export function LabCaseAttachmentPreview({
  caseId,
  attachment,
  loadBlob,
  className = 'h-full w-full',
}: LabCaseAttachmentPreviewProps) {
  const [url, setUrl] = useState<string | null>(null);
  const [failed, setFailed] = useState(false);

  useEffect(() => {
    let cancelled = false;
    let objectUrl: string | null = null;

    void (async () => {
      try {
        const blob = await loadBlob(caseId, attachment.id);
        if (cancelled) return;
        objectUrl = URL.createObjectURL(blob);
        setUrl(objectUrl);
        setFailed(false);
      } catch {
        if (!cancelled) setFailed(true);
      }
    })();

    return () => {
      cancelled = true;
      if (objectUrl) URL.revokeObjectURL(objectUrl);
    };
  }, [caseId, attachment.id, loadBlob]);

  const isImage = attachment.mimeType.startsWith('image/');
  const isPdf = attachment.mimeType === 'application/pdf';

  return (
    <div
      className={`${className} rounded-[var(--radius-md)] border border-border/60 bg-background-secondary overflow-hidden`}
      title={attachment.fileName}
    >
      {url && isImage ? (
        <img src={url} alt={attachment.fileName} className="h-full w-full object-cover" />
      ) : url && isPdf ? (
        <iframe src={url} title={attachment.fileName} className="h-full w-full border-0" />
      ) : (
        <div className="flex h-full w-full flex-col items-center justify-center gap-1.5 p-2 text-text-muted">
          <FileText className="h-8 w-8 shrink-0 icon-flat" aria-hidden />
          <span className="line-clamp-2 text-center text-[10px] leading-tight">
            {failed ? 'Preview unavailable' : attachment.fileName}
          </span>
        </div>
      )}
    </div>
  );
}
