'use client';

import { useState, useEffect, useCallback } from 'react';
import Image from 'next/image';
import { Button } from '@/components/ui/Button';
import { Modal } from '@/components/ui/Modal';
import {
  listFiles,
  deleteFile,
  isImageMime,
  formatFileSize,
  getThumbnailUrl,
  type FileResponse,
} from '@/lib/files';

interface FileListProps {
  vehicleId: string;
  onFileDeleted?: () => void;
}

export function FileList({ vehicleId, onFileDeleted }: FileListProps) {
  const [files, setFiles] = useState<FileResponse[]>([]);
  const [total, setTotal] = useState(0);
  const [page, setPage] = useState(1);
  const [pageSize] = useState(20);
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const [deleteTarget, setDeleteTarget] = useState<FileResponse | null>(null);
  const [deleting, setDeleting] = useState(false);

  const fetchFiles = useCallback(async () => {
    setLoading(true);
    setError(null);
    try {
      const data = await listFiles(vehicleId, page, pageSize);
      setFiles(data.items);
      setTotal(data.total);
    } catch (err: unknown) {
      const apiErr = err as { error?: { message?: string } };
      setError(apiErr?.error?.message || 'Failed to load files');
    } finally {
      setLoading(false);
    }
  }, [vehicleId, page, pageSize]);

  useEffect(() => {
    fetchFiles();
  }, [fetchFiles]);

  const handleDelete = async () => {
    if (!deleteTarget) return;
    setDeleting(true);
    try {
      await deleteFile(vehicleId, deleteTarget.id);
      setDeleteTarget(null);
      await fetchFiles();
      onFileDeleted?.();
    } catch (err: unknown) {
      const apiErr = err as { error?: { message?: string } };
      setError(apiErr?.error?.message || 'Failed to delete file');
    } finally {
      setDeleting(false);
    }
  };

  const handleDownload = (file: FileResponse) => {
    const token = typeof window !== 'undefined'
      ? localStorage.getItem('access_token')
      : null;
    const API_BASE_URL = process.env.NEXT_PUBLIC_API_URL || 'http://localhost:8000/api/v1';
    const url = `${API_BASE_URL}/vehicles/${vehicleId}/files/${file.id}`;

    // Use fetch with auth header to download as blob
    fetch(url, {
      headers: token ? { Authorization: `Bearer ${token}` } : {},
    })
      .then((res) => res.blob())
      .then((blob) => {
        const downloadUrl = URL.createObjectURL(blob);
        const a = document.createElement('a');
        a.href = downloadUrl;
        a.download = file.original_filename;
        document.body.appendChild(a);
        a.click();
        document.body.removeChild(a);
        URL.revokeObjectURL(downloadUrl);
      })
      .catch(() => setError('Failed to download file'));
  };

  if (loading && files.length === 0) {
    return (
      <div className="text-center py-8 text-text-muted" data-testid="file-list-loading">
        Loading files...
      </div>
    );
  }

  if (error) {
    return (
      <div className="text-center py-8 text-error" data-testid="file-list-error">
        {error}
      </div>
    );
  }

  if (files.length === 0) {
    return (
      <div className="text-center py-8 text-text-muted" data-testid="file-list-empty">
        No files uploaded yet.
      </div>
    );
  }

  return (
    <div data-testid="file-list">
      <div className="grid grid-cols-1 sm:grid-cols-2 md:grid-cols-3 lg:grid-cols-4 gap-4">
        {files.map((file) => {
          const thumbUrl = getThumbnailUrl(file);
          const isImg = isImageMime(file.mime_type);
          return (
            <div
              key={file.id}
              className="border border-border rounded-lg overflow-hidden bg-surface"
              data-testid={`file-item-${file.id}`}
            >
              {/* Thumbnail or file icon */}
              <div className="aspect-square bg-background flex items-center justify-center relative">
                {isImg && thumbUrl ? (
                  <Image
                    src={thumbUrl}
                    alt={file.original_filename}
                    fill
                    className="object-cover"
                    data-testid={`file-thumb-${file.id}`}
                    unoptimized
                  />
                ) : (
                  <div className="flex flex-col items-center gap-2 text-text-muted">
                    <svg className="h-12 w-12" fill="none" viewBox="0 0 24 24" stroke="currentColor">
                      <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2}
                        d="M9 12h6m-6 4h6m2 5H7a2 2 0 01-2-2V5a2 2 0 012-2h5.586a1 1 0 01.707.293l5.414 5.414a1 1 0 01.293.707V19a2 2 0 01-2 2z" />
                    </svg>
                    <span className="text-xs uppercase">{file.mime_type.split('/')[1]}</span>
                  </div>
                )}
              </div>

              {/* File info */}
              <div className="p-3">
                <p className="text-sm font-medium text-text truncate" title={file.original_filename}>
                  {file.original_filename}
                </p>
                <p className="text-xs text-text-muted mt-1">
                  {formatFileSize(file.file_size)}
                </p>

                {/* Actions */}
                <div className="flex gap-2 mt-2">
                  <Button
                    variant="ghost"
                    className="text-xs px-2 py-1"
                    onClick={() => handleDownload(file)}
                    data-testid={`download-btn-${file.id}`}
                  >
                    Download
                  </Button>
                  <Button
                    variant="danger"
                    className="text-xs px-2 py-1"
                    onClick={() => setDeleteTarget(file)}
                    data-testid={`delete-btn-${file.id}`}
                  >
                    Delete
                  </Button>
                </div>
              </div>
            </div>
          );
        })}
      </div>

      {/* Pagination */}
      {total > pageSize && (
        <div className="flex items-center justify-center gap-4 mt-6">
          <Button
            variant="secondary"
            disabled={page <= 1}
            onClick={() => setPage((p) => p - 1)}
          >
            Previous
          </Button>
          <span className="text-text-muted">
            Page {page} of {Math.ceil(total / pageSize)}
          </span>
          <Button
            variant="secondary"
            disabled={page * pageSize >= total}
            onClick={() => setPage((p) => p + 1)}
          >
            Next
          </Button>
        </div>
      )}

      {/* Delete confirmation modal */}
      <Modal
        open={!!deleteTarget}
        onClose={() => setDeleteTarget(null)}
        title="Delete File"
      >
        <div data-testid="delete-confirm">
          <p className="text-text mb-4">
            Are you sure you want to delete <strong>{deleteTarget?.original_filename}</strong>?
            This action cannot be undone.
          </p>
          <div className="flex justify-end gap-2">
            <Button variant="secondary" onClick={() => setDeleteTarget(null)}>
              Cancel
            </Button>
            <Button
              variant="danger"
              loading={deleting}
              onClick={handleDelete}
              data-testid="confirm-delete-btn"
            >
              Delete
            </Button>
          </div>
        </div>
      </Modal>
    </div>
  );
}