"use client";

import { useState } from "react";
import {
  ColumnDef,
  flexRender,
  getCoreRowModel,
  getPaginationRowModel,
  getSortedRowModel,
  useReactTable,
  SortingState,
  RowSelectionState,
} from "@tanstack/react-table";
import { useQuery } from "@tanstack/react-query";

interface FileData {
  id: string;
  filename: string;
  mimetype: string;
  size: number;
  createdAt: string;
  updatedAt: string;
}

const columns: ColumnDef<FileData>[] = [
  {
    id: "select",
    header: ({ table }) => (
      <div className="px-6 py-3">
        <input
          type="checkbox"
          checked={table.getIsAllPageRowsSelected()}
          onChange={(e) => table.toggleAllPageRowsSelected(!!e.target.checked)}
          className="w-4 h-4 text-blue-600 bg-gray-100 border-gray-300 rounded focus:ring-blue-500"
        />
      </div>
    ),
    cell: ({ row }) => (
      <div className="px-6 py-4">
        <input
          type="checkbox"
          checked={row.getIsSelected()}
          onChange={(e) => row.toggleSelected(!!e.target.checked)}
          className="w-4 h-4 text-blue-600 bg-gray-100 border-gray-300 rounded focus:ring-blue-500"
        />
      </div>
    ),
    enableSorting: false,
    enableHiding: false,
  },
  {
    accessorKey: "filename",
    header: "File Name",
    cell: ({ row }) => (
      <div className="font-medium text-gray-900">{row.getValue("filename")}</div>
    ),
  },
  {
    accessorKey: "mimetype",
    header: "Type",
    cell: ({ row }) => (
      <div className="text-sm text-gray-600">{row.getValue("mimetype")}</div>
    ),
  },
  {
    accessorKey: "size",
    header: "Size",
    cell: ({ row }) => {
      const bytes = row.getValue("size") as number;
      if (bytes === 0) return "0 Bytes";
      
      const k = 1024;
      const sizes = ["Bytes", "KB", "MB", "GB"];
      const i = Math.floor(Math.log(bytes) / Math.log(k));
      
      return parseFloat((bytes / Math.pow(k, i)).toFixed(2)) + " " + sizes[i];
    },
  },
  {
    accessorKey: "createdAt",
    header: "Created",
    cell: ({ row }) => {
      const date = new Date(row.getValue("createdAt"));
      return date.toLocaleDateString("en-US", {
        year: "numeric",
        month: "short",
        day: "numeric",
        hour: "2-digit",
        minute: "2-digit",
      });
    },
  },
  {
    accessorKey: "updatedAt",
    header: "Updated",
    cell: ({ row }) => {
      const date = new Date(row.getValue("updatedAt"));
      return date.toLocaleDateString("en-US", {
        year: "numeric",
        month: "short",
        day: "numeric",
        hour: "2-digit",
        minute: "2-digit",
      });
    },
  },
];

export function FilesTable() {
  const [sorting, setSorting] = useState<SortingState>([]);
  const [rowSelection, setRowSelection] = useState<RowSelectionState>({});

  const { data, isLoading, isError, error, refetch } = useQuery({
    queryKey: ["files"],
    queryFn: async () => {
      const response = await fetch("/api/files");
      if (!response.ok) {
        throw new Error("Failed to fetch files");
      }
      const data = await response.json();
      return data.files as FileData[];
    },
  });

  const table = useReactTable({
    data: data || [],
    columns,
    state: {
      sorting,
      rowSelection,
    },
    onSortingChange: setSorting,
    onRowSelectionChange: setRowSelection,
    getCoreRowModel: getCoreRowModel(),
    getPaginationRowModel: getPaginationRowModel(),
    getSortedRowModel: getSortedRowModel(),
    enableRowSelection: true,
  });

  const handleRefresh = () => {
    refetch();
  };

  const handleDownload = (fileId: string, filename: string) => {
    const downloadUrl = `/api/files/${fileId}`;
    const link = document.createElement('a');
    link.href = downloadUrl;
    link.download = filename;
    document.body.appendChild(link);
    link.click();
    document.body.removeChild(link);
  };

  const handleDownloadSelected = () => {
    const selectedRows = table.getSelectedRowModel().rows;
    if (selectedRows.length === 0) return;
    
    if (selectedRows.length === 1) {
      // Single file download
      const selected = selectedRows[0];
      handleDownload(selected.original.id, selected.original.filename);
    } else {
      // Multiple files - download each one
      selectedRows.forEach((row, index) => {
        setTimeout(() => {
          handleDownload(row.original.id, row.original.filename);
        }, index * 500); // Stagger downloads by 500ms to avoid browser blocking
      });
    }
  };

  if (isLoading) {
    return (
      <div className="bg-white rounded-lg shadow-sm border border-gray-200">
        <div className="p-6">
          <div className="flex justify-between items-center mb-4">
            <h2 className="text-xl font-semibold text-gray-900">Files in Database</h2>
            <div className="h-8 w-24 bg-gray-200 rounded animate-pulse"></div>
          </div>
          <div className="space-y-3">
            {[...Array(5)].map((_, i) => (
              <div key={i} className="h-12 bg-gray-100 rounded animate-pulse"></div>
            ))}
          </div>
        </div>
      </div>
    );
  }

  if (isError) {
    return (
      <div className="bg-red-50 border border-red-200 rounded-lg p-6">
        <div className="flex items-center">
          <svg className="w-5 h-5 text-red-500 mr-2" fill="currentColor" viewBox="0 0 20 20">
            <path fillRule="evenodd" d="M10 18a8 8 0 100-16 8 8 0 000 16zM8.707 7.293a1 1 0 00-1.414 1.414L8.586 10l-1.293 1.293a1 1 0 101.414 1.414L10 11.414l1.293 1.293a1 1 0 001.414-1.414L11.414 10l1.293-1.293a1 1 0 00-1.414-1.414L10 8.586 8.707 7.293z" clipRule="evenodd" />
          </svg>
          <span className="text-red-700">Error: {error?.message || "Failed to load files"}</span>
        </div>
        <button
          onClick={handleRefresh}
          className="mt-3 px-4 py-2 bg-red-600 text-white rounded-md hover:bg-red-700 transition-colors"
        >
          Retry
        </button>
      </div>
    );
  }

  if (!data || data.length === 0) {
    return (
      <div className="bg-white rounded-lg shadow-sm border border-gray-200 p-6">
        <div className="text-center">
          <svg className="mx-auto h-12 w-12 text-gray-400" fill="none" viewBox="0 0 24 24" stroke="currentColor">
            <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M9 13h6m-3-3v6m-9 1V7a2 2 0 012-2h6l2 2h6a2 2 0 012 2v8a2 2 0 01-2 2H5a2 2 0 01-2-2z" />
          </svg>
          <h3 className="mt-2 text-sm font-medium text-gray-900">No files found</h3>
          <p className="mt-1 text-sm text-gray-500">Upload some files to get started.</p>
        </div>
      </div>
    );
  }

  return (
    <div className="bg-white rounded-lg shadow-sm border border-gray-200">
      <div className="p-6">
        <div className="flex justify-between items-center mb-4">
          <h2 className="text-xl font-semibold text-gray-900">Files in Database</h2>
          <div className="flex gap-2">
            <button
              onClick={handleDownloadSelected}
              disabled={table.getSelectedRowModel().rows.length === 0 || isLoading}
              className="px-4 py-2 bg-green-600 text-white rounded-md hover:bg-green-700 transition-colors disabled:opacity-50 disabled:cursor-not-allowed flex items-center"
            >
              <svg
                className="w-4 h-4 mr-2"
                fill="none"
                stroke="currentColor"
                viewBox="0 0 24 24"
              >
                <path
                  strokeLinecap="round"
                  strokeLinejoin="round"
                  strokeWidth={2}
                  d="M12 10v6m0 0l-3-3m3 3l3-3m2 8H7a2 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>
              Download Selected
            </button>
            <button
              onClick={handleRefresh}
              disabled={isLoading}
              className="px-4 py-2 bg-blue-600 text-white rounded-md hover:bg-blue-700 transition-colors disabled:opacity-50 disabled:cursor-not-allowed flex items-center"
            >
              <svg
                className={`w-4 h-4 mr-2 ${isLoading ? "animate-spin" : ""}`}
                fill="none"
                stroke="currentColor"
                viewBox="0 0 24 24"
              >
                <path
                  strokeLinecap="round"
                  strokeLinejoin="round"
                  strokeWidth={2}
                  d="M4 4v5h.582m15.356 2A8.001 8.001 0 004.582 9m0 0H9m11 11v-5h-.581m0 0a8.003 8.003 0 01-15.357-2m15.357 2H15"
                />
              </svg>
              Refresh
            </button>
          </div>
        </div>

        <div className="overflow-x-auto">
          <table className="min-w-full divide-y divide-gray-200">
            <thead className="bg-gray-50">
              {table.getHeaderGroups().map((headerGroup) => (
                <tr key={headerGroup.id}>
                  {headerGroup.headers.map((header) => (
                    <th
                      key={header.id}
                      className="px-6 py-3 text-left text-xs font-medium text-gray-500 uppercase tracking-wider cursor-pointer hover:bg-gray-100"
                      onClick={header.column.getToggleSortingHandler()}
                    >
                      <div className="flex items-center">
                        {flexRender(header.column.columnDef.header, header.getContext())}
                        {header.column.getIsSorted() && (
                          <span className="ml-1">
                            {header.column.getIsSorted() === "asc" ? "↑" : "↓"}
                          </span>
                        )}
                      </div>
                    </th>
                  ))}
                </tr>
              ))}
            </thead>
            <tbody className="bg-white divide-y divide-gray-200">
              {table.getRowModel().rows.map((row) => (
                <tr
                  key={row.id}
                  className={`hover:bg-gray-50 ${row.getIsSelected() ? 'bg-blue-50' : ''}`}
                >
                  {row.getVisibleCells().map((cell) => (
                    <td key={cell.id} className="px-6 py-4 whitespace-nowrap text-sm text-gray-900">
                      {flexRender(cell.column.columnDef.cell, cell.getContext())}
                    </td>
                  ))}
                </tr>
              ))}
            </tbody>
          </table>
        </div>

        {/* Pagination */}
        <div className="flex items-center justify-between mt-4">
          <div className="text-sm text-gray-700">
            Showing {table.getRowModel().rows.length} of {data.length} results
          </div>
          <div className="flex gap-2">
            <button
              onClick={() => table.previousPage()}
              disabled={!table.getCanPreviousPage()}
              className="px-3 py-1 text-sm bg-gray-100 text-gray-700 rounded hover:bg-gray-200 disabled:opacity-50"
            >
              Previous
            </button>
            <button
              onClick={() => table.nextPage()}
              disabled={!table.getCanNextPage()}
              className="px-3 py-1 text-sm bg-gray-100 text-gray-700 rounded hover:bg-gray-200 disabled:opacity-50"
            >
              Next
            </button>
          </div>
        </div>
      </div>
    </div>
  );
}