/**
 * ExportButton Component
 * 
 * CSV export dropdown with two options:
 * 1. Export Selected Rows (client-side, immediate)
 * 2. Export All Filtered Results (server-side via Server Action, max 5000)
 * 
 * Features:
 * - Dropdown menu with export options
 * - Disabled state when no data/selection
 * - Loading state for server-side export
 * - Warning when result set > 5000 rows
 */

'use client';

import { useState } from 'react';
import { Button } from '@/components/ui/button';
import {
  DropdownMenu,
  DropdownMenuContent,
  DropdownMenuItem,
  DropdownMenuLabel,
  DropdownMenuSeparator,
  DropdownMenuTrigger,
} from '@/components/ui/dropdown-menu';
import { Download, Loader2 } from 'lucide-react';
import { generatePolicySettingsCsv, downloadCsv, generateCsvFilename } from '@/lib/utils/csv-export';
import { exportPolicySettingsCSV } from '@/lib/actions/policySettings';
import type { PolicySettingRow } from '@/lib/types/policy-table';
import { toast } from 'sonner';

interface ExportButtonProps {
  selectedRows: PolicySettingRow[];
  selectedCount: number;
  totalCount: number;
  // Filter state for server-side export
  policyTypes?: string[];
  searchQuery?: string;
  sortBy?: string;
  sortDir?: 'asc' | 'desc';
}

export function ExportButton({
  selectedRows,
  selectedCount,
  totalCount,
  policyTypes,
  searchQuery,
  sortBy,
  sortDir,
}: ExportButtonProps) {
  const [isExporting, setIsExporting] = useState(false);

  const hasSelection = selectedCount > 0;
  const hasData = totalCount > 0;
  const exceedsLimit = totalCount > 5000;

  // Client-side export: Export selected rows
  const handleExportSelected = () => {
    if (!hasSelection) return;

    try {
      const csvContent = generatePolicySettingsCsv(selectedRows);
      const filename = generateCsvFilename('policy-settings', selectedCount);
      downloadCsv(csvContent, filename);
      
      toast.success(`Exported ${selectedCount} rows to ${filename}`);
    } catch (error) {
      console.error('Export error:', error);
      toast.error('Failed to export selected rows');
    }
  };

  // Server-side export: Export all filtered results
  const handleExportAll = async () => {
    setIsExporting(true);

    try {
      const result = await exportPolicySettingsCSV({
        policyTypes: policyTypes && policyTypes.length > 0 ? policyTypes : undefined,
        searchQuery: searchQuery || undefined,
        sortBy: sortBy as 'settingName' | 'policyName' | 'policyType' | 'lastSyncedAt' | undefined,
        sortDir,
        maxRows: 5000,
      });

      if (result.success && result.csv && result.filename) {
        downloadCsv(result.csv, result.filename);
        toast.success(`Exported ${result.rowCount} rows to ${result.filename}`);
      } else {
        toast.error(result.error || 'Failed to export data');
      }
    } catch (error) {
      console.error('Export error:', error);
      toast.error('An unexpected error occurred during export');
    } finally {
      setIsExporting(false);
    }
  };

  return (
    <DropdownMenu>
      <DropdownMenuTrigger asChild>
        <Button
          variant="outline"
          size="sm"
          className="h-8"
          disabled={!hasData || isExporting}
        >
          {isExporting ? (
            <>
              <Loader2 className="mr-2 h-4 w-4 animate-spin" />
              Exporting...
            </>
          ) : (
            <>
              <Download className="mr-2 h-4 w-4" />
              Export
            </>
          )}
        </Button>
      </DropdownMenuTrigger>
      <DropdownMenuContent align="end" className="w-[220px]">
        <DropdownMenuLabel>Export to CSV</DropdownMenuLabel>
        <DropdownMenuSeparator />
        
        <DropdownMenuItem
          onClick={handleExportSelected}
          disabled={!hasSelection}
        >
          <div className="flex flex-col gap-1">
            <span className="font-medium">Export Selected</span>
            <span className="text-xs text-muted-foreground">
              {hasSelection ? `${selectedCount} rows` : 'No rows selected'}
            </span>
          </div>
        </DropdownMenuItem>

        <DropdownMenuItem
          onClick={handleExportAll}
          disabled={!hasData || isExporting}
        >
          <div className="flex flex-col gap-1">
            <span className="font-medium">Export All Filtered</span>
            <span className="text-xs text-muted-foreground">
              {exceedsLimit 
                ? `${totalCount} rows (limited to 5000)` 
                : `${totalCount} rows`}
            </span>
          </div>
        </DropdownMenuItem>

        {exceedsLimit && (
          <>
            <DropdownMenuSeparator />
            <div className="px-2 py-1.5 text-xs text-amber-600">
              ⚠️ Results exceed 5000 rows. Export will be limited.
            </div>
          </>
        )}
      </DropdownMenuContent>
    </DropdownMenu>
  );
}