import { useState } from 'react';
import { useTranslation } from 'react-i18next';
import {
  FileSpreadsheet,
  FolderArchive,
  ArrowRight,
  RefreshCw,
  X,
} from 'lucide-react';
import * as XLSX from 'xlsx';
import { Button } from '@/components/ui/button';
import { Progress } from '@/components/ui/progress';
import { cn } from '@/lib/utils';
import { api } from '@/services/api';

interface DownloadJob {
  fileName: string;
  progress: number;
  processedFiles: number;
  totalFiles: number;
}

export default function ExportSection() {
  const { t } = useTranslation();
  const [activeDownload, setActiveDownload] = useState<DownloadJob | null>(null);

  const handleCancelDownload = () => {
    setActiveDownload(null);
  };

  const handleExportExcel = async () => {
    const dateStr = new Date().toISOString().split('T')[0];
    const fileName = `ICC_Transactions_${dateStr}.xlsx`;

    setActiveDownload({ fileName, progress: 10, processedFiles: 0, totalFiles: 0 });

    try {
      // Use fast export endpoint — no pagination overhead
      const result = await api.get<{ transactions: any[]; total: number }>('/transactions/export');
      const rows = result.transactions;

      setActiveDownload({ fileName, progress: 50, processedFiles: rows.length, totalFiles: rows.length });

      const wsData = rows.map((tx: any) => ({
        [t('table.date')]: tx.date ? new Date(tx.date).toLocaleDateString('fr-CA', { timeZone: 'America/Toronto' }) : '',
        [t('table.sender')]: tx.sender || '',
        [t('table.envelopeNumber')]: tx.envelopeNumber || '',
        [t('table.amount')]: tx.amount,
        'Currency': tx.currency || 'CAD',
        [t('table.reference')]: tx.reference || '',
        [t('table.branch')]: tx.branch || 'Montreal',
        [t('table.status')]: tx.reviewed ? t('status.verified') : t('status.notVerified'),
        'Email': tx.recipientEmail || '',
        'Message': tx.message || '',
      }));

      setActiveDownload({ fileName, progress: 80, processedFiles: rows.length, totalFiles: rows.length });

      const ws = XLSX.utils.json_to_sheet(wsData);
      ws['!cols'] = [
        { wch: 12 },  // Date
        { wch: 25 },  // Sender
        { wch: 16 },  // Envelope Number
        { wch: 12 },  // Amount
        { wch: 6 },   // Currency
        { wch: 20 },  // Reference
        { wch: 20 },  // Branch
        { wch: 12 },  // Status
        { wch: 35 },  // Email
        { wch: 30 },  // Message
      ];

      const wb = XLSX.utils.book_new();
      XLSX.utils.book_append_sheet(wb, ws, 'Transactions');
      XLSX.writeFile(wb, fileName);

      setActiveDownload({ fileName, progress: 100, processedFiles: rows.length, totalFiles: rows.length });
      setTimeout(() => setActiveDownload(null), 2000);
    } catch (err) {
      console.error('Export failed:', err);
      setActiveDownload(null);
    }
  };

  const handleExportPdf = () => {
    // TODO: Trigger PDF batch download
    console.log('Export PDF batch');
  };

  return (
    <div className="mt-4 pb-12">
      <h2 className="text-xl font-bold text-foreground mb-6 flex items-center gap-2">
        <span className="w-1.5 h-6 bg-primary rounded-full" />
        {t('reports.export.title')}
      </h2>

      <div className="bg-card rounded-xl border border-border p-6 md:p-8 shadow-[0_1px_3px_0_rgba(0,0,0,0.1),0_1px_2px_0_rgba(0,0,0,0.06)]">
        {/* Active Download Progress */}
        {activeDownload && (
          <div className="flex flex-col md:flex-row gap-8 items-start md:items-center justify-between bg-slate-50 p-6 rounded-xl border border-slate-100 mb-8">
            <div className="flex-1 w-full">
              <div className="flex items-center justify-between mb-3">
                <div className="flex items-center gap-2">
                  <div className="bg-primary/10 p-1.5 rounded-full">
                    <RefreshCw className="h-3.5 w-3.5 text-primary animate-spin" />
                  </div>
                  <span className="text-sm font-bold text-foreground">
                    {t('reports.export.downloading')}
                  </span>
                </div>
                <span className="text-sm font-bold text-primary">
                  {activeDownload.progress}%
                </span>
              </div>
              <Progress value={activeDownload.progress} className="h-2 mb-2" />
              <p className="text-xs text-muted-foreground font-medium">
                {t('reports.export.generating')}{' '}
                <span className="text-foreground font-bold">
                  {activeDownload.fileName}
                </span>{' '}
                ({activeDownload.processedFiles}/{activeDownload.totalFiles}{' '}
                {t('reports.export.filesProcessed')})
              </p>
            </div>
            <div className="flex gap-2 w-full md:w-auto">
              <Button
                variant="ghost"
                size="sm"
                className="w-full md:w-auto text-red-600 hover:bg-red-50 hover:text-red-700 font-semibold"
                onClick={handleCancelDownload}
              >
                <X className="h-3.5 w-3.5 mr-1" />
                {t('common.cancel')}
              </Button>
            </div>
          </div>
        )}

        {/* Export Cards */}
        <div className="grid grid-cols-1 md:grid-cols-2 gap-6">
          {/* Excel Export */}
          <div
            className="group relative flex flex-col p-6 rounded-xl border border-slate-200 hover:border-green-400 hover:shadow-md transition-all cursor-pointer bg-white"
            onClick={handleExportExcel}
          >
            <div className="flex items-start justify-between mb-4">
              <div className="p-3 bg-green-50 rounded-lg text-green-600 ring-1 ring-green-100 group-hover:bg-green-100 transition-colors">
                <FileSpreadsheet className="h-7 w-7" />
              </div>
              <div className="p-2 rounded-full hover:bg-slate-50 transition-colors">
                <ArrowRight className="h-5 w-5 text-slate-300 group-hover:text-green-500 transition-colors" />
              </div>
            </div>
            <h3 className="text-lg font-bold text-foreground mb-2 group-hover:text-green-700 transition-colors">
              {t('reports.export.excelTitle')}
            </h3>
            <p className="text-sm text-muted-foreground mb-8 leading-relaxed">
              {t('reports.export.excelDescription')}
            </p>
            <Button
              variant="outline"
              className={cn(
                'mt-auto w-full py-3 border-2 border-slate-100 font-bold',
                'group-hover:border-green-500 group-hover:text-green-600 transition-all'
              )}
            >
              {t('reports.export.generateReport')}
            </Button>
          </div>

          {/* PDF Batch Export */}
          <div
            className="group relative flex flex-col p-6 rounded-xl border border-slate-200 hover:border-primary/50 hover:shadow-md transition-all cursor-pointer bg-white"
            onClick={handleExportPdf}
          >
            <div className="flex items-start justify-between mb-4">
              <div className="p-3 bg-blue-50 rounded-lg text-primary ring-1 ring-blue-100 group-hover:bg-blue-100 transition-colors">
                <FolderArchive className="h-7 w-7" />
              </div>
              <div className="p-2 rounded-full hover:bg-slate-50 transition-colors">
                <ArrowRight className="h-5 w-5 text-slate-300 group-hover:text-primary transition-colors" />
              </div>
            </div>
            <h3 className="text-lg font-bold text-foreground mb-2 group-hover:text-primary transition-colors">
              {t('reports.export.pdfTitle')}
            </h3>
            <p className="text-sm text-muted-foreground mb-8 leading-relaxed">
              {t('reports.export.pdfDescription')}
            </p>
            <Button className="mt-auto w-full py-3 font-bold shadow-lg shadow-blue-500/20">
              {t('reports.export.startDownload')}
            </Button>
          </div>
        </div>
      </div>
    </div>
  );
}