import { useEffect, useState } from 'react';
import { Download, RotateCcw } from 'lucide-react';
import type { SystemLogExportResult } from '@/api/adminApi';
import { Button } from './Button';

type Filters = { keyword?: string; level?: string; module?: string; range?: string };

export function SystemLogExport({
  portal,
  filters,
  exportLogs,
}: {
  portal: 'admin' | 'client';
  filters: Filters;
  exportLogs: (filters: Filters) => Promise<SystemLogExportResult>;
}) {
  const storageKey = `cmpp:${portal}:system-log-export-recovery`;
  const [exporting, setExporting] = useState(false);
  const [result, setResult] = useState<SystemLogExportResult | null>(null);
  const [error, setError] = useState('');
  const [retryFilters, setRetryFilters] = useState<Filters | null>(null);

  useEffect(() => {
    try {
      const saved = sessionStorage.getItem(storageKey);
      if (saved) {
        setRetryFilters(JSON.parse(saved) as Filters);
        setError('上次导出未完成，筛选条件已保留，可直接重试。');
      }
    } catch {
      sessionStorage.removeItem(storageKey);
    }
  }, [storageKey]);

  async function run(nextFilters: Filters) {
    setExporting(true);
    setError('');
    setResult(null);
    setRetryFilters(nextFilters);
    sessionStorage.setItem(storageKey, JSON.stringify(nextFilters));
    try {
      const exported = await exportLogs(nextFilters);
      setResult(exported);
      setRetryFilters(null);
      sessionStorage.removeItem(storageKey);
    } catch (reason) {
      setError(reason instanceof Error ? reason.message : '日志导出失败，请重试');
    } finally {
      setExporting(false);
    }
  }

  function download() {
    if (!result) return;
    const url = URL.createObjectURL(new Blob([`\uFEFF${result.content}`], { type: 'text/csv;charset=utf-8' }));
    const anchor = document.createElement('a');
    anchor.href = url;
    anchor.download = result.fileName;
    anchor.click();
    URL.revokeObjectURL(url);
  }

  return (
    <div className="system-log-export">
      <Button disabled={exporting} icon={<Download size={17} />} onClick={() => run(filters)} variant="secondary">
        {exporting ? '导出中…' : '导出日志'}
      </Button>
      {result ? (
        <div className="system-log-export__result" role="status">
          <span>导出完成，共 {result.recordCount} 条{result.truncated ? '（已截取前 10000 条）' : ''}，操作单号 {result.operationId}</span>
          <Button icon={<Download size={15} />} onClick={download} size="sm" variant="ghost">下载文件</Button>
        </div>
      ) : null}
      {error ? (
        <div className="system-log-export__error" role="alert">
          <span>{error}</span>
          <Button disabled={exporting} icon={<RotateCcw size={15} />} onClick={() => run(retryFilters ?? filters)} size="sm" variant="ghost">重试</Button>
        </div>
      ) : null}
    </div>
  );
}