import { useCallback, useEffect, useRef, useState } from 'react';

import {
  downloadAdminErrorReport,
  formatAdminApiError,
  getAdminErrorReport,
  isAdminApiError,
  listAdminErrorReports,
  updateAdminErrorReport,
} from '../api/adminApiClient';
import type {
  AdminErrorReportDetail,
  AdminErrorReportEntry,
} from '../api/adminApiTypes';

type Props = { token: string; onUnauthorized: (message?: string) => void };

const ADMIN_ERROR_REPORT_STATUSES = ['new', 'in-progress', 'resolved'] as const;
const ERROR_REPORT_PAGE_SIZE = 50;

export function AdminErrorReportsPage({ token, onUnauthorized }: Props) {
  const [reports, setReports] = useState<AdminErrorReportEntry[]>([]);
  const [selected, setSelected] = useState<AdminErrorReportDetail | null>(null);
  const [status, setStatus] = useState('');
  const [downloading, setDownloading] = useState(false);
  const [busy, setBusy] = useState(false);
  const [filterStatus, setFilterStatus] = useState('');
  const [pageOffset, setPageOffset] = useState(0);
  const [pageInfo, setPageInfo] = useState({ total: 0, hasMore: false });
  const openReportRequestId = useRef(0);
  const loadRequestId = useRef(0);

  const load = useCallback(async () => {
    const requestId = ++loadRequestId.current;
    setStatus('');
    try {
      const response = await listAdminErrorReports(token, {
        status: filterStatus || undefined,
        limit: ERROR_REPORT_PAGE_SIZE,
        offset: pageOffset,
      });
      if (requestId === loadRequestId.current) {
        const lastValidOffset = response.total
          ? Math.floor((response.total - 1) / ERROR_REPORT_PAGE_SIZE) *
            ERROR_REPORT_PAGE_SIZE
          : 0;
        if (pageOffset > lastValidOffset) {
          setPageOffset(lastValidOffset);
          return;
        }
        setReports(response.reports);
        setPageInfo({ total: response.total, hasMore: response.hasMore });
      }
    } catch (error) {
      if (requestId !== loadRequestId.current) return;
      if (isAdminApiError(error) && error.status === 401)
        return onUnauthorized();
      setStatus(formatAdminApiError(error));
    }
  }, [filterStatus, onUnauthorized, pageOffset, token]);

  const loadRef = useRef(load);
  useEffect(() => {
    loadRef.current = load;
  }, [load]);

  useEffect(() => {
    void load();
  }, [load]);

  async function openReport(batchId: string) {
    const requestId = ++openReportRequestId.current;
    setStatus('');
    try {
      const detail = await getAdminErrorReport(token, batchId);
      if (requestId === openReportRequestId.current) setSelected(detail);
    } catch (error) {
      if (requestId !== openReportRequestId.current) return;
      if (isAdminApiError(error) && error.status === 401)
        return onUnauthorized();
      setStatus(formatAdminApiError(error));
    }
  }

  async function saveStatus(nextStatus: string) {
    if (!selected || busy) return;
    setBusy(true);
    setStatus('');
    try {
      const updated = await updateAdminErrorReport(token, selected.batchId, {
        status: nextStatus,
        note: selected.note,
      });
      setSelected((current) =>
        current ? { ...current, ...updated } : current,
      );
      await loadRef.current();
    } catch (error) {
      if (isAdminApiError(error) && error.status === 401) onUnauthorized();
      else setStatus(formatAdminApiError(error));
    } finally {
      setBusy(false);
    }
  }

  async function download(batchId: string) {
    if (downloading) return;
    setDownloading(true);
    setStatus('');
    try {
      const blob = await downloadAdminErrorReport(token, batchId);
      const url = URL.createObjectURL(blob);
      const anchor = document.createElement('a');
      anchor.href = url;
      anchor.download = `${batchId}.zip`;
      document.body.appendChild(anchor);
      anchor.click();
      anchor.remove();
      setTimeout(() => URL.revokeObjectURL(url), 10_000);
    } catch (error) {
      if (isAdminApiError(error) && error.status === 401) onUnauthorized();
      else setStatus(formatAdminApiError(error));
    } finally {
      setDownloading(false);
    }
  }

  return (
    <section className="admin-panel">
      <div className="admin-panel-header">
        <div>
          <h1>错误报告</h1>
          <p>查看用户提交的脱敏诊断包。</p>
        </div>
        <label>
          状态{' '}
          <select
            value={filterStatus}
            onChange={(event) => {
              setFilterStatus(event.target.value);
              setPageOffset(0);
            }}
          >
            <option value="">全部</option>
            {ADMIN_ERROR_REPORT_STATUSES.map((value) => (
              <option key={value} value={value}>
                {value}
              </option>
            ))}
          </select>
        </label>
      </div>
      {status ? (
        <p className="admin-alert" role="status">
          {status}
        </p>
      ) : null}
      <div className="admin-table-wrap">
        <table className="admin-table">
          <thead>
            <tr>
              <th>报告</th>
              <th>事件</th>
              <th>来源</th>
              <th>状态</th>
              <th>用户</th>
              <th>时间</th>
            </tr>
          </thead>
          <tbody>
            {reports.map((report) => (
              <tr
                key={report.batchId}
                onClick={() => void openReport(report.batchId)}
                role="button"
                tabIndex={0}
                onKeyDown={(event) => {
                  if (event.key === 'Enter' || event.key === ' ') {
                    event.preventDefault();
                    void openReport(report.batchId);
                  }
                }}
              >
                <td>{report.batchId}</td>
                <td>{report.eventCount}</td>
                <td>{report.source ?? '-'}</td>
                <td>{report.status}</td>
                <td>{report.userId}</td>
                <td>{new Date(report.createdAt).toLocaleString()}</td>
              </tr>
            ))}
          </tbody>
        </table>
      </div>
      <div className="admin-detail-modal__actions" aria-label="错误报告分页">
        <span>
          {pageInfo.total === 0
            ? '暂无报告'
            : `第 ${pageOffset + 1}-${Math.min(pageOffset + reports.length, pageInfo.total)} 条，共 ${pageInfo.total} 条`}
        </span>
        <button
          type="button"
          onClick={() =>
            setPageOffset((offset) =>
              Math.max(0, offset - ERROR_REPORT_PAGE_SIZE),
            )
          }
          disabled={pageOffset === 0}
        >
          上一页
        </button>
        <button
          type="button"
          onClick={() =>
            setPageOffset((offset) => offset + ERROR_REPORT_PAGE_SIZE)
          }
          disabled={!pageInfo.hasMore}
        >
          下一页
        </button>
      </div>
      {selected ? (
        <div
          className="admin-detail-modal"
          role="dialog"
          aria-label="错误报告详情"
        >
          <div className="admin-detail-modal__panel">
            <header>
              <h2>{selected.batchId}</h2>
              <button type="button" onClick={() => setSelected(null)}>
                关闭
              </button>
            </header>
            <p>
              用户：{selected.userId} · 事件：{selected.eventCount} · 日志：
              {selected.logCount}
            </p>
            <pre>{JSON.stringify(selected.events.slice(0, 20), null, 2)}</pre>
            {selected.userDescription ? (
              <p>用户描述：{selected.userDescription}</p>
            ) : null}
            <label className="admin-detail-modal__note">
              处理备注
              <textarea
                value={selected.note ?? ''}
                onChange={(event) =>
                  setSelected((current) =>
                    current
                      ? { ...current, note: event.target.value }
                      : current,
                  )
                }
                maxLength={2000}
                rows={4}
                placeholder="记录处理结论或后续跟进事项"
                disabled={busy}
              />
            </label>
            <div className="admin-detail-modal__actions">
              <select
                value={selected.status}
                onChange={(event) => void saveStatus(event.target.value)}
                disabled={busy}
              >
                {ADMIN_ERROR_REPORT_STATUSES.map((value) => (
                  <option key={value} value={value}>
                    {value}
                  </option>
                ))}
              </select>
              <button
                type="button"
                onClick={() => void saveStatus(selected.status)}
                disabled={busy}
              >
                保存备注
              </button>
              <button
                type="button"
                onClick={() => void download(selected.batchId)}
                disabled={downloading}
              >
                {downloading ? '下载中…' : '下载诊断包'}
              </button>
            </div>
          </div>
        </div>
      ) : null}
    </section>
  );
}