import { useEffect, useMemo, useState } from 'react';
import { Clock3, Layers3, Pencil, Plus, RadioTower, Search, Trash2 } from 'lucide-react';
import { useNavigate } from 'react-router-dom';
import { Breadcrumb, Button, Input, Modal, Pagination, Tag } from '@/components/ui';
import { adminApi, type ChannelGroup } from '@/api/adminApi';

type GroupCarrier = 'mobile' | 'unicom' | 'telecom';

const carrierLabels: Record<GroupCarrier, string> = {
  mobile: '移动',
  unicom: '联通',
  telecom: '电信',
};

function formatRetryLimit(group: ChannelGroup) {
  if (group.retryEnabled === false) return '已关闭';
  const totalMinutes = group.retryTimeLimitMinutes ?? (group.retryTimeLimitHours ?? 12) * 60;
  return `${Math.floor(totalMinutes / 60)}小时${totalMinutes % 60}分钟`;
}

function getGroupSummary(group: ChannelGroup) {
  const items = group.items ?? [];
  const provinceCount = items.filter((item) => item.province).length;
  const nationalCount = items.length - provinceCount;
  const connectedCount = items.filter((item) => (item.channel?.connectionStates ?? []).some((connection) =>
    connection.status === 'connected'
    && connection.desiredConnections > 0
    && connection.currentConnections > 0
  )).length;
  return { connectedCount, nationalCount, provinceCount, totalCount: items.length };
}

export function AdminChannelGroupsPage() {
  const navigate = useNavigate();
  const [groupName, setGroupName] = useState('');
  const [groups, setGroups] = useState<ChannelGroup[]>([]);
  const [deleteTarget, setDeleteTarget] = useState<ChannelGroup | null>(null);
  const [page, setPage] = useState(1);
  const [error, setError] = useState('');
  const pageSize = 10;

  function loadData() {
    adminApi.listChannelGroups()
      .then((items) => {
        setGroups(items);
        setError('');
      })
      .catch((failure: Error) => setError(failure.message || '通道组加载失败'));
  }

  useEffect(() => {
    loadData();
  }, []);

  const filteredGroups = useMemo(() => groups.filter((group) => !groupName.trim() || group.name.includes(groupName.trim())), [groupName, groups]);
  const totalPages = Math.max(1, Math.ceil(filteredGroups.length / pageSize));
  const currentPage = Math.min(page, totalPages);
  const visibleGroups = filteredGroups.slice((currentPage - 1) * pageSize, currentPage * pageSize);

  useEffect(() => {
    setPage(1);
  }, [groupName, groups.length]);

  function deleteGroup() {
    if (!deleteTarget) return;
    adminApi.deleteChannelGroup(deleteTarget.id)
      .then(() => {
        setDeleteTarget(null);
        loadData();
      })
      .catch((failure: Error) => setError(failure.message || '通道组删除失败'));
  }

  return (
    <div className="page-stack sms-channel-group-page">
      <div className="page-heading">
        <div>
          <Breadcrumb items={['短信通道组管理']} />
        </div>
        <Button icon={<Plus size={16} />} onClick={() => navigate('/admin/channel-groups/new')}>
          添加通道组
        </Button>
      </div>
      {error ? <p className="form-error">{error}</p> : null}

      <section className="surface channel-group-filter">
        <Input label="通道组名称" onChange={(event) => setGroupName(event.target.value)} placeholder="请输入通道组名称" value={groupName} />
        <div className="channel-group-filter__actions">
          <Button icon={<Search size={16} />} onClick={loadData}>查询</Button>
          <Button onClick={() => setGroupName('')} variant="ghost">重置</Button>
        </div>
      </section>

      <section className="surface channel-group-list">
        <div className="channel-group-config-list">
          {visibleGroups.map((group) => {
            const summary = getGroupSummary(group);
            const previewItems = (group.items ?? []).slice(0, 4);
            return (
              <article className="channel-group-config-item" key={group.id}>
                <div className="channel-group-config-item__identity">
                  <span className="channel-group-config-item__icon"><Layers3 size={18} /></span>
                  <div>
                    <strong>{group.name}</strong>
                    <span>{carrierLabels[group.carrier] ?? group.carrier}通道组</span>
                  </div>
                </div>

                <div className="channel-group-config-item__metrics" aria-label="通道组配置摘要">
                  <div>
                    <span>省网</span>
                    <strong>{summary.provinceCount}</strong>
                  </div>
                  <div>
                    <span>全国</span>
                    <strong>{summary.nationalCount}</strong>
                  </div>
                  <div>
                    <span>链接正常</span>
                    <strong>{summary.connectedCount}/{summary.totalCount}</strong>
                  </div>
                </div>

                <div className="channel-group-config-item__policy">
                  <Tag tone={group.retryEnabled === false ? 'neutral' : 'success'}>
                    {group.retryEnabled === false ? '补发关闭' : '补发开启'}
                  </Tag>
                  <span><Clock3 size={15} />{formatRetryLimit(group)}</span>
                  <span><RadioTower size={15} />{summary.totalCount ? `${summary.totalCount} 个通道` : '暂无通道'}</span>
                </div>

                <div className="channel-group-config-item__channels">
                  {previewItems.map((item) => (
                    <span key={item.id}>
                      {item.province ? `${item.province} / ` : `P${item.priority} / `}
                      {item.channel?.name ?? '未命名通道'}
                    </span>
                  ))}
                  {summary.totalCount > previewItems.length ? <span>+{summary.totalCount - previewItems.length}</span> : null}
                  {summary.totalCount === 0 ? <span>暂无绑定通道</span> : null}
                </div>

                <div className="channel-group-config-item__actions">
                  <button onClick={() => navigate(`/admin/channel-groups/${group.id}/edit`)} type="button">
                    <Pencil size={15} />编辑
                  </button>
                  <button className="is-danger" onClick={() => setDeleteTarget(group)} type="button">
                    <Trash2 size={15} />删除
                  </button>
                </div>
              </article>
            );
          })}
        </div>
        <Pagination
          nextDisabled={currentPage >= totalPages}
          onNext={() => setPage((value) => Math.min(totalPages, value + 1))}
          onPrevious={() => setPage((value) => Math.max(1, value - 1))}
          page={currentPage}
          previousDisabled={currentPage <= 1}
          total={filteredGroups.length}
        />
      </section>

      <Modal
        footer={(
          <>
            <Button onClick={() => setDeleteTarget(null)} variant="ghost">取消</Button>
            <Button onClick={deleteGroup} variant="danger">确认删除</Button>
          </>
        )}
        onClose={() => setDeleteTarget(null)}
        open={Boolean(deleteTarget)}
        title="删除通道组"
      >
        <div className="channel-confirm">
          <strong>{deleteTarget?.name}</strong>
          <p>删除前会校验真实路由绑定；已被企业应用使用的通道组不会被删除。</p>
        </div>
      </Modal>
    </div>
  );
}