/**
 * @componentName  Pager
 * @describe   --  分页列表组件
 * @author liulei
 * @since  12.13 开发完成
 *
 */

import Taro, { Component } from '@tarojs/taro';
import { ScrollView } from '@tarojs/components';

interface IProps {
  /** 请求列表数据的异步方法，页码改变时触发 */
  onChange: (page: number) => void;

  /** 下拉刷新回调函数 */
  onPullDown?: () => void;
  /** 当前页码 */
  current: number;
  /** 列表总条目，用于计算总页数 */
  total: number;
  /** 每页显示数量，选填，默认20 */
  page_size?: number;
}
interface IState {
  scrollY: boolean,
}
class Pager extends Component<IProps, IState> {
  static defaultProps = {
    current: 1,
    page_size: 20,
    onChange: () => {},
    onPullDown: () => {},
  }

  constructor(props) {
    super(props);
    this.state = {
      scrollY: true,
    };
  }

  onScrollToLower = () => {
    const { onChange, total, page_size, current } = this.props;
    const pageNum = Math.ceil(total / (page_size || 20));
    if (!onChange) return;
    if (current < pageNum) {
      onChange(current + 1);
    }
  }

  render() {
    const { scrollY } = this.state;
    return (
      <ScrollView
        style="height: 100%;"
        scrollY={scrollY}
        onScrollToLower={this.onScrollToLower}
      >
        {this.props.children}
      </ScrollView>
    );
  }
}

export default Pager;