/**
 * @file 用于显示日志的组件，比如显示命令行的输出结果
 */
import React from 'react';
import {Renderer, RendererProps} from '../factory';
import {BaseSchema, SchemaTpl} from '../Schema';
import Ansi from 'ansi-to-react';
import {filter} from '../utils/tpl';
import {buildApi} from '../utils/api';

/**
 * 日志展示组件
 */
export interface LogSchema extends BaseSchema {
  /**
   * 指定为 link 链接展示控件
   */
  type: 'log';

  /**
   * 自定义 CSS 类名
   */
  className?: string;

  /**
   * 获取日志的地址
   */
  source: string;

  /**
   * 控件高度
   */
  height?: number;

  /**
   * 是否自动滚动到最底部
   */
  autoScroll?: boolean;

  /**
   * 返回内容字符编码
   */
  encoding?: string;
}

export interface LogProps
  extends RendererProps,
    Omit<LogSchema, 'type' | 'className'> {}

export interface LogState {
  lastLine: string;
  logs: string[];
}

export class Log extends React.Component<LogProps, LogState> {
  static defaultProps = {
    height: 500,
    autoScroll: true,
    placeholder: 'loading',
    encoding: 'utf-8'
  };

  isDone: boolean = false;

  autoScroll: boolean = false;

  logRef: React.RefObject<HTMLDivElement>;

  state: LogState = {
    lastLine: '',
    logs: []
  };

  constructor(props: LogProps) {
    super(props);
    this.logRef = React.createRef();
    this.autoScroll = props.autoScroll || false;
    this.pauseOrResumeScrolling = this.pauseOrResumeScrolling.bind(this);
  }

  componentWillUnmount() {
    if (this.logRef && this.logRef.current) {
      this.logRef.current.removeEventListener(
        'scroll',
        this.pauseOrResumeScrolling
      );
    }
  }

  componentDidMount() {
    if (this.autoScroll && this.logRef && this.logRef.current) {
      this.logRef.current.addEventListener(
        'scroll',
        this.pauseOrResumeScrolling
      );
    }
    if (this.props.source) {
      this.loadLogs();
    }
  }

  componentDidUpdate() {
    if (this.autoScroll && this.logRef && this.logRef.current) {
      this.logRef.current.scrollTop = this.logRef.current.scrollHeight;
    }
  }

  // 如果向上滚动就停止自动滚动，除非滚到底部
  pauseOrResumeScrolling() {
    if (this.logRef && this.logRef.current) {
      const {scrollHeight, scrollTop, offsetHeight} = this.logRef.current;
      this.autoScroll = scrollHeight - (scrollTop + offsetHeight) < 50;
    }
  }

  async loadLogs() {
    const {source, data, env, translate: __, encoding} = this.props;
    // 因为这里返回结果是流式的，和普通 api 请求不一样，如果直接用 fetcher 经过 responseAdaptor 可能会导致出错，所以就直接 fetch 了
    const api = buildApi(source, data);
    const res = await fetch(api.url);
    if (res.status === 200) {
      const body = res.body;
      if (!body) {
        return;
      }
      const reader = body.getReader();
      let lastline = '';
      let logs: string[] = [];
      for (;;) {
        let {done, value} = await reader.read();
        if (value) {
          let text = new TextDecoder(encoding).decode(value, {stream: true});
          // 不考虑只有 \r 换行符的情况，几乎没人用
          const lines = text.split('\n');
          // 如果没有换行符就只更新最后一行
          if (lines.length === 1) {
            lastline += lines[0];
            this.setState({
              lastLine: lastline
            });
          } else {
            // 将之前的数据补上
            lines[0] = lastline + lines[0];
            // 最后一个要么是空，要么是下一行的数据
            lastline = lines.pop() || '';
            logs = logs.concat(lines);
            this.setState({
              logs: logs,
              lastLine: lastline
            });
          }
        }

        if (done) {
          this.isDone = true;
          return;
        }
      }
    } else {
      env.notify('error', __('fetchFailed'));
    }
  }

  render() {
    const {
      source,
      className,
      classnames: cx,
      placeholder,
      height,
      translate: __
    } = this.props;

    let loading = __(placeholder);

    if (!source) {
      loading = __('Log.mustHaveSource');
    }

    const lines = this.state.logs.map((line, index) => {
      return (
        <div className={cx('Log-line')} key={index}>
          <Ansi useClasses>{line}</Ansi>
        </div>
      );
    });

    return (
      <div
        ref={this.logRef}
        className={cx('Log', className)}
        style={{height: height}}
      >
        {lines.length ? lines : loading}
        <div className={cx('Log-line')} key="last">
          <code>{this.state.lastLine}</code>
        </div>
      </div>
    );
  }
}

@Renderer({
  type: 'log'
})
export class LogRenderer extends Log {}
