import { autorun, computed, observable } from "mobx";

import { IPodLogsQuery, Pod, podsApi } from "../../api/endpoints";
import { autobind, interval } from "../../utils";
import { dockStore, TabId } from "./dock.store";
import { isLogsTab, logTabStore } from "./log-tab.store";

type PodLogLine = string;

const logLinesToLoad = 500;

@autobind()
export class LogStore {
  private refresher = interval(10, () => {
    const id = dockStore.selectedTabId;

    if (!this.podLogs.get(id)) return;
    this.loadMore(id);
  });

  @observable podLogs = observable.map<TabId, PodLogLine[]>();

  constructor() {
    autorun(() => {
      const { selectedTab, isOpen } = dockStore;

      if (isLogsTab(selectedTab) && isOpen) {
        this.refresher.start();
      } else {
        this.refresher.stop();
      }
    }, { delay: 500 });
  }

  /**
   * Function prepares tailLines param for passing to API request
   * Each time it increasing it's number, caused to fetch more logs.
   * Also, it handles loading errors, rewriting whole logs with error
   * messages
   * @param tabId
   */
  load = async (tabId: TabId) => {
    try {
      const logs = await this.loadLogs(tabId, {
        tailLines: this.lines + logLinesToLoad
      });

      this.refresher.start();
      this.podLogs.set(tabId, logs);
    } catch ({error}) {
      const message = [
        `Failed to load logs: ${error.message}`,
        `Reason: ${error.reason} (${error.code})`
      ];

      this.refresher.stop();
      this.podLogs.set(tabId, message);
    }
  };

  /**
   * Function is used to refreser/stream-like requests.
   * It changes 'sinceTime' param each time allowing to fetch logs
   * starting from last line recieved.
   * @param tabId
   */
  loadMore = async (tabId: TabId) => {
    if (!this.podLogs.get(tabId).length) return;
    const oldLogs = this.podLogs.get(tabId);
    const logs = await this.loadLogs(tabId, {
      sinceTime: this.getLastSinceTime(tabId)
    });

    // Add newly received logs to bottom
    this.podLogs.set(tabId, [...oldLogs, ...logs]);
  };

  /**
   * Main logs loading function adds necessary data to payload and makes
   * an API request
   * @param tabId
   * @param params request parameters described in IPodLogsQuery interface
   * @returns {Promise} A fetch request promise
   */
  loadLogs = async (tabId: TabId, params: Partial<IPodLogsQuery>) => {
    const data = logTabStore.getData(tabId);
    const { selectedContainer, previous } = data;
    const pod = new Pod(data.selectedPod);
    const namespace = pod.getNs();
    const name = pod.getName();

    return podsApi.getLogs({ namespace, name }, {
      ...params,
      timestamps: true,  // Always setting timestampt to separate old logs from new ones
      container: selectedContainer.name,
      previous
    }).then(result => {
      const logs = [...result.split("\n")]; // Transform them into array

      logs.pop();  // Remove last empty element

      return logs;
    });
  };

  /**
   * Converts logs into a string array
   * @returns {number} Length of log lines
   */
  @computed
  get lines() {
    const id = dockStore.selectedTabId;
    const logs = this.podLogs.get(id);

    return logs ? logs.length : 0;
  }


  /**
   * Returns logs with timestamps for selected tab
   */
  get logs() {
    const id = dockStore.selectedTabId;

    if (!this.podLogs.has(id)) return [];

    return this.podLogs.get(id);
  }

  /**
   * Removes timestamps from each log line and returns changed logs
   * @returns Logs without timestamps
   */
  get logsWithoutTimestamps() {
    return this.logs.map(item => this.removeTimestamps(item));
  }

  /**
   * It gets timestamps from all logs then returns last one + 1 second
   * (this allows to avoid getting the last stamp in the selection)
   * @param tabId
   */
  getLastSinceTime(tabId: TabId) {
    const logs = this.podLogs.get(tabId);
    const timestamps = this.getTimestamps(logs[logs.length - 1]);
    const stamp = new Date(timestamps ? timestamps[0] : null);

    stamp.setSeconds(stamp.getSeconds() + 1); // avoid duplicates from last second

    return stamp.toISOString();
  }

  getTimestamps(logs: string) {
    return logs.match(/^\d+\S+/gm);
  }

  removeTimestamps(logs: string) {
    return logs.replace(/^\d+.*?\s/gm, "");
  }

  clearLogs(tabId: TabId) {
    this.podLogs.delete(tabId);
  }
}

export const logStore = new LogStore();