// Copyright 2021 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import '../strings.m.js';
import 'chrome://resources/cr_elements/cr_toolbar/cr_toolbar.js';

import {addWebUIListener} from 'chrome://resources/js/cr.m.js';
import {loadTimeData} from 'chrome://resources/js/load_time_data.m.js';
import {dom, html, PolymerElement,} from 'chrome://resources/polymer/v3_0/polymer/polymer_bundled.min.js';

import {BrowserSwitchInternalsProxy, BrowserSwitchInternalsProxyImpl, Decision, RuleSet, RuleSetList, RulesetSources, TimestampPair,} from './browser_switch_internals_proxy.js';

type ListName = 'sitelist'|'greylist';

const BrowserSwitchInternalsAppElementBase = PolymerElement;

class BrowserSwitchInternalsAppElement extends
    BrowserSwitchInternalsAppElementBase {
  static get is() {
    return 'browser-switch-internals-app';
  }

  static get template() {
    return html`{__html_template__}`;
  }

  static get properties() {
    return {
      isBrowserSwitcherEnabled_: {
        type: Boolean,
        value: true,
      },
      showSearch_: {
        type: Boolean,
        value: false,
      },
      lastFetch_: {
        type: String,
        value: '',
      },
      nextFetch_: {
        type: String,
        value: '',
      },
      urlCheckerInput_: {
        type: String,
        observer: 'checkUrl_',
      },
      urlCheckerOutput_: {
        type: Array,
        value: [],
      },
      browserName_: {
        type: String,
        value: getBrowserName,
      },
      altBrowserName_: {
        type: String,
        value: getAltBrowserName,
      },
      greyListRules_: {
        type: Array,
        value: [],
      },
      siteListRules_: {
        type: Array,
        value: [],
      },
      xmlSiteLists_: {
        type: Array,
        value: [],
      },
    };
  }

  private isBrowserSwitcherEnabled_: boolean;
  private showSearch_: boolean;
  private browserName_: string;
  private altBrowserName_: string;
  private greyListRules_: object[];
  private siteListRules_: object[];
  private xmlSiteLists_: object[];
  private urlCheckerInput_: string;
  private urlCheckerOutput_: string[];
  private lastFetch_: string;
  private nextFetch_: string;

  /** @override */
  ready() {
    super.ready();

    this.updateEverything();

    document.addEventListener('DOMContentLoaded', () => {
      addWebUIListener('data-changed', () => this.updateEverything());
    });
  }

  getRuleBrowserName(rule: string) {
    return rule.startsWith('!') ? getBrowserName() : getAltBrowserName();
  }

  getPolicyFromRuleset(ruleSetName: string) {
    const rulesetToPolicy: Record<string, string> = {
      gpo: 'BrowserSwitcherUrlList',
      ieem: 'BrowserSwitcherUseIeSitelist',
      external_sitelist: 'BrowserSwitcherExternalSitelistUrl',
      external_greylist: 'BrowserSwitcherExternalGreylistUrl',
    };
    return rulesetToPolicy[ruleSetName];
  }
  /**
   * Updates the content of all tables after receiving data from the backend.
   */
  updateTables(rulesets: RuleSetList) {
    const listNameToProperty: Record<string, string> = {
      sitelist: 'siteListRules_',
      greylist: 'greyListRules_',
    };
    this.siteListRules_ = [];
    this.greyListRules_ = [];

    for (const [rulesetName, ruleset] of Object.entries(rulesets)) {
      for (const [listName, rules] of Object.entries(ruleset as RuleSet)) {
        this.push(listNameToProperty[listName], ...rules.map((rule) => ({
                                                               rulesetName,
                                                               rule,
                                                             })));
      }
    }
  }

  /**
   * Takes the json from the url checker and makes it readable.
   */
  urlOutputText(decision: Decision): Array<string> {
    let opensIn = '';
    const altBrowserName = getAltBrowserName();
    const browserName = getBrowserName();

    switch (decision.action) {
      case 'stay':
        opensIn = `Opens in: ${browserName}\n`;
        break;
      case 'go':
        opensIn = `Opens in: ${altBrowserName}\n`;
        break;
    }

    let reason = '';
    if (decision.matching_rule) {
      if (decision.matching_rule.startsWith('!')) {
        reason += `Reason: The inverted rule ${
            JSON.stringify(decision.matching_rule)} was found in `;
      } else {
        reason +=
            `Reason: ${JSON.stringify(decision.matching_rule)} was found in `;
      }
    }
    // if undefined - add nothing to the output

    switch (decision.reason) {
      case 'globally_disabled':
        reason += 'Reason: The BrowserSwitcherEnabled policy is false.\n';
        break;
      case 'protocol':
        reason +=
            'Reason: LBS only supports http://, https://, and file:// URLs.\n';
        break;
      case 'sitelist':
        reason += 'the "Force open in" list.\n';
        break;
      case 'greylist':
        reason += 'the "Ignore" list.\n';
        break;
      case 'default':
        reason += `Reason: LBS stays in ${browserName} by default.\n`;
        break;
    }

    return [opensIn, reason];
  }

  checkUrl_(url: string) {
    if (!url) {
      this.urlCheckerOutput_ = [];
      return;
    }

    if (!url.includes('://')) {
      url = 'http://' + url;
    }

    getProxy()
        .getDecision(url)
        .then((decision) => {
          // URL is valid.
          this.urlCheckerOutput_ = this.urlOutputText(decision);
        })
        .catch((errorMessage) => {
          // URL is invalid.
          console.warn(errorMessage);
          this.urlCheckerOutput_ = [
            'Invalid URL. Make sure it is formatted properly.',
          ];
        });
  }

  refreshXml() {
    getProxy().refreshXml();
  }

  /**
   * Update the paragraphs under the "XML sitelists" section.
   */
  updateTimestamps(timestamps: TimestampPair|null) {
    if (!timestamps) {
      return;
    }
    const {last_fetch, next_fetch} = timestamps;

    this.lastFetch_ = last_fetch !== 0 ? formatTime(last_fetch) : '';
    this.nextFetch_ = next_fetch !== 0 ? formatTime(next_fetch) : '';
  }

  /**
   * Update the table under the "XML sitelists" section.
   */
  updateXmlTable(rulesetSources: RulesetSources) {
    this.xmlSiteLists_ = [];
    this.push(
        'xmlSiteLists_',
        ...Object.entries(rulesetSources)
            .map(([prefName, url]) => ({
                   // Hacky name guessing
                   policyName: 'BrowserSwitcher' +
                       snakeCaseToUpperCamelCase(prefName.split('.')[1]),
                   url: url || '(not configured)',
                 })));
  }

  /**
   * Called by C++ when we need to update everything on the page.
   */
  async updateEverything() {
    this.isBrowserSwitcherEnabled_ =
        await getProxy().isBrowserSwitcherEnabled();
    if (this.isBrowserSwitcherEnabled_) {
      getProxy().getAllRulesets().then(
          (rulesets) => this.updateTables(rulesets));
      getProxy().getTimestamps().then(
          (timestamps) => this.updateTimestamps(timestamps));
      getProxy().getRulesetSources().then(
          (sources) => this.updateXmlTable(sources));
    }
  }
}

customElements.define(
    BrowserSwitchInternalsAppElement.is, BrowserSwitchInternalsAppElement);

/**
 * Converts 'this_word' to 'ThisWord'
 */
function snakeCaseToUpperCamelCase(symbol: string): string {
  if (!symbol) {
    return symbol;
  }
  return symbol.replace(/(?:^|_)([a-z])/g, (_, letter) => {
    return letter.toUpperCase();
  });
}

/**
 * Formats |date| as "HH:MM:SS".
 */
function formatTime(dateNumber: number): string {
  const date = new Date(dateNumber);
  const hh = date.getHours().toString().padStart(2, '0');
  const mm = date.getMinutes().toString().padStart(2, '0');
  const ss = date.getSeconds().toString().padStart(2, '0');
  return `${hh}:${mm}:${ss}`;
}

/**
 * Gets the English name of the alternate browser.
 */
function getAltBrowserName(): string {
  // TODO (crbug.com/1258133): if you change the AlternativeBrowserPath
  // policy, then loadTimeData can contain stale data. It won't update
  // until you refresh (despite the rest of the page auto-updating).
  return loadTimeData.getString('altBrowserName') || 'alternative browser';
}

/**
 * Gets the English name of the browser.
 */
function getBrowserName(): string {
  // TODO (crbug.com/1258133): if you change the AlternativeBrowserPath
  // policy, then loadTimeData can contain stale data. It won't update
  // until you refresh (despite the rest of the page auto-updating).
  return loadTimeData.getString('browserName');
}

function getProxy(): BrowserSwitchInternalsProxy {
  return BrowserSwitchInternalsProxyImpl.getInstance();
}