// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
import * as Common from '../../core/common/common.js';
import * as i18n from '../../core/i18n/i18n.js';
import * as Platform from '../../core/platform/platform.js';
import * as TextUtils from '../../models/text_utils/text_utils.js';
import type * as Workspace from '../../models/workspace/workspace.js';
import * as UI from '../../ui/legacy/legacy.js';
import {html, render, type TemplateResult} from '../../ui/lit/lit.js';

import searchResultsPaneStyles from './searchResultsPane.css.js';
import type {SearchResult} from './SearchScope.js';

const UIStrings = {
  /**
   * @description Accessibility label for number of matches in each file in search results pane
   * @example {2} PH1
   */
  matchesCountS: 'Matches Count {PH1}',
  /**
   * @description Search result label for results in the Search tool
   * @example {2} PH1
   */
  lineS: 'Line {PH1}',
  /**
   * @description Text in Search Results Pane of the Search tab
   * @example {2} PH1
   */
  showDMore: 'Show {PH1} more',
} as const;
const str_ = i18n.i18n.registerUIStrings('panels/search/SearchResultsPane.ts', UIStrings);
const i18nString = i18n.i18n.getLocalizedString.bind(undefined, str_);
const {ifExpanded} = UI.TreeOutline;

interface SearchMatch {
  lineContent: string;
  matchRanges: TextUtils.TextRange.SourceRange[];
  resultLabel: string|number;
}

interface ViewInput {
  results: SearchResult[];
  matches: WeakMap<SearchResult, SearchMatch[]>;
  expandedResults: WeakSet<SearchResult>;
  onSelectMatch: (searchResult: SearchResult, matchIndex: number) => void;
  onExpandSearchResult: (searchResult: SearchResult) => void;
  onShowMoreMatches: (searchResult: SearchResult) => void;
}

export type View = (input: ViewInput, output: unknown, target: HTMLElement) => void;

export const DEFAULT_VIEW: View = (input, _output, target) => {
  const {results, matches, expandedResults, onSelectMatch, onExpandSearchResult, onShowMoreMatches} = input;

  const onExpand =
      (searchResult: SearchResult, {detail: {expanded}}: UI.TreeOutline.TreeViewElement.ExpandEvent): void => {
        if (expanded) {
          expandedResults.add(searchResult);
          onExpandSearchResult(searchResult);
        } else {
          expandedResults.delete(searchResult);
        }
      };

  // clang-format off
  render(html`
    <devtools-tree hide-overflow .template=${html`
      <ul role="tree">
        ${results.map(searchResult => html`
          <li @expand=${(e: UI.TreeOutline.TreeViewElement.ExpandEvent) => onExpand(searchResult, e)}
              role="treeitem"
              class="search-result"
              ?open=${expandedResults.has(searchResult)}>
            <style>${searchResultsPaneStyles}</style>
            ${renderSearchResult(searchResult)}
            <ul role="group">
              ${ifExpanded(renderSearchMatches(searchResult, matches, onSelectMatch, onShowMoreMatches))}
            </ul>
          </li>`)}
      </ul>
    `}></devtools-tree>`,
    target,
  );
  // clang-format on
};

const renderSearchResult = (searchResult: SearchResult): TemplateResult => {
  // clang-format off
  return html`
    <span class="search-result-file-name">${searchResult.label()}
      <span class="search-result-dash">${'\u2014'}</span>
      <span class="search-result-qualifier">${searchResult.description()}</span>
    </span>
    <span class="search-result-matches-count"
        aria-label=${i18nString(UIStrings.matchesCountS, {PH1: searchResult.matchesCount()})}>
        ${searchResult.matchesCount()}
    </span>`;
  // clang-format on
};

const renderSearchMatches =
    (searchResult: SearchResult, matches: WeakMap<SearchResult, SearchMatch[]>,
     onSelectMatch: (searchResult: SearchResult, matchIndex: number) => void,
     onShowMoreMatches: (searchResult: SearchResult) => void): TemplateResult => {
      const visibleMatches = matches.get(searchResult) ?? [];
      const matchesLeftCount = searchResult.matchesCount() - visibleMatches.length;
      // clang-format off
  return html`
      ${visibleMatches.map(({lineContent, matchRanges, resultLabel}, i) => html`
        <li role="treeitem" class="search-match" @click=${() => onSelectMatch(searchResult, i)}
          @keydown=${(event: KeyboardEvent) => {
            if (event.key === 'Enter') {
              onSelectMatch(searchResult, i);
            }
          }}
        >
          <button class="devtools-link text-button link-style search-match-link"
                  jslog="Link; context: search-match; track: click" role="link" tabindex="0"
                  @click=${() => void Common.Revealer.reveal(searchResult.matchRevealable(i))}>
            <span class="search-match-line-number"
                aria-label=${typeof resultLabel === 'number' && !isNaN(resultLabel)
                                ? i18nString(UIStrings.lineS, {PH1: resultLabel}) : resultLabel}>
              ${resultLabel}
            </span>
            <span class="search-match-content" aria-label="${lineContent} line"
                  ${UI.TreeOutline.TreeSearch.highlight(matchRanges, undefined)}>
              ${lineContent}
            </span>
          </button>
        </li>`)}
      ${
      matchesLeftCount > 0 ? html`
        <li role="treeitem" class="show-more-matches" @click=${() => onShowMoreMatches(searchResult)}>
          ${i18nString(UIStrings.showDMore, { PH1: matchesLeftCount })}
        </li>` : ''}`;
      // clang-format on
    };

export class SearchResultsPane extends UI.Widget.VBox {
  #searchConfig: Workspace.SearchConfig.SearchConfig|null = null;
  #searchResults: SearchResult[] = [];
  #resultsUpdated = false;
  #expandedResults = new WeakSet<SearchResult>();
  readonly #searchMatches = new WeakMap<SearchResult, SearchMatch[]>();
  #view: View;

  constructor(element: HTMLElement|undefined, view: View = DEFAULT_VIEW) {
    super(element, {useShadowDom: true});
    this.#view = view;
  }

  get searchResults(): SearchResult[] {
    return this.#searchResults;
  }

  set searchResults(searchResults: SearchResult[]) {
    if (this.#searchResults === searchResults) {
      return;
    }
    if (this.#searchResults.length !== searchResults.length) {
      this.#resultsUpdated = true;
    } else if (this.#searchResults.length === searchResults.length) {
      for (let i = 0; i < this.#searchResults.length; ++i) {
        if (this.#searchResults[i] === searchResults[i]) {
          continue;
        }
        this.#resultsUpdated = true;
        break;
      }
    }
    if (!this.#resultsUpdated) {
      return;
    }
    this.#searchResults = searchResults;
    this.requestUpdate();
  }

  get searchConfig(): Workspace.SearchConfig.SearchConfig|null {
    return this.#searchConfig;
  }

  set searchConfig(searchConfig: Workspace.SearchConfig.SearchConfig|null) {
    this.#searchConfig = searchConfig;
    this.requestUpdate();
  }

  showAllMatches(): void {
    for (const searchResult of this.#searchResults) {
      const startMatchIndex = this.#searchMatches.get(searchResult)?.length ?? 0;
      this.#appendSearchMatches(searchResult, startMatchIndex, searchResult.matchesCount());
      this.#expandedResults.add(searchResult);
    }
    this.requestUpdate();
  }

  collapseAllResults(): void {
    this.#expandedResults = new WeakSet<SearchResult>();
    this.requestUpdate();
  }

  #onExpandSearchResult(searchResult: SearchResult): void {
    const toIndex = Math.min(searchResult.matchesCount(), matchesShownAtOnce);
    this.#appendSearchMatches(searchResult, 0, toIndex);
    this.requestUpdate();
  }

  #appendSearchMatches(searchResult: SearchResult, fromIndex: number, toIndex: number): void {
    if (!this.#searchConfig) {
      return;
    }
    const queries = this.#searchConfig.queries();
    const regexes = [];
    for (let i = 0; i < queries.length; ++i) {
      regexes.push(Platform.StringUtilities.createSearchRegex(
          queries[i], !this.#searchConfig.ignoreCase(), this.#searchConfig.isRegex()));
    }

    const searchMatches = this.#searchMatches.get(searchResult) ?? [];
    this.#searchMatches.set(searchResult, searchMatches);
    if (searchMatches.length >= toIndex) {
      return;
    }

    for (let i = fromIndex; i < toIndex; ++i) {
      let lineContent = searchResult.matchLineContent(i);
      let matchRanges: TextUtils.TextRange.SourceRange[] = [];
      // Searching in scripts and network response bodies produces one result entry per match. We can skip re-doing the
      // search since we have the exact match range.
      // For matches found in headers or the request URL we re-do the search to find all match ranges.
      const column = searchResult.matchColumn(i);
      const matchLength = searchResult.matchLength(i);
      if (column !== undefined && matchLength !== undefined) {
        const {matchRange, lineSegment} =
            lineSegmentForMatch(lineContent, new TextUtils.TextRange.SourceRange(column, matchLength));
        lineContent = lineSegment;
        matchRanges = [matchRange];
      } else {
        lineContent = lineContent.trim();
        for (let j = 0; j < regexes.length; ++j) {
          matchRanges = matchRanges.concat(this.#regexMatchRanges(lineContent, regexes[j]));
        }
        ({lineSegment: lineContent, matchRanges} = lineSegmentForMultipleMatches(lineContent, matchRanges));
      }

      const resultLabel = searchResult.matchLabel(i);
      searchMatches.push({lineContent, matchRanges, resultLabel});
    }
  }

  override performUpdate(): void {
    if (this.#resultsUpdated) {
      let matchesExpandedCount = 0;
      for (const searchResult of this.#searchResults) {
        if (this.#expandedResults.has(searchResult)) {
          matchesExpandedCount += this.#searchMatches.get(searchResult)?.length ?? 0;
        }
      }
      for (const searchResult of this.#searchResults) {
        if (matchesExpandedCount < matchesExpandedByDefault && !this.#expandedResults.has(searchResult)) {
          this.#expandedResults.add(searchResult);
          this.#onExpandSearchResult(searchResult);
          matchesExpandedCount += this.#searchMatches.get(searchResult)?.length ?? 0;
        }
      }
      this.#resultsUpdated = false;
    }
    this.#view(
        {
          results: this.#searchResults,
          matches: this.#searchMatches,
          expandedResults: this.#expandedResults,
          onSelectMatch: (searchResult, matchIndex) => {
            void Common.Revealer.reveal(searchResult.matchRevealable(matchIndex));
          },
          onExpandSearchResult: this.#onExpandSearchResult.bind(this),
          onShowMoreMatches: this.#onShowMoreMatches.bind(this),
        },
        {}, this.contentElement);
  }

  #regexMatchRanges(lineContent: string, regex: RegExp): TextUtils.TextRange.SourceRange[] {
    regex.lastIndex = 0;
    let match;
    const matchRanges = [];
    while ((regex.lastIndex < lineContent.length) && (match = regex.exec(lineContent))) {
      matchRanges.push(new TextUtils.TextRange.SourceRange(match.index, match[0].length));
    }

    return matchRanges;
  }

  #onShowMoreMatches(searchResult: SearchResult): void {
    const startMatchIndex = this.#searchMatches.get(searchResult)?.length ?? 0;
    this.#appendSearchMatches(searchResult, startMatchIndex, searchResult.matchesCount());
    this.requestUpdate();
  }
}

export const matchesExpandedByDefault = 200;
export const matchesShownAtOnce = 20;

const DEFAULT_OPTS = {
  prefixLength: 25,
  maxLength: 1000,
};

/**
 * Takes a whole line and calculates the substring we want to actually display in the UI.
 * Also returns a translated {matchRange} (the parameter is relative to {lineContent} but the
 * caller needs it relative to {lineSegment}).
 *
 * {lineContent} is modified in the following way:
 *
 *   * Whitespace is trimmed from the beginning (unless the match includes it).
 *   * We only leave {options.prefixLength} characters before the match (and add an ellipsis in
 *     case we removed anything)
 *   * Truncate the remainder to {options.maxLength} characters.
 */
export function lineSegmentForMatch(
    lineContent: string, range: TextUtils.TextRange.SourceRange,
    optionsArg: Partial<typeof DEFAULT_OPTS> =
        DEFAULT_OPTS): {lineSegment: string, matchRange: TextUtils.TextRange.SourceRange} {
  const options = {...DEFAULT_OPTS, ...optionsArg};

  // Remove the whitespace at the beginning, but stop where the match starts.
  const attemptedTrimmedLine = lineContent.trimStart();
  const potentiallyRemovedWhitespaceLength = lineContent.length - attemptedTrimmedLine.length;
  const actuallyRemovedWhitespaceLength = Math.min(range.offset, potentiallyRemovedWhitespaceLength);

  // Apply {options.prefixLength} and {options.maxLength}.
  const lineSegmentBegin = Math.max(actuallyRemovedWhitespaceLength, range.offset - options.prefixLength);
  const lineSegmentEnd = Math.min(lineContent.length, lineSegmentBegin + options.maxLength);
  const lineSegmentPrefix = lineSegmentBegin > actuallyRemovedWhitespaceLength ? '…' : '';

  // Build the resulting line segment and match range.
  const lineSegment = lineSegmentPrefix + lineContent.substring(lineSegmentBegin, lineSegmentEnd);
  const rangeOffset = range.offset - lineSegmentBegin + lineSegmentPrefix.length;
  const rangeLength = Math.min(range.length, lineSegment.length - rangeOffset);
  const matchRange = new TextUtils.TextRange.SourceRange(rangeOffset, rangeLength);

  return {lineSegment, matchRange};
}

/**
 * Takes a line and multiple match ranges and trims/cuts the line accordingly.
 * The match ranges are then adjusted to reflect the transformation.
 *
 * Ideally prefer `lineSegmentForMatch`, it can center the line on the match
 * whereas this method risks cutting matches out of the string.
 */
function lineSegmentForMultipleMatches(lineContent: string, ranges: TextUtils.TextRange.SourceRange[]):
    {lineSegment: string, matchRanges: TextUtils.TextRange.SourceRange[]} {
  let trimBy = 0;
  let matchRanges = ranges;
  if (matchRanges.length > 0 && matchRanges[0].offset > 20) {
    trimBy = 15;
  }
  let lineSegment = lineContent.substring(trimBy, 1000 + trimBy);
  if (trimBy) {
    matchRanges =
        matchRanges.map(range => new TextUtils.TextRange.SourceRange(range.offset - trimBy + 1, range.length));
    lineSegment = '…' + lineSegment;
  }
  return {lineSegment, matchRanges};
}