/*---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *  Licensed under the MIT License. See License.txt in the project root for license information.
 *--------------------------------------------------------------------------------------------*/

import {
  ScopedLineTokens,
  ignoreBracketsInToken,
} from '../../../../../vs/editor/common/modes/supports';
import {
  BracketsUtils,
  RichEditBrackets,
} from '../../../../../vs/editor/common/modes/supports/richEditBrackets';

/**
 * Interface used to support electric characters
 * @internal
 */
export interface IElectricAction {
  // The line will be indented at the same level of the line
  // which contains the matching given bracket type.
  matchOpenBracket: string;
}

export class BracketElectricCharacterSupport {
  private readonly _richEditBrackets: RichEditBrackets | null;

  constructor(richEditBrackets: RichEditBrackets | null) {
    this._richEditBrackets = richEditBrackets;
  }

  public getElectricCharacters(): string[] {
    let result: string[] = [];

    if (this._richEditBrackets) {
      for (const bracket of this._richEditBrackets.brackets) {
        for (const close of bracket.close) {
          const lastChar = close.charAt(close.length - 1);
          result.push(lastChar);
        }
      }
    }

    // Filter duplicate entries
    result = result.filter((item, pos, array) => {
      return array.indexOf(item) === pos;
    });

    return result;
  }

  public onElectricCharacter(
    character: string,
    context: ScopedLineTokens,
    column: number
  ): IElectricAction | null {
    if (
      !this._richEditBrackets ||
      this._richEditBrackets.brackets.length === 0
    ) {
      return null;
    }

    const tokenIndex = context.findTokenIndexAtOffset(column - 1);
    if (ignoreBracketsInToken(context.getStandardTokenType(tokenIndex))) {
      return null;
    }

    const reversedBracketRegex = this._richEditBrackets.reversedRegex;
    const text = context.getLineContent().substring(0, column - 1) + character;

    const r = BracketsUtils.findPrevBracketInRange(
      reversedBracketRegex,
      1,
      text,
      0,
      text.length
    );
    if (!r) {
      return null;
    }

    const bracketText = text
      .substring(r.startColumn - 1, r.endColumn - 1)
      .toLowerCase();

    const isOpen = this._richEditBrackets.textIsOpenBracket[bracketText];
    if (isOpen) {
      return null;
    }

    const textBeforeBracket = context.getActualLineContentBefore(
      r.startColumn - 1
    );
    if (!/^\s*$/.test(textBeforeBracket)) {
      // There is other text on the line before the bracket
      return null;
    }

    return {
      matchOpenBracket: bracketText,
    };
  }
}