// Copyright (c) Microsoft Corporation. All rights reserved.

// Licensed under the MIT License.

'use strict';

import '../common/extensions';

import { IDataScienceSettings } from '../common/types';

import { noop } from '../common/utils/misc';

import { RegExpValues } from './constants';

export class CellMatcher {

private codeMatchRegEx: RegExp;

private markdownMatchRegEx: RegExp;

private codeExecRegEx: RegExp;

private markdownExecRegEx: RegExp;

private defaultCellMarker: string;

private defaultCellMarkerExec: RegExp;

constructor(settings?: IDataScienceSettings) {

this.codeMatchRegEx = this.createRegExp(

settings ? settings.codeRegularExpression : undefined,

RegExpValues.PythonCellMarker

);

this.markdownMatchRegEx = this.createRegExp(

settings ? settings.markdownRegularExpression : undefined,

RegExpValues.PythonMarkdownCellMarker

);

this.codeExecRegEx = new RegExp(`${this.codeMatchRegEx.source}(.*)`);

this.markdownExecRegEx = new RegExp(`${this.markdownMatchRegEx.source}(.*)`);

this.defaultCellMarker = settings?.defaultCellMarker ? settings.defaultCellMarker : '# %%';

this.defaultCellMarkerExec = this.createRegExp(`${this.defaultCellMarker}(.*)`, /# %%(.*)/);

}

public isCell(code: string): boolean {

return this.isCode(code) || this.isMarkdown(code);

}

public isMarkdown(code: string): boolean {

return this.markdownMatchRegEx.test(code);

}

public isCode(code: string): boolean {

return this.codeMatchRegEx.test(code) || code.trim() === this.defaultCellMarker;

}

public getCellType(code: string): string {

return this.isMarkdown(code) ? 'markdown' : 'code';

}

public stripFirstMarker(code: string): string {

const lines = code.splitLines({ trim: false, removeEmptyEntries: false });

// Only strip this off the first line. Otherwise we want the markers in the code.

if (lines.length > 0 && (this.isCode(lines[0]) || this.isMarkdown(lines[0]))) {

return lines.slice(1).join('\n');

}

return code;

}

public exec(code: string): string | undefined {

let result: RegExpExecArray | null = null;

if (this.defaultCellMarkerExec.test(code)) {

this.defaultCellMarkerExec.lastIndex = -1;

result = this.defaultCellMarkerExec.exec(code);

} else if (this.codeMatchRegEx.test(code)) {

this.codeExecRegEx.lastIndex = -1;

result = this.codeExecRegEx.exec(code);

} else if (this.markdownMatchRegEx.test(code)) {

this.markdownExecRegEx.lastIndex = -1;

result = this.markdownExecRegEx.exec(code);

}

if (result) {

return result.length > 1 ? result[result.length - 1].trim() : '';

}

return undefined;

}

private createRegExp(potential: string | undefined, backup: RegExp): RegExp {

try {

if (potential) {

return new RegExp(potential);

}

} catch {

noop();

}

return backup;

}

}