/********************************************************************************
 * Copyright (C) 2018 Red Hat, Inc. and others.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the Eclipse
 * Public License v. 2.0 are satisfied: GNU General Public License, version 2
 * with the GNU Classpath Exception which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 ********************************************************************************/

// based on https://github.com/Microsoft/vscode/blob/bf7ac9201e7a7d01741d4e6e64b5dc9f3197d97b/src/vs/base/common/strings.ts
/*---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *  Licensed under the MIT License. See License.txt in the project root for license information.
 *--------------------------------------------------------------------------------------------*/

import { CharCode } from './char-code';
/**
 * Determines if haystack ends with needle.
 */
export function endsWith(haystack: string, needle: string): boolean {
    const diff = haystack.length - needle.length;
    if (diff > 0) {
        return haystack.indexOf(needle, diff) === diff;
    } else if (diff === 0) {
        return haystack === needle;
    } else {
        return false;
    }
}
export function isLowerAsciiLetter(code: number): boolean {
    return code >= CharCode.a && code <= CharCode.z;
}

export function isUpperAsciiLetter(code: number): boolean {
    return code >= CharCode.A && code <= CharCode.Z;
}

function isAsciiLetter(code: number): boolean {
    return isLowerAsciiLetter(code) || isUpperAsciiLetter(code);
}
export function equalsIgnoreCase(a: string, b: string): boolean {
    const len1 = a ? a.length : 0;
    const len2 = b ? b.length : 0;

    if (len1 !== len2) {
        return false;
    }

    return doEqualsIgnoreCase(a, b);
}

function doEqualsIgnoreCase(a: string, b: string, stopAt = a.length): boolean {
    if (typeof a !== 'string' || typeof b !== 'string') {
        return false;
    }

    for (let i = 0; i < stopAt; i++) {
        const codeA = a.charCodeAt(i);
        const codeB = b.charCodeAt(i);

        if (codeA === codeB) {
            continue;
        }

        // a-z A-Z
        if (isAsciiLetter(codeA) && isAsciiLetter(codeB)) {
            const diff = Math.abs(codeA - codeB);
            if (diff !== 0 && diff !== 32) {
                return false;
            }
        }

        // Any other charcode
        // tslint:disable-next-line:one-line
        else {
            if (String.fromCharCode(codeA).toLowerCase() !== String.fromCharCode(codeB).toLowerCase()) {
                return false;
            }
        }
    }

    return true;
}

/**
 * Escapes regular expression characters in a given string
 */
export function escapeRegExpCharacters(value: string): string {
    return value.replace(/[\-\\\{\}\*\+\?\|\^\$\.\[\]\(\)\#]/g, '\\$&');
}

export function startsWithIgnoreCase(str: string, candidate: string): boolean {
    const candidateLength = candidate.length;
    if (candidate.length > str.length) {
        return false;
    }

    return doEqualsIgnoreCase(str, candidate, candidateLength);
}

export function* split(s: string, splitter: string): IterableIterator<string> {
    let start = 0;
    while (start < s.length) {
        let end = s.indexOf(splitter, start);
        if (end === -1) {
            end = s.length;
        }

        yield s.substring(start, end);
        start = end + splitter.length;
    }
}

export function escapeInvisibleChars(value: string): string {
    return value.replace(/\n/g, '\\n').replace(/\r/g, '\\r');
}

export function unescapeInvisibleChars(value: string): string {
    return value.replace(/\\n/g, '\n').replace(/\\r/g, '\r');
}