// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
// See LICENSE.txt for license information.
import * as reselect from 'reselect';
import shallowEqual from 'shallow-equals';
import {Dictionary} from '@mm-redux/types/utilities';
export function memoizeResult<F extends Function>(func: F): any {
    let lastArgs: IArguments|null = null;
    let lastResult: any = null;

    // we reference arguments instead of spreading them for performance reasons
    return function shallowCompare() {
        if (!shallowEqual(lastArgs, arguments)) { //eslint-disable-line prefer-rest-params
            //eslint-disable-line prefer-rest-params
            // apply arguments instead of spreading for performance.
            const result = Reflect.apply(func, null, arguments); //eslint-disable-line prefer-rest-params
            if (!shallowEqual(lastResult, result)) {
                lastResult = result;
            }
        }

        lastArgs = arguments; //eslint-disable-line prefer-rest-params
        return lastResult;
    };
}

// Use this selector when you want a shallow comparison of the arguments and you want to memoize the result
// try and use this only when your selector returns an array of ids
export const createIdsSelector = reselect.createSelectorCreator(memoizeResult);

// Use this selector when you want a shallow comparison of the arguments and you don't need to memoize the result
export const createShallowSelector = reselect.createSelectorCreator(reselect.defaultMemoize, shallowEqual as any);

// isMinimumServerVersion will return true if currentVersion is equal to higher or than
// the provided minimum version. A non-equal major version will ignore minor and dot
// versions, and a non-equal minor version will ignore dot version.
// currentVersion is a string, e.g '4.6.0'
// minMajorVersion, minMinorVersion, minDotVersion are integers
export const isMinimumServerVersion = (currentVersion: string, minMajorVersion = 0, minMinorVersion = 0, minDotVersion = 0): boolean => {
    if (!currentVersion || typeof currentVersion !== 'string') {
        return false;
    }

    const split = currentVersion.split('.');

    const major = parseInt(split[0], 10);
    const minor = parseInt(split[1] || '0', 10);
    const dot = parseInt(split[2] || '0', 10);

    if (major > minMajorVersion) {
        return true;
    }
    if (major < minMajorVersion) {
        return false;
    }

    // Major version is equal, check minor
    if (minor > minMinorVersion) {
        return true;
    }
    if (minor < minMinorVersion) {
        return false;
    }

    // Minor version is equal, check dot
    if (dot > minDotVersion) {
        return true;
    }
    if (dot < minDotVersion) {
        return false;
    }

    // Dot version is equal
    return true;
};

// Generates a RFC-4122 version 4 compliant globally unique identifier.
export function generateId(): string {
    // implementation taken from http://stackoverflow.com/a/2117523
    let id = 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx';
    id = id.replace(/[xy]/g, (c) => {
        const r = Math.floor(Math.random() * 16);
        let v;

        if (c === 'x') {
            v = r;
        } else {
            // eslint-disable-next-line no-mixed-operators
            v = r & 0x3 | 0x8;
        }

        return v.toString(16);
    });
    return id;
}

export function isEmail(email: string): boolean {
    // writing a regex to match all valid email addresses is really, really hard. (see http://stackoverflow.com/a/201378)
    // this regex ensures:
    // - at least one character that is not a space, comma, or @ symbol
    // - followed by a single @ symbol
    // - followed by at least one character that is not a space, comma, or @ symbol
    // this prevents <Outlook Style> outlook.style@domain.com addresses and multiple comma-separated addresses from being accepted
    return (/^[^ ,@]+@[^ ,@]+$/).test(email);
}

export function buildQueryString(parameters: Dictionary<any>): string {
    const keys = Object.keys(parameters);
    if (keys.length === 0) {
        return '';
    }

    let query = '?';
    for (let i = 0; i < keys.length; i++) {
        const key = keys[i];
        query += key + '=' + encodeURIComponent(parameters[key]);

        if (i < keys.length - 1) {
            query += '&';
        }
    }

    return query;
}
