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

const _typeof = {
    number: 'number',
    string: 'string',
    undefined: 'undefined',
    object: 'object',
    function: 'function'
};

/**
 * @returns whether the provided parameter is a JavaScript Array or not.
 */
export function isArray(array: any): array is any[] {
    if (Array.isArray) {
        return Array.isArray(array);
    }

    if (array && typeof (array.length) === _typeof.number && array.constructor === Array) {
        return true;
    }

    return false;
}

/**
 * @returns whether the provided parameter is a JavaScript String or not.
 */
export function isString(str: any): str is string {
    if (typeof (str) === _typeof.string || str instanceof String) {
        return true;
    }

    return false;
}

/**
 * @returns whether the provided parameter is a JavaScript Array and each element in the array is a string.
 */
export function isStringArray(value: any): value is string[] {
    return isArray(value) && (<any[]>value).every(elem => isString(elem));
}

/**
 *
 * @returns whether the provided parameter is of type `object` but **not**
 *	`null`, an `array`, a `regexp`, nor a `date`.
 */
export function isObject(obj: any): obj is any {
    return typeof obj === _typeof.object
        && obj !== null
        && !Array.isArray(obj)
        && !(obj instanceof RegExp)
        && !(obj instanceof Date);
}

/**
 * In **contrast** to just checking `typeof` this will return `false` for `NaN`.
 * @returns whether the provided parameter is a JavaScript Number or not.
 */
export function isNumber(obj: any): obj is number {
    if ((typeof (obj) === _typeof.number || obj instanceof Number) && !isNaN(obj)) {
        return true;
    }

    return false;
}

/**
 * @returns whether the provided parameter is a JavaScript Boolean or not.
 */
export function isBoolean(obj: any): obj is boolean {
    return obj === true || obj === false;
}

/**
 * @returns whether the provided parameter is undefined.
 */
export function isUndefined(obj: any): boolean {
    return typeof (obj) === _typeof.undefined;
}

/**
 * @returns whether the provided parameter is undefined or null.
 */
export function isUndefinedOrNull(obj: any): boolean {
    return isUndefined(obj) || obj === null;
}


const hasOwnProperty = Object.prototype.hasOwnProperty;

/**
 * @returns whether the provided parameter is an empty JavaScript Object or not.
 */
export function isEmptyObject(obj: any): obj is any {
    if (!isObject(obj)) {
        return false;
    }

    for (let key in obj) {
        if (hasOwnProperty.call(obj, key)) {
            return false;
        }
    }

    return true;
}

/**
 * @returns whether the provided parameter is a JavaScript Function or not.
 */
export function isFunction(obj: any): obj is Function {
    return typeof obj === _typeof.function;
}

/**
 * @returns whether the provided parameters is are JavaScript Function or not.
 */
export function areFunctions(...objects: any[]): boolean {
    return objects && objects.length > 0 && objects.every(isFunction);
}

export type TypeConstraint = string | Function;

export function validateConstraints(args: any[], constraints: TypeConstraint[]): void {
    const len = Math.min(args.length, constraints.length);
    for (let i = 0; i < len; i++) {
        validateConstraint(args[i], constraints[i]);
    }
}

export function validateConstraint(arg: any, constraint: TypeConstraint): void {

    if (isString(constraint)) {
        if (typeof arg !== constraint) {
            throw new Error(`argument does not match constraint: typeof ${constraint}`);
        }
    } else if (isFunction(constraint)) {
        if (arg instanceof constraint) {
            return;
        }
        if (arg && arg.constructor === constraint) {
            return;
        }
        if (constraint.length === 1 && constraint.call(undefined, arg) === true) {
            return;
        }
        throw new Error(`argument does not match one of these constraints: arg instanceof constraint, arg.constructor === constraint, nor constraint(arg) === true`);
    }
}
