export function countChars(text: string, pattern: RegExp) {
	return text.length - text.replaceAll(pattern, '').length;
}

export function createHex(length: number) {
	return Array(length).fill(null).map(() => Math.round(Math.random() * 0xF).toString(16)).join('');
}

/**
 * String of all letters
 *
 */
const LETTER_LIST = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';

/**
 * String of all numbers
 *
 */
const NUMBER_LIST = '0123456789';

/**
 * String of all symbols
 */
const SYMBOL_LIST = '~`!@#$%^&*()_-+={[}]|\\:;"\'<,>.?/';

/**
 * String of all letters, numbers & symbols
 */
const CHAR_LIST = LETTER_LIST + NUMBER_LIST + SYMBOL_LIST;

export function formatPhoneNumber(number: string) {
	const parts = /(\+?1)?.*?(\d{3}).*?(\d{3}).*?(\d{4})/g.exec(number);
	if(!parts) throw new Error(`Number cannot be parsed: ${number}`);
	return `${parts[1] ?? ''} (${parts[2]}) ${parts[3]}-${parts[4]}`.trim();
}

/**
 * Insert a string into another string at a given position
 *
 * @example
 * ```
 * console.log(insertAt('Hello world!', ' glorious', 5);
 * // Output: Hello glorious world!
 * ```
 *
 * @param {string} target - Parent string you want to modify
 * @param {string} str - Value that will be injected to parent
 * @param {number} index - Position to inject string at
 * @returns {string} - New string
 */
export function insertAt(target: string, str: string, index: number): String {
	return `${target.slice(0, index)}${str}${target.slice(index + 1)}`;
}

/**
 * Generate a string of random characters.
 *
 * @example
 * ```ts
 * const random = randomString();
 * const randomByte = randomString(8, "01")
 * ```
 *
 * @param {number} length - length of generated string
 * @param {string} pool - character pool to generate string from
 * @return {string} generated string
 */
export function randomString(length: number, pool: string = CHAR_LIST): string {
	return Array(length).fill(null).map(() => {
		const n = ~~(Math.random() * pool.length);
		return pool[n];
	}).join('');
}

/**
 * Generate a random string with fine control over letters, numbers & symbols
 *
 * @example
 * ```ts
 * const randomLetter = randomString(1, true);
 * const randomChar = randomString(1, true, true, true);
 * ```
 *
 * @param {number} length - length of generated string
 * @param {boolean} letters - Add letters to pool
 * @param {boolean} numbers - Add numbers to pool
 * @param {boolean} symbols - Add symbols to pool
 * @return {string} generated string
 */
export function randomStringBuilder(length: number, letters = false, numbers = false, symbols = false): string {
	if(!letters && !numbers && !symbols) throw new Error('Must enable at least one: letters, numbers, symbols');
	return Array(length).fill(null).map(() => {
		let c;
		do {
			const type = ~~(Math.random() * 3);
			if(letters && type == 0) {
				c = LETTER_LIST[~~(Math.random() * LETTER_LIST.length)];
			} else if(numbers && type == 1) {
				c = NUMBER_LIST[~~(Math.random() * NUMBER_LIST.length)];
			} else if(symbols && type == 2) {
				c = SYMBOL_LIST[~~(Math.random() * SYMBOL_LIST.length)];
			}
		} while(!c);
		return c;
	}).join('');
}

/**
 * Find all substrings that match a given pattern.
 *
 * Roughly based on `String.prototype.matchAll`.
 *
 * @param {string} value - String to search.
 * @param {RegExp | string} regex - Regular expression to match.
 * @return {RegExpExecArray[]} Found matches.
 */
export function matchAll(value: string, regex: RegExp | string): RegExpExecArray[] {
	if(typeof regex === 'string') {
		regex = new RegExp(regex, 'g');
	}

	// https://stackoverflow.com/a/60290199
	if(!regex.global) {
		throw new TypeError('Regular expression must be global.');
	}

	let ret: RegExpExecArray[] = [];
	let match: RegExpExecArray | null;
	while((match = regex.exec(value)) !== null) {
		ret.push(match);
	}

	return ret;
}

/**
 * Create MD5 hash using native javascript
 * @param d String to hash
 * @returns {string} Hashed string
 */
export function md5(d)  {
	var r = M(V(Y(X(d),8*d.length)));return r.toLowerCase()};function M(d){for(var _,m="0123456789ABCDEF",f="",r=0;r<d.length;r++)_=d.charCodeAt(r),f+=m.charAt(_>>>4&15)+m.charAt(15&_);return f}function X(d){for(var _=Array(d.length>>2),m=0;m<_.length;m++)_[m]=0;for(m=0;m<8*d.length;m+=8)_[m>>5]|=(255&d.charCodeAt(m/8))<<m%32;return _}function V(d){for(var _="",m=0;m<32*d.length;m+=8)_+=String.fromCharCode(d[m>>5]>>>m%32&255);return _}function Y(d,_){d[_>>5]|=128<<_%32,d[14+(_+64>>>9<<4)]=_;for(var m=1732584193,f=-271733879,r=-1732584194,i=271733878,n=0;n<d.length;n+=16){var h=m,t=f,g=r,e=i;f=md5_ii(f=md5_ii(f=md5_ii(f=md5_ii(f=md5_hh(f=md5_hh(f=md5_hh(f=md5_hh(f=md5_gg(f=md5_gg(f=md5_gg(f=md5_gg(f=md5_ff(f=md5_ff(f=md5_ff(f=md5_ff(f,r=md5_ff(r,i=md5_ff(i,m=md5_ff(m,f,r,i,d[n+0],7,-680876936),f,r,d[n+1],12,-389564586),m,f,d[n+2],17,606105819),i,m,d[n+3],22,-1044525330),r=md5_ff(r,i=md5_ff(i,m=md5_ff(m,f,r,i,d[n+4],7,-176418897),f,r,d[n+5],12,1200080426),m,f,d[n+6],17,-1473231341),i,m,d[n+7],22,-45705983),r=md5_ff(r,i=md5_ff(i,m=md5_ff(m,f,r,i,d[n+8],7,1770035416),f,r,d[n+9],12,-1958414417),m,f,d[n+10],17,-42063),i,m,d[n+11],22,-1990404162),r=md5_ff(r,i=md5_ff(i,m=md5_ff(m,f,r,i,d[n+12],7,1804603682),f,r,d[n+13],12,-40341101),m,f,d[n+14],17,-1502002290),i,m,d[n+15],22,1236535329),r=md5_gg(r,i=md5_gg(i,m=md5_gg(m,f,r,i,d[n+1],5,-165796510),f,r,d[n+6],9,-1069501632),m,f,d[n+11],14,643717713),i,m,d[n+0],20,-373897302),r=md5_gg(r,i=md5_gg(i,m=md5_gg(m,f,r,i,d[n+5],5,-701558691),f,r,d[n+10],9,38016083),m,f,d[n+15],14,-660478335),i,m,d[n+4],20,-405537848),r=md5_gg(r,i=md5_gg(i,m=md5_gg(m,f,r,i,d[n+9],5,568446438),f,r,d[n+14],9,-1019803690),m,f,d[n+3],14,-187363961),i,m,d[n+8],20,1163531501),r=md5_gg(r,i=md5_gg(i,m=md5_gg(m,f,r,i,d[n+13],5,-1444681467),f,r,d[n+2],9,-51403784),m,f,d[n+7],14,1735328473),i,m,d[n+12],20,-1926607734),r=md5_hh(r,i=md5_hh(i,m=md5_hh(m,f,r,i,d[n+5],4,-378558),f,r,d[n+8],11,-2022574463),m,f,d[n+11],16,1839030562),i,m,d[n+14],23,-35309556),r=md5_hh(r,i=md5_hh(i,m=md5_hh(m,f,r,i,d[n+1],4,-1530992060),f,r,d[n+4],11,1272893353),m,f,d[n+7],16,-155497632),i,m,d[n+10],23,-1094730640),r=md5_hh(r,i=md5_hh(i,m=md5_hh(m,f,r,i,d[n+13],4,681279174),f,r,d[n+0],11,-358537222),m,f,d[n+3],16,-722521979),i,m,d[n+6],23,76029189),r=md5_hh(r,i=md5_hh(i,m=md5_hh(m,f,r,i,d[n+9],4,-640364487),f,r,d[n+12],11,-421815835),m,f,d[n+15],16,530742520),i,m,d[n+2],23,-995338651),r=md5_ii(r,i=md5_ii(i,m=md5_ii(m,f,r,i,d[n+0],6,-198630844),f,r,d[n+7],10,1126891415),m,f,d[n+14],15,-1416354905),i,m,d[n+5],21,-57434055),r=md5_ii(r,i=md5_ii(i,m=md5_ii(m,f,r,i,d[n+12],6,1700485571),f,r,d[n+3],10,-1894986606),m,f,d[n+10],15,-1051523),i,m,d[n+1],21,-2054922799),r=md5_ii(r,i=md5_ii(i,m=md5_ii(m,f,r,i,d[n+8],6,1873313359),f,r,d[n+15],10,-30611744),m,f,d[n+6],15,-1560198380),i,m,d[n+13],21,1309151649),r=md5_ii(r,i=md5_ii(i,m=md5_ii(m,f,r,i,d[n+4],6,-145523070),f,r,d[n+11],10,-1120210379),m,f,d[n+2],15,718787259),i,m,d[n+9],21,-343485551),m=safe_add(m,h),f=safe_add(f,t),r=safe_add(r,g),i=safe_add(i,e)}return Array(m,f,r,i)}function md5_cmn(d,_,m,f,r,i){return safe_add(bit_rol(safe_add(safe_add(_,d),safe_add(f,i)),r),m)}function md5_ff(d,_,m,f,r,i,n){return md5_cmn(_&m|~_&f,d,_,r,i,n)}function md5_gg(d,_,m,f,r,i,n){return md5_cmn(_&f|m&~f,d,_,r,i,n)}function md5_hh(d,_,m,f,r,i,n){return md5_cmn(_^m^f,d,_,r,i,n)}function md5_ii(d,_,m,f,r,i,n){return md5_cmn(m^(_|~f),d,_,r,i,n)}function safe_add(d,_){var m=(65535&d)+(65535&_);return(d>>16)+(_>>16)+(m>>16)<<16|65535&m}function bit_rol(d,_){return d<<_|d>>>32-_
}

/**
 * Check if email is valid
 *
 * @param {string} email - Target
 * @returns {boolean} - Follows format
 */
export function validateEmail(email: string) {
	return /^[a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]+@[a-zA-Z0-9-]+(?:\.[a-zA-Z0-9-]+)*$/.test(email);
}
