'use strict';
var $ = require('../internals/export');
var createIteratorConstructor = require('../internals/create-iterator-constructor');
var requireObjectCoercible = require('../internals/require-object-coercible');
var toLength = require('../internals/to-length');
var aFunction = require('../internals/a-function');
var anObject = require('../internals/an-object');
var classof = require('../internals/classof');
var getFlags = require('../internals/regexp-flags');
var hide = require('../internals/hide');
var wellKnownSymbol = require('../internals/well-known-symbol');
var speciesConstructor = require('../internals/species-constructor');
var advanceStringIndex = require('../internals/advance-string-index');
var InternalStateModule = require('../internals/internal-state');
var IS_PURE = require('../internals/is-pure');

var MATCH_ALL = wellKnownSymbol('matchAll');
var REGEXP_STRING = 'RegExp String';
var REGEXP_STRING_ITERATOR = REGEXP_STRING + ' Iterator';
var setInternalState = InternalStateModule.set;
var getInternalState = InternalStateModule.getterFor(REGEXP_STRING_ITERATOR);
var RegExpPrototype = RegExp.prototype;
var regExpBuiltinExec = RegExpPrototype.exec;

var regExpExec = function (R, S) {
  var exec = R.exec;
  var result;
  if (typeof exec == 'function') {
    result = exec.call(R, S);
    if (typeof result != 'object') throw TypeError('Incorrect exec result');
    return result;
  } return regExpBuiltinExec.call(R, S);
};

// eslint-disable-next-line max-len
var $RegExpStringIterator = createIteratorConstructor(function RegExpStringIterator(regexp, string, global, fullUnicode) {
  setInternalState(this, {
    type: REGEXP_STRING_ITERATOR,
    regexp: regexp,
    string: string,
    global: global,
    unicode: fullUnicode,
    done: false
  });
}, REGEXP_STRING, function next() {
  var state = getInternalState(this);
  if (state.done) return { value: undefined, done: true };
  var R = state.regexp;
  var S = state.string;
  var match = regExpExec(R, S);
  if (match === null) return { value: undefined, done: state.done = true };
  if (state.global) {
    if (String(match[0]) == '') R.lastIndex = advanceStringIndex(S, toLength(R.lastIndex), state.unicode);
    return { value: match, done: false };
  }
  state.done = true;
  return { value: match, done: false };
});

var $matchAll = function (string) {
  var R = anObject(this);
  var S = String(string);
  var C, flagsValue, flags, matcher, global, fullUnicode;
  C = speciesConstructor(R, RegExp);
  flagsValue = R.flags;
  if (flagsValue === undefined && R instanceof RegExp && !('flags' in RegExpPrototype)) {
    flagsValue = getFlags.call(R);
  }
  flags = flagsValue === undefined ? '' : String(flagsValue);
  matcher = new C(C === RegExp ? R.source : R, flags);
  global = !!~flags.indexOf('g');
  fullUnicode = !!~flags.indexOf('u');
  matcher.lastIndex = toLength(R.lastIndex);
  return new $RegExpStringIterator(matcher, S, global, fullUnicode);
};

// `String.prototype.matchAll` method
// https://github.com/tc39/proposal-string-matchall
$({ target: 'String', proto: true }, {
  matchAll: function matchAll(regexp) {
    var O = requireObjectCoercible(this);
    var S, matcher, rx;
    if (regexp != null) {
      matcher = regexp[MATCH_ALL];
      if (matcher === undefined && IS_PURE && classof(regexp) == 'RegExp') matcher = $matchAll;
      if (matcher != null) return aFunction(matcher).call(regexp, O);
    }
    S = String(O);
    rx = new RegExp(regexp, 'g');
    return IS_PURE ? $matchAll.call(rx, S) : rx[MATCH_ALL](S);
  }
});

IS_PURE || MATCH_ALL in RegExpPrototype || hide(RegExpPrototype, MATCH_ALL, $matchAll);