// src/index.ts
var DoneIteratorResult = Object.freeze({ value: void 0, done: true });
function hasMethods(methods, obj) {
  return methods.every((method) => typeof obj[method] === "function");
}
function isIterable(value) {
  return typeof value[Symbol.iterator] === "function";
}
function isIterator(value) {
  return typeof value.next === "function";
}
function isBuffer(value) {
  return ArrayBuffer.isView(value);
}
function isArrayLike(value) {
  return Array.isArray(value) || value instanceof Array;
}
var IteratorEnumerator = class _IteratorEnumerator {
  _iterator;
  _consumed = false;
  _current;
  get current() {
    return this._current;
  }
  constructor(iterator) {
    this._iterator = iterator;
  }
  static from(iterator) {
    return new _IteratorEnumerator(iterator);
  }
  moveNext() {
    if (!this._consumed) {
      const { value, done } = this._iterator.next();
      this._current = value;
      if (done) {
        this._consumed = true;
      }
      return !done;
    } else {
      return false;
    }
  }
  reset() {
  }
  toIterator() {
    return this;
  }
  next(...[_value]) {
    const done = this.moveNext();
    return { value: this.current, done };
  }
  return(value) {
    return this._iterator.return?.(value) ?? DoneIteratorResult;
  }
  throw(e) {
    return this._iterator.throw?.(e) ?? DoneIteratorResult;
  }
};
var CachedIteratorEnumerator = class _CachedIteratorEnumerator {
  _iterator;
  _cache = [];
  _index = -1;
  get current() {
    return this._cache[this._index];
  }
  constructor(iterator) {
    this._iterator = new IteratorEnumerator(iterator);
  }
  static from(iterator) {
    return new _CachedIteratorEnumerator(iterator);
  }
  moveNext() {
    this._index += 1;
    if (this._cache.length > this._index) {
      return true;
    } else if (this._iterator.moveNext()) {
      this._cache.push(this._iterator.current);
      return true;
    } else {
      return false;
    }
  }
  reset() {
    this._index = -1;
  }
  toIterator() {
    return this;
  }
  next(...[_value]) {
    const done = this.moveNext();
    return { value: this.current, done };
  }
  return(value) {
    return this._iterator.return(value);
  }
  throw(e) {
    return this._iterator.throw(e);
  }
};
var IterableEnumerator = class {
  _iterable;
  _factory;
  _enumerator;
  get current() {
    return this._enumerator?.current;
  }
  constructor(iterable, factory = IteratorEnumerator.from) {
    this._iterable = iterable;
    this._factory = factory;
    this._enumerator = this._createEnumerator();
  }
  static fromIterable(iterable, factory) {
    return new this(iterable, factory);
  }
  moveNext() {
    return this._enumerator?.moveNext() ?? false;
  }
  _createIterator() {
    return this._iterable[Symbol.iterator]();
  }
  _createEnumerator() {
    return this._factory(this._createIterator());
  }
  reset() {
    this._enumerator = this._createEnumerator();
  }
  toIterator() {
    return this._createIterator();
  }
  next(...[_value]) {
    const done = !this.moveNext();
    return { value: this.current, done };
  }
  return(value) {
    if (isIterator(this._enumerator)) {
      return this._enumerator?.return?.(value) || DoneIteratorResult;
    } else {
      return DoneIteratorResult;
    }
  }
  throw(e) {
    if (isIterator(this._enumerator)) {
      return this._enumerator?.throw?.(e) || DoneIteratorResult;
    } else {
      return DoneIteratorResult;
    }
  }
};
function toArrayLikeBuffer(buffer) {
  return Object.defineProperty(buffer, "length", {
    get: function() {
      return buffer.byteLength;
    }
  });
}
var ArrayEnumerator = class _ArrayEnumerator {
  _array;
  _index = -1;
  get current() {
    return this._array[this._index];
  }
  constructor(array) {
    this._array = array;
  }
  static from(array) {
    if (ArrayBuffer.isView(array)) {
      return new _ArrayEnumerator(toArrayLikeBuffer(array));
    } else {
      return new _ArrayEnumerator(array);
    }
  }
  [Symbol.iterator]() {
    return this._array[Symbol.iterator]();
  }
  setIndex(index) {
    this._index = index;
  }
  moveNext() {
    this._index += 1;
    return this._index < this._array.length;
  }
  reset() {
    this._index = -1;
  }
  toIterator() {
    return this._array[Symbol.iterator]();
  }
  next(...[_value]) {
    const done = this.moveNext();
    return { value: this.current, done };
  }
  return(_value) {
    return DoneIteratorResult;
  }
  throw(_e) {
    return DoneIteratorResult;
  }
};
var Enumerator = class _Enumerator {
  _enumerator;
  _index = 0;
  get current() {
    return this._enumerator.current;
  }
  constructor(enumerator) {
    this._enumerator = enumerator;
  }
  static fromIterable(iterable) {
    if (isArrayLike(iterable) || ArrayBuffer.isView(iterable)) {
      return ArrayEnumerator.from(iterable);
    } else {
      return new this(new IterableEnumerator(iterable));
    }
  }
  static fromIterator(iterator, cache = true) {
    if (cache) {
      return new CachedIteratorEnumerator(iterator);
    } else {
      return new IteratorEnumerator(iterator);
    }
  }
  static toIterator(enumerator) {
    return new this(enumerator);
  }
  [Symbol.iterator]() {
    return this.toIterator();
  }
  toIterator() {
    return _Enumerator.toIterator(this);
  }
  moveNext() {
    this._index += 1;
    return this._enumerator.moveNext();
  }
  reset() {
    this._enumerator.reset();
  }
  next(...[_value]) {
    const done = this.moveNext();
    return { value: this.current, done };
  }
  return(_value) {
    return DoneIteratorResult;
  }
  throw(_e) {
    return DoneIteratorResult;
  }
};
var HelperEnumerator = class _HelperEnumerator {
  _enumerator;
  _index = 0;
  get current() {
    return this._enumerator.current;
  }
  constructor(enumerator) {
    this._enumerator = enumerator;
  }
  static toIterator(enumerator) {
    return new this(enumerator);
  }
  [Symbol.iterator]() {
    return this.toIterator();
  }
  toIterator() {
    return _HelperEnumerator.toIterator(this);
  }
  moveNext() {
    this._index += 1;
    return this._enumerator.moveNext();
  }
  reset() {
    this._enumerator.reset();
  }
  next(...[_value]) {
    const done = this.moveNext();
    return { value: this.current, done };
  }
  return(_value) {
    return DoneIteratorResult;
  }
  throw(_e) {
    return DoneIteratorResult;
  }
};
var DropEnumerator = class extends HelperEnumerator {
  _limit;
  constructor(enumerator, limit) {
    super(enumerator);
    this._limit = limit;
  }
  moveNext() {
    let next = super.moveNext();
    while (this._limit > 0 && next) {
      next = super.moveNext();
      this._limit -= 1;
    }
    return next;
  }
};
var FilterEnumerator = class extends HelperEnumerator {
  _filter;
  constructor(enumerator, filter) {
    super(enumerator);
    this._filter = filter;
  }
  moveNext() {
    let next = super.moveNext();
    while (next && !this._filter(this.current, this._index)) {
      next = super.moveNext();
    }
    return next;
  }
};
var FlatMapEnumerator = class {
  _enumerator;
  _flatMap;
  _inner;
  _index = -1;
  constructor(enumerator, flatMap) {
    this._enumerator = enumerator;
    this._flatMap = flatMap;
  }
  get current() {
    return this._inner?.current;
  }
  moveNext() {
    if (this._inner && this._inner.moveNext()) {
      return true;
    }
    const next = this._enumerator.moveNext();
    if (!next) {
      return false;
    }
    this._index += 1;
    this._inner = this._flatMap(this._enumerator.current, this._index);
    return this._inner.moveNext();
  }
  reset() {
    this._index = -1;
    this._inner = void 0;
    this._enumerator.reset();
  }
  toIterator() {
    return HelperEnumerator.toIterator(this);
  }
};
var MapEnumerator = class {
  _enumerator;
  _map;
  _current;
  _index = -1;
  get current() {
    return this._current;
  }
  constructor(enumerator, map) {
    this._enumerator = enumerator;
    this._map = map;
  }
  toIterator() {
    return HelperEnumerator.toIterator(this);
  }
  moveNext() {
    this._index += 1;
    const next = this._enumerator.moveNext();
    if (next) {
      this._current = this._map(this._enumerator.current, this._index);
    }
    return next;
  }
  reset() {
    this._index = -1;
    this._enumerator.reset();
  }
};
var TakeEnumerator = class extends HelperEnumerator {
  _limit;
  constructor(enumerator, limit) {
    super(enumerator);
    this._limit = limit;
  }
  moveNext() {
    if (this._limit < 0) {
      return false;
    } else {
      super.moveNext();
      this._limit -= 1;
      return true;
    }
  }
};
var FusedEnumerator = class {
  _enumerators;
  _index = 0;
  get current() {
    return this._cur()?.current;
  }
  constructor(enumerators) {
    this._enumerators = enumerators;
  }
  _cur() {
    return this._enumerators[this._index];
  }
  _done() {
    return this._index >= this._enumerators.length;
  }
  toIterator() {
    return HelperEnumerator.toIterator(this);
  }
  moveNext() {
    while (!this._done() && !this._cur().moveNext()) {
      this._index += 1;
    }
    return this._done();
  }
  reset() {
    const len = this._enumerators.length;
    for (let i = 0; i < len; i++) {
      this._enumerators[i].reset();
    }
    this._index = 0;
  }
};
var Enumerable = class _Enumerable {
  _enumerator;
  constructor(enumerator) {
    this._enumerator = enumerator;
  }
  static from(value) {
    if (this.isEnumerable(value)) {
      return value;
    } else if (this.isEnumerator(value)) {
      return new _Enumerable(value);
    } else if (isIterable(value)) {
      const enumerator = Enumerator.fromIterable(value);
      if (isArrayLike(value)) {
        return new ArrayEnumerble(enumerator);
      } else {
        return new _Enumerable(enumerator);
      }
    } else if (isIterator(value)) {
      return new _Enumerable(
        Enumerator.fromIterator(value)
      );
    } else {
      throw new TypeError("value is not enumerable");
    }
  }
  static isEnumerable(value) {
    return typeof value["enumerator"] === "function";
  }
  static isEnumerator(value) {
    return hasMethods(["moveNext", "reset", "toIterator"], value);
  }
  [Symbol.iterator]() {
    return this._enumerator.toIterator();
  }
  at(index) {
    while (index >= 0 && this._enumerator.moveNext()) {
      index -= 1;
    }
    const value = this._enumerator.current;
    this._enumerator.reset();
    return value;
  }
  atOrDefault(index, defaultValue) {
    const value = this.at(index);
    return value || defaultValue;
  }
  atOrElse(index, defaultValue) {
    const value = this.at(index);
    return value || defaultValue();
  }
  concat(other) {
    return new _Enumerable(
      new FusedEnumerator([this._enumerator, other.enumerator()])
    );
  }
  drop(limit) {
    return new _Enumerable(new DropEnumerator(this._enumerator, limit));
  }
  enumerator() {
    return this._enumerator;
  }
  //entries(): IEnumerator<T> {
  //}
  every(predicate) {
    let index = 0;
    while (this._enumerator.moveNext()) {
      if (!predicate(this._enumerator.current, index)) {
        return false;
      }
      index += 1;
    }
    this._enumerator.reset();
    return true;
  }
  filter(predicate) {
    return new _Enumerable(new FilterEnumerator(this._enumerator, predicate));
  }
  flatMap(fn) {
    return new _Enumerable(new FlatMapEnumerator(this._enumerator, fn));
  }
  map(fn) {
    return new _Enumerable(new MapEnumerator(this._enumerator, fn));
  }
  some(predicate) {
    let index = 0;
    while (this._enumerator.moveNext()) {
      if (predicate(this._enumerator.current, index)) {
        return true;
      }
      index += 1;
    }
    this._enumerator.reset();
    return false;
  }
  take(limit) {
    return new _Enumerable(new TakeEnumerator(this._enumerator, limit));
  }
};
var ArrayEnumerble = class extends Enumerable {
  at(index) {
    if (this._enumerator instanceof ArrayEnumerator) {
      this._enumerator.setIndex(index);
      return this._enumerator.current;
    } else {
      return super.at(index);
    }
  }
};
export {
  ArrayEnumerator,
  ArrayEnumerble,
  CachedIteratorEnumerator,
  DropEnumerator,
  Enumerable,
  Enumerator,
  FilterEnumerator,
  FlatMapEnumerator,
  FusedEnumerator,
  HelperEnumerator,
  IterableEnumerator,
  IteratorEnumerator,
  MapEnumerator,
  TakeEnumerator,
  isArrayLike,
  isBuffer,
  isIterable,
  isIterator
};