<?php
class LazyCollection implements IteratorAggregate
{
    protected $source;

    public function __construct($source = null)
    {
        if ($source instanceof Closure || $source instanceof self) {
            $this->source = $source;
        } elseif (is_null($source)) {
            $this->source = static::empty();
        } else {
            $this->source = $this->getArrayableItems($source);
        }
    }

    public function getIterator(): Traversable
    {
        return $this->makeIterator($this->source);
    }

    protected function makeIterator($source)
    {
        if ($source instanceof Closure) {
            $source = $source();
        }

        if (is_array($source)) {
            return new ArrayIterator($source);
        }

        return $source;
    }

    public static function make($source = null)
    {
        return new static($source instanceof Closure ? $source() : $source);
    }

    public function each(callable $callback)
    {
        foreach ($this->getIterator() as $key => $value) {
            if ($callback($value, $key) === false) {
                break;
            }
        }

        return $this;
    }

    protected function getArrayableItems($items)
    {
        if (is_array($items)) {
            return $items;
        } elseif ($items instanceof Traversable) {
            return iterator_to_array($items);
        } elseif (is_object($items) && method_exists($items, 'toArray')) {
            return $items->toArray();
        }

        return (array) $items;
    }
}