<?php

/*
* Copyright 2012 Johannes M. Schmitt <schmittjoh@gmail.com>
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

namespace PhpOption;

use Traversable;

/**
* @template T
*
* @extends Option<T>
*/
final class LazyOption extends Option
{
/** @var callable(mixed...):(Option<T>) */
private $callback;

/** @var array<int, mixed> */
private $arguments;

/** @var Option<T>|null */
private $option;

/**
* @template S
* @param callable(mixed...):(Option<S>) $callback
* @param array<int, mixed> $arguments
*
* @return LazyOption<S>
*/
public static function create($callback, array $arguments = []): self
{
return new self($callback, $arguments);
}

/**
* @param callable(mixed...):(Option<T>) $callback
* @param array<int, mixed> $arguments
*/
public function __construct($callback, array $arguments = [])
{
if (!is_callable($callback)) {
throw new \InvalidArgumentException('Invalid callback given');
}

$this->callback = $callback;
$this->arguments = $arguments;
}

public function isDefined(): bool
{
return $this->option()->isDefined();
}

public function isEmpty(): bool
{
return $this->option()->isEmpty();
}

public function get()
{
return $this->option()->get();
}

public function getOrElse($default)
{
return $this->option()->getOrElse($default);
}

public function getOrCall($callable)
{
return $this->option()->getOrCall($callable);
}

public function getOrThrow(\Exception $ex)
{
return $this->option()->getOrThrow($ex);
}

public function orElse(Option $else)
{
return $this->option()->orElse($else);
}

public function ifDefined($callable)
{
$this->option()->forAll($callable);
}

public function forAll($callable)
{
return $this->option()->forAll($callable);
}

public function map($callable)
{
return $this->option()->map($callable);
}

public function flatMap($callable)
{
return $this->option()->flatMap($callable);
}

public function filter($callable)
{
return $this->option()->filter($callable);
}

public function filterNot($callable)
{
return $this->option()->filterNot($callable);
}

public function select($value)
{
return $this->option()->select($value);
}

public function reject($value)
{
return $this->option()->reject($value);
}

/**
* @return Traversable<T>
*/
public function getIterator(): Traversable
{
return $this->option()->getIterator();
}

public function foldLeft($initialValue, $callable)
{
return $this->option()->foldLeft($initialValue, $callable);
}

public function foldRight($initialValue, $callable)
{
return $this->option()->foldRight($initialValue, $callable);
}

/**
* @return Option<T>
*/
private function option(): Option
{
if (null === $this->option) {
/** @var mixed */
$option = call_user_func_array($this->callback, $this->arguments);
if ($option instanceof Option) {
$this->option = $option;
} else {
throw new \RuntimeException(sprintf('Expected instance of %s', Option::class));
}
}

return $this->option;
}
}