<?php

namespace React\Promise;

/**
* Creates a promise for the supplied `$promiseOrValue`.
*
* If `$promiseOrValue` is a value, it will be the resolution value of the
* returned promise.
*
* If `$promiseOrValue` is a thenable (any object that provides a `then()` method),
* a trusted promise that follows the state of the thenable is returned.
*
* If `$promiseOrValue` is a promise, it will be returned as is.
*
* @param mixed $promiseOrValue
* @return PromiseInterface
*/
function resolve($promiseOrValue = null)
{
if ($promiseOrValue instanceof ExtendedPromiseInterface) {
return $promiseOrValue;
}

// Check is_object() first to avoid method_exists() triggering
// class autoloaders if $promiseOrValue is a string.
if (\is_object($promiseOrValue) && \method_exists($promiseOrValue, 'then')) {
$canceller = null;

if (\method_exists($promiseOrValue, 'cancel')) {
$canceller = [$promiseOrValue, 'cancel'];
}

return new Promise(function ($resolve, $reject, $notify) use ($promiseOrValue) {
$promiseOrValue->then($resolve, $reject, $notify);
}, $canceller);
}

return new FulfilledPromise($promiseOrValue);
}

/**
* Creates a rejected promise for the supplied `$promiseOrValue`.
*
* If `$promiseOrValue` is a value, it will be the rejection value of the
* returned promise.
*
* If `$promiseOrValue` is a promise, its completion value will be the rejected
* value of the returned promise.
*
* This can be useful in situations where you need to reject a promise without
* throwing an exception. For example, it allows you to propagate a rejection with
* the value of another promise.
*
* @param mixed $promiseOrValue
* @return PromiseInterface
*/
function reject($promiseOrValue = null)
{
if ($promiseOrValue instanceof PromiseInterface) {
return resolve($promiseOrValue)->then(function ($value) {
return new RejectedPromise($value);
});
}

return new RejectedPromise($promiseOrValue);
}

/**
* Returns a promise that will resolve only once all the items in
* `$promisesOrValues` have resolved. The resolution value of the returned promise
* will be an array containing the resolution values of each of the items in
* `$promisesOrValues`.
*
* @param array $promisesOrValues
* @return PromiseInterface
*/
function all($promisesOrValues)
{
return map($promisesOrValues, function ($val) {
return $val;
});
}

/**
* Initiates a competitive race that allows one winner. Returns a promise which is
* resolved in the same way the first settled promise resolves.
*
* The returned promise will become **infinitely pending** if `$promisesOrValues`
* contains 0 items.
*
* @param array $promisesOrValues
* @return PromiseInterface
*/
function race($promisesOrValues)
{
$cancellationQueue = new CancellationQueue();
$cancellationQueue->enqueue($promisesOrValues);

return new Promise(function ($resolve, $reject, $notify) use ($promisesOrValues, $cancellationQueue) {
resolve($promisesOrValues)
->done(function ($array) use ($cancellationQueue, $resolve, $reject, $notify) {
if (!is_array($array) || !$array) {
$resolve();
return;
}

foreach ($array as $promiseOrValue) {
$cancellationQueue->enqueue($promiseOrValue);

resolve($promiseOrValue)
->done($resolve, $reject, $notify);
}
}, $reject, $notify);
}, $cancellationQueue);
}

/**
* Returns a promise that will resolve when any one of the items in
* `$promisesOrValues` resolves. The resolution value of the returned promise
* will be the resolution value of the triggering item.
*
* The returned promise will only reject if *all* items in `$promisesOrValues` are
* rejected. The rejection value will be an array of all rejection reasons.
*
* The returned promise will also reject with a `React\Promise\Exception\LengthException`
* if `$promisesOrValues` contains 0 items.
*
* @param array $promisesOrValues
* @return PromiseInterface
*/
function any($promisesOrValues)
{
return some($promisesOrValues, 1)
->then(function ($val) {
return \array_shift($val);
});
}

/**
* Returns a promise that will resolve when `$howMany` of the supplied items in
* `$promisesOrValues` resolve. The resolution value of the returned promise
* will be an array of length `$howMany` containing the resolution values of the
* triggering items.
*
* The returned promise will reject if it becomes impossible for `$howMany` items
* to resolve (that is, when `(count($promisesOrValues) - $howMany) + 1` items
* reject). The rejection value will be an array of
* `(count($promisesOrValues) - $howMany) + 1` rejection reasons.
*
* The returned promise will also reject with a `React\Promise\Exception\LengthException`
* if `$promisesOrValues` contains less items than `$howMany`.
*
* @param array $promisesOrValues
* @param int $howMany
* @return PromiseInterface
*/
function some($promisesOrValues, $howMany)
{
$cancellationQueue = new CancellationQueue();
$cancellationQueue->enqueue($promisesOrValues);

return new Promise(function ($resolve, $reject, $notify) use ($promisesOrValues, $howMany, $cancellationQueue) {
resolve($promisesOrValues)
->done(function ($array) use ($howMany, $cancellationQueue, $resolve, $reject, $notify) {
if (!\is_array($array) || $howMany < 1) {
$resolve([]);
return;
}

$len = \count($array);

if ($len < $howMany) {
throw new Exception\LengthException(
\sprintf(
'Input array must contain at least %d item%s but contains only %s item%s.',
$howMany,
1 === $howMany ? '' : 's',
$len,
1 === $len ? '' : 's'
)
);
}

$toResolve = $howMany;
$toReject = ($len - $toResolve) + 1;
$values = [];
$reasons = [];

foreach ($array as $i => $promiseOrValue) {
$fulfiller = function ($val) use ($i, &$values, &$toResolve, $toReject, $resolve) {
if ($toResolve < 1 || $toReject < 1) {
return;
}

$values[$i] = $val;

if (0 === --$toResolve) {
$resolve($values);
}
};

$rejecter = function ($reason) use ($i, &$reasons, &$toReject, $toResolve, $reject) {
if ($toResolve < 1 || $toReject < 1) {
return;
}

$reasons[$i] = $reason;

if (0 === --$toReject) {
$reject($reasons);
}
};

$cancellationQueue->enqueue($promiseOrValue);

resolve($promiseOrValue)
->done($fulfiller, $rejecter, $notify);
}
}, $reject, $notify);
}, $cancellationQueue);
}

/**
* Traditional map function, similar to `array_map()`, but allows input to contain
* promises and/or values, and `$mapFunc` may return either a value or a promise.
*
* The map function receives each item as argument, where item is a fully resolved
* value of a promise or value in `$promisesOrValues`.
*
* @param array $promisesOrValues
* @param callable $mapFunc
* @return PromiseInterface
*/
function map($promisesOrValues, callable $mapFunc)
{
$cancellationQueue = new CancellationQueue();
$cancellationQueue->enqueue($promisesOrValues);

return new Promise(function ($resolve, $reject, $notify) use ($promisesOrValues, $mapFunc, $cancellationQueue) {
resolve($promisesOrValues)
->done(function ($array) use ($mapFunc, $cancellationQueue, $resolve, $reject, $notify) {
if (!\is_array($array) || !$array) {
$resolve([]);
return;
}

$toResolve = \count($array);
$values = [];

foreach ($array as $i => $promiseOrValue) {
$cancellationQueue->enqueue($promiseOrValue);
$values[$i] = null;

resolve($promiseOrValue)
->then($mapFunc)
->done(
function ($mapped) use ($i, &$values, &$toResolve, $resolve) {
$values[$i] = $mapped;

if (0 === --$toResolve) {
$resolve($values);
}
},
$reject,
$notify
);
}
}, $reject, $notify);
}, $cancellationQueue);
}

/**
* Traditional reduce function, similar to `array_reduce()`, but input may contain
* promises and/or values, and `$reduceFunc` may return either a value or a
* promise, *and* `$initialValue` may be a promise or a value for the starting
* value.
*
* @param array $promisesOrValues
* @param callable $reduceFunc
* @param mixed $initialValue
* @return PromiseInterface
*/
function reduce($promisesOrValues, callable $reduceFunc, $initialValue = null)
{
$cancellationQueue = new CancellationQueue();
$cancellationQueue->enqueue($promisesOrValues);

return new Promise(function ($resolve, $reject, $notify) use ($promisesOrValues, $reduceFunc, $initialValue, $cancellationQueue) {
resolve($promisesOrValues)
->done(function ($array) use ($reduceFunc, $initialValue, $cancellationQueue, $resolve, $reject, $notify) {
if (!\is_array($array)) {
$array = [];
}

$total = \count($array);
$i = 0;

// Wrap the supplied $reduceFunc with one that handles promises and then
// delegates to the supplied.
$wrappedReduceFunc = function ($current, $val) use ($reduceFunc, $cancellationQueue, $total, &$i) {
$cancellationQueue->enqueue($val);

return $current
->then(function ($c) use ($reduceFunc, $total, &$i, $val) {
return resolve($val)
->then(function ($value) use ($reduceFunc, $total, &$i, $c) {
return $reduceFunc($c, $value, $i++, $total);
});
});
};

$cancellationQueue->enqueue($initialValue);

\array_reduce($array, $wrappedReduceFunc, resolve($initialValue))
->done($resolve, $reject, $notify);
}, $reject, $notify);
}, $cancellationQueue);
}

/**
* @internal
*/
function _checkTypehint(callable $callback, $object)
{
if (!\is_object($object)) {
return true;
}

if (\is_array($callback)) {
$callbackReflection = new \ReflectionMethod($callback[0], $callback[1]);
} elseif (\is_object($callback) && !$callback instanceof \Closure) {
$callbackReflection = new \ReflectionMethod($callback, '__invoke');
} else {
$callbackReflection = new \ReflectionFunction($callback);
}

$parameters = $callbackReflection->getParameters();

if (!isset($parameters[0])) {
return true;
}

$expectedException = $parameters[0];

// PHP before v8 used an easy API:
if (\PHP_VERSION_ID < 70100 || \defined('HHVM_VERSION')) {
if (!$expectedException->getClass()) {
return true;
}

return $expectedException->getClass()->isInstance($object);
}

// Extract the type of the argument and handle different possibilities
$type = $expectedException->getType();

$isTypeUnion = true;
$types = [];

switch (true) {
case $type === null:
break;
case $type instanceof \ReflectionNamedType:
$types = [$type];
break;
case $type instanceof \ReflectionIntersectionType:
$isTypeUnion = false;
case $type instanceof \ReflectionUnionType;
$types = $type->getTypes();
break;
default:
throw new \LogicException('Unexpected return value of ReflectionParameter::getType');
}

// If there is no type restriction, it matches
if (empty($types)) {
return true;
}

foreach ($types as $type) {

if ($type instanceof \ReflectionIntersectionType) {
foreach ($type->getTypes() as $typeToMatch) {
if (!($matches = ($typeToMatch->isBuiltin() && \gettype($object) === $typeToMatch->getName())
|| (new \ReflectionClass($typeToMatch->getName()))->isInstance($object))) {
break;
}
}
} else {
$matches = ($type->isBuiltin() && \gettype($object) === $type->getName())
|| (new \ReflectionClass($type->getName()))->isInstance($object);
}

// If we look for a single match (union), we can return early on match
// If we look for a full match (intersection), we can return early on mismatch
if ($matches) {
if ($isTypeUnion) {
return true;
}
} else {
if (!$isTypeUnion) {
return false;
}
}
}

// If we look for a single match (union) and did not return early, we matched no type and are false
// If we look for a full match (intersection) and did not return early, we matched all types and are true
return $isTypeUnion ? false : true;
}