<?php

declare (strict_types=1);
namespace Rector\TypeDeclaration\TypeInferer\ReturnTypeInferer;

use PhpParser\Node;
use PhpParser\Node\Expr;
use PhpParser\Node\Expr\Yield_;
use PhpParser\Node\Expr\YieldFrom;
use PhpParser\Node\FunctionLike;
use PhpParser\Node\Identifier;
use PhpParser\Node\Name;
use PhpParser\NodeTraverser;
use PHPStan\Type\MixedType;
use PHPStan\Type\Type;
use Rector\NodeNameResolver\NodeNameResolver;
use Rector\NodeTypeResolver\NodeTypeResolver;
use Rector\NodeTypeResolver\PHPStan\Type\TypeFactory;
use Rector\PhpDocParser\NodeTraverser\SimpleCallableNodeTraverser;
use Rector\StaticTypeMapper\ValueObject\Type\FullyQualifiedGenericObjectType;
use Rector\StaticTypeMapper\ValueObject\Type\FullyQualifiedObjectType;
use Rector\TypeDeclaration\Contract\TypeInferer\ReturnTypeInfererInterface;
final class YieldNodesReturnTypeInfererTypeInferer implements ReturnTypeInfererInterface
{
    /**
     * @readonly
     * @var \Rector\NodeTypeResolver\NodeTypeResolver
     */
    private $nodeTypeResolver;
    /**
     * @readonly
     * @var \Rector\NodeTypeResolver\PHPStan\Type\TypeFactory
     */
    private $typeFactory;
    /**
     * @readonly
     * @var \Rector\PhpDocParser\NodeTraverser\SimpleCallableNodeTraverser
     */
    private $simpleCallableNodeTraverser;
    /**
     * @readonly
     * @var \Rector\NodeNameResolver\NodeNameResolver
     */
    private $nodeNameResolver;
    public function __construct(NodeTypeResolver $nodeTypeResolver, TypeFactory $typeFactory, SimpleCallableNodeTraverser $simpleCallableNodeTraverser, NodeNameResolver $nodeNameResolver)
    {
        $this->nodeTypeResolver = $nodeTypeResolver;
        $this->typeFactory = $typeFactory;
        $this->simpleCallableNodeTraverser = $simpleCallableNodeTraverser;
        $this->nodeNameResolver = $nodeNameResolver;
    }
    public function inferFunctionLike(FunctionLike $functionLike) : Type
    {
        $yieldNodes = $this->findCurrentScopeYieldNodes($functionLike);
        if ($yieldNodes === []) {
            return new MixedType();
        }
        $types = [];
        foreach ($yieldNodes as $yieldNode) {
            $value = $this->resolveYieldValue($yieldNode);
            if (!$value instanceof Expr) {
                continue;
            }
            $resolvedType = $this->nodeTypeResolver->getType($value);
            if ($resolvedType instanceof MixedType) {
                continue;
            }
            $types[] = $resolvedType;
        }
        $returnType = $functionLike->getReturnType();
        $className = 'Generator';
        if ($returnType instanceof Identifier && $returnType->name === 'iterable') {
            $className = 'Iterator';
        }
        if ($returnType instanceof Name && !$this->nodeNameResolver->isName($returnType, 'Generator')) {
            $className = $this->nodeNameResolver->getName($returnType);
        }
        if ($types === []) {
            return new FullyQualifiedObjectType($className);
        }
        $types = $this->typeFactory->createMixedPassedOrUnionType($types);
        return new FullyQualifiedGenericObjectType($className, [$types]);
    }
    public function getPriority() : int
    {
        return 1200;
    }
    /**
     * @return Yield_[]|YieldFrom[]
     */
    private function findCurrentScopeYieldNodes(FunctionLike $functionLike) : array
    {
        $yieldNodes = [];
        $this->simpleCallableNodeTraverser->traverseNodesWithCallable((array) $functionLike->getStmts(), static function (Node $node) use(&$yieldNodes) : ?int {
            // skip nested scope
            if ($node instanceof FunctionLike) {
                return NodeTraverser::DONT_TRAVERSE_CHILDREN;
            }
            if (!$node instanceof Yield_ && !$node instanceof YieldFrom) {
                return null;
            }
            $yieldNodes[] = $node;
            return null;
        });
        return $yieldNodes;
    }
    /**
     * @param \PhpParser\Node\Expr\Yield_|\PhpParser\Node\Expr\YieldFrom $yieldExpr
     */
    private function resolveYieldValue($yieldExpr) : ?Expr
    {
        if ($yieldExpr instanceof Yield_) {
            return $yieldExpr->value;
        }
        return $yieldExpr->expr;
    }
}
