<?php declare(strict_types = 1);

namespace SlevomatCodingStandard\Sniffs\TypeHints;

use PHP_CodeSniffer\Files\File;
use PHP_CodeSniffer\Sniffs\Sniff;
use PHPStan\PhpDocParser\Ast\Type\ArrayTypeNode;
use PHPStan\PhpDocParser\Ast\Type\GenericTypeNode;
use PHPStan\PhpDocParser\Ast\Type\IdentifierTypeNode;
use PHPStan\PhpDocParser\Ast\Type\TypeNode;
use PHPStan\PhpDocParser\Ast\Type\UnionTypeNode;
use SlevomatCodingStandard\Helpers\Annotation\Annotation;
use SlevomatCodingStandard\Helpers\Annotation\GenericAnnotation;
use SlevomatCodingStandard\Helpers\Annotation\ParameterAnnotation;
use SlevomatCodingStandard\Helpers\Annotation\ReturnAnnotation;
use SlevomatCodingStandard\Helpers\AnnotationHelper;
use SlevomatCodingStandard\Helpers\AnnotationTypeHelper;
use SlevomatCodingStandard\Helpers\FunctionHelper;
use SlevomatCodingStandard\Helpers\NamespaceHelper;
use SlevomatCodingStandard\Helpers\SniffSettingsHelper;
use SlevomatCodingStandard\Helpers\TokenHelper;
use SlevomatCodingStandard\Helpers\TypeHintHelper;
use function array_flip;
use function array_key_exists;
use function array_map;
use function count;
use function in_array;
use function sprintf;
use const T_DOC_COMMENT_OPEN_TAG;
use const T_FUNCTION;

class DisallowArrayTypeHintSyntaxSniff implements Sniff
{

	public const CODE_DISALLOWED_ARRAY_TYPE_HINT_SYNTAX = 'DisallowedArrayTypeHintSyntax';

	/** @var string[] */
	public $traversableTypeHints = [];

	/** @var array<string, int>|null */
	private $normalizedTraversableTypeHints;

	/**
	 * @return array<int, (int|string)>
	 */
	public function register(): array
	{
		return [
			T_DOC_COMMENT_OPEN_TAG,
		];
	}

	/**
	 * @phpcsSuppress SlevomatCodingStandard.TypeHints.ParameterTypeHint.MissingNativeTypeHint
	 * @param File $phpcsFile
	 * @param int $docCommentOpenPointer
	 */
	public function process(File $phpcsFile, $docCommentOpenPointer): void
	{
		$annotations = AnnotationHelper::getAnnotations($phpcsFile, $docCommentOpenPointer);

		foreach ($annotations as $annotationByName) {
			foreach ($annotationByName as $annotation) {
				if ($annotation instanceof GenericAnnotation) {
					continue;
				}

				if ($annotation->isInvalid()) {
					continue;
				}

				foreach (AnnotationHelper::getAnnotationTypes($annotation) as $annotationType) {
					$unionTypeNodes = AnnotationTypeHelper::getUnionTypeNodes($annotationType);
					foreach ($this->getArrayTypeNodes($annotationType) as $arrayTypeNode) {
						$fix = $phpcsFile->addFixableError(
							sprintf(
								'Usage of array type hint syntax in "%s" is disallowed, use generic type hint syntax instead.',
								AnnotationTypeHelper::export($arrayTypeNode)
							),
							$annotation->getStartPointer(),
							self::CODE_DISALLOWED_ARRAY_TYPE_HINT_SYNTAX
						);

						if (!$fix) {
							continue;
						}

						$unionTypeNode = $this->findUnionTypeThatContainsArrayType($arrayTypeNode, $unionTypeNodes);

						if ($unionTypeNode !== null) {
							$genericIdentifier = $this->findGenericIdentifier($phpcsFile, $unionTypeNode, $annotation);
							if ($genericIdentifier !== null) {
								$genericTypeNode = new GenericTypeNode(
									new IdentifierTypeNode($genericIdentifier),
									[$this->fixArrayNode($arrayTypeNode->type)]
								);
								$fixedAnnotationContent = AnnotationHelper::fixAnnotationType(
									$phpcsFile,
									$annotation,
									$unionTypeNode,
									$genericTypeNode
								);
							} else {
								$genericTypeNode = new GenericTypeNode(
									new IdentifierTypeNode('array'),
									[$this->fixArrayNode($arrayTypeNode->type)]
								);
								$fixedAnnotationContent = AnnotationHelper::fixAnnotationType(
									$phpcsFile,
									$annotation,
									$arrayTypeNode,
									$genericTypeNode
								);
							}
						} else {
							$genericIdentifier = $this->findGenericIdentifier($phpcsFile, $arrayTypeNode, $annotation) ?? 'array';

							$genericTypeNode = new GenericTypeNode(
								new IdentifierTypeNode($genericIdentifier),
								[$this->fixArrayNode($arrayTypeNode->type)]
							);
							$fixedAnnotationContent = AnnotationHelper::fixAnnotationType(
								$phpcsFile,
								$annotation,
								$arrayTypeNode,
								$genericTypeNode
							);
						}

						$phpcsFile->fixer->beginChangeset();
						$phpcsFile->fixer->replaceToken($annotation->getStartPointer(), $fixedAnnotationContent);
						for ($i = $annotation->getStartPointer() + 1; $i <= $annotation->getEndPointer(); $i++) {
							$phpcsFile->fixer->replaceToken($i, '');
						}
						$phpcsFile->fixer->endChangeset();
					}
				}
			}
		}
	}

	/**
	 * @param TypeNode $typeNode
	 * @return ArrayTypeNode[]
	 */
	public function getArrayTypeNodes(TypeNode $typeNode): array
	{
		$arrayTypeNodes = AnnotationTypeHelper::getArrayTypeNodes($typeNode);

		$arrayTypeNodesToIgnore = [];
		foreach ($arrayTypeNodes as $arrayTypeNode) {
			if (!($arrayTypeNode->type instanceof ArrayTypeNode)) {
				continue;
			}

			$arrayTypeNodesToIgnore[] = $arrayTypeNode->type;
		}

		foreach ($arrayTypeNodes as $no => $arrayTypeNode) {
			if (!in_array($arrayTypeNode, $arrayTypeNodesToIgnore, true)) {
				continue;
			}

			unset($arrayTypeNodes[$no]);
		}

		return $arrayTypeNodes;
	}

	private function fixArrayNode(TypeNode $node): TypeNode
	{
		if (!$node instanceof ArrayTypeNode) {
			return $node;
		}

		return new GenericTypeNode(new IdentifierTypeNode('array'), [$this->fixArrayNode($node->type)]);
	}

	/**
	 * @param ArrayTypeNode $arrayTypeNode
	 * @param UnionTypeNode[] $unionTypeNodes
	 * @return UnionTypeNode|null
	 */
	private function findUnionTypeThatContainsArrayType(ArrayTypeNode $arrayTypeNode, array $unionTypeNodes): ?UnionTypeNode
	{
		foreach ($unionTypeNodes as $unionTypeNode) {
			if (in_array($arrayTypeNode, $unionTypeNode->types, true)) {
				return $unionTypeNode;
			}
		}

		return null;
	}

	private function findGenericIdentifier(File $phpcsFile, TypeNode $typeNode, Annotation $annotation): ?string
	{
		if (!$typeNode instanceof UnionTypeNode) {
			if (!$annotation instanceof ParameterAnnotation && !$annotation instanceof ReturnAnnotation) {
				return null;
			}

			$functionPointer = TokenHelper::findNext($phpcsFile, TokenHelper::$functionTokenCodes, $annotation->getStartPointer() + 1);

			if ($functionPointer === null || $phpcsFile->getTokens()[$functionPointer]['code'] !== T_FUNCTION) {
				return null;
			}

			if ($annotation instanceof ParameterAnnotation) {
				$parameterTypeHints = FunctionHelper::getParametersTypeHints($phpcsFile, $functionPointer);
				return array_key_exists(
					$annotation->getParameterName(),
					$parameterTypeHints
				) && $parameterTypeHints[$annotation->getParameterName()] !== null
					? $parameterTypeHints[$annotation->getParameterName()]->getTypeHint()
					: null;
			}

			$returnType = FunctionHelper::findReturnTypeHint($phpcsFile, $functionPointer);
			return $returnType !== null ? $returnType->getTypeHint() : null;
		}

		if (count($typeNode->types) !== 2) {
			return null;
		}

		if (
			$typeNode->types[0] instanceof ArrayTypeNode
			&& $typeNode->types[1] instanceof IdentifierTypeNode
			&& $this->isTraversableType(
				TypeHintHelper::getFullyQualifiedTypeHint($phpcsFile, $annotation->getStartPointer(), $typeNode->types[1]->name)
			)
		) {
			return $typeNode->types[1]->name;
		}

		if (
			$typeNode->types[1] instanceof ArrayTypeNode
			&& $typeNode->types[0] instanceof IdentifierTypeNode
			&& $this->isTraversableType(
				TypeHintHelper::getFullyQualifiedTypeHint($phpcsFile, $annotation->getStartPointer(), $typeNode->types[0]->name)
			)
		) {
			return $typeNode->types[0]->name;
		}

		return null;
	}

	private function isTraversableType(string $type): bool
	{
		return TypeHintHelper::isSimpleIterableTypeHint($type) || array_key_exists($type, $this->getNormalizedTraversableTypeHints());
	}

	/**
	 * @return array<string, int>
	 */
	private function getNormalizedTraversableTypeHints(): array
	{
		if ($this->normalizedTraversableTypeHints === null) {
			$this->normalizedTraversableTypeHints = array_flip(array_map(static function (string $typeHint): string {
				return NamespaceHelper::isFullyQualifiedName($typeHint) ? $typeHint : sprintf(
					'%s%s',
					NamespaceHelper::NAMESPACE_SEPARATOR,
					$typeHint
				);
			}, SniffSettingsHelper::normalizeArray($this->traversableTypeHints)));
		}
		return $this->normalizedTraversableTypeHints;
	}

}