<?php declare(strict_types = 1);

namespace SlevomatCodingStandard\Sniffs\TypeHints;

use PHP_CodeSniffer\Files\File;
use PHP_CodeSniffer\Sniffs\Sniff;
use PHPStan\PhpDocParser\Ast\Type\ArrayShapeNode;
use PHPStan\PhpDocParser\Ast\Type\ArrayTypeNode;
use PHPStan\PhpDocParser\Ast\Type\CallableTypeNode;
use PHPStan\PhpDocParser\Ast\Type\GenericTypeNode;
use PHPStan\PhpDocParser\Ast\Type\IdentifierTypeNode;
use PHPStan\PhpDocParser\Ast\Type\IntersectionTypeNode;
use PHPStan\PhpDocParser\Ast\Type\NullableTypeNode;
use PHPStan\PhpDocParser\Ast\Type\ThisTypeNode;
use PHPStan\PhpDocParser\Ast\Type\UnionTypeNode;
use SlevomatCodingStandard\Helpers\Annotation\VariableAnnotation;
use SlevomatCodingStandard\Helpers\AnnotationHelper;
use SlevomatCodingStandard\Helpers\AnnotationTypeHelper;
use SlevomatCodingStandard\Helpers\DocCommentHelper;
use SlevomatCodingStandard\Helpers\NamespaceHelper;
use SlevomatCodingStandard\Helpers\PropertyHelper;
use SlevomatCodingStandard\Helpers\PropertyTypeHint;
use SlevomatCodingStandard\Helpers\SniffSettingsHelper;
use SlevomatCodingStandard\Helpers\SuppressHelper;
use SlevomatCodingStandard\Helpers\TokenHelper;
use SlevomatCodingStandard\Helpers\TypeHintHelper;
use function array_map;
use function array_unique;
use function array_values;
use function count;
use function in_array;
use function sprintf;
use function strtolower;
use const T_AS;
use const T_COMMA;
use const T_CONST;
use const T_DOC_COMMENT_CLOSE_TAG;
use const T_DOC_COMMENT_STAR;
use const T_FUNCTION;
use const T_PRIVATE;
use const T_PROTECTED;
use const T_PUBLIC;
use const T_SEMICOLON;
use const T_STATIC;
use const T_VAR;
use const T_VARIABLE;

class PropertyTypeHintSniff implements Sniff
{

	public const CODE_MISSING_ANY_TYPE_HINT = 'MissingAnyTypeHint';

	public const CODE_MISSING_NATIVE_TYPE_HINT = 'MissingNativeTypeHint';

	public const CODE_MISSING_TRAVERSABLE_TYPE_HINT_SPECIFICATION = 'MissingTraversableTypeHintSpecification';

	public const CODE_USELESS_ANNOTATION = 'UselessAnnotation';

	private const NAME = 'SlevomatCodingStandard.TypeHints.PropertyTypeHint';

	/** @var bool|null */
	public $enableNativeTypeHint = null;

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

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

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

	/**
	 * @phpcsSuppress SlevomatCodingStandard.TypeHints.ParameterTypeHint.MissingNativeTypeHint
	 * @param File $phpcsFile
	 * @param int $visibilityPointer
	 */
	public function process(File $phpcsFile, $visibilityPointer): void
	{
		$this->enableNativeTypeHint = SniffSettingsHelper::isEnabledByPhpVersion($this->enableNativeTypeHint, 70400);

		$tokens = $phpcsFile->getTokens();

		$asPointer = TokenHelper::findPreviousEffective($phpcsFile, $visibilityPointer - 1);
		if ($tokens[$asPointer]['code'] === T_AS) {
			return;
		}

		$propertyPointer = TokenHelper::findNext($phpcsFile, [T_FUNCTION, T_CONST, T_VARIABLE], $visibilityPointer + 1);

		if ($tokens[$propertyPointer]['code'] !== T_VARIABLE) {
			return;
		}

		if (SuppressHelper::isSniffSuppressed($phpcsFile, $propertyPointer, self::NAME)) {
			return;
		}

		if (DocCommentHelper::hasInheritdocAnnotation($phpcsFile, $propertyPointer)) {
			return;
		}

		/** @var VariableAnnotation[] $varAnnotations */
		$varAnnotations = AnnotationHelper::getAnnotationsByName($phpcsFile, $propertyPointer, '@var');
		$prefixedPropertyAnnotations = $this->getValidPrefixedAnnotations($phpcsFile, $propertyPointer);

		$propertyTypeHint = PropertyHelper::findTypeHint($phpcsFile, $propertyPointer);
		$propertyAnnotation = count($varAnnotations) > 0 ? $varAnnotations[0] : null;

		$this->checkTypeHint($phpcsFile, $propertyPointer, $propertyTypeHint, $propertyAnnotation, $prefixedPropertyAnnotations);
		$this->checkTraversableTypeHintSpecification(
			$phpcsFile,
			$propertyPointer,
			$propertyTypeHint,
			$propertyAnnotation,
			$prefixedPropertyAnnotations
		);
		$this->checkUselessAnnotation($phpcsFile, $propertyPointer, $propertyTypeHint, $propertyAnnotation);
	}

	/**
	 * @param File $phpcsFile
	 * @param int $propertyPointer
	 * @param PropertyTypeHint|null $propertyTypeHint
	 * @param VariableAnnotation|null $propertyAnnotation
	 * @param VariableAnnotation[] $prefixedPropertyAnnotations
	 */
	private function checkTypeHint(
		File $phpcsFile,
		int $propertyPointer,
		?PropertyTypeHint $propertyTypeHint,
		?VariableAnnotation $propertyAnnotation,
		array $prefixedPropertyAnnotations
	): void
	{
		if ($propertyTypeHint !== null) {
			return;
		}

		if (!$this->hasAnnotation($propertyAnnotation)) {
			if (SuppressHelper::isSniffSuppressed($phpcsFile, $propertyPointer, self::getSniffName(self::CODE_MISSING_ANY_TYPE_HINT))) {
				return;
			}

			if (count($prefixedPropertyAnnotations) !== 0) {
				return;
			}

			$phpcsFile->addError(
				sprintf(
					$this->enableNativeTypeHint ? 'Property %s does not have native type hint nor @var annotation for its value.' : 'Property %s does not have @var annotation for its value.',
					PropertyHelper::getFullyQualifiedName($phpcsFile, $propertyPointer)
				),
				$propertyPointer,
				self::CODE_MISSING_ANY_TYPE_HINT
			);

			return;
		}

		if (!$this->enableNativeTypeHint) {
			return;
		}

		if (SuppressHelper::isSniffSuppressed($phpcsFile, $propertyPointer, self::getSniffName(self::CODE_MISSING_NATIVE_TYPE_HINT))) {
			return;
		}

		$typeNode = $propertyAnnotation->getType();
		$originalTypeNode = $typeNode;
		if ($typeNode instanceof NullableTypeNode) {
			$typeNode = $typeNode->type;
		}

		$typeHints = [];
		$nullableTypeHint = false;

		if (AnnotationTypeHelper::containsOneType($typeNode)) {
			/** @var ArrayTypeNode|ArrayShapeNode|IdentifierTypeNode|ThisTypeNode|GenericTypeNode|CallableTypeNode $typeNode */
			$typeNode = $typeNode;
			$typeHints[] = AnnotationTypeHelper::getTypeHintFromOneType($typeNode);

		} elseif ($typeNode instanceof UnionTypeNode || $typeNode instanceof IntersectionTypeNode) {
			$traversableTypeHints = [];
			foreach ($typeNode->types as $innerTypeNode) {
				if (!AnnotationTypeHelper::containsOneType($innerTypeNode)) {
					return;
				}

				/** @var ArrayTypeNode|ArrayShapeNode|IdentifierTypeNode|ThisTypeNode|GenericTypeNode|CallableTypeNode $innerTypeNode */
				$innerTypeNode = $innerTypeNode;

				$typeHint = AnnotationTypeHelper::getTypeHintFromOneType($innerTypeNode);

				if (strtolower($typeHint) === 'null') {
					$nullableTypeHint = true;
					continue;
				}

				$isTraversable = TypeHintHelper::isTraversableType(
					TypeHintHelper::getFullyQualifiedTypeHint($phpcsFile, $propertyPointer, $typeHint),
					$this->getTraversableTypeHints()
				);

				if (!$isTraversable && count($traversableTypeHints) > 0) {
					return;
				}

				if (
					!$innerTypeNode instanceof ArrayTypeNode
					&& !$innerTypeNode instanceof ArrayShapeNode
					&& $isTraversable
				) {
					$traversableTypeHints[] = $typeHint;
				}

				$typeHints[] = $typeHint;
			}

			$traversableTypeHints = array_values(array_unique($traversableTypeHints));
			if (count($traversableTypeHints) > 1) {
				return;
			}
		}

		$typeHints = array_values(array_unique($typeHints));

		if (count($typeHints) === 1) {
			$possibleTypeHint = $typeHints[0];
		} elseif (count($typeHints) === 2) {
			/** @var UnionTypeNode|IntersectionTypeNode $typeNode */
			$typeNode = $typeNode;

			$itemsSpecificationTypeHint = AnnotationTypeHelper::getItemsSpecificationTypeFromType($typeNode);
			if ($itemsSpecificationTypeHint === null) {
				return;
			}

			$possibleTypeHint = AnnotationTypeHelper::getTraversableTypeHintFromType(
				$typeNode,
				$phpcsFile,
				$propertyPointer,
				$this->getTraversableTypeHints()
			);
			if ($possibleTypeHint === null) {
				return;
			}
		} else {
			return;
		}

		if ($possibleTypeHint === 'callable') {
			return;
		}

		if (!TypeHintHelper::isValidTypeHint($possibleTypeHint, true)) {
			return;
		}

		if ($originalTypeNode instanceof NullableTypeNode) {
			$nullableTypeHint = true;
		}

		$fix = $phpcsFile->addFixableError(
			sprintf(
				'Property %s does not have native type hint for its value but it should be possible to add it based on @var annotation "%s".',
				PropertyHelper::getFullyQualifiedName($phpcsFile, $propertyPointer),
				AnnotationTypeHelper::export($typeNode)
			),
			$propertyPointer,
			self::CODE_MISSING_NATIVE_TYPE_HINT
		);
		if (!$fix) {
			return;
		}

		$propertyTypeHint = TypeHintHelper::isSimpleTypeHint($possibleTypeHint)
			? TypeHintHelper::convertLongSimpleTypeHintToShort($possibleTypeHint)
			: $possibleTypeHint;

		$propertyStartPointer = TokenHelper::findPrevious(
			$phpcsFile,
			[T_PRIVATE, T_PROTECTED, T_PUBLIC, T_VAR, T_STATIC],
			$propertyPointer - 1
		);

		$tokens = $phpcsFile->getTokens();

		$pointerAfterProperty = null;
		if ($nullableTypeHint) {
			$pointerAfterProperty = TokenHelper::findNextEffective($phpcsFile, $propertyPointer + 1);
		}

		$phpcsFile->fixer->beginChangeset();
		$phpcsFile->fixer->addContent($propertyStartPointer, sprintf(' %s%s', ($nullableTypeHint ? '?' : ''), $propertyTypeHint));

		if (
			$pointerAfterProperty !== null
			&& in_array($tokens[$pointerAfterProperty]['code'], [T_SEMICOLON, T_COMMA], true)
		) {
			$phpcsFile->fixer->addContent($propertyPointer, ' = null');
		}

		$phpcsFile->fixer->endChangeset();
	}

	/**
	 * @param File $phpcsFile
	 * @param int $propertyPointer
	 * @param PropertyTypeHint|null $propertyTypeHint
	 * @param VariableAnnotation|null $propertyAnnotation
	 * @param VariableAnnotation[] $prefixedPropertyAnnotations
	 */
	private function checkTraversableTypeHintSpecification(
		File $phpcsFile,
		int $propertyPointer,
		?PropertyTypeHint $propertyTypeHint,
		?VariableAnnotation $propertyAnnotation,
		array $prefixedPropertyAnnotations
	): void
	{
		if (SuppressHelper::isSniffSuppressed(
			$phpcsFile,
			$propertyPointer,
			$this->getSniffName(self::CODE_MISSING_TRAVERSABLE_TYPE_HINT_SPECIFICATION)
		)) {
			return;
		}

		$hasTraversableTypeHint = $this->hasTraversableTypeHint($phpcsFile, $propertyPointer, $propertyTypeHint, $propertyAnnotation);
		$hasAnnotation = $this->hasAnnotation($propertyAnnotation);

		if ($hasTraversableTypeHint && !$hasAnnotation) {
			if (count($prefixedPropertyAnnotations) !== 0) {
				return;
			}

			$phpcsFile->addError(
				sprintf(
					'@var annotation of property %s does not specify type hint for its items.',
					PropertyHelper::getFullyQualifiedName($phpcsFile, $propertyPointer)
				),
				$propertyPointer,
				self::CODE_MISSING_TRAVERSABLE_TYPE_HINT_SPECIFICATION
			);

			return;
		}

		if (!$hasAnnotation) {
			return;
		}

		$typeNode = $propertyAnnotation->getType();

		if (
			!$hasTraversableTypeHint
			&& !AnnotationTypeHelper::containsTraversableType($typeNode, $phpcsFile, $propertyPointer, $this->getTraversableTypeHints())
		) {
			return;
		}

		if (AnnotationTypeHelper::containsItemsSpecificationForTraversable(
			$typeNode,
			$phpcsFile,
			$propertyPointer,
			$this->getTraversableTypeHints()
		)) {
			return;
		}

		$phpcsFile->addError(
			sprintf(
				'@var annotation of property %s does not specify type hint for its items.',
				PropertyHelper::getFullyQualifiedName($phpcsFile, $propertyPointer)
			),
			$propertyAnnotation->getStartPointer(),
			self::CODE_MISSING_TRAVERSABLE_TYPE_HINT_SPECIFICATION
		);
	}

	private function checkUselessAnnotation(
		File $phpcsFile,
		int $propertyPointer,
		?PropertyTypeHint $propertyTypeHint,
		?VariableAnnotation $propertyAnnotation
	): void
	{
		if ($propertyAnnotation === null) {
			return;
		}

		if (SuppressHelper::isSniffSuppressed($phpcsFile, $propertyPointer, self::getSniffName(self::CODE_USELESS_ANNOTATION))) {
			return;
		}

		if (!AnnotationHelper::isAnnotationUseless(
			$phpcsFile,
			$propertyPointer,
			$propertyTypeHint,
			$propertyAnnotation,
			$this->getTraversableTypeHints()
		)) {
			return;
		}

		$fix = $phpcsFile->addFixableError(
			sprintf(
				'Property %s has useless @var annotation.',
				PropertyHelper::getFullyQualifiedName($phpcsFile, $propertyPointer)
			),
			$propertyAnnotation->getStartPointer(),
			self::CODE_USELESS_ANNOTATION
		);

		if (!$fix) {
			return;
		}

		if ($this->isDocCommentUseless($phpcsFile, $propertyPointer)) {
			/** @var int $docCommentOpenPointer */
			$docCommentOpenPointer = DocCommentHelper::findDocCommentOpenToken($phpcsFile, $propertyPointer);
			$docCommentClosePointer = $phpcsFile->getTokens()[$docCommentOpenPointer]['comment_closer'];

			$changeStart = $docCommentOpenPointer;
			/** @var int $changeEnd */
			$changeEnd = TokenHelper::findNextEffective($phpcsFile, $docCommentClosePointer + 1) - 1;

			$phpcsFile->fixer->beginChangeset();
			for ($i = $changeStart; $i <= $changeEnd; $i++) {
				$phpcsFile->fixer->replaceToken($i, '');
			}
			$phpcsFile->fixer->endChangeset();

			return;
		}

		/** @var int $changeStart */
		$changeStart = TokenHelper::findPrevious($phpcsFile, T_DOC_COMMENT_STAR, $propertyAnnotation->getStartPointer() - 1);
		/** @var int $changeEnd */
		$changeEnd = TokenHelper::findNext(
			$phpcsFile,
			[T_DOC_COMMENT_CLOSE_TAG, T_DOC_COMMENT_STAR],
			$propertyAnnotation->getEndPointer() + 1
		) - 1;
		$phpcsFile->fixer->beginChangeset();
		for ($i = $changeStart; $i <= $changeEnd; $i++) {
			$phpcsFile->fixer->replaceToken($i, '');
		}
		$phpcsFile->fixer->endChangeset();
	}

	private function isDocCommentUseless(File $phpcsFile, int $propertyPointer): bool
	{
		if (DocCommentHelper::hasDocCommentDescription($phpcsFile, $propertyPointer)) {
			return false;
		}

		$annotations = AnnotationHelper::getAnnotations($phpcsFile, $propertyPointer);
		unset($annotations['@var']);

		return count($annotations) === 0;
	}

	private function getSniffName(string $sniffName): string
	{
		return sprintf('%s.%s', self::NAME, $sniffName);
	}

	/**
	 * @return array<int, string>
	 */
	private function getTraversableTypeHints(): array
	{
		if ($this->normalizedTraversableTypeHints === null) {
			$this->normalizedTraversableTypeHints = 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;
	}

	private function hasAnnotation(?VariableAnnotation $propertyAnnotation): bool
	{
		return $propertyAnnotation !== null && $propertyAnnotation->getContent() !== null && !$propertyAnnotation->isInvalid();
	}

	private function hasTraversableTypeHint(
		File $phpcsFile,
		int $propertyPointer,
		?PropertyTypeHint $propertyTypeHint,
		?VariableAnnotation $propertyAnnotation
	): bool
	{
		if (
			$propertyTypeHint !== null
			&& TypeHintHelper::isTraversableType(
				TypeHintHelper::getFullyQualifiedTypeHint($phpcsFile, $propertyPointer, $propertyTypeHint->getTypeHint()),
				$this->getTraversableTypeHints()
			)
		) {
			return true;
		}

		return
			$this->hasAnnotation($propertyAnnotation)
			&& AnnotationTypeHelper::containsTraversableType(
				$propertyAnnotation->getType(),
				$phpcsFile,
				$propertyPointer,
				$this->getTraversableTypeHints()
			);
	}

	/**
	 * @param File $phpcsFile
	 * @param int $propertyPointer
	 * @return VariableAnnotation[]
	 */
	private function getValidPrefixedAnnotations(File $phpcsFile, int $propertyPointer): array
	{
		$returnAnnotations = [];

		foreach (AnnotationHelper::PREFIXES as $prefix) {
			/** @var VariableAnnotation[] $annotations */
			$annotations = AnnotationHelper::getAnnotationsByName($phpcsFile, $propertyPointer, sprintf('@%s-var', $prefix));
			foreach ($annotations as $annotation) {
				if (!$annotation->isInvalid()) {
					$returnAnnotations[] = $annotation;
					break;
				}
			}
		}

		return $returnAnnotations;
	}

}