<?php declare(strict_types=1);

/**
 * This file is part of the Nette Framework (https://nette.org)
 * Copyright (c) 2004 David Grudl (https://davidgrudl.com)
 */

namespace Nette\PhpGenerator;

use Nette;
use PhpParser;
use PhpParser\Modifiers;
use PhpParser\Node;
use PhpParser\NodeFinder;
use PhpParser\ParserFactory;
use function addcslashes, array_map, assert, class_exists, end, in_array, is_array, is_string, rtrim, str_contains, str_repeat, str_replace, str_starts_with, strlen, substr, substr_replace, usort;


/**
 * Extracts information from PHP code.
 * @internal
 */
final class Extractor
{
	private string $code;

	/** @var array<Node> */
	private array $statements;
	private PhpParser\PrettyPrinterAbstract $printer;


	public function __construct(string $code)
	{
		if (!class_exists(ParserFactory::class)) {
			throw new Nette\NotSupportedException("PHP-Parser is required to load method bodies, install package 'nikic/php-parser' 4.7 or newer.");
		}

		$this->printer = new PhpParser\PrettyPrinter\Standard;
		$this->parseCode($code);
	}


	private function parseCode(string $code): void
	{
		if (!str_starts_with($code, '<?php')) {
			throw new Nette\InvalidStateException('The input string is not a PHP code.');
		}

		$this->code = Nette\Utils\Strings::unixNewLines($code);
		$parser = (new ParserFactory)->createForNewestSupportedVersion();
		$stmts = $parser->parse($this->code);
		assert($stmts !== null);

		$traverser = new PhpParser\NodeTraverser;
		$traverser->addVisitor(new PhpParser\NodeVisitor\ParentConnectingVisitor);
		$traverser->addVisitor(new PhpParser\NodeVisitor\NameResolver(null, ['preserveOriginalNames' => true]));
		$this->statements = $traverser->traverse($stmts);
	}


	/** @return array<string, string> */
	public function extractMethodBodies(string $className): array
	{
		$nodeFinder = new NodeFinder;
		$classNode = $nodeFinder->findFirst(
			$this->statements,
			fn(Node $node) => $node instanceof Node\Stmt\ClassLike && $node->namespacedName !== null && $node->namespacedName->toString() === $className,
		);
		if (!$classNode) {
			return [];
		}

		$res = [];
		foreach ($nodeFinder->findInstanceOf($classNode, Node\Stmt\ClassMethod::class) as $methodNode) {
			if ($methodNode->stmts) {
				$res[$methodNode->name->toString()] = $this->getReformattedContents($methodNode->stmts, 2);
			}
		}

		return $res;
	}


	/** @return array<string, array<string, array{string, bool}>> */
	public function extractPropertyHookBodies(string $className): array
	{
		if (!class_exists(Node\PropertyHook::class)) {
			return [];
		}

		$nodeFinder = new NodeFinder;
		$classNode = $nodeFinder->findFirst(
			$this->statements,
			fn(Node $node) => $node instanceof Node\Stmt\ClassLike && $node->namespacedName !== null && $node->namespacedName->toString() === $className,
		);
		if (!$classNode) {
			return [];
		}

		$res = [];
		foreach ($nodeFinder->findInstanceOf($classNode, Node\Stmt\Property::class) as $propertyNode) {
			foreach ($propertyNode->props as $propNode) {
				$propName = $propNode->name->toString();
				foreach ($propertyNode->hooks as $hookNode) {
					$body = $hookNode->body;
					if ($body !== null) {
						$contents = $this->getReformattedContents(is_array($body) ? $body : [$body], 3);
						$res[$propName][$hookNode->name->toString()] = [$contents, !is_array($body)];
					}
				}
			}
		}
		return $res;
	}


	public function extractFunctionBody(string $name): string
	{
		$functionNode = (new NodeFinder)->findFirst(
			$this->statements,
			fn(Node $node) => $node instanceof Node\Stmt\Function_ && $node->namespacedName !== null && $node->namespacedName->toString() === $name,
		);
		assert($functionNode instanceof Node\Stmt\Function_);

		return $this->getReformattedContents($functionNode->stmts, 1);
	}


	/** @param  Node[]  $nodes */
	private function getReformattedContents(array $nodes, int $level): string
	{
		if (!$nodes) {
			return '';
		}
		$body = $this->getNodeContents(...$nodes);
		$body = $this->performReplacements($body, $this->prepareReplacements($nodes, $level));
		return Helpers::unindent($body, $level);
	}


	/**
	 * @param  Node[]  $nodes
	 * @return array<array{int, int, string}>
	 */
	private function prepareReplacements(array $nodes, int $level): array
	{
		$start = $this->getNodeStartPos($nodes[0]);
		$replacements = [];
		$indent = "\n" . str_repeat("\t", $level);
		(new NodeFinder)->find($nodes, function (Node $node) use (&$replacements, $start, $level, $indent) {
			if ($node instanceof Node\Name\FullyQualified) {
				if ($node->getAttribute('originalName') instanceof Node\Name) {
					$of = match (true) {
						$node->getAttribute('parent') instanceof Node\Expr\ConstFetch => PhpNamespace::NameConstant,
						$node->getAttribute('parent') instanceof Node\Expr\FuncCall => PhpNamespace::NameFunction,
						default => PhpNamespace::NameNormal,
					};
					$replacements[] = [
						$node->getStartFilePos() - $start,
						$node->getEndFilePos() - $start,
						Helpers::tagName($node->toCodeString(), $of),
					];
				}

			} elseif (
				$node instanceof Node\Scalar\String_
				&& in_array($node->getAttribute('kind'), [Node\Scalar\String_::KIND_SINGLE_QUOTED, Node\Scalar\String_::KIND_DOUBLE_QUOTED], strict: true)
				&& str_contains($node->getAttribute('rawValue'), "\n")
			) { // multi-line strings -> single line
				$replacements[] = [
					$node->getStartFilePos() - $start,
					$node->getEndFilePos() - $start,
					'"' . addcslashes($node->value, "\x00..\x1F\"") . '"',
				];

			} elseif (
				$node instanceof Node\Scalar\String_
				&& in_array($node->getAttribute('kind'), [Node\Scalar\String_::KIND_NOWDOC, Node\Scalar\String_::KIND_HEREDOC], strict: true)
				&& Helpers::unindent($node->getAttribute('docIndentation'), $level) === $node->getAttribute('docIndentation')
			) { // fix indentation of NOWDOW/HEREDOC
				$replacements[] = [
					$node->getStartFilePos() - $start,
					$node->getEndFilePos() - $start,
					str_replace("\n", $indent, $this->getNodeContents($node)),
				];

			} elseif (
				$node instanceof Node\Scalar\Encapsed
				&& $node->getAttribute('kind') === Node\Scalar\String_::KIND_DOUBLE_QUOTED
			) { // multi-line strings -> single line
				foreach ($node->parts as $part) {
					if ($part instanceof Node\Scalar\EncapsedStringPart) {
						$replacements[] = [
							$part->getStartFilePos() - $start,
							$part->getEndFilePos() - $start,
							addcslashes($part->value, "\x00..\x1F\""),
						];
					}
				}
			} elseif (
				$node instanceof Node\Scalar\Encapsed && $node->getAttribute('kind') === Node\Scalar\String_::KIND_HEREDOC
				&& Helpers::unindent($node->getAttribute('docIndentation'), $level) === $node->getAttribute('docIndentation')
			) { // fix indentation of HEREDOC
				$replacements[] = [
					$tmp = $node->getStartFilePos() - $start + strlen($node->getAttribute('docLabel')) + 3, // <<<
					$tmp,
					$indent,
				];
				$replacements[] = [
					$tmp = $node->getEndFilePos() - $start - strlen($node->getAttribute('docLabel')),
					$tmp,
					$indent,
				];
				foreach ($node->parts as $part) {
					if ($part instanceof Node\Scalar\EncapsedStringPart) {
						$replacements[] = [
							$part->getStartFilePos() - $start,
							$part->getEndFilePos() - $start,
							str_replace("\n", $indent, $this->getNodeContents($part)),
						];
					}
				}
			}
		});
		return $replacements;
	}


	/** @param  array<array{int, int, string}>  $replacements */
	private function performReplacements(string $s, array $replacements): string
	{
		usort($replacements, fn($a, $b) => $b[0] <=> $a[0]);

		foreach ($replacements as [$start, $end, $replacement]) {
			$s = substr_replace($s, $replacement, $start, $end - $start + 1);
		}

		return $s;
	}


	public function extractAll(): PhpFile
	{
		$phpFile = new PhpFile;

		if (
			($firstStmt = $this->statements[0] ?? null)
			&& ($firstStmt = $firstStmt instanceof Node\Stmt\Declare_ ? $this->statements[1] ?? null : $firstStmt)
			&& !$firstStmt instanceof Node\Stmt\ClassLike
			&& !$firstStmt instanceof Node\Stmt\Function_
		) {
			$comments = $firstStmt->getComments();
			foreach ($comments as $i => $comment) {
				if ($comment instanceof PhpParser\Comment\Doc) {
					$phpFile->setComment(Helpers::unformatDocComment($comment->getReformattedText()));
					break;
				}
			}
		}

		$namespaces = ['' => $this->statements];
		foreach ($this->statements as $node) {
			if ($node instanceof Node\Stmt\Declare_
				&& $node->declares[0]->key->name === 'strict_types'
				&& $node->declares[0]->value instanceof Node\Scalar\LNumber
			) {
				$phpFile->setStrictTypes((bool) $node->declares[0]->value->value);

			} elseif ($node instanceof Node\Stmt\Namespace_) {
				$namespaces[$node->name?->toString() ?? ''] = $node->stmts;
			}
		}

		foreach ($namespaces as $name => $nodes) {
			foreach ($nodes as $node) {
				match (true) {
					$node instanceof Node\Stmt\Use_ => $this->addUseToNamespace($phpFile->addNamespace($name), $node),
					$node instanceof Node\Stmt\ClassLike => $this->addClassLikeToFile($phpFile, $node),
					$node instanceof Node\Stmt\Function_ => $this->addFunctionToFile($phpFile, $node),
					default => null,
				};
			}
		}

		return $phpFile;
	}


	private function addUseToNamespace(PhpNamespace $namespace, Node\Stmt\Use_ $node): void
	{
		$of = [
			$node::TYPE_NORMAL => PhpNamespace::NameNormal,
			$node::TYPE_FUNCTION => PhpNamespace::NameFunction,
			$node::TYPE_CONSTANT => PhpNamespace::NameConstant,
		][$node->type];
		foreach ($node->uses as $use) {
			$namespace->addUse($use->name->toString(), $use->alias?->toString(), $of);
		}
	}


	private function addClassLikeToFile(PhpFile $phpFile, Node\Stmt\ClassLike $node): ClassLike
	{
		assert($node->namespacedName !== null);
		if ($node instanceof Node\Stmt\Class_) {
			$class = $phpFile->addClass($node->namespacedName->toString());
			$class->setFinal($node->isFinal());
			$class->setAbstract($node->isAbstract());
			$class->setReadOnly($node->isReadonly());
			if ($node->extends) {
				$class->setExtends($node->extends->toString());
			}
			foreach ($node->implements as $item) {
				$class->addImplement($item->toString());
			}
		} elseif ($node instanceof Node\Stmt\Interface_) {
			$class = $phpFile->addInterface($node->namespacedName->toString());
			foreach ($node->extends as $item) {
				$class->addExtend($item->toString());
			}
		} elseif ($node instanceof Node\Stmt\Trait_) {
			$class = $phpFile->addTrait($node->namespacedName->toString());

		} elseif ($node instanceof Node\Stmt\Enum_) {
			$class = $phpFile->addEnum($node->namespacedName->toString());
			$class->setType($node->scalarType?->toString());
			foreach ($node->implements as $item) {
				$class->addImplement($item->toString());
			}
		} else {
			throw new Nette\ShouldNotHappenException;
		}

		$this->addCommentAndAttributes($class, $node);
		$this->addClassMembers($class, $node);
		return $class;
	}


	private function addClassMembers(ClassLike $class, Node\Stmt\ClassLike $node): void
	{
		foreach ($node->stmts as $stmt) {
			match (true) {
				$stmt instanceof Node\Stmt\TraitUse => $this->addTraitToClass($class, $stmt),
				$stmt instanceof Node\Stmt\Property => $this->addPropertyToClass($class, $stmt),
				$stmt instanceof Node\Stmt\ClassMethod => $this->addMethodToClass($class, $stmt),
				$stmt instanceof Node\Stmt\ClassConst => $this->addConstantToClass($class, $stmt),
				$stmt instanceof Node\Stmt\EnumCase => $this->addEnumCaseToClass($class, $stmt),
				default => null,
			};
		}
	}


	private function addTraitToClass(ClassLike $class, Node\Stmt\TraitUse $node): void
	{
		foreach ($node->traits as $item) {
			$trait = $class->addTrait($item->toString());
		}
		assert($trait instanceof TraitUse);

		foreach ($node->adaptations as $item) {
			$trait->addResolution(rtrim($this->getReformattedContents([$item], 0), ';'));
		}

		$this->addCommentAndAttributes($trait, $node);
	}


	private function addPropertyToClass(ClassLike $class, Node\Stmt\Property $node): void
	{
		foreach ($node->props as $item) {
			$prop = $class->addProperty($item->name->toString());
			$prop->setStatic($node->isStatic());
			$prop->setVisibility($this->toVisibility($node->flags), $this->toSetterVisibility($node->flags));
			$prop->setType($node->type ? $this->toPhp($node->type) : null);
			if ($item->default) {
				$prop->setValue($this->toValue($item->default));
			}

			$prop->setReadOnly($node->isReadonly() || ($class instanceof ClassType && $class->isReadOnly()));
			$this->addCommentAndAttributes($prop, $node);

			$prop->setAbstract((bool) ($node->flags & Modifiers::ABSTRACT));
			$prop->setFinal((bool) ($node->flags & Modifiers::FINAL));
			$this->addHooksToProperty($prop, $node);
		}
	}


	private function addHooksToProperty(Property|PromotedParameter $prop, Node\Stmt\Property|Node\Param $node): void
	{
		if (!class_exists(Node\PropertyHook::class)) {
			return;
		}

		foreach ($node->hooks as $hookNode) {
			/** @var 'set'|'get' $hookType */
			$hookType = $hookNode->name->toString();
			$hook = $prop->addHook($hookType);
			$hook->setFinal((bool) ($hookNode->flags & Modifiers::FINAL));
			$this->setupFunction($hook, $hookNode);
			if ($hookNode->body === null) {
				$hook->setAbstract();
			} elseif (!is_array($hookNode->body)) {
				$hook->setBody($this->getReformattedContents([$hookNode->body], 1), short: true);
			}
		}
	}


	private function addMethodToClass(ClassLike $class, Node\Stmt\ClassMethod $node): void
	{
		$method = $class->addMethod($node->name->toString());
		$method->setAbstract($node->isAbstract());
		$method->setFinal($node->isFinal());
		$method->setStatic($node->isStatic());
		$method->setVisibility($this->toVisibility($node->flags));
		$this->setupFunction($method, $node);
		if ($method->getName() === Method::Constructor && $class instanceof ClassType && $class->isReadOnly()) {
			array_map(fn($param) => $param instanceof PromotedParameter ? $param->setReadOnly() : $param, $method->getParameters());
		}
	}


	private function addConstantToClass(ClassLike $class, Node\Stmt\ClassConst $node): void
	{
		foreach ($node->consts as $item) {
			$const = $class->addConstant($item->name->toString(), $this->toValue($item->value));
			$const->setVisibility($this->toVisibility($node->flags));
			$const->setFinal($node->isFinal());
			$this->addCommentAndAttributes($const, $node);
		}
	}


	private function addEnumCaseToClass(EnumType $class, Node\Stmt\EnumCase $node): void
	{
		$value = match (true) {
			$node->expr === null => null,
			$node->expr instanceof Node\Scalar\LNumber, $node->expr instanceof Node\Scalar\String_ => $node->expr->value,
			default => $this->toValue($node->expr),
		};
		$case = $class->addCase($node->name->toString(), $value);
		$this->addCommentAndAttributes($case, $node);
	}


	private function addFunctionToFile(PhpFile $phpFile, Node\Stmt\Function_ $node): void
	{
		assert($node->namespacedName !== null);
		$function = $phpFile->addFunction($node->namespacedName->toString());
		$this->setupFunction($function, $node);
	}


	private function addCommentAndAttributes(
		ClassLike|Constant|Property|GlobalFunction|Method|Parameter|EnumCase|TraitUse|PropertyHook $element,
		Node $node,
	): void
	{
		if ($node->getDocComment()) {
			$comment = $node->getDocComment()->getReformattedText();
			$comment = Helpers::unformatDocComment($comment);
			$element->setComment($comment);
			$node->setDocComment(new PhpParser\Comment\Doc(''));
		}

		foreach ($node->attrGroups ?? [] as $group) {
			foreach ($group->attrs as $attribute) {
				$args = [];
				foreach ($attribute->args as $arg) {
					if ($arg->name) {
						$args[$arg->name->toString()] = $this->toValue($arg->value);
					} else {
						$args[] = $this->toValue($arg->value);
					}
				}

				$element->addAttribute($attribute->name->toString(), $args);
			}
		}
	}


	private function setupFunction(GlobalFunction|Method|PropertyHook $function, Node\FunctionLike $node): void
	{
		$function->setReturnReference($node->returnsByRef());
		if (!$function instanceof PropertyHook) {
			$function->setReturnType($node->getReturnType() ? $this->toPhp($node->getReturnType()) : null);
		}

		foreach ($node->getParams() as $item) {
			assert($item->var instanceof Node\Expr\Variable && is_string($item->var->name));
			$getVisibility = $this->toVisibility($item->flags);
			$setVisibility = $this->toSetterVisibility($item->flags);
			$final = (bool) ($item->flags & Modifiers::FINAL);
			if ($getVisibility || $setVisibility || $final) {
				assert($function instanceof Method);
				$param = $function->addPromotedParameter($item->var->name)
					->setVisibility($getVisibility, $setVisibility)
					->setReadOnly($item->isReadonly())
					->setFinal($final);
				$this->addHooksToProperty($param, $item);
			} else {
				$param = $function->addParameter($item->var->name);
			}
			$param->setType($item->type ? $this->toPhp($item->type) : null);
			$param->setReference($item->byRef);
			if (!$function instanceof PropertyHook) {
				$function->setVariadic($item->variadic);
			}
			if ($item->default) {
				$param->setDefaultValue($this->toValue($item->default));
			}

			$this->addCommentAndAttributes($param, $item);
		}

		$this->addCommentAndAttributes($function, $node);
		if ($node->getStmts()) {
			$indent = $function instanceof GlobalFunction ? 1 : 2;
			$function->setBody($this->getReformattedContents($node->getStmts(), $indent));
		}
	}


	private function toValue(Node\Expr $node): mixed
	{
		if ($node instanceof Node\Expr\ConstFetch) {
			return match ($node->name->toLowerString()) {
				'null' => null,
				'true' => true,
				'false' => false,
				default => new Literal($this->getReformattedContents([$node], 0)),
			};
		} elseif ($node instanceof Node\Scalar\LNumber
			|| $node instanceof Node\Scalar\DNumber
			|| $node instanceof Node\Scalar\String_
		) {
			return $node->value;

		} elseif ($node instanceof Node\Expr\Array_) {
			$res = [];
			foreach ($node->items as $item) {
				if ($item->unpack) {
					return new Literal($this->getReformattedContents([$node], 0));

				} elseif ($item->key) {
					$key = $this->toValue($item->key);
					if ($key instanceof Literal) {
						return new Literal($this->getReformattedContents([$node], 0));
					}

					$res[$key] = $this->toValue($item->value);

				} else {
					$res[] = $this->toValue($item->value);
				}
			}
			return $res;

		} else {
			return new Literal($this->getReformattedContents([$node], 0));
		}
	}


	private function toVisibility(int $flags): ?Visibility
	{
		return match (true) {
			(bool) ($flags & Modifiers::PUBLIC) => Visibility::Public,
			(bool) ($flags & Modifiers::PROTECTED) => Visibility::Protected,
			(bool) ($flags & Modifiers::PRIVATE) => Visibility::Private,
			default => null,
		};
	}


	private function toSetterVisibility(int $flags): ?Visibility
	{
		return match (true) {
			!class_exists(Node\PropertyHook::class) => null,
			(bool) ($flags & Modifiers::PUBLIC_SET) => Visibility::Public,
			(bool) ($flags & Modifiers::PROTECTED_SET) => Visibility::Protected,
			(bool) ($flags & Modifiers::PRIVATE_SET) => Visibility::Private,
			default => null,
		};
	}


	private function toPhp(Node $value): string
	{
		$dolly = clone $value;
		$dolly->setAttribute('comments', []);
		return $this->printer->prettyPrint([$dolly]);
	}


	private function getNodeContents(Node ...$nodes): string
	{
		$start = $this->getNodeStartPos($nodes[0]);
		$last = end($nodes);
		assert($last !== false);
		return substr($this->code, $start, $last->getEndFilePos() - $start + 1);
	}


	private function getNodeStartPos(Node $node): int
	{
		return ($comments = $node->getComments())
			? $comments[0]->getStartFilePos()
			: $node->getStartFilePos();
	}
}