<?php
/**
 * This file is part of TypePHP.
 *
 * Resolves native return types, inheritance compatibility, and converted call arguments.
 */

namespace TypePhp\TypeSystem;

use TypePhp\Type;

use PhpParser\Node;
use TypePhp\Entity\ArgInfo;

trait NativeTypeCompatibilityTrait
{
    protected function getReturnType(): string
    {
        $type = $this->functionDef->returnType;
        if ($type === Type::STREAM) {
            return Type::VAR;
        }
        return $type;
    }

    protected function getReturnClass(): string
    {
        return $this->functionDef->returnClass;
    }

    protected function isInheritedFrom(string $class, string $expected): bool
    {
        // 继承关系判断的唯一入口。调用者不应直接使用 PHP 运行时反射函数判断普通项目类。
        // 对 AOT 已扫描到的项目类/接口，必须走 classDef/interfaceDef 中的 extends/implements 图；
        // 对 PHP 内置类/接口，可以使用 Zend 运行时反射，因为这部分属于目标 PHP 运行时的固定能力；
        // 对动态类返回 true 表示“静态阶段无法否定”，后续必须保留运行时检查兜底。
        $class = ltrim($class, '\\');
        $expected = ltrim($expected, '\\');
        if (strcasecmp($class, $expected) === 0) {
            return true;
        }

        $internal = ($this->isInternalClass($expected) or $this->isInternalInterface($expected));
        $isInterface = ($this->hasInterface($expected) or $this->isInternalInterface($expected));

        if ($this->hasInterface($class)) {
            if (!$isInterface) {
                return false;
            }
            return $this->interfaceExtends($class, $expected);
        }

        if ($this->isInternalClass($class) or $this->isInternalInterface($class)) {
            // 只允许内置类型之间使用 Zend 的继承关系。这里不是查询任意用户类，
            // 因此不会把编译器进程加载过的外部库类混入项目静态类型系统。
            if (!$internal) {
                return false;
            }
            return is_subclass_of($class, $expected);
        }

        // 类不存在，说明这是一个动态类，跳过静态检查，需要运行时检查
        if (!$this->hasClass($class)) {
            return true;
        }
        $classDef = $this->getClass($class);
        while (true) {
            if ($isInterface) {
                if ($classDef->implements and in_array($expected, $classDef->implements)) {
                    return true;
                }
                // Check transitive interface inheritance (e.g., Iterator extends Traversable)
                foreach ($classDef->implements as $iface) {
                    $stack = [$iface];
                    while ($stack) {
                        $check = array_pop($stack);
                        if (strcasecmp($check, $expected) === 0) {
                            return true;
                        }
                        if (!$this->hasInterface($check)) {
                            if ($internal && $this->isInternalInterface($check) && is_subclass_of($check, $expected)) {
                                return true;
                            }
                            continue;
                        }
                        $interfaceDef = $this->getInterface($check);
                        foreach ($interfaceDef->extendsList ?: ($interfaceDef->extends ? [$interfaceDef->extends] : []) as $parentIface) {
                            $stack[] = $parentIface;
                        }
                    }
                }
            } else {
                if (strcasecmp($class, $expected) === 0) {
                    return true;
                }
                if (!$this->hasClass($class)) {
                    // 原生类继承自一个内置类，例如: UserError extends Exception ，然后 $expected 预期是 Throwable
                    // 这种情况，需要使用 ZendVM 获取继承关系
                    if ($this->isInternalClass($class) and $internal) {
                        return $class === $expected or is_subclass_of($class, $expected);
                    }
                    return false;
                }
            }
            if (!$classDef->extends) {
                return false;
            }
            $class = $classDef->extends;
            if ($this->isInternalClass($class)) {
                // 项目类可以继承内置类。进入内置父类链后，后续关系交给 Zend 判断；
                // 但 expected 也必须是内置类/接口，否则不能跨到外部用户类命名空间做运行时反射。
                return $internal && is_subclass_of($class, $expected);
            }
            $classDef = $this->getClass($class);
        }
    }

    private function interfaceExtends(string $interface, string $expected): bool
    {
        // 接口继承需要单独处理，因为 interfaceDef 没有 classDef 的父类链。
        // 这里同样只遍历 AOT 已知接口图；遇到内置接口时，才允许使用 Zend 的 is_subclass_of()。
        $stack = [$interface];
        while ($stack) {
            $check = array_pop($stack);
            if (strcasecmp($check, $expected) === 0) {
                return true;
            }
            if (!$this->hasInterface($check)) {
                if ($this->isInternalInterface($check) && $this->isInternalInterface($expected) && is_subclass_of($check, $expected)) {
                    return true;
                }
                continue;
            }
            $interfaceDef = $this->getInterface($check);
            foreach ($interfaceDef->extendsList ?: ($interfaceDef->extends ? [$interfaceDef->extends] : []) as $parentInterface) {
                $stack[] = $parentInterface;
            }
        }
        return false;
    }

    protected function getTypeConvertedArg(
        Node\Arg $arg,
        ArgInfo $argInfo,
        string $callableName = '',
        int $argIndex = 0
    ): string
    {
        $type = $this->detectTypeOfExpr($arg->value);
        $this->assertExprCanBeUsedAsValue($arg->value, 'function argument');

        if (!empty($argInfo->typeCheck)) {
            $this->checkCompositeTypeAssignment(
                $arg,
                $argInfo->typeCheck,
                $argInfo->typeStr,
                $arg->value,
                'argument `$' . ($argInfo->phpName ?: $this->unescapeVarName($argInfo->name)) . '`'
            );
        }

        if ($argInfo->byRef) {
            if ($this->isReferenceWrapperCall($arg->value)) {
                $inner = $this->unwrapReferenceWrapperCall($arg->value, $arg);
                $this->assertReadonlyPropertyReferenceForbidden($inner, $arg, false);
                if ($this->isVarExpr($inner)) {
                    $arg->value = $inner;
                } else {
                    $expr = $this->expandRefvalExpr($inner, $arg);
                    if ($expr !== null) {
                        return $expr;
                    }
                    $this->fatalError($arg, 'The refval function only accepts a variable, array element, or object property');
                }
            } else {
                $this->assertReadonlyPropertyReferenceForbidden($arg->value, $arg, false);
            }
            if ($this->isVarExpr($arg->value)) {
                $var = $this->parseVariable($arg->value);
                // 若参数是引用类型，可以传入未定义变量，将立即创建变量作为引用
                if (!$this->hasLocalVar($var)) {
                    $this->addLocalVar($var, Type::VAR);
                }
            }
            return $this->convertToRef($arg->value);
        }

        $expr = $this->parseOrderedArg($arg);
        $expr = $this->materializeCallArgValue($arg->value, $expr);

        if (($type === Type::VAR || $type === Type::REF) && $this->isStrictScalarType($argInfo->type)) {
            // A native scalar ABI value has already lost its zval type. Preserve
            // the dynamic value until strict_types validation has completed.
            // Keep the check inside the argument expression: beforeStmtLines
            // may run before an enclosing assignment or comma expression has
            // initialized a compiler-generated argument temporary.
            $checkedArg = 'typephp_checked_arg';
            $check = rtrim($this->genStrictScalarParamCheck(
                $argInfo,
                $checkedArg,
                $callableName,
                (string) ($argIndex + 1)
            ));
            $expr = '([&](php::Var ' . $checkedArg . ') -> php::Var {' . PHP_EOL
                . $check . PHP_EOL
                . $this->getIndent() . 'return ' . $checkedArg . ';' . PHP_EOL
                . $this->getIndent() . '})(' . $expr . ')';
        }

        $this->checkVarAssignExpr($arg, $argInfo->type, $type);

        if ($argInfo->type === Type::VAR && $this->isVarExpr($arg->value)) {
            $varName = $this->parseIdentifier($arg->value);
            if ($this->isStdContainer($varName)) {
                return $varName;
            }
        }

        if ($argInfo->type === Type::OBJECT) {
            $declaredClass = $argInfo->declaredClass ?: $argInfo->class;
            if ($declaredClass !== '') {
                $class = $this->detectDeclaredClassOfExpr($arg->value);
                if ($class !== '') {
                    // native call 是性能热点，若静态阶段已经证明实参 is-a 声明类型，
                    // 就不要再生成 php::toObject($expr, target_ce) 做重复运行时检查。
                    // 如果无法证明，但右值是已知 concrete object，说明一定不兼容，直接编译期 fatal；
                    // 其他动态/外部库/any 场景保留 php::toObject() 作为运行时兜底。
                    if ($this->isObjectClassStaticallyAssignableTo($class, $declaredClass)) {
                        return $type === Type::OBJECT ? $expr : $this->convertObjectExpr($expr);
                    }
                    if ($this->isKnownConcreteObjectExpr($arg->value, $class)) {
                        $argName = $argInfo->phpName ?: $this->unescapeVarName($argInfo->name);
                        $this->fatalError($arg, "Argument `{$argName}` must be an instance of `{$declaredClass}`, `{$class}` given");
                    }
                }
                return $this->convertObjectExpr($expr, $this->getClassEntryPtr($declaredClass));
            }
            return $type === Type::OBJECT ? $expr : $this->convertObjectExpr($expr);
        }

        return $this->convertExprType($expr, $argInfo->type, $type);
    }

}