<?php declare(strict_types=1);

namespace PhpParser\Node\Stmt;

use PhpParser\Error;
use PhpParser\Node;

class Class_ extends ClassLike
{
    const MODIFIER_PUBLIC    =  1;
    const MODIFIER_PROTECTED =  2;
    const MODIFIER_PRIVATE   =  4;
    const MODIFIER_STATIC    =  8;
    const MODIFIER_ABSTRACT  = 16;
    const MODIFIER_FINAL     = 32;

    const VISIBILITY_MODIFIER_MASK = 7; // 1 | 2 | 4

    /** @var int Type */
    public $flags;
    /** @var null|Node\Name Name of extended class */
    public $extends;
    /** @var Node\Name[] Names of implemented interfaces */
    public $implements;

    /**
     * Constructs a class node.
     *
     * @param string|Node\Identifier|null $name Name
     * @param array       $subNodes   Array of the following optional subnodes:
     *                                'flags'      => 0      : Flags
     *                                'extends'    => null   : Name of extended class
     *                                'implements' => array(): Names of implemented interfaces
     *                                'stmts'      => array(): Statements
     * @param array       $attributes Additional attributes
     */
    public function __construct($name, array $subNodes = [], array $attributes = []) {
        parent::__construct($attributes);
        $this->flags = $subNodes['flags'] ?? $subNodes['type'] ?? 0;
        $this->name = \is_string($name) ? new Node\Identifier($name) : $name;
        $this->extends = $subNodes['extends'] ?? null;
        $this->implements = $subNodes['implements'] ?? [];
        $this->stmts = $subNodes['stmts'] ?? [];
    }

    public function getSubNodeNames() : array {
        return ['flags', 'name', 'extends', 'implements', 'stmts'];
    }

    /**
     * Whether the class is explicitly abstract.
     *
     * @return bool
     */
    public function isAbstract() : bool {
        return (bool) ($this->flags & self::MODIFIER_ABSTRACT);
    }

    /**
     * Whether the class is final.
     *
     * @return bool
     */
    public function isFinal() : bool {
        return (bool) ($this->flags & self::MODIFIER_FINAL);
    }

    /**
     * Whether the class is anonymous.
     *
     * @return bool
     */
    public function isAnonymous() : bool {
        return null === $this->name;
    }

    /**
     * @internal
     */
    public static function verifyModifier($a, $b) {
        if ($a & self::VISIBILITY_MODIFIER_MASK && $b & self::VISIBILITY_MODIFIER_MASK) {
            throw new Error('Multiple access type modifiers are not allowed');
        }

        if ($a & self::MODIFIER_ABSTRACT && $b & self::MODIFIER_ABSTRACT) {
            throw new Error('Multiple abstract modifiers are not allowed');
        }

        if ($a & self::MODIFIER_STATIC && $b & self::MODIFIER_STATIC) {
            throw new Error('Multiple static modifiers are not allowed');
        }

        if ($a & self::MODIFIER_FINAL && $b & self::MODIFIER_FINAL) {
            throw new Error('Multiple final modifiers are not allowed');
        }

        if ($a & 48 && $b & 48) {
            throw new Error('Cannot use the final modifier on an abstract class member');
        }
    }
}