<?php
declare(strict_types=1);

namespace Fendx\Core\Container;

use Fendx\Common\Exception\BusinessException;
use ReflectionClass;
use ReflectionException;

final class Container
{
    private static ?Container $instance = null;
    private array $bindings = [];
    private array $instances = [];
    private array $singletons = [];

    private function __construct()
    {
    }

    public static function getInstance(): self
    {
        if (self::$instance === null) {
            self::$instance = new self();
        }
        return self::$instance;
    }

    public function bind(string $abstract, mixed $concrete = null, bool $singleton = false): void
    {
        if ($concrete === null) {
            $concrete = $abstract;
        }

        $this->bindings[$abstract] = $concrete;
        $this->singletons[$abstract] = $singleton;
    }

    public function singleton(string $abstract, mixed $concrete = null): void
    {
        $this->bind($abstract, $concrete, true);
    }

    public function make(string $abstract, array $parameters = []): mixed
    {
        // 如果已存在实例且为单例
        if (isset($this->instances[$abstract])) {
            return $this->instances[$abstract];
        }

        $concrete = $this->bindings[$abstract] ?? $abstract;

        // 如果是闭包
        if ($concrete instanceof \Closure) {
            $object = $concrete($this, $parameters);
        } else {
            $object = $this->build($concrete, $parameters);
        }

        // 如果是单例，缓存实例
        if (isset($this->singletons[$abstract]) && $this->singletons[$abstract]) {
            $this->instances[$abstract] = $object;
        }

        return $object;
    }

    private function build(string $concrete, array $parameters): mixed
    {
        try {
            $reflector = new ReflectionClass($concrete);
        } catch (ReflectionException $e) {
            throw new BusinessException(500, 'CLASS_NOT_FOUND', ['class' => $concrete]);
        }

        if (!$reflector->isInstantiable()) {
            throw new BusinessException(500, 'CLASS_NOT_INSTANTIABLE', ['class' => $concrete]);
        }

        $constructor = $reflector->getConstructor();

        if ($constructor === null) {
            return new $concrete();
        }

        $dependencies = $constructor->getParameters();
        $instances = $this->getDependencies($dependencies, $parameters);

        return $reflector->newInstanceArgs($instances);
    }

    private function getDependencies(array $parameters, array $primitives): array
    {
        $dependencies = [];

        foreach ($parameters as $parameter) {
            $type = $parameter->getType();

            if ($type === null || $type->isBuiltin()) {
                $name = $parameter->getName();
                $dependencies[] = $primitives[$name] ?? $parameter->getDefaultValue();
            } else {
                $dependencies[] = $this->make($type->getName());
            }
        }

        return $dependencies;
    }

    public function has(string $abstract): bool
    {
        return isset($this->bindings[$abstract]);
    }

    public function forget(string $abstract): void
    {
        unset($this->bindings[$abstract], $this->instances[$abstract], $this->singletons[$abstract]);
    }

    public function flush(): void
    {
        $this->bindings = [];
        $this->instances = [];
        $this->singletons = [];
    }
}