<?php

declare(strict_types=1);

namespace App\Core;

use Exception;
use ReflectionClass;
use ReflectionNamedType;

final class Container
{
    private array $instances = [];

    public function set(string $id, mixed $concrete): void
    {
        $this->instances[$id] = $concrete;
    }

    public function get(string $id): mixed
    {
        if (isset($this->instances[$id])) {
            if ($this->instances[$id] instanceof \Closure) {
                $this->instances[$id] = ($this->instances[$id])($this);
            }
            return $this->instances[$id];
        }

        return $this->resolve($id);
    }

    public function resolve(string $id): mixed
    {
        if (!class_exists($id)) {
            throw new Exception("Class {$id} cannot be resolved.");
        }

        $reflection = new ReflectionClass($id);

        if (!$reflection->isInstantiable()) {
            throw new Exception("Class {$id} is not instantiable.");
        }

        $constructor = $reflection->getConstructor();

        if (is_null($constructor)) {
            return new $id();
        }

        $parameters = $constructor->getParameters();
        $dependencies = [];

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

            if (!$type instanceof ReflectionNamedType || $type->isBuiltin()) {
                if ($parameter->isDefaultValueAvailable()) {
                    $dependencies[] = $parameter->getDefaultValue();
                    continue;
                }
                throw new Exception("Unable to resolve parameter '{$parameter->getName()}' in class {$id}");
            }

            $dependencies[] = $this->get($type->getName());
        }

        $instance = $reflection->newInstanceArgs($dependencies);
        $this->instances[$id] = $instance;

        return $instance;
    }
}