<?php

declare(strict_types=1);

/** 
 * @author Robert Strutts
 * @copyright Copyright (c) 2010-2026, Robert Strutts.
 * @license MIT
 */

namespace IOcornerstone\Framework;

final class DI 
{

    protected $services = [];

    // alias to register
    public function set(...$args): void {
        $this->register(...$args);
    }

    // alias to get_service
    public function get(...$args) {
        return $this->get_service(...$args);
    }

    public function register(string $serviceName, callable $callable): void 
    {
        $this->services[$serviceName] = $callable;
    }

    public function has(string $serviceName): bool 
    {
        return (array_key_exists($serviceName, $this->services));
    }

    public function exists(string $serviceName) 
    {   // an Alias to has
        return $this->has($serviceName);
    }

    /* Note args may be an object or an array maybe more...!
    * This will Call/Execute the service
    */
    public function get_service(
        string $serviceName, 
        $args = [], 
        ...$more
    ) {
        if ($this->has($serviceName) ) {
            $entry = $this->services[$serviceName];
            
            if (is_callable($entry)) {
                return $entry($args, $more);
            }
            
            $serviceName = $entry;
        }
        return $this->resolve($serviceName); // Try to Auto-Wire
    }

    public function get_auto(string $serviceName) 
    {
        if ($this->has($serviceName) ) {
            return $this->services[$serviceName]($this);
        }
        return $this->resolve($serviceName); // Try to Auto-Wire
    }

    public function __set(string $serviceName, callable $callable): void 
    {
        $this->register($serviceName, $callable);
    }

    public function __get(string $serviceName) 
    {
        return $this->get_service($serviceName);
    }

    public function list_services_as_array(): array 
    {
        return array_keys($this->services);
    }

    public function list_services_as_string(): string 
    {
        return implode(',', array_keys($this->services));
    }
    // Reflection API Autowiring FROM-> https://www.youtube.com/watch?v=78Vpg97rQwE&list=PLr3d3QYzkw2xabQRUpcZ_IBk9W50M9pe-&index=72
    public function resolve(string $serviceName) 
    {
        try {
            $reflection_class = new \ReflectionClass($serviceName);
        } catch (\ReflectionException $e) {
            // if (! is_live()) {
            //     var_dump($e->getTrace());
            //     echo $e->getMessage(); 
            //     exit;
            // } else {
                throw new \Exception("Failed to resolve resource: {$serviceName}!");
            // }
        }
        if (! $reflection_class->isInstantiable()) {
            throw new \Exception("The Service class: {$serviceName} is not instantiable.");
        }
        $constructor = $reflection_class->getConstructor();
        if (! $constructor) {
            return new $serviceName;
        }
        $parameters = $constructor->getParameters();
        if (! $parameters) {
            return new $serviceName;
        }
        $dependencies = array_map(
            function(\ReflectionParameter $param) use ($serviceName) {
                $name = $param->getName();
                $type = $param->getType();
                if (! $type) {
                    throw new \Exception("Failed to resolve class: {$serviceName} because param {$name} is missing a type hint.");
                }
                if ($type instanceof \ReflectionUnionType) {
                    throw new \Exception("Failed to resolve class: {$serviceName} because of union type for param {$name}.");
                }
                if ($type instanceof \ReflectionNamedType && ! $type->isBuiltin()) {
                    return $this->get_auto($type->getName());
                }
                
                throw new \Exception("Failed to resolve class {$serviceName} because of invalid param {$param}.");
            }, $parameters
        );
        return $reflection_class->newInstanceArgs($dependencies);
    }

}