<?php

/*
 * This file is part of the Symfony package.
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace KTXC;

use KTXC\Http\Request\Request;
use KTXC\Http\Response\Response;
use KTXC\Http\Middleware\MiddlewarePipeline;
use KTXC\Http\Middleware\TenantMiddleware;
use KTXC\Http\Middleware\FirewallMiddleware;
use KTXC\Http\Middleware\AuthenticationMiddleware;
use KTXC\Http\Middleware\RouterMiddleware;
use KTXC\Injection\Builder;
use KTXC\Injection\Container;
use Psr\Container\ContainerInterface;
use KTXC\Module\ModuleManager;
use Psr\Log\LoggerInterface;
use KTXC\Logger\FileLogger;
use KTXF\Event\EventBus;
use KTXF\Cache\EphemeralCacheInterface;
use KTXF\Cache\PersistentCacheInterface;
use KTXF\Cache\BlobCacheInterface;
use KTXF\Cache\Store\FileEphemeralCache;
use KTXF\Cache\Store\FilePersistentCache;
use KTXF\Cache\Store\FileBlobCache;

class Kernel
{
    public const VERSION = '1.0.0';
    public const VERSION_ID = 10000;
    public const MAJOR_VERSION = 1;
    public const MINOR_VERSION = 0;
    public const RELEASE_VERSION = 0;
    public const EXTRA_VERSION = '';

    protected bool $initialized = false;
    protected bool $booted = false;
    protected ?float $startTime = null;
    protected ?ContainerInterface $container = null;
    protected ?LoggerInterface $logger = null;
    protected ?MiddlewarePipeline $pipeline = null;

    private string $projectDir;
    private array $config;

    public function __construct(
        protected string $environment = 'prod',
        protected bool $debug = false,
        array $config = [],
        ?string $projectDir = null,
    ) {
        if (!$environment) {
            throw new \InvalidArgumentException(\sprintf('Invalid environment provided to "%s": the environment cannot be empty.', get_debug_type($this)));
        }
        
        $this->config = $config;

        if ($projectDir !== null) {
            $this->projectDir = $projectDir;
        }
    }

    public function __clone()
    {
        $this->initialized = false;
        $this->booted = false;
        $this->container = null;
    }
    
    private function initialize(): void
    {
        
        if ($this->debug) {
            $this->startTime = microtime(true);
        }
        if ($this->debug && !isset($_ENV['SHELL_VERBOSITY']) && !isset($_SERVER['SHELL_VERBOSITY'])) {
            if (\function_exists('putenv')) {
                putenv('SHELL_VERBOSITY=3');
            }
            $_ENV['SHELL_VERBOSITY'] = 3;
            $_SERVER['SHELL_VERBOSITY'] = 3;
        }

        // Create logger with config support
        $logDir = $this->config['log.directory'] ?? $this->getLogDir();
        $logChannel = $this->config['log.channel'] ?? 'app';
        $this->logger = new FileLogger($logDir, $logChannel);

        $this->initializeErrorHandlers();

        $container = $this->initializeContainer();

        $this->container = $container;
        $this->initialized = true;
    }

    /**
     * Set up global error and exception handlers
     */
    protected function initializeErrorHandlers(): void
    {
        // Convert PHP errors to exceptions
        set_error_handler(function ($errno, $errstr, $errfile, $errline) {
            // Don't throw exception if error reporting is turned off
            if (!(error_reporting() & $errno)) {
                return false;
            }
            
            $message = sprintf(
                "PHP Error [%d]: %s in %s:%d",
                $errno,
                $errstr,
                $errfile,
                $errline
            );
            
            $this->logger->error($message, ['errno' => $errno, 'file' => $errfile, 'line' => $errline]);
            
            // Throw exception for fatal errors
            if ($errno === E_ERROR || $errno === E_CORE_ERROR || $errno === E_COMPILE_ERROR || $errno === E_USER_ERROR) {
                throw new \ErrorException($errstr, 0, $errno, $errfile, $errline);
            }
            
            return true;
        });

        // Handle uncaught exceptions
        set_exception_handler(function (\Throwable $exception) {
            $this->logger->error('Exception caught: ' . $exception->getMessage(), [
                'exception' => $exception,
                'file' => $exception->getFile(),
                'line' => $exception->getLine(),
                'trace' => $exception->getTraceAsString(),
            ]);
            
            if ($this->debug) {
                echo '<pre>Uncaught Exception: ' . $exception . '</pre>';
            } else {
                echo 'An unexpected error occurred. Please try again later.';
            }
            
            exit(1);
        });

        // Handle fatal errors
        register_shutdown_function(function () {
            $error = error_get_last();
            if ($error !== null && in_array($error['type'], [E_ERROR, E_CORE_ERROR, E_COMPILE_ERROR, E_PARSE])) {
                $message = sprintf(
                    "Fatal Error [%d]: %s in %s:%d",
                    $error['type'],
                    $error['message'],
                    $error['file'],
                    $error['line']
                );
                
                $this->logger->error($message, $error);
                
                if ($this->debug) {
                    echo '<pre>' . $message . '</pre>';
                } else {
                    echo 'A fatal error occurred. Please try again later.';
                }
            }
        });
    }

    public function boot(): void
    {
        if (!$this->initialized) {
            $this->initialize();
        }

        if (!$this->booted) {
            /** @var ModuleManager $moduleManager */
            $moduleManager = $this->container->get(ModuleManager::class);
            $moduleManager->modulesBoot();
            
            // Build middleware pipeline
            $this->pipeline = $this->buildMiddlewarePipeline();
            
            $this->booted = true;
        }
    }

    public function reboot(): void
    {
        $this->shutdown();
        $this->boot();
    }

    public function shutdown(): void
    {
        if (false === $this->initialized) {
            return;
        }

        $this->initialized = false;
        $this->booted = false;
        $this->container = null;
    }

    public function handle(Request $request): Response
    {
        if (!$this->booted) {
            $this->boot();
        }

        // Use middleware pipeline to handle the request
        return $this->pipeline->handle($request);
    }

    /**
     * Build the middleware pipeline
     */
    protected function buildMiddlewarePipeline(): MiddlewarePipeline
    {
        $pipeline = new MiddlewarePipeline($this->container);
        
        // Register middleware in execution order
        $pipeline->pipe(TenantMiddleware::class);
        $pipeline->pipe(FirewallMiddleware::class);
        $pipeline->pipe(AuthenticationMiddleware::class);
        $pipeline->pipe(RouterMiddleware::class);
        
        return $pipeline;
    }

    /**
     * Process deferred events at the end of the request
     */
    public function processEvents(): void
    {
        try {
            if ($this->container && $this->container->has(EventBus::class)) {
                /** @var EventBus $eventBus */
                $eventBus = $this->container->get(EventBus::class);
                $eventBus->processDeferred();
            }
        } catch (\Throwable $e) {
            error_log('Event processing error: ' . $e->getMessage());
        }
    }

    /**
     * Returns the kernel parameters.
     *
     * @return array<string, array|bool|string|int|float|\UnitEnum|null>
     */
    protected function parameters(): array
    {
        return [
            'kernel.project_dir' => realpath($this->folderRoot()) ?: $this->folderRoot(),
            'kernel.environment' => $this->environment,
            'kernel.runtime_environment' => '%env(default:kernel.environment:APP_RUNTIME_ENV)%',
            'kernel.runtime_mode' => '%env(query_string:default:container.runtime_mode:APP_RUNTIME_MODE)%',
            'kernel.runtime_mode.web' => '%env(bool:default::key:web:default:kernel.runtime_mode:)%',
            'kernel.runtime_mode.cli' => '%env(not:default:kernel.runtime_mode.web:)%',
            'kernel.runtime_mode.worker' => '%env(bool:default::key:worker:default:kernel.runtime_mode:)%',
            'kernel.debug' => $this->debug,
            'kernel.build_dir' => realpath($this->getBuildDir()) ?: $this->getBuildDir(),
            'kernel.cache_dir' => realpath($this->getCacheDir()) ?: $this->getCacheDir(),
            'kernel.logs_dir' => realpath($this->getLogDir()) ?: $this->getLogDir(),
            'kernel.charset' => $this->getCharset(),
        ];
    }

    public function environment(): string
    {
        return $this->environment;
    }

    public function debug(): bool
    {
        return $this->debug;
    }

    public function container(): ContainerInterface
    {
        if (!$this->container) {
            throw new \LogicException('Cannot retrieve the container from a non-booted kernel.');
        }

        return $this->container;
    }

    public function getStartTime(): float
    {
        return $this->debug && null !== $this->startTime ? $this->startTime : -\INF;
    }

    /**
     * Gets the application root dir (path of the project's composer file).
     */
    public function folderRoot(): string
    {
        if (!isset($this->projectDir)) {
            $r = new \ReflectionObject($this);

            if (!is_file($dir = $r->getFileName())) {
                throw new \LogicException(\sprintf('Cannot auto-detect project dir for kernel of class "%s".', $r->name));
            }

            $dir = $rootDir = \dirname($dir);
            while (!is_file($dir.'/composer.json')) {
                if ($dir === \dirname($dir)) {
                    return $this->projectDir = $rootDir;
                }
                $dir = \dirname($dir);
            }
            $this->projectDir = $dir;
        }

        return $this->projectDir;
    }

    
    /**
     * Gets the path to the configuration directory.
     */
    private function getConfigDir(): string
    {
        return $this->folderRoot().'/config';
    }

    public function getCacheDir(): string
    {
        return $this->folderRoot().'/var/cache/'.$this->environment;
    }

    public function getBuildDir(): string
    {
        return $this->getCacheDir();
    }

    public function getLogDir(): string
    {
        return $this->folderRoot().'/var/log';
    }

    public function getCharset(): string
    {
        return 'UTF-8';
    }

    /**
     * Initializes the service container
     */
    protected function initializeContainer(): Container
    {
        $container = $this->buildContainer();
        $container->set('kernel', $this);

        return $container;
    }

    /**
     * Builds the service container.
     *
     * @throws \RuntimeException
     */
    protected function buildContainer(): Container
    {
        $builder = new Builder(Container::class);
        $builder->useAutowiring(true);
        $builder->useAttributes(true);
        $builder->addDefinitions($this->parameters());
        $builder->addDefinitions($this->config);
        
        $this->configureContainer($builder);

        return $builder->build();
    }

    protected function configureContainer(Builder $builder): void
    {
        // Service definitions
        $projectDir = $this->folderRoot();
        $moduleDir = $projectDir . '/modules';
        $environment = $this->environment;
        
        $builder->addDefinitions([

            // Provide primitives for injection
            'rootDir' => \DI\value($projectDir),
            'moduleDir' => \DI\value($moduleDir),
            'environment' => \DI\value($environment),

            // IMPORTANT: ensure Container::class resolves to the *current* container instance.
            // Without this alias, PHP-DI will happily autowire a new empty Container when asked
            Container::class => \DI\get(ContainerInterface::class),

            // Use the kernel's logger instance
            LoggerInterface::class => \DI\value($this->logger),
            
            // EventBus as singleton for consistent event handling
            EventBus::class => \DI\create(EventBus::class),
            // Ephemeral Cache - for short-lived data (sessions, rate limits, challenges)
            EphemeralCacheInterface::class => function(ContainerInterface $c) use ($projectDir) {
                $storeType = $c->has('cache.ephemeral') ? $c->get('cache.ephemeral') : 'file';
                
                $storeMap = [
                    'file' => FileEphemeralCache::class,
                    // 'redis' => RedisEphemeralCache::class,
                ];
                
                $storeClass = $storeMap[$storeType] ?? $storeType;
                
                if (!class_exists($storeClass)) {
                    throw new \RuntimeException("Ephemeral cache store not found: {$storeClass}");
                }
                
                $cache = new $storeClass($projectDir);
                
                // Set tenant/user context if available
                if ($c->has(SessionTenant::class)) {
                    $tenant = $c->get(SessionTenant::class);
                    $cache->setTenantContext($tenant->identifier());
                }
                if ($c->has(SessionIdentity::class)) {
                    $identity = $c->get(SessionIdentity::class);
                    $cache->setUserContext($identity->identifier());
                }
                
                return $cache;
            },
            // Persistent Cache - for long-lived data (routes, modules, compiled configs)
            PersistentCacheInterface::class => function(ContainerInterface $c) use ($projectDir) {
                $storeType = $c->has('cache.persistent') ? $c->get('cache.persistent') : 'file';
                
                $storeMap = [
                    'file' => FilePersistentCache::class,
                    // 'database' => DatabasePersistentCache::class,
                ];
                
                $storeClass = $storeMap[$storeType] ?? $storeType;
                
                if (!class_exists($storeClass)) {
                    throw new \RuntimeException("Persistent cache store not found: {$storeClass}");
                }
                
                $cache = new $storeClass($projectDir);
                
                // Set tenant/user context if available
                if ($c->has(SessionTenant::class)) {
                    $tenant = $c->get(SessionTenant::class);
                    $cache->setTenantContext($tenant->identifier());
                }
                if ($c->has(SessionIdentity::class)) {
                    $identity = $c->get(SessionIdentity::class);
                    $cache->setUserContext($identity->identifier());
                }
                
                return $cache;
            },
            // Blob Cache - for binary/media data (previews, thumbnails)
            BlobCacheInterface::class => function(ContainerInterface $c) use ($projectDir) {
                $storeType = $c->has('cache.blob') ? $c->get('cache.blob') : 'file';
                
                $storeMap = [
                    'file' => FileBlobCache::class,
                    // 's3' => S3BlobCache::class,
                ];
                
                $storeClass = $storeMap[$storeType] ?? $storeType;
                
                if (!class_exists($storeClass)) {
                    throw new \RuntimeException("Blob cache store not found: {$storeClass}");
                }
                
                $cache = new $storeClass($projectDir);
                
                // Set tenant/user context if available
                if ($c->has(SessionTenant::class)) {
                    $tenant = $c->get(SessionTenant::class);
                    $cache->setTenantContext($tenant->identifier());
                }
                if ($c->has(SessionIdentity::class)) {
                    $identity = $c->get(SessionIdentity::class);
                    $cache->setUserContext($identity->identifier());
                }
                
                return $cache;
            },
        ]);
    }

}