<?php
declare(strict_types=1);

namespace FlysystemOffload;

use FlysystemOffload\Admin\HealthCheck;
use FlysystemOffload\Config\ConfigLoader;
use FlysystemOffload\Filesystem\FilesystemFactory;
use FlysystemOffload\Media\MediaHooks;
use FlysystemOffload\Settings\SettingsPage;
use FlysystemOffload\StreamWrapper\FlysystemStreamWrapper;
use League\Flysystem\FilesystemOperator;
use League\Flysystem\Visibility;

final class Plugin {
    private static bool $bootstrapped = false;
    private static ?Plugin $instance = null;

    private array $config;
    private FilesystemOperator $filesystem;
    private MediaHooks $mediaHooks;
    private ?SettingsPage $settingsPage;
    private HealthCheck $healthCheck;

    private function __construct(
        array $config,
        FilesystemOperator $filesystem,
        MediaHooks $mediaHooks,
        ?SettingsPage $settingsPage,
        HealthCheck $healthCheck
    ) {
        $this->config = $config;
        $this->filesystem = $filesystem;
        $this->mediaHooks = $mediaHooks;
        $this->settingsPage = $settingsPage;
        $this->healthCheck = $healthCheck;
    }

    public static function bootstrap(): void {
        if (self::$bootstrapped) {
            return;
        }

        $configDirectory = \defined('FLYSYSTEM_OFFLOAD_CONFIG_PATH')
            ? FLYSYSTEM_OFFLOAD_CONFIG_PATH
            : \dirname(__DIR__) . '/config';

        $configLoader = new ConfigLoader($configDirectory);
        $config = self::normaliseConfig($configLoader->load());

        $filesystemFactory = new FilesystemFactory();
        $filesystem = $filesystemFactory->make($config);

        FlysystemStreamWrapper::register(
            $filesystem,
            $config['stream']['protocol'],
            $config['stream']['root_prefix'],
            $config['visibility']
        );

        $mediaHooks = new MediaHooks($filesystem, $config);
        $mediaHooks->register();

        $settingsPage = null;
        if (! empty($config['admin']['enabled']) && \is_admin()) {
            $settingsPage = new SettingsPage($filesystem, $config);
            $settingsPage->register();
        }

        $healthCheck = new HealthCheck($filesystem, $config);
        $healthCheck->register();

        self::$instance = new self($config, $filesystem, $mediaHooks, $settingsPage, $healthCheck);
        self::$bootstrapped = true;
    }

    public static function instance(): ?self {
        return self::$instance;
    }

    public function config(): array {
        return $this->config;
    }

    public function filesystem(): FilesystemOperator {
        return $this->filesystem;
    }

    private static function normaliseConfig(array $config): array {
        $defaults = [
            'driver' => 's3',
            'visibility' => Visibility::PUBLIC,
            'cache_ttl' => 900,
            'stream' => [
                'protocol' => 'flysystem',
                'root_prefix' => '',
                'host' => 'uploads',
            ],
            'uploads' => [
                'base_url' => '',
                'delete_remote' => true,
                'prefer_local_for_missing' => false,
                'cache_control' => 'public, max-age=31536000, immutable',
                'expires' => null,
                'expires_ttl' => 31536000,
            ],
            'admin' => [
                'enabled' => false,
            ],
            's3' => [
                'acl_public' => 'public-read',
                'acl_private' => 'private',
                'default_options' => [],
            ],
        ];

        $config = array_replace_recursive($defaults, $config);

        $config['visibility'] = self::normaliseVisibility((string) ($config['visibility'] ?? Visibility::PUBLIC));
        $config['stream']['protocol'] = self::sanitizeProtocol((string) $config['stream']['protocol']);
        $config['stream']['root_prefix'] = self::normalizePathSegment((string) $config['stream']['root_prefix']);
        $config['stream']['host'] = self::normalizePathSegment((string) $config['stream']['host']) ?: 'uploads';

        if (empty($config['uploads']['base_url'])) {
            $config['uploads']['base_url'] = rtrim(content_url('uploads'), '/');
        } else {
            $config['uploads']['base_url'] = rtrim((string) $config['uploads']['base_url'], '/');
        }

        $config['uploads']['delete_remote'] = (bool) $config['uploads']['delete_remote'];
        $config['uploads']['prefer_local_for_missing'] = (bool) $config['uploads']['prefer_local_for_missing'];
        $config['uploads']['cache_control'] = trim((string) $config['uploads']['cache_control']);
        $config['uploads']['expires'] = $config['uploads']['expires']
            ? trim((string) $config['uploads']['expires'])
            : null;
        $config['uploads']['expires_ttl'] = max(0, (int) ($config['uploads']['expires_ttl'] ?? 0));

        $config['s3']['acl_public'] = (string) ($config['s3']['acl_public'] ?? 'public-read');
        $config['s3']['acl_private'] = (string) ($config['s3']['acl_private'] ?? 'private');
        $config['s3']['default_options'] = is_array($config['s3']['default_options'])
            ? $config['s3']['default_options']
            : [];

        return $config;
    }

    private static function normaliseVisibility(string $visibility): string {
        $visibility = \strtolower($visibility);

        return $visibility === Visibility::PRIVATE
            ? Visibility::PRIVATE
            : Visibility::PUBLIC;
    }

    private static function sanitizeProtocol(string $protocol): string {
        $protocol = \preg_replace('/[^A-Za-z0-9_\-]/', '', $protocol) ?? 'flysystem';
        $protocol = \strtolower($protocol);

        return $protocol !== '' ? $protocol : 'flysystem';
    }

    private static function normalizePathSegment(string $segment): string {
        return \trim($segment, " \t\n\r\0\x0B/");
    }
}