<?php
/**
 * License Manager class.
 *
 * @package Magdev\WpBnb\License
 */

declare( strict_types=1 );

namespace Magdev\WpBnb\License;

use Magdev\WcLicensedProductClient\SecureLicenseClient;
use Magdev\WcLicensedProductClient\LicenseClient;
use Magdev\WcLicensedProductClient\DTO\LicenseState;
use Magdev\WcLicensedProductClient\Exception\LicenseNotFoundException;
use Magdev\WcLicensedProductClient\Exception\LicenseExpiredException;
use Magdev\WcLicensedProductClient\Exception\LicenseRevokedException;
use Magdev\WcLicensedProductClient\Exception\LicenseInactiveException;
use Magdev\WcLicensedProductClient\Exception\DomainMismatchException;
use Magdev\WcLicensedProductClient\Exception\MaxActivationsReachedException;
use Magdev\WcLicensedProductClient\Exception\RateLimitExceededException;
use Magdev\WcLicensedProductClient\Security\SignatureException;
use Symfony\Component\HttpClient\HttpClient;

/**
 * Manages license validation and activation.
 */
final class Manager {

	// Option keys.
	public const OPTION_LICENSE_KEY    = 'wp_bnb_license_key';
	public const OPTION_SERVER_URL     = 'wp_bnb_license_server_url';
	public const OPTION_SERVER_SECRET  = 'wp_bnb_license_server_secret';
	public const OPTION_LICENSE_STATUS = 'wp_bnb_license_status';
	public const OPTION_LICENSE_DATA   = 'wp_bnb_license_data';
	public const OPTION_LAST_CHECK     = 'wp_bnb_license_last_check';

	// Transient keys.
	private const TRANSIENT_LICENSE_CHECK = 'wp_bnb_license_check';

	// Cache TTL (24 hours).
	private const CACHE_TTL = 86400;

	/**
	 * Singleton instance.
	 *
	 * @var Manager|null
	 */
	private static ?Manager $instance = null;

	/**
	 * License client.
	 *
	 * @var SecureLicenseClient|LicenseClient|null
	 */
	private SecureLicenseClient|LicenseClient|null $client = null;

	/**
	 * Get singleton instance.
	 *
	 * @return Manager
	 */
	public static function get_instance(): Manager {
		if ( null === self::$instance ) {
			self::$instance = new self();
		}
		return self::$instance;
	}

	/**
	 * Private constructor.
	 */
	private function __construct() {
		$this->init_hooks();
	}

	/**
	 * Initialize WordPress hooks.
	 *
	 * @return void
	 */
	private function init_hooks(): void {
		// AJAX handlers.
		add_action( 'wp_ajax_wp_bnb_validate_license', array( $this, 'ajax_validate_license' ) );
		add_action( 'wp_ajax_wp_bnb_activate_license', array( $this, 'ajax_activate_license' ) );
		add_action( 'wp_ajax_wp_bnb_check_status', array( $this, 'ajax_check_status' ) );
	}

	/**
	 * Initialize the license client.
	 *
	 * @return bool
	 */
	private function init_client(): bool {
		if ( null !== $this->client ) {
			return true;
		}

		$server_url    = self::get_server_url();
		$server_secret = self::get_server_secret();

		if ( empty( $server_url ) ) {
			return false;
		}

		try {
			// Use SecureLicenseClient if server secret is configured.
			if ( ! empty( $server_secret ) ) {
				$this->client = new SecureLicenseClient(
					httpClient: HttpClient::create(),
					baseUrl: $server_url,
					serverSecret: $server_secret,
				);
			} else {
				$this->client = new LicenseClient(
					httpClient: HttpClient::create(),
					baseUrl: $server_url,
				);
			}
			return true;
		} catch ( \Throwable $e ) {
			return false;
		}
	}

	/**
	 * Check if license is valid.
	 *
	 * Localhost environments bypass the license check to allow
	 * full functionality during development.
	 *
	 * @return bool
	 */
	public static function is_license_valid(): bool {
		// Bypass license check for localhost environments.
		if ( self::is_localhost() ) {
			return true;
		}

		$status = get_option( self::OPTION_LICENSE_STATUS, 'unchecked' );
		return 'valid' === $status;
	}

	/**
	 * Check if running on localhost.
	 *
	 * Detects common local development environments:
	 * - localhost / 127.0.0.1 / ::1
	 * - .local, .test, .localhost domains
	 * - Private IP ranges (192.168.x.x, 10.x.x.x, 172.16-31.x.x)
	 *
	 * @return bool
	 */
	public static function is_localhost(): bool {
		$site_url = get_site_url();
		$parsed   = wp_parse_url( $site_url );
		$host     = $parsed['host'] ?? '';

		// Check for localhost variations.
		if ( in_array( $host, array( 'localhost', '127.0.0.1', '::1' ), true ) ) {
			return true;
		}

		// Check for common local development TLDs.
		$local_tlds = array( '.local', '.test', '.localhost', '.dev', '.ddev.site' );
		foreach ( $local_tlds as $tld ) {
			if ( str_ends_with( $host, $tld ) ) {
				return true;
			}
		}

		// Check for private IP ranges.
		if ( filter_var( $host, FILTER_VALIDATE_IP ) ) {
			// 10.x.x.x, 172.16-31.x.x, 192.168.x.x.
			if ( ! filter_var( $host, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE ) ) {
				return true;
			}
		}

		return false;
	}

	/**
	 * Get license key.
	 *
	 * @return string
	 */
	public static function get_license_key(): string {
		return get_option( self::OPTION_LICENSE_KEY, '' );
	}

	/**
	 * Get server URL.
	 *
	 * @return string
	 */
	public static function get_server_url(): string {
		return get_option( self::OPTION_SERVER_URL, '' );
	}

	/**
	 * Get server secret.
	 *
	 * @return string
	 */
	public static function get_server_secret(): string {
		return get_option( self::OPTION_SERVER_SECRET, '' );
	}

	/**
	 * Get cached license status.
	 *
	 * @return string
	 */
	public static function get_cached_status(): string {
		$server_url  = self::get_server_url();
		$license_key = self::get_license_key();

		if ( empty( $server_url ) || empty( $license_key ) ) {
			return 'unconfigured';
		}

		return get_option( self::OPTION_LICENSE_STATUS, 'unchecked' );
	}

	/**
	 * Get cached license data.
	 *
	 * @return array
	 */
	public static function get_cached_data(): array {
		return get_option( self::OPTION_LICENSE_DATA, array() );
	}

	/**
	 * Get last check timestamp.
	 *
	 * @return int
	 */
	public static function get_last_check(): int {
		return (int) get_option( self::OPTION_LAST_CHECK, 0 );
	}

	/**
	 * Save license settings.
	 *
	 * @param array $data Settings data.
	 * @return bool
	 */
	public static function save_settings( array $data ): bool {
		if ( isset( $data['license_key'] ) ) {
			update_option( self::OPTION_LICENSE_KEY, sanitize_text_field( $data['license_key'] ) );
		}

		if ( isset( $data['server_url'] ) ) {
			update_option( self::OPTION_SERVER_URL, esc_url_raw( $data['server_url'] ) );
		}

		// Only update secret if provided (not empty).
		if ( ! empty( $data['server_secret'] ) ) {
			update_option( self::OPTION_SERVER_SECRET, sanitize_text_field( $data['server_secret'] ) );
		}

		// Clear cached status when settings change.
		delete_transient( self::TRANSIENT_LICENSE_CHECK );

		return true;
	}

	/**
	 * Clear all license data.
	 *
	 * @return void
	 */
	public static function clear_license_data(): void {
		update_option( self::OPTION_LICENSE_STATUS, 'unchecked' );
		update_option( self::OPTION_LICENSE_DATA, array() );
		update_option( self::OPTION_LAST_CHECK, 0 );
		delete_transient( self::TRANSIENT_LICENSE_CHECK );
	}

	/**
	 * Validate license.
	 *
	 * @return array
	 */
	public function validate(): array {
		if ( ! $this->init_client() ) {
			return array(
				'success' => false,
				'message' => __( 'License client could not be initialized. Please check server URL and secret.', 'wp-bnb' ),
				'status'  => 'unconfigured',
			);
		}

		$license_key = self::get_license_key();
		if ( empty( $license_key ) ) {
			return array(
				'success' => false,
				'message' => __( 'Please enter a license key.', 'wp-bnb' ),
				'status'  => 'unconfigured',
			);
		}

		$domain = $this->get_current_domain();

		try {
			$license_info = $this->client->validate( $license_key, $domain );

			// Store license data.
			$license_data = array(
				'product_id' => $license_info->productId,
				'expires'    => $license_info->expiresAt?->format( 'Y-m-d H:i:s' ),
			);

			update_option( self::OPTION_LICENSE_STATUS, 'valid' );
			update_option( self::OPTION_LICENSE_DATA, $license_data );
			update_option( self::OPTION_LAST_CHECK, time() );
			set_transient( self::TRANSIENT_LICENSE_CHECK, 'valid', self::CACHE_TTL );

			return array(
				'success' => true,
				'message' => __( 'License is valid.', 'wp-bnb' ),
				'status'  => 'valid',
				'data'    => $license_data,
			);
		} catch ( LicenseNotFoundException $e ) {
			return $this->handle_license_error( 'invalid', __( 'License key not found.', 'wp-bnb' ) );
		} catch ( LicenseExpiredException $e ) {
			return $this->handle_license_error( 'expired', __( 'License has expired.', 'wp-bnb' ) );
		} catch ( LicenseRevokedException $e ) {
			return $this->handle_license_error( 'revoked', __( 'License has been revoked.', 'wp-bnb' ) );
		} catch ( LicenseInactiveException $e ) {
			return $this->handle_license_error( 'inactive', __( 'License is inactive. Please activate it first.', 'wp-bnb' ) );
		} catch ( DomainMismatchException $e ) {
			return $this->handle_license_error( 'invalid', __( 'License is not valid for this domain.', 'wp-bnb' ) );
		} catch ( SignatureException $e ) {
			return $this->handle_license_error( 'invalid', __( 'Response signature verification failed. Please check server secret.', 'wp-bnb' ) );
		} catch ( RateLimitExceededException $e ) {
			return array(
				'success' => false,
				'message' => sprintf(
					/* translators: %d: Seconds to wait */
					__( 'Rate limit exceeded. Please try again in %d seconds.', 'wp-bnb' ),
					$e->retryAfter
				),
				'status'  => self::get_cached_status(),
			);
		} catch ( \Throwable $e ) {
			return $this->handle_license_error( 'invalid', __( 'An error occurred while validating the license.', 'wp-bnb' ) );
		}
	}

	/**
	 * Activate license.
	 *
	 * @return array
	 */
	public function activate(): array {
		if ( ! $this->init_client() ) {
			return array(
				'success' => false,
				'message' => __( 'License client could not be initialized. Please check server URL and secret.', 'wp-bnb' ),
				'status'  => 'unconfigured',
			);
		}

		$license_key = self::get_license_key();
		if ( empty( $license_key ) ) {
			return array(
				'success' => false,
				'message' => __( 'Please enter a license key.', 'wp-bnb' ),
				'status'  => 'unconfigured',
			);
		}

		$domain = $this->get_current_domain();

		try {
			$result = $this->client->activate( $license_key, $domain );

			if ( $result->success ) {
				// Validate after activation to get full license info.
				return $this->validate();
			}

			return array(
				'success' => false,
				'message' => __( 'Activation failed.', 'wp-bnb' ),
				'status'  => 'inactive',
			);
		} catch ( MaxActivationsReachedException $e ) {
			return $this->handle_license_error( 'invalid', __( 'Maximum activations reached for this license.', 'wp-bnb' ) );
		} catch ( LicenseNotFoundException $e ) {
			return $this->handle_license_error( 'invalid', __( 'License key not found.', 'wp-bnb' ) );
		} catch ( LicenseExpiredException $e ) {
			return $this->handle_license_error( 'expired', __( 'License has expired.', 'wp-bnb' ) );
		} catch ( SignatureException $e ) {
			return $this->handle_license_error( 'invalid', __( 'Response signature verification failed. Please check server secret.', 'wp-bnb' ) );
		} catch ( RateLimitExceededException $e ) {
			return array(
				'success' => false,
				'message' => sprintf(
					/* translators: %d: Seconds to wait */
					__( 'Rate limit exceeded. Please try again in %d seconds.', 'wp-bnb' ),
					$e->retryAfter
				),
				'status'  => self::get_cached_status(),
			);
		} catch ( \Throwable $e ) {
			return $this->handle_license_error( 'invalid', __( 'An error occurred while activating the license.', 'wp-bnb' ) );
		}
	}

	/**
	 * Get license status.
	 *
	 * @param bool $force_refresh Whether to force a refresh from server.
	 * @return array
	 */
	public function get_status( bool $force_refresh = false ): array {
		// Check transient cache first.
		if ( ! $force_refresh ) {
			$cached = get_transient( self::TRANSIENT_LICENSE_CHECK );
			if ( false !== $cached ) {
				return array(
					'success' => 'valid' === $cached,
					'status'  => $cached,
					'data'    => self::get_cached_data(),
					'cached'  => true,
				);
			}
		}

		if ( ! $this->init_client() ) {
			return array(
				'success' => false,
				'status'  => 'unconfigured',
				'message' => __( 'License client not configured.', 'wp-bnb' ),
			);
		}

		$license_key = self::get_license_key();
		if ( empty( $license_key ) ) {
			return array(
				'success' => false,
				'status'  => 'unconfigured',
				'message' => __( 'No license key configured.', 'wp-bnb' ),
			);
		}

		try {
			$status_info = $this->client->status( $license_key );

			$status = match ( $status_info->status ) {
				LicenseState::Active   => 'valid',
				LicenseState::Inactive => 'inactive',
				LicenseState::Expired  => 'expired',
				LicenseState::Revoked  => 'revoked',
			};

			update_option( self::OPTION_LICENSE_STATUS, $status );
			update_option( self::OPTION_LAST_CHECK, time() );
			set_transient( self::TRANSIENT_LICENSE_CHECK, $status, self::CACHE_TTL );

			return array(
				'success' => 'valid' === $status,
				'status'  => $status,
				'data'    => self::get_cached_data(),
				'cached'  => false,
			);
		} catch ( \Throwable $e ) {
			return array(
				'success' => false,
				'status'  => 'invalid',
				'message' => __( 'Failed to check license status.', 'wp-bnb' ),
			);
		}
	}

	/**
	 * Handle license error.
	 *
	 * @param string $status  Status code.
	 * @param string $message Error message.
	 * @return array
	 */
	private function handle_license_error( string $status, string $message ): array {
		update_option( self::OPTION_LICENSE_STATUS, $status );
		update_option( self::OPTION_LAST_CHECK, time() );
		delete_transient( self::TRANSIENT_LICENSE_CHECK );

		return array(
			'success' => false,
			'message' => $message,
			'status'  => $status,
		);
	}

	/**
	 * Get current domain.
	 *
	 * @return string
	 */
	private function get_current_domain(): string {
		$site_url = get_site_url();
		$parsed   = wp_parse_url( $site_url );
		return $parsed['host'] ?? '';
	}

	/**
	 * AJAX handler: Validate license.
	 *
	 * @return void
	 */
	public function ajax_validate_license(): void {
		check_ajax_referer( 'wp_bnb_admin_nonce', 'nonce' );

		if ( ! current_user_can( 'manage_options' ) ) {
			wp_send_json_error( array(
				'message' => __( 'You do not have permission to perform this action.', 'wp-bnb' ),
			) );
		}

		$result = $this->validate();

		if ( $result['success'] ) {
			wp_send_json_success( $result );
		} else {
			wp_send_json_error( $result );
		}
	}

	/**
	 * AJAX handler: Activate license.
	 *
	 * @return void
	 */
	public function ajax_activate_license(): void {
		check_ajax_referer( 'wp_bnb_admin_nonce', 'nonce' );

		if ( ! current_user_can( 'manage_options' ) ) {
			wp_send_json_error( array(
				'message' => __( 'You do not have permission to perform this action.', 'wp-bnb' ),
			) );
		}

		$result = $this->activate();

		if ( $result['success'] ) {
			wp_send_json_success( $result );
		} else {
			wp_send_json_error( $result );
		}
	}

	/**
	 * AJAX handler: Check status.
	 *
	 * @return void
	 */
	public function ajax_check_status(): void {
		check_ajax_referer( 'wp_bnb_admin_nonce', 'nonce' );

		if ( ! current_user_can( 'manage_options' ) ) {
			wp_send_json_error( array(
				'message' => __( 'You do not have permission to perform this action.', 'wp-bnb' ),
			) );
		}

		$force_refresh = isset( $_POST['force'] ) && 'true' === $_POST['force'];
		$result        = $this->get_status( $force_refresh );

		if ( $result['success'] ) {
			wp_send_json_success( $result );
		} else {
			wp_send_json_error( $result );
		}
	}
}