<?php
/**
 * License management class.
 *
 * Wraps the wc-licensed-product-client library for WordPress integration.
 *
 * @package WP_FediStream
 */

namespace WP_FediStream\License;

use Magdev\WcLicensedProductClient\SecureLicenseClient;
use Magdev\WcLicensedProductClient\Dto\LicenseInfo;
use Magdev\WcLicensedProductClient\Dto\LicenseStatus;
use Magdev\WcLicensedProductClient\Dto\LicenseState;
use Magdev\WcLicensedProductClient\Dto\ActivationResult;
use Magdev\WcLicensedProductClient\Exception\LicenseException;
use Magdev\WcLicensedProductClient\Exception\LicenseNotFoundException;
use Magdev\WcLicensedProductClient\Exception\LicenseExpiredException;
use Magdev\WcLicensedProductClient\Exception\LicenseInvalidException;
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;

// Prevent direct file access.
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * License Manager class.
 *
 * Handles license validation, activation, and status checking.
 */
final class Manager {

	/**
	 * Option names for license settings.
	 */
	public const OPTION_LICENSE_KEY     = 'wp_fedistream_license_key';
	public const OPTION_SERVER_URL      = 'wp_fedistream_license_server_url';
	public const OPTION_SERVER_SECRET   = 'wp_fedistream_license_server_secret';
	public const OPTION_LICENSE_STATUS  = 'wp_fedistream_license_status';
	public const OPTION_LICENSE_DATA    = 'wp_fedistream_license_data';
	public const OPTION_LAST_CHECK      = 'wp_fedistream_license_last_check';

	/**
	 * Transient name for caching license validation.
	 */
	private const TRANSIENT_LICENSE_CHECK = 'wp_fedistream_license_check';

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

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

	/**
	 * License client instance.
	 *
	 * @var SecureLicenseClient|null
	 */
	private ?SecureLicenseClient $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 {
		add_action( 'wp_ajax_fedistream_validate_license', array( $this, 'ajax_validate_license' ) );
		add_action( 'wp_ajax_fedistream_activate_license', array( $this, 'ajax_activate_license' ) );
		add_action( 'wp_ajax_fedistream_deactivate_license', array( $this, 'ajax_deactivate_license' ) );
		add_action( 'wp_ajax_fedistream_check_license_status', array( $this, 'ajax_check_status' ) );
	}

	/**
	 * Initialize the license client.
	 *
	 * @return bool True if client was initialized successfully.
	 */
	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 ) || empty( $server_secret ) ) {
			return false;
		}

		try {
			$this->client = new SecureLicenseClient(
				httpClient: HttpClient::create(),
				baseUrl: $server_url,
				serverSecret: $server_secret,
			);
			return true;
		} catch ( \Throwable $e ) {
			return false;
		}
	}

	/**
	 * Validate the current license.
	 *
	 * @return array{success: bool, message: string, data?: array}
	 */
	public function validate(): array {
		if ( ! $this->init_client() ) {
			return array(
				'success' => false,
				'message' => __( 'License server configuration is incomplete.', 'wp-fedistream' ),
			);
		}

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

		$domain = wp_parse_url( home_url(), PHP_URL_HOST );

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

			// Update cached status.
			$this->update_cached_status( 'valid', array(
				'product_id' => $result->productId,
				'expires_at' => $result->expiresAt?->format( 'c' ),
				'version_id' => $result->versionId,
			) );

			return array(
				'success' => true,
				'message' => __( 'License validated successfully.', 'wp-fedistream' ),
				'data'    => array(
					'status'     => 'valid',
					'product_id' => $result->productId,
					'expires_at' => $result->expiresAt?->format( 'Y-m-d' ),
					'lifetime'   => $result->isLifetime(),
				),
			);
		} catch ( LicenseNotFoundException $e ) {
			$this->update_cached_status( 'invalid' );
			return array(
				'success' => false,
				'message' => __( 'License key not found. Please check your license key.', 'wp-fedistream' ),
			);
		} catch ( LicenseExpiredException $e ) {
			$this->update_cached_status( 'expired' );
			return array(
				'success' => false,
				'message' => __( 'Your license has expired. Please renew to continue.', 'wp-fedistream' ),
			);
		} catch ( LicenseRevokedException $e ) {
			$this->update_cached_status( 'revoked' );
			return array(
				'success' => false,
				'message' => __( 'Your license has been revoked.', 'wp-fedistream' ),
			);
		} catch ( LicenseInactiveException $e ) {
			$this->update_cached_status( 'inactive' );
			return array(
				'success' => false,
				'message' => __( 'License is inactive. Please activate it first.', 'wp-fedistream' ),
			);
		} catch ( DomainMismatchException $e ) {
			$this->update_cached_status( 'invalid' );
			return array(
				'success' => false,
				'message' => __( 'This license is not activated for this domain.', 'wp-fedistream' ),
			);
		} catch ( SignatureException $e ) {
			return array(
				'success' => false,
				'message' => __( 'License verification failed. Please check your server secret.', 'wp-fedistream' ),
			);
		} catch ( RateLimitExceededException $e ) {
			return array(
				'success' => false,
				'message' => __( 'Too many requests. Please try again later.', 'wp-fedistream' ),
			);
		} catch ( LicenseException $e ) {
			return array(
				'success' => false,
				'message' => sprintf(
					/* translators: %s: Error message */
					__( 'License validation failed: %s', 'wp-fedistream' ),
					$e->getMessage()
				),
			);
		} catch ( \Throwable $e ) {
			return array(
				'success' => false,
				'message' => __( 'Unable to verify license. Please try again later.', 'wp-fedistream' ),
			);
		}
	}

	/**
	 * Activate the license for this domain.
	 *
	 * @return array{success: bool, message: string, data?: array}
	 */
	public function activate(): array {
		if ( ! $this->init_client() ) {
			return array(
				'success' => false,
				'message' => __( 'License server configuration is incomplete.', 'wp-fedistream' ),
			);
		}

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

		$domain = wp_parse_url( home_url(), PHP_URL_HOST );

		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' => $result->message,
			);
		} catch ( MaxActivationsReachedException $e ) {
			return array(
				'success' => false,
				'message' => __( 'Maximum number of activations reached. Please deactivate another site first.', 'wp-fedistream' ),
			);
		} catch ( LicenseNotFoundException $e ) {
			return array(
				'success' => false,
				'message' => __( 'License key not found. Please check your license key.', 'wp-fedistream' ),
			);
		} catch ( LicenseExpiredException $e ) {
			return array(
				'success' => false,
				'message' => __( 'Your license has expired. Please renew to continue.', 'wp-fedistream' ),
			);
		} catch ( SignatureException $e ) {
			return array(
				'success' => false,
				'message' => __( 'License verification failed. Please check your server secret.', 'wp-fedistream' ),
			);
		} catch ( LicenseException $e ) {
			return array(
				'success' => false,
				'message' => sprintf(
					/* translators: %s: Error message */
					__( 'License activation failed: %s', 'wp-fedistream' ),
					$e->getMessage()
				),
			);
		} catch ( \Throwable $e ) {
			return array(
				'success' => false,
				'message' => __( 'Unable to activate license. Please try again later.', 'wp-fedistream' ),
			);
		}
	}

	/**
	 * Get the current license status.
	 *
	 * @param bool $force_refresh Force a fresh check from the server.
	 * @return array{success: bool, message: string, data?: array}
	 */
	public function get_status( bool $force_refresh = false ): array {
		// Check cached status first.
		if ( ! $force_refresh ) {
			$cached = $this->get_cached_validation();
			if ( null !== $cached ) {
				return $cached;
			}
		}

		if ( ! $this->init_client() ) {
			return array(
				'success' => false,
				'message' => __( 'License server configuration is incomplete.', 'wp-fedistream' ),
				'data'    => array(
					'status' => 'unconfigured',
				),
			);
		}

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

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

			$status_map = array(
				LicenseState::Active->value   => 'valid',
				LicenseState::Inactive->value => 'inactive',
				LicenseState::Expired->value  => 'expired',
				LicenseState::Revoked->value  => 'revoked',
			);

			$status = $status_map[ $result->status->value ] ?? 'invalid';

			$data = array(
				'status'            => $status,
				'valid'             => $result->valid,
				'domain'            => $result->domain,
				'expires_at'        => $result->expiresAt?->format( 'Y-m-d' ),
				'lifetime'          => $result->isLifetime(),
				'activations_count' => $result->activationsCount,
				'max_activations'   => $result->maxActivations,
			);

			// Cache the result.
			$this->cache_validation( array(
				'success' => $result->valid,
				'message' => $result->valid
					? __( 'License is active.', 'wp-fedistream' )
					: __( 'License is not active.', 'wp-fedistream' ),
				'data'    => $data,
			) );

			$this->update_cached_status( $status, $data );

			return array(
				'success' => $result->valid,
				'message' => $result->valid
					? __( 'License is active.', 'wp-fedistream' )
					: __( 'License is not active.', 'wp-fedistream' ),
				'data'    => $data,
			);
		} catch ( LicenseNotFoundException $e ) {
			$this->update_cached_status( 'invalid' );
			return array(
				'success' => false,
				'message' => __( 'License key not found.', 'wp-fedistream' ),
				'data'    => array(
					'status' => 'invalid',
				),
			);
		} catch ( SignatureException $e ) {
			return array(
				'success' => false,
				'message' => __( 'License verification failed. Please check your server secret.', 'wp-fedistream' ),
				'data'    => array(
					'status' => 'error',
				),
			);
		} catch ( \Throwable $e ) {
			return array(
				'success' => false,
				'message' => __( 'Unable to check license status.', 'wp-fedistream' ),
				'data'    => array(
					'status' => 'error',
				),
			);
		}
	}

	/**
	 * Deactivate the license (clear local data).
	 *
	 * @return bool
	 */
	public function deactivate(): bool {
		self::clear_license_data();
		return true;
	}

	/**
	 * Check if the license is currently valid.
	 *
	 * Uses cached status for performance.
	 *
	 * @return bool
	 */
	public static function is_license_valid(): bool {
		$status = get_option( self::OPTION_LICENSE_STATUS, 'unchecked' );
		return 'valid' === $status;
	}

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

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

	/**
	 * Get the 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 {
		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'] ) );
		}

		if ( isset( $data['server_secret'] ) ) {
			// Only update if a new secret is provided.
			$secret = sanitize_text_field( $data['server_secret'] );
			if ( ! empty( $secret ) ) {
				update_option( self::OPTION_SERVER_SECRET, $secret );
			}
		}

		// Reset status when settings change.
		update_option( self::OPTION_LICENSE_STATUS, 'unchecked' );
		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 );
	}

	/**
	 * Update cached license status.
	 *
	 * @param string $status Status value.
	 * @param array  $data   Additional data.
	 * @return void
	 */
	private function update_cached_status( string $status, array $data = array() ): void {
		update_option( self::OPTION_LICENSE_STATUS, $status );
		update_option( self::OPTION_LICENSE_DATA, $data );
		update_option( self::OPTION_LAST_CHECK, time() );
	}

	/**
	 * Cache validation result.
	 *
	 * @param array $result Validation result.
	 * @return void
	 */
	private function cache_validation( array $result ): void {
		set_transient( self::TRANSIENT_LICENSE_CHECK, $result, self::CACHE_TTL );
	}

	/**
	 * Get cached validation result.
	 *
	 * @return array|null
	 */
	private function get_cached_validation(): ?array {
		$cached = get_transient( self::TRANSIENT_LICENSE_CHECK );
		return false === $cached ? null : $cached;
	}

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

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

		$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( 'fedistream_license_action', 'nonce' );

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

		$result = $this->activate();

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

	/**
	 * AJAX handler: Deactivate license.
	 *
	 * @return void
	 */
	public function ajax_deactivate_license(): void {
		check_ajax_referer( 'fedistream_license_action', 'nonce' );

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

		$this->deactivate();

		wp_send_json_success( array(
			'success' => true,
			'message' => __( 'License deactivated.', 'wp-fedistream' ),
		) );
	}

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

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

		$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 );
		}
	}
}