<?php
/**
 * Client data wrapper for Parallax AI.
 *
 * @package AIContentByParallax
 */

namespace AIContentByParallax\Core;

defined( 'ABSPATH' ) || exit;

use AIContentByParallax\Core\Settings;
use AIContentByParallax\Config\Endpoints;
use AIContentByParallax\Api\GenericRequest;

/**
 * Client value object + helper for authenticated client data.
 * Responsible for fetching/storing client-facing attributes and
 * rendering the admin notice snippet related to client state.
 */
class Client {
	/**
	 * Transient cache TTL (seconds).
	 */
	private const CACHE_TTL = 90;

	/**
	 * Register hooks.
	 */
	public static function register(): void {
		add_action( 'update_option_' . Settings::OPTION_KEY, array( __CLASS__, 'handle_api_key_update' ), 10, 2 );
	}

	/**
	 * Clear cached client data when API key changes.
	 *
	 * @param mixed $old_value Old option value.
	 * @param mixed $value New option value.
	 */
	public static function handle_api_key_update( $old_value, $value ): void {
		$old_key = is_array( $old_value ) && isset( $old_value[ Settings::CLIENT_API_KEY_KEY ] ) ? trim( (string) $old_value[ Settings::CLIENT_API_KEY_KEY ] ) : '';
		$new_key = is_array( $value ) && isset( $value[ Settings::CLIENT_API_KEY_KEY ] ) ? trim( (string) $value[ Settings::CLIENT_API_KEY_KEY ] ) : '';

		if ( $old_key === $new_key ) {
			return;
		}

		foreach ( array_unique( array_filter( array( $old_key, $new_key ) ) ) as $api_key ) {
			delete_transient( self::get_transient_key( $api_key ) );
		}
	}

	/**
	 * Whether the client is authenticated.
	 *
	 * @var bool
	 */
	private $authenticated = false;

	/**
	 * The API key.
	 *
	 * @var string
	 */
	private $api_key = '';

	/**
	 * The client ID.
	 *
	 * @var string
	 */
	private $client_id = '';

	/**
	 * Available credits.
	 *
	 * @var int
	 */
	private $credits = 0;

	/**
	 * The client name.
	 *
	 * @var string
	 */
	private $name = '';

	/**
	 * The client description.
	 *
	 * @var string
	 */
	private $description = '';

	/**
	 * Build client data.
	 */
	public static function load(): self {
		$instance = new self();
		$api_key  = Settings::get_client_api_key();

		$instance->api_key     = $api_key;
		$instance->name        = Settings::get_client_name();
		$instance->description = Settings::get_client_desc();

		if ( '' === $api_key ) {
			$instance->api_key       = '';
			$instance->name          = Settings::get_client_name();
			$instance->description   = Settings::get_client_desc();
			$instance->credits       = 0;
			$instance->client_id     = '';
			$instance->authenticated = false;
			return $instance;
		}

		$transient_key = self::get_transient_key( $api_key );
		$cached        = get_transient( $transient_key );
		if ( is_array( $cached ) ) {
			$instance->authenticated = ! empty( $cached['authenticated'] );
			$instance->api_key       = $api_key;
			$instance->client_id     = (string) ( $cached['client_id'] ?? '' );
			$instance->credits       = (int) ( $cached['credits'] ?? 0 );
			$instance->name          = Settings::get_client_name();
			$instance->description   = Settings::get_client_desc();
			return $instance;
		}

		$instance->api_key     = $api_key;
		$instance->name        = Settings::get_client_name();
		$instance->description = Settings::get_client_desc();
		$client                = GenericRequest::get_request_payload( Endpoints::credits(), GenericRequest::get_request_args( $api_key ) );

		if ( is_array( $client ) && empty( $client['error'] ) ) {
			$instance->credits       = (int) ( $client['effectiveCredits'] ?? $client['credits'] ?? 0 );
			$instance->client_id     = (string) ( $client['clientId'] ?? '' );
			$instance->authenticated = '' !== $instance->client_id;

			set_transient(
				$transient_key,
				array(
					'authenticated' => $instance->authenticated,
					'client_id'     => $instance->client_id,
					'credits'       => $instance->credits,
				),
				self::CACHE_TTL
			);
		} else {
			$instance->credits       = 0;
			$instance->client_id     = '';
			$instance->authenticated = false;
		}

		return $instance;
	}

	/**
	 * Load the client from the transient cache only — never triggers a remote API call.
	 *
	 * When the transient is absent or expired the returned client is unauthenticated
	 * with 0 credits.  Use this for read-only rendering paths where blocking on an
	 * outbound HTTP request is not acceptable (e.g. product-edit metabox render).
	 *
	 * @return self
	 */
	public static function get_cached(): self {
		$instance                = new self();
		$api_key                 = Settings::get_client_api_key();
		$instance->api_key       = $api_key;
		$instance->name          = Settings::get_client_name();
		$instance->description   = Settings::get_client_desc();
		$instance->authenticated = false;
		$instance->credits       = 0;
		$instance->client_id     = '';

		if ( '' === $api_key ) {
			return $instance;
		}

		$cached = get_transient( self::get_transient_key( $api_key ) );
		if ( is_array( $cached ) ) {
			$instance->authenticated = ! empty( $cached['authenticated'] );
			$instance->client_id     = (string) ( $cached['client_id'] ?? '' );
			$instance->credits       = (int) ( $cached['credits'] ?? 0 );
		}

		return $instance;
	}

	/**
	 * Build transient cache key for API key.
	 *
	 * @param string $api_key API key.
	 * @return string
	 */
	private static function get_transient_key( string $api_key ): string {
		return 'ai_content_by_parallax_client_' . md5( $api_key );
	}

	/**
	 * Determine if the client is authenticated with the API.
	 *
	 * @return bool
	 */
	public function is_user_authenticated(): bool {
		return $this->authenticated;
	}

	/**
	 * Get the client ID.
	 *
	 * @return string
	 */
	public function get_client_id(): string {
		return $this->client_id;
	}

	/**
	 * Get the API key.
	 *
	 * @return string
	 */
	public function get_api_key(): string {
		return $this->api_key;
	}

	/**
	 * Get available credits.
	 *
	 * @return int
	 */
	public function get_credits(): int {
		return $this->credits;
	}

	/**
	 * Get the client name.
	 *
	 * @return string
	 */
	public function get_name(): string {
		return $this->name;
	}

	/**
	 * Get the client description.
	 *
	 * @return string
	 */
	public function get_description(): string {
		return $this->description;
	}

	/**
	 * Build a site-based identifier.
	 *
	 * @return string
	 */
	public function get_client_identifier(): string {
		return str_replace( '.', '_', wp_parse_url( site_url(), PHP_URL_HOST ) );
	}

	/**
	 * Represent client data as an array suitable for display.
	 *
	 * @return array
	 */
	public function get_info_array(): array {
		return array(
			array(
				'Key'   => 'Authenticated',
				'Value' => $this->is_user_authenticated() ? 'yes' : 'no',
			),
			array(
				'Key'   => 'Client ID',
				'Value' => (string) $this->get_client_id(),
			),
			array(
				'Key'   => 'Credits',
				'Value' => (string) $this->get_credits(),
			),
			array(
				'Key'   => 'Name',
				'Value' => (string) $this->get_name(),
			),
			array(
				'Key'   => 'Description',
				'Value' => (string) $this->get_description(),
			),
			array(
				'Key'   => 'Identifier',
				'Value' => (string) $this->get_client_identifier(),
			),
			array(
				'Key'   => 'API Key',
				'Value' => (string) $this->get_api_key(),
			),
		);
	}
}