<?php
/**
 * A message to deliver.
 *
 * @package Rahkar\WP
 */

declare( strict_types = 1 );

namespace Rahkar\WP\Notifications;

defined( 'ABSPATH' ) || exit;

/**
 * What to send, to whom, and on behalf of which event.
 *
 * Carries both a rendered body and the raw variables that produced it, because
 * the two send modes need different things: free-text SMS and email want the
 * body, while pattern SMS discards it and sends the variables against an
 * operator-approved template. A message that only carried a body could not be
 * sent over a service line at all.
 */
final class Message {

	/**
	 * Build a message ready to hand to a driver.
	 *
	 * @param string               $event     Event name, e.g. `otp.login`.
	 * @param string               $to        Recipient: canonical phone number, or email address.
	 * @param string               $body      Rendered text, used for free-text SMS and email.
	 * @param array<string,scalar> $variables Template variables, used for pattern sends.
	 * @param string               $subject   Email subject. Ignored by SMS.
	 * @param bool                 $urgent    Whether a person is waiting on this right now.
	 * @param string               $pattern   Approved provider pattern to send with. Empty lets the
	 *                                        driver resolve one for the event, or send the body.
	 * @param string               $id        Stable id of this message across retries; generated when empty.
	 * @param array<string,string> $context   Non-personal ids the message is about, e.g. `cart_id`; reported
	 *                                        with `message.*` so the dashboard can tie a send to its cart.
	 * @param string               $module    Slug of the module sending it, for the dashboard's cost per module.
	 */
	public function __construct(
		public string $event,
		public string $to,
		public string $body = '',
		public array $variables = [],
		public string $subject = '',
		public bool $urgent = false,
		public string $pattern = '',
		public string $id = '',
		public array $context = [],
		public string $module = ''
	) {
		if ( '' === $this->id ) {
			$this->id = wp_generate_uuid4();
		}
	}

	/**
	 * Serialise for the job queue.
	 *
	 * @return array<string, mixed>
	 */
	public function toArray(): array {
		return [
			'event'     => $this->event,
			'to'        => $this->to,
			'body'      => $this->body,
			'variables' => $this->variables,
			'subject'   => $this->subject,
			'urgent'    => $this->urgent,
			'pattern'   => $this->pattern,
			'id'        => $this->id,
			'context'   => $this->context,
			'module'    => $this->module,
		];
	}

	/**
	 * Rebuild from a queued payload.
	 *
	 * @param array<string, mixed> $data Stored payload.
	 */
	public static function fromArray( array $data ): self {
		$variables = $data['variables'] ?? [];

		return new self(
			(string) ( $data['event'] ?? '' ),
			(string) ( $data['to'] ?? '' ),
			(string) ( $data['body'] ?? '' ),
			is_array( $variables ) ? $variables : [],
			(string) ( $data['subject'] ?? '' ),
			(bool) ( $data['urgent'] ?? false ),
			(string) ( $data['pattern'] ?? '' ),
			// Jobs queued before 0.26.0 have no id; they get one now.
			(string) ( $data['id'] ?? '' ),
			// Jobs queued before 0.27.0 have neither; both are optional.
			self::context( $data['context'] ?? [] ),
			sanitize_key( (string) ( $data['module'] ?? '' ) )
		);
	}

	/**
	 * Loggable form.
	 *
	 * The recipient is masked and the variables are dropped entirely: for an OTP
	 * event they hold the code itself, and a log that records live codes is a way
	 * to hand someone an account.
	 *
	 * @return array<string, mixed>
	 */
	public function toLog(): array {
		$phone = PhoneNumber::parse( $this->to );

		return [
			'event' => $this->event,
			'to'    => null !== $phone ? $phone->masked() : self::maskEmail( $this->to ),
		];
	}

	/**
	 * Context ids as the contract allows them: lower-case keys, non-empty string
	 * values of at most 64 characters (EVENTS-v1.md §9).
	 *
	 * @param mixed $raw Stored context.
	 *
	 * @return array<string, string>
	 */
	public static function context( $raw ): array {
		$context = [];

		foreach ( is_array( $raw ) ? $raw : [] as $key => $value ) {
			if ( is_string( $key ) && 1 === preg_match( '/^[a-z_]+$/', $key ) && ( is_string( $value ) || is_int( $value ) ) ) {
				$value = (string) $value;

				if ( '' !== $value && strlen( $value ) <= 64 ) {
					$context[ $key ] = $value;
				}
			}
		}

		return $context;
	}

	/**
	 * Partly hide an email address.
	 *
	 * @param string $email Address to mask.
	 */
	private static function maskEmail( string $email ): string {
		$at = strpos( $email, '@' );

		if ( false === $at || $at < 2 ) {
			return '***';
		}

		return substr( $email, 0, 2 ) . '***' . substr( $email, $at );
	}
}