<?php
/**
 * Viber to SMS fallback processor.
 *
 * @package IntelTele
 */

namespace IntelTele\Services;

use IntelTele\Api\ClientFactory;
use IntelTele\Repositories\MessageLogRepository;
use IntelTele\Repositories\SettingsRepository;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

final class ViberFallbackProcessor {
	/**
	 * Log repository.
	 *
	 * @var MessageLogRepository
	 */
	private $log_repository;

	/**
	 * Settings repository.
	 *
	 * @var SettingsRepository
	 */
	private $settings_repository;

	/**
	 * Constructor.
	 */
	public function __construct() {
		$this->log_repository      = new MessageLogRepository();
		$this->settings_repository = new SettingsRepository();
	}

	/**
	 * Process SMS fallback candidates.
	 *
	 * @return int Number of fallback SMS messages sent.
	 */
	public function process(): int {
		$candidates = $this->log_repository->get_viber_fallback_candidates( 50 );

		if ( empty( $candidates ) ) {
			PluginLogger::log(
				'info',
				'fallback_processing_skipped',
				__( 'No Viber SMS fallback candidates found.', 'inteltele' ),
				array(),
				'ViberFallbackProcessor'
			);
			return 0;
		}

		$settings = $this->settings_repository->get_all();
		$client   = ClientFactory::create( $settings );
		$sent     = 0;

		foreach ( $candidates as $candidate ) {
			if ( StatusMapper::is_viber_success( (string) $candidate->api_status ) ) {
				continue;
			}

			$fallback_message = isset( $candidate->fallback_message ) && '' !== trim( (string) $candidate->fallback_message ) ? (string) $candidate->fallback_message : (string) $candidate->message;
			$result = $client->send_sms( $fallback_message, array( (string) $candidate->recipient_phone ) );
			$data   = $result->get_data();
			$item   = $this->first_item( $data );
			$error_code = $result->is_success() ? '' : $this->derive_error_code( $result );

			$this->log_repository->insert(
				array(
					'campaign_id'       => empty( $candidate->campaign_id ) ? null : (int) $candidate->campaign_id,
					'order_id'          => empty( $candidate->order_id ) ? null : (int) $candidate->order_id,
					'send_type'         => (string) $candidate->send_type,
					'recipient_phone'   => (string) $candidate->recipient_phone,
					'recipient_name'    => (string) $candidate->recipient_name,
					'recipient_role'    => (string) $candidate->recipient_role,
					'channel'           => 'sms',
					'scheme'            => 'viber_sms',
					'message'           => $fallback_message,
					'api_message_id'    => isset( $item['message_id'] ) ? (string) $item['message_id'] : '',
					'api_status'        => $result->is_success() ? 'OK' : '',
					'api_status_code'   => $result->get_status_code(),
					'error_code'        => $error_code,
					'api_response'      => $this->encode_api_response( $result ),
					'status'            => $result->is_success() ? 'sent' : 'failed',
					'error_reason'      => $result->is_success() ? null : $result->get_error(),
					'status_updated_at' => current_time( 'mysql' ),
				)
			);

			$this->log_repository->mark_sms_fallback_sent( (int) $candidate->id );

			if ( $result->is_success() ) {
				$sent++;
			}

			PluginLogger::log(
				$result->is_success() ? 'info' : 'error',
				$result->is_success() ? 'fallback_sms_sent' : 'fallback_sms_failed',
				$result->is_success() ? __( 'SMS fallback accepted by API.', 'inteltele' ) : $result->get_error(),
				array(
					'original_log_id' => (int) $candidate->id,
					'phone'           => (string) $candidate->recipient_phone,
					'api_message_id'  => isset( $item['message_id'] ) ? (string) $item['message_id'] : '',
					'http_status'     => $result->get_status_code(),
					'error_code'      => $error_code,
				),
				'ViberFallbackProcessor'
			);
		}

		return $sent;
	}

	/**
	 * Get first response item.
	 *
	 * @param array<string,mixed> $data API data.
	 * @return array<string,mixed>
	 */
	private function first_item( array $data ): array {
		$items = isset( $data['items'] ) && is_array( $data['items'] ) ? $data['items'] : array();
		$item  = reset( $items );

		return is_array( $item ) ? $item : array();
	}

	/**
	 * Encode API response for diagnostics.
	 *
	 * @param \IntelTele\Api\ApiResult $result API result.
	 */
	private function encode_api_response( \IntelTele\Api\ApiResult $result ): string {
		$raw = $result->get_raw();

		if ( is_wp_error( $raw ) ) {
			$raw = array(
				'errors' => $raw->errors,
				'data'   => $raw->error_data,
			);
		}

		return (string) wp_json_encode(
			array(
				'http_status' => $result->get_status_code(),
				'data'        => $result->get_data(),
				'error'       => $result->get_error(),
				'raw'         => $raw,
			),
			JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES
		);
	}

	/**
	 * Derive a stable error code for failed API requests.
	 *
	 * @param \IntelTele\Api\ApiResult $result API result.
	 */
	private function derive_error_code( \IntelTele\Api\ApiResult $result ): string {
		$raw = $result->get_raw();

		if ( is_wp_error( $raw ) ) {
			$codes = $raw->get_error_codes();
			return isset( $codes[0] ) ? $this->normalize_error_code( (string) $codes[0] ) : 'wp_error';
		}

		if ( $result->get_status_code() > 0 && ! $result->is_success() ) {
			return 'http_' . $result->get_status_code();
		}

		return $this->normalize_error_code( $result->get_error() );
	}

	/**
	 * Normalize arbitrary API/WP error text to a searchable code.
	 *
	 * @param string $value Error text.
	 */
	private function normalize_error_code( string $value ): string {
		$value = preg_replace( '/^error:\s*/i', '', $value );
		$value = strtolower( trim( (string) $value ) );
		$value = preg_replace( '/[^a-z0-9_:-]+/', '_', $value );
		$value = trim( (string) $value, '_' );

		return '' === $value ? 'unknown_error' : substr( $value, 0, 191 );
	}
}