<?php
if ( ! defined( 'ABSPATH' ) ) exit;

class PXSYNC_CAPI {

    private $token;
    private $pixel_id;
    private $test_code;
    private $api_url = 'https://business-api.tiktok.com/open_api/v1.3/pixel/track/';

    public function __construct() {
        $this->token     = trim( (string) get_option('pxsync_capi_token') );
        $this->pixel_id  = trim( (string) get_option('pxsync_pixel_id') );
        $this->test_code = trim( (string) get_option('pxsync_test_event_code') );
    }

    public function send( $event_name, $event_id, $external_id, $properties = [], $user_context = [] ) {
        if ( empty($this->token) || empty($this->pixel_id) ) return false;

        $payload = $this->build_payload($event_name, $event_id, $external_id, $properties, $user_context);

        if ( ! empty( $this->test_code ) ) {
            $payload['test_event_code'] = $this->test_code;
        }

        $response = wp_remote_post( $this->api_url, [
            'headers' => [
                'Access-Token' => $this->token,
                'Content-Type' => 'application/json'
            ],
            'body'    => wp_json_encode($payload),
            'timeout' => 20,
        ]);

        $status_code = wp_remote_retrieve_response_code( $response );

        // ✅ NEW: Retry queue with exponential backoff
        // Never forget comments: Uses Action Scheduler (bundled with WooCommerce).
        // _pxsync_retry tracks attempt count — max 3 retries total (1min, 2min, 4min).
        if ( $status_code !== 200 && function_exists('as_schedule_single_action') ) {
            $retry_count = isset($properties['_pxsync_retry']) ? (int) $properties['_pxsync_retry'] : 0;
            if ( $retry_count < 3 ) {
                as_schedule_single_action(
                    time() + ( 60 * pow( 2, $retry_count ) ),
                    'pxsync_retry_capi_event',
                    [[
                        'event'       => $event_name,
                        'event_id'    => $event_id,
                        'external_id' => $external_id,
                        'properties'  => array_merge( $properties, ['_pxsync_retry' => $retry_count + 1] ),
                        'user'        => $user_context,
                    ]],
                    'pxsync-capi'
                );
            }
        }

        return $response;
    }

    private function build_payload( $event_name, $event_id, $external_id, $properties = [], $user_context = [] ) {


        // TikTok rejects empty-string identifiers ("Email address is invalid"), so only send what we have.
        $user = array_filter( [
            'external_id' => $external_id,
            'email'       => $user_context['email'] ?? '',
            'phone'       => $user_context['phone'] ?? '',
            'ttp'        => isset( $_COOKIE['_ttp'] ) ? sanitize_text_field( wp_unslash( $_COOKIE['_ttp'] ) ) : '',
        ], function ( $v ) { return $v !== '' && $v !== null; } );
        $ad = ! empty( $_COOKIE['ttclid'] ) ? [ 'callback' => sanitize_text_field( wp_unslash( $_COOKIE['ttclid'] ) ) ] : [];

        return [
            'pixel_code' => $this->pixel_id,
            'event'      => $event_name,
            'event_id'   => $event_id,
            'timestamp'  => gmdate('Y-m-d\TH:i:s\Z'),
            'context'    => [
                'ad'   => (object) $ad,
                'user' => (object) $user,
                'user_agent' => $this->get_user_agent(),
                'ip'         => $this->get_client_ip(), // 
                'library'    => ['name' => 'php', 'version' => '1.0.0'],
                'page'       => [
                    'url'      => $user_context['url'] ?? $this->get_current_url(),
                    'referrer'   => isset( $_SERVER['HTTP_REFERER'] ) ? esc_url_raw( wp_unslash( $_SERVER['HTTP_REFERER'] ) ) : '',                ],
            ],
            'properties' => $properties
        ];
    }

    private function get_current_url() {
        $host = isset( $_SERVER['HTTP_HOST'] )   ? sanitize_text_field( wp_unslash( $_SERVER['HTTP_HOST'] ) )   : '';
        $uri  = isset( $_SERVER['REQUEST_URI'] ) ? sanitize_text_field( wp_unslash( $_SERVER['REQUEST_URI'] ) ) : '';

        return esc_url_raw( ( is_ssl() ? 'https://' : 'http://' ) . $host . $uri );    }

    // Cloudflare-aware IP detection
    //  Behind Cloudflare, REMOTE_ADDR is the CDN IP.
    // CF-Connecting-IP is the real visitor IP and must be trusted first.
    public function get_client_ip() {
        $headers = [ 'HTTP_CF_CONNECTING_IP', 'HTTP_X_REAL_IP', 'HTTP_X_FORWARDED_FOR', 'HTTP_CLIENT_IP', 'REMOTE_ADDR' ];
        foreach ( $headers as $h ) {
            if ( empty( $_SERVER[ $h ] ) ) continue;
            $raw = sanitize_text_field( wp_unslash( $_SERVER[ $h ] ) );
            foreach ( explode( ',', $raw ) as $candidate ) {
                $candidate = trim( $candidate );
                if ( filter_var( $candidate, FILTER_VALIDATE_IP ) ) return $candidate;
            }
        }
        return '127.0.0.1';
    }

    public function get_user_agent() {
        return isset( $_SERVER['HTTP_USER_AGENT'] ) ? sanitize_text_field( wp_unslash( $_SERVER['HTTP_USER_AGENT'] ) ) : '';
    }
    }