<?php

defined('ABSPATH') || exit;

function ridoway_pixel_capi_is_active() {
    $pixel_id = ridoway_pixel_option('pixel_id', '');
    $api_key  = ridoway_pixel_option('capi_key', '');
    return !empty($pixel_id) && !empty($api_key);
}

function ridoway_pixel_capi_get_source_url() {
    $scheme = is_ssl() ? 'https://' : 'http://';
    $host   = isset($_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 $scheme . $host . $uri;
}

function ridoway_pixel_capi_get_ip_address() {
    if (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) {
        $ips = explode(',', sanitize_text_field(wp_unslash($_SERVER['HTTP_X_FORWARDED_FOR'])));
        return trim($ips[0]);
    }
    if (!empty($_SERVER['REMOTE_ADDR'])) {
        return sanitize_text_field(wp_unslash($_SERVER['REMOTE_ADDR']));
    }
    return '';
}

function ridoway_pixel_capi_get_user_agent() {
    if (!empty($_SERVER['HTTP_USER_AGENT'])) {
        return sanitize_text_field(wp_unslash($_SERVER['HTTP_USER_AGENT']));
    }
    return '';
}

/**
 * Assemble one Conversions API event.
 *
 * @param string $event_id   Shared with the browser so OpenAI deduplicates.
 * @param string $event_type OpenAI event name.
 * @param array  $data       The event data object.
 * @param array  $user       Extra user fields (e.g. email_sha256, obref).
 * @return array
 */
function ridoway_pixel_capi_build_event($event_id, $event_type, $data, $user = array()) {
    $event = array(
        'id'           => $event_id,
        'type'         => $event_type,
        'timestamp_ms' => (int) (microtime(true) * 1000),
        'action_source' => 'web',
        'source_url'   => ridoway_pixel_capi_get_source_url(),
        'data'         => $data,
    );

    // The ad-click identifier ties the conversion back to a specific ChatGPT
    // ad click on the server side, the same value the browser reports.
    $oppref = ridoway_pixel_capi_get_oppref();

    if ($oppref !== '') {
        $event['oppref'] = $oppref;
    }

    $user_data = array_merge(array(
        'ip_address' => ridoway_pixel_capi_get_ip_address(),
        'user_agent' => ridoway_pixel_capi_get_user_agent(),
    ), (array) $user);

    $obref = ridoway_pixel_capi_get_obref();

    if ($obref !== '') {
        $user_data['obref'] = $obref;
    }

    $user_data = array_filter($user_data, function ($value) {
        return $value !== '';
    });

    if (!empty($user_data)) {
        $event['user'] = $user_data;
    }

    return $event;
}

/**
 * Send one event to the Conversions API synchronously.
 *
 * @param array $event A built Conversions API event.
 * @return array|\WP_Error
 */
function ridoway_pixel_capi_http_post($event) {
    $pixel_id = ridoway_pixel_option('pixel_id', '');
    $api_key  = ridoway_pixel_option('capi_key', '');

    $body = array(
        'integration_source' => 'ridoway-pixel',
        'validate_only'      => ridoway_pixel_option_enabled('validate_only'),
        'events'             => array($event),
    );

    $url = add_query_arg('pid', $pixel_id, 'https://bzr.openai.com/v1/events');

    return wp_remote_post($url, array(
        'headers'     => array(
            'Authorization' => 'Bearer ' . $api_key,
            'Content-Type'  => 'application/json',
        ),
        'body'        => wp_json_encode($body, JSON_UNESCAPED_SLASHES),
        'timeout'     => 5,
        'redirection' => 0,
    ));
}

/**
 * Has a CAPI request gone wrong?
 *
 * @param array|\WP_Error $response
 * @return bool
 */
function ridoway_pixel_capi_send_failed($response) {
    if (is_wp_error($response)) {
        return true;
    }

    $code = (int) wp_remote_retrieve_response_code($response);

    return $code < 200 || $code >= 300;
}

/**
 * Add an event to the retry queue and schedule a flush.
 *
 * @param array $event
 * @param int   $attempts
 */
function ridoway_pixel_capi_enqueue($event, $attempts = 0) {
    $queue = get_transient('ridoway_pixel_capi_retry_queue');

    if (!is_array($queue)) {
        $queue = array();
    }

    $queue[] = array(
        'event'    => $event,
        'attempts' => (int) $attempts,
        'time'     => time(),
    );

    // Keep the queue bounded so a broken site cannot grow it forever.
    $queue = array_slice($queue, -50);

    set_transient('ridoway_pixel_capi_retry_queue', $queue, DAY_IN_SECONDS);

    ridoway_pixel_capi_schedule_flush();
}

/**
 * Schedule the retry flush, only once.
 */
function ridoway_pixel_capi_schedule_flush() {
    if (get_option('ridoway_pixel_capi_flush_scheduled', '0') === '1') {
        return;
    }

    $scheduled = wp_schedule_single_event(time() + 30, 'ridoway_pixel_capi_flush');

    if (false !== $scheduled) {
        update_option('ridoway_pixel_capi_flush_scheduled', '1', false);
    }
}

/**
 * Cron handler: drain the retry queue.
 */
function ridoway_pixel_capi_cron_flush() {
    delete_option('ridoway_pixel_capi_flush_scheduled');

    $queue = get_transient('ridoway_pixel_capi_retry_queue');

    if (empty($queue) || !is_array($queue)) {
        return;
    }

    if (!ridoway_pixel_capi_is_active()) {
        return;
    }

    $remaining  = array();
    $reschedule = false;

    foreach ($queue as $item) {
        $attempts = isset($item['attempts']) ? (int) $item['attempts'] : 0;

        // Give up after repeated failures or when the event is stale.
        if ($attempts >= 6 || (time() - (int) $item['time']) > DAY_IN_SECONDS) {
            continue;
        }

        $response = ridoway_pixel_capi_http_post($item['event']);

        if (ridoway_pixel_capi_send_failed($response)) {
            $item['attempts'] = $attempts + 1;
            $remaining[]      = $item;
            $reschedule       = true;

            if (ridoway_pixel_option_enabled('debug_mode')) {
                ridoway_pixel_capi_log($item['event'], $response);
            }
        }
    }

    if (!empty($remaining)) {
        set_transient('ridoway_pixel_capi_retry_queue', $remaining, DAY_IN_SECONDS);
    } else {
        delete_transient('ridoway_pixel_capi_retry_queue');
    }

    if ($reschedule) {
        ridoway_pixel_capi_schedule_flush();
    }
}

add_action('ridoway_pixel_capi_flush', 'ridoway_pixel_capi_cron_flush');

function ridoway_pixel_capi_log($event, $response) {
    if (is_wp_error($response)) {
        error_log('[Ridoway Pixel CAPI] Error: ' . $response->get_error_message() . ' | Event: ' . $event['type']);
    } else {
        $code = wp_remote_retrieve_response_code($response);
        $body = wp_remote_retrieve_body($response);
        error_log('[Ridoway Pixel CAPI] Sent: ' . $event['type'] . ' | Status: ' . $code . ' | Response: ' . $body);
    }
}

/**
 * Send a server-side event.
 *
 * Debug mode sends synchronously and logs the result. Otherwise the event is
 * queued and delivered by cron, so the visitor's request is never delayed, and
 * failures are retried a few times instead of being lost.
 *
 * @param string $event_id   Shared event id, used for browser<->server dedup.
 * @param string $event_type OpenAI event name.
 * @param array  $data       Event data object.
 * @param array  $user       Extra user fields, all optional.
 * @return bool Whether the event was accepted for delivery.
 */
function ridoway_pixel_capi_send_event($event_id, $event_type, $data, $user = array()) {
    if (!ridoway_pixel_capi_is_active()) {
        return false;
    }

    if (!ridoway_pixel_consent_rule()) {
        return false;
    }

    $event = ridoway_pixel_capi_build_event($event_id, $event_type, $data, $user);

    // In debug mode send inline so the result can be inspected.
    if (ridoway_pixel_option_enabled('debug_mode')) {
        $response = ridoway_pixel_capi_http_post($event);
        ridoway_pixel_capi_log($event, $response);

        return !ridoway_pixel_capi_send_failed($response);
    }

    // Synchronous mode: try now, queue for retry on failure.
    if (!ridoway_pixel_option_enabled('async_capi', '1')) {
        $response = ridoway_pixel_capi_http_post($event);

        if (ridoway_pixel_capi_send_failed($response)) {
            ridoway_pixel_capi_enqueue($event);
            return false;
        }

        return true;
    }

    // Async mode (default): queue and let the cron flush deliver.
    ridoway_pixel_capi_enqueue($event);

    return true;
}