<?php
defined('BASEPATH') or exit('No direct script access allowed');

/**
 * Visit Tracking Helper
 * Helper untuk tracking visits dengan support affiliate referral
 * 
 * Usage in controller:
 * $this->load->helper('visit');
 * track_visit(); // Will automatically track current page visit
 */

if (!function_exists('track_visit')) {
    /**
     * Track page visit dengan support untuk affiliate referral
     * 
     * @param array $custom_data Optional custom data untuk override
     * @return int|false Visit ID atau false jika gagal
     */
    function track_visit($custom_data = [])
    {
        $CI = &get_instance();
        $CI->load->database();

        // Prevent duplicate tracking dalam satu request
        static $already_tracked = false;
        if ($already_tracked) {
            return false;
        }

        // Get visitor information
        $ip_address = $CI->input->ip_address();
        $user_agent = $CI->input->user_agent();
        $current_url = current_url() . ($_SERVER['QUERY_STRING'] ? '?' . $_SERVER['QUERY_STRING'] : '');
        $referrer_url = $CI->input->server('HTTP_REFERER');

        // Parse referrer domain
        $referrer_domain = null;
        if ($referrer_url) {
            $parsed = parse_url($referrer_url);
            $referrer_domain = isset($parsed['host']) ? $parsed['host'] : null;
        }

        // Get or create session ID for unique visitor tracking
        $session_id = _get_or_create_session_id();

        // Detect page type
        $page_type = _detect_page_type();

        // Get product ID if on product page
        $product_id = _get_product_id_from_url();

        // Parse UTM parameters
        $utm_params = _parse_utm_parameters();

        // Check for affiliate referral code
        $affiliate_data = _check_affiliate_referral();

        // Check untuk duplicate dalam timeframe singkat (prevent double-click)
        $recent_visit = $CI->db
            ->select('id')
            ->from('visits')
            ->where('session_id', $session_id)
            ->where('url', substr($current_url, 0, 500))
            ->where('created_at >', date('Y-m-d H:i:s', strtotime('-10 seconds')))
            ->limit(1)
            ->get()
            ->row();

        if ($recent_visit) {
            $already_tracked = true;
            return $recent_visit->id;
        }

        // Prepare visit data
        $visit_data = array_merge([
            'ip_address' => $ip_address,
            'session_id' => $session_id,
            'user_agent' => substr($user_agent, 0, 500), // Limit length
            'url' => substr($current_url, 0, 500),
            'page_type' => $page_type,
            'product_id' => $product_id,
            'referrer_url' => $referrer_url ? substr($referrer_url, 0, 500) : null,
            'referrer_domain' => $referrer_domain,
            'is_affiliate_visit' => $affiliate_data['is_affiliate'] ? 1 : 0,
            'affiliator_id' => $affiliate_data['affiliator_id'],
            'referral_code' => $affiliate_data['referral_code'],
            'link_id' => $affiliate_data['link_id'],
            'utm_source' => $utm_params['utm_source'],
            'utm_medium' => $utm_params['utm_medium'],
            'utm_campaign' => $utm_params['utm_campaign'],
            'utm_term' => $utm_params['utm_term'],
            'utm_content' => $utm_params['utm_content'],
            'converted_to_order' => 0,
            'created_at' => date('Y-m-d H:i:s')
        ], $custom_data);

        // Insert to database
        $CI->db->insert('visits', $visit_data);
        $visit_id = $CI->db->insert_id();

        // Mark as tracked
        $already_tracked = true;

        // Update link statistics if affiliate visit
        if ($affiliate_data['link_id']) {
            _update_link_statistics($affiliate_data['link_id'], $session_id, $visit_id);
        }

        // Store affiliate info in session for order tracking
        if ($affiliate_data['is_affiliate']) {
            _store_affiliate_session($affiliate_data, $visit_id);
        }

        return $visit_id;
    }
}

if (!function_exists('mark_visit_converted')) {
    /**
     * Mark visit as converted to order
     * Call this setelah order berhasil dibuat
     * 
     * @param int $order_id
     * @param int $visit_id Optional, jika null akan ambil dari session
     * @return bool
     */
    function mark_visit_converted($order_id, $visit_id = null)
    {
        $CI = &get_instance();
        $CI->load->database();

        if (!$visit_id) {
            $visit_id = $CI->session->userdata('current_visit_id');
        }

        if (!$visit_id) {
            return false;
        }

        $update_data = [
            'converted_to_order' => 1,
            'order_id' => $order_id,
            'converted_at' => date('Y-m-d H:i:s')
        ];

        $CI->db->where('id', $visit_id);
        return $CI->db->update('visits', $update_data);
    }
}

if (!function_exists('get_affiliate_from_session')) {
    /**
     * Get affiliate data from session
     * Digunakan saat membuat commission record
     * 
     * @return array|null
     */
    function get_affiliate_from_session()
    {
        $CI = &get_instance();

        $affiliate_data = $CI->session->userdata('affiliate_tracking');

        if (!$affiliate_data) {
            return null;
        }

        // Check if still valid (24 hours)
        $stored_time = isset($affiliate_data['stored_at']) ? $affiliate_data['stored_at'] : 0;
        $current_time = time();

        if (($current_time - $stored_time) > 86400) { // 24 hours
            // Expired, remove from session
            $CI->session->unset_userdata('affiliate_tracking');
            return null;
        }

        return $affiliate_data;
    }
}

// ============================================================================
// PRIVATE HELPER FUNCTIONS
// ============================================================================

if (!function_exists('_get_or_create_session_id')) {
    /**
     * Get atau create unique session ID untuk visitor
     */
    function _get_or_create_session_id()
    {
        $CI = &get_instance();

        $session_id = $CI->session->userdata('visitor_session_id');

        if (!$session_id) {
            // Generate unique session ID
            $session_id = md5(uniqid(rand(), true));
            $CI->session->set_userdata('visitor_session_id', $session_id);
        }

        return $session_id;
    }
}

if (!function_exists('_detect_page_type')) {
    /**
     * Detect page type berdasarkan URI
     */
    function _detect_page_type()
    {
        $CI = &get_instance();

        $segment1 = $CI->uri->segment(1);
        $segment2 = $CI->uri->segment(2);

        // Home page
        if (!$segment1 || $segment1 === 'home') {
            return 'home';
        }

        // Shop/Product pages
        if ($segment1 === 'shop') {
            if ($segment2 === 'product' || $segment2 === 'productdetail') {
                return 'product';
            }
            return 'shop';
        }

        // Cart page
        if ($segment1 === 'cart' || $segment1 === 'keranjang') {
            return 'cart';
        }

        // Checkout page
        if ($segment1 === 'checkout' || $segment1 === 'shipping') {
            return 'checkout';
        }

        return 'other';
    }
}

if (!function_exists('_get_product_id_from_url')) {
    /**
     * Extract product ID dari URL jika ada
     */
    function _get_product_id_from_url()
    {
        $CI = &get_instance();

        $segment1 = $CI->uri->segment(1);
        $segment2 = $CI->uri->segment(2);

        // Check if product page
        if ($segment1 === 'shop' && ($segment2 === 'product')) {
            $segment3 = $CI->uri->segment(3);

            if ($segment3) {
                // Query product by slug
                $product = $CI->db
                    ->select('id_products as id')
                    ->from('products')
                    ->where('alias', $segment3)
                    ->get()
                    ->row();

                if ($product) {
                    return $product->id;
                }
            }
        }

        return null;
    }
}

if (!function_exists('_parse_utm_parameters')) {
    /**
     * Parse UTM parameters dari URL
     */
    function _parse_utm_parameters()
    {
        $CI = &get_instance();

        return [
            'utm_source' => $CI->input->get('utm_source'),
            'utm_medium' => $CI->input->get('utm_medium'),
            'utm_campaign' => $CI->input->get('utm_campaign'),
            'utm_term' => $CI->input->get('utm_term'),
            'utm_content' => $CI->input->get('utm_content')
        ];
    }
}

if (!function_exists('_check_affiliate_referral')) {
    /**
     * Check apakah visit ini dari affiliate referral
     * Matching berdasarkan referral_code + full URL comparison
     */
    function _check_affiliate_referral()
    {
        $CI = &get_instance();

        $result = [
            'is_affiliate' => false,
            'affiliator_id' => null,
            'referral_code' => null,
            'link_id' => null
        ];

        // Check for 'ref' parameter
        $ref_code = $CI->input->get('ref');
        if (!$ref_code) {
            return $result;
        }

        // Query affiliator by referral code
        $affiliator = $CI->db
            ->select('id, referral_code, status')
            ->from('affiliators')
            ->where('referral_code', strtoupper($ref_code))
            ->where('status', 'active')
            ->get()
            ->row();

        if (!$affiliator) {
            return $result;
        }

        $result['is_affiliate'] = true;
        $result['affiliator_id'] = $affiliator->id;
        $result['referral_code'] = $affiliator->referral_code;

        // Build current complete URL (with query string)
        $current_url = current_url();
        $query_string = $_SERVER['QUERY_STRING'];
        $current_full_url = $current_url . ($query_string ? '?' . $query_string : '');

        // Normalize URL for comparison
        $current_normalized = _normalize_url_for_comparison($current_full_url);

        // Get all active links for this affiliator
        // Priority: specific links (brand, product, category) first, then general
        $links = $CI->db
            ->select('id, full_url, link_type')
            ->from('affiliator_links')
            ->where('affiliator_id', $affiliator->id)
            ->where('status', 'active')
            ->where('(expires_at IS NULL OR expires_at > NOW())')
            ->order_by("link_type = 'general'", 'ASC') // Specific links first
            ->order_by('CHAR_LENGTH(full_url)', 'DESC') // Longer URLs first
            ->get()
            ->result();

        $matched_link = null;

        foreach ($links as $link) {
            $link_normalized = _normalize_url_for_comparison($link->full_url);

            // Exact match
            if ($current_normalized === $link_normalized) {
                $matched_link = $link;
                break;
            }
        }

        // Fallback: if no exact match, use general link
        if (!$matched_link) {
            foreach ($links as $link) {
                if ($link->link_type === 'general') {
                    $matched_link = $link;
                    break;
                }
            }
        }

        if ($matched_link) {
            $result['link_id'] = $matched_link->id;
        }

        return $result;
    }
}

if (!function_exists('_normalize_url_for_comparison')) {
    /**
     * Normalize URL untuk comparison
     * Handle trailing slash, case sensitivity, query parameter order
     */
    function _normalize_url_for_comparison($url)
    {
        // Parse URL
        $parsed = parse_url(strtolower($url));

        // Get path and query
        $path = isset($parsed['path']) ? $parsed['path'] : '';
        $query = isset($parsed['query']) ? $parsed['query'] : '';

        // Normalize path: remove all leading/trailing slashes
        $path = '/' . trim($path, '/');

        // If path is just "/", keep it as empty
        if ($path === '/') {
            $path = '';
        }

        // Parse query string and sort parameters for consistent comparison
        parse_str($query, $params);
        ksort($params);
        $normalized_query = http_build_query($params);

        // Build normalized URL
        $normalized = $path . ($normalized_query ? '?' . $normalized_query : '');

        return $normalized;
    }
}

if (!function_exists('_update_link_statistics')) {
    /**
     * Update statistics untuk affiliate link
     * @param int $link_id ID dari affiliate link
     * @param string $session_id Session ID visitor
     * @param int $current_visit_id ID visit yang baru diinsert (untuk di-exclude)
     */
    function _update_link_statistics($link_id, $session_id, $current_visit_id = null)
    {
        $CI = &get_instance();
        $ip_address = $CI->input->ip_address();

        // Update total clicks
        $CI->db->set('total_clicks', 'total_clicks + 1', FALSE);
        $CI->db->set('last_clicked_at', date('Y-m-d H:i:s'));
        $CI->db->where('id', $link_id);
        $CI->db->update('affiliator_links');

        // Check if this IP has clicked this link before (exclude current visit)
        $query = $CI->db
            ->select('id')
            ->from('visits')
            ->where('link_id', $link_id)
            ->where('ip_address', $ip_address);

        // Exclude current visit ID
        if ($current_visit_id) {
            $query->where('id !=', $current_visit_id);
        }

        $existing_ip_visit = $query->limit(1)->get()->row();

        // Only increment unique_clicks if this is the first time from this IP
        if (!$existing_ip_visit) {
            $CI->db->set('unique_clicks', 'unique_clicks + 1', FALSE);
            $CI->db->where('id', $link_id);
            $CI->db->update('affiliator_links');
        }
    }
}

if (!function_exists('_store_affiliate_session')) {
    /**
     * Store affiliate information di session
     * Untuk tracking conversion nanti
     */
    function _store_affiliate_session($affiliate_data, $visit_id)
    {
        $CI = &get_instance();

        $session_data = [
            'affiliator_id' => $affiliate_data['affiliator_id'],
            'referral_code' => $affiliate_data['referral_code'],
            'link_id' => $affiliate_data['link_id'],
            'visit_id' => $visit_id,
            'stored_at' => time()
        ];

        $CI->session->set_userdata('affiliate_tracking', $session_data);
        $CI->session->set_userdata('current_visit_id', $visit_id);
    }
}