upskill-event-manager/docs/FIND-TRAINER-FILTER-FIX-REPORT.md

Find a Trainer Filter Fix Report

Date: August 28, 2025
Issue: Find a Trainer page dropdown filter logic and display functionality not working
Status: ✅ RESOLVED (local testing) / ⚠️ STAGING DEPLOYMENT ISSUE

🎯 Problem Summary

The Find a Trainer page filtering system was completely non-functional due to missing backend AJAX handlers and frontend JavaScript issues.

🔍 Root Cause Analysis

1. Missing Backend AJAX Handlers

• JavaScript was calling hvac_filter_trainers and hvac_get_filter_options AJAX endpoints
• No corresponding PHP handlers were registered in WordPress
• Result: All filter requests returned 400 errors

2. Frontend JavaScript Issues

• Using mock/hardcoded data instead of dynamic database queries
• CSS selector mismatches (.hvac-filter-button vs .hvac-filter-btn)
• Search input selector issues (#hvac-trainer-search vs .hvac-search-input)

3. CSS Display Conflicts

• Modal had display: none !important preventing JavaScript visibility changes
• Transition conflicts between CSS and JavaScript modal show/hide

🔧 Technical Implementation

Backend Fixes (PHP)

File: includes/find-trainer/class-hvac-find-trainer-page.php

Added missing AJAX handler registrations in init_hooks():

// AJAX handlers for filtering
add_action('wp_ajax_hvac_filter_trainers', [$this, 'ajax_filter_trainers']);
add_action('wp_ajax_nopriv_hvac_filter_trainers', [$this, 'ajax_filter_trainers']);
add_action('wp_ajax_hvac_get_filter_options', [$this, 'ajax_get_filter_options']);
add_action('wp_ajax_nopriv_hvac_get_filter_options', [$this, 'ajax_get_filter_options']);

Implemented complete AJAX handlers:

• ajax_filter_trainers() - Handles trainer filtering with database queries
• ajax_get_filter_options() - Returns dynamic filter options
• Helper methods for state, business type, training format options
• Security: Nonce verification and input sanitization

Frontend Fixes (JavaScript)

File: assets/js/find-trainer.js

• Updated handleFilterClick() to use real AJAX instead of mock data
• Fixed showFilterModal() to apply styles with !important priority:

  $filterModal[0].style.setProperty('display', 'flex', 'important');
  $filterModal[0].style.setProperty('visibility', 'visible', 'important');
  $filterModal[0].style.setProperty('opacity', '1', 'important');
  

• Fixed closeModals() to properly reset modal state
• Corrected CSS selectors throughout the file

Styling Fixes (CSS)

File: assets/css/find-trainer.css

• Removed conflicting !important rule from modal default display
• Added smooth transitions for modal show/hide
• Ensured proper CSS specificity for modal active states

✅ Verified Functionality

Through comprehensive browser testing, confirmed:

✅ Filter buttons clickable and responsive
✅ Modal opens with correct title and dynamic database options
✅ Options can be selected via checkboxes
✅ Apply button processes selections correctly
✅ Modal closes automatically after apply
✅ Active filters display with remove functionality
✅ Clear All button available
✅ Backend filtering works correctly
✅ End-to-end AJAX communication functioning

⚠️ Current Status: Staging Deployment Issue

Issue

After deployment to staging, the site shows a "Critical error" message. This is likely due to:

• PHP compatibility issues in staging environment
• Missing safety checks in AJAX handlers
• Potential namespace or dependency conflicts

Resolution in Progress

Added safety checks to AJAX handlers:

// Check if this is a valid AJAX request
if (!defined('DOING_AJAX') || !DOING_AJAX) {
    wp_send_json_error('Not an AJAX request');
    return;
}

// Verify nonce with null checks
if (!isset($_POST['nonce']) || !wp_verify_nonce($_POST['nonce'], 'hvac_find_trainer')) {
    wp_send_json_error('Invalid nonce');
    return;
}

📋 Next Steps

1. Complete AJAX handler safety updates
2. Test locally again to ensure no regressions
3. Deploy safer version to staging
4. Verify full functionality on staging environment

📊 Files Modified

• includes/find-trainer/class-hvac-find-trainer-page.php - Added AJAX handlers
• assets/js/find-trainer.js - Fixed frontend JavaScript
• assets/css/find-trainer.css - Resolved CSS conflicts

🎉 Impact

When fully deployed, this fix will restore complete functionality to the Find a Trainer page filtering system, enabling users to:

• Filter trainers by state/province, business type, training format, and resources
• See real-time results from the database
• Have a smooth, responsive user experience
• Access all trainer profiles and contact information

The system now properly integrates frontend user interactions with backend database queries through secure AJAX endpoints.