upskill-event-manager/docs/API-REFERENCE.md

# HVAC Plugin API Reference

## Table of Contents
- [PHP Classes](#php-classes)
- [JavaScript APIs](#javascript-apis)
- [WordPress Hooks](#wordpress-hooks)
- [AJAX Endpoints](#ajax-endpoints)
- [Shortcodes](#shortcodes)
- [Database Schema](#database-schema)

## PHP Classes

### HVAC_Plugin

Main plugin initialization class.

```php
class HVAC_Plugin {
    /**
     * Get plugin instance (Singleton)
     * @return HVAC_Plugin
     */
    public static function instance()
    
    /**
     * Initialize plugin components
     * @return void
     */
    public function init()
}
```

### HVAC_Event_Manager

Manages event creation and manipulation.

```php
class HVAC_Event_Manager {
    /**
     * Create a new event
     * @param array $event_data Event information
     * @return int|WP_Error Event ID or error
     */
    public static function create_event($event_data)
    
    /**
     * Get trainer events
     * @param int $trainer_id Trainer user ID
     * @param array $args Query arguments
     * @return array Array of event objects
     */
    public static function get_trainer_events($trainer_id, $args = array())
    
    /**
     * Update event
     * @param int $event_id Event ID
     * @param array $data Event data to update
     * @return bool Success status
     */
    public static function update_event($event_id, $data)
}
```

### HVAC_Certificate_Generator

Handles PDF certificate generation.

```php
class HVAC_Certificate_Generator {
    /**
     * Generate certificate for attendee
     * @param int $event_id Event ID
     * @param array $attendee Attendee data
     * @return string|WP_Error PDF file path or error
     */
    public function generate_certificate($event_id, $attendee)
    
    /**
     * Generate bulk certificates
     * @param int $event_id Event ID
     * @param array $attendees Array of attendee data
     * @return array Results array with successes and failures
     */
    public function generate_bulk_certificates($event_id, $attendees)
}
```

### HVAC_Trainer_Profile

Manages trainer profile functionality.

```php
class HVAC_Trainer_Profile {
    /**
     * Get trainer profile data
     * @param int $trainer_id User ID
     * @return array Profile data
     */
    public static function get_profile($trainer_id)
    
    /**
     * Update trainer profile
     * @param int $trainer_id User ID
     * @param array $data Profile data
     * @return bool Success status
     */
    public static function update_profile($trainer_id, $data)
    
    /**
     * Get trainer statistics
     * @param int $trainer_id User ID
     * @return array Statistics data
     */
    public static function get_statistics($trainer_id)
}
```

### HVAC_Menu_System

Handles navigation menu rendering.

```php
class HVAC_Menu_System {
    /**
     * Render trainer navigation menu
     * @return void Outputs HTML
     */
    public function render_trainer_menu()
    
    /**
     * Get menu structure for current user
     * @return array Menu items array
     */
    private function get_menu_structure()
}
```

## JavaScript APIs

### Global Objects

```javascript
// Main HVAC object
window.HVAC = {
    // Initialize components
    init: function() {},
    
    // Event management
    events: {
        create: function(data) {},
        update: function(eventId, data) {},
        delete: function(eventId) {}
    },
    
    // Profile management
    profile: {
        load: function(userId) {},
        save: function(data) {},
        uploadPhoto: function(file) {}
    },
    
    // Utilities
    utils: {
        showMessage: function(message, type) {},
        confirm: function(message, callback) {},
        formatDate: function(date) {}
    }
};

// AJAX helper
window.hvacAjax = {
    post: function(action, data, success, error) {},
    get: function(action, data, success, error) {}
};
```

### jQuery Plugins

```javascript
// Dashboard initialization
jQuery(document).ready(function($) {
    // Initialize date pickers
    $('.hvac-datepicker').datepicker({
        dateFormat: 'yy-mm-dd'
    });
    
    // Initialize form validation
    $('.hvac-form').validate({
        rules: {
            event_title: 'required',
            event_date: 'required'
        }
    });
});
```

## WordPress Hooks

### Actions

```php
// Plugin lifecycle
do_action('hvac_plugin_activated');
do_action('hvac_plugin_deactivated');
do_action('hvac_plugin_updated', $old_version, $new_version);

// Page creation
do_action('hvac_before_create_pages');
do_action('hvac_after_create_pages', $page_ids);

// Event management
do_action('hvac_before_event_save', $event_data);
do_action('hvac_after_event_save', $event_id, $event_data);
do_action('hvac_event_deleted', $event_id);

// Certificate generation
do_action('hvac_before_certificate_generate', $event_id, $attendee);
do_action('hvac_after_certificate_generate', $certificate_path);

// User profile
do_action('hvac_profile_updated', $user_id, $profile_data);
do_action('hvac_trainer_registered', $user_id);
```

### Filters

```php
// Capability checks
apply_filters('hvac_user_can_manage_event', $can_manage, $user_id, $event_id);
apply_filters('hvac_user_can_generate_certificates', $can_generate, $user_id);

// Data manipulation
apply_filters('hvac_event_data', $event_data, $event_id);
apply_filters('hvac_certificate_data', $certificate_data, $event_id, $attendee);
apply_filters('hvac_profile_fields', $fields, $user_id);

// Display filters
apply_filters('hvac_menu_items', $menu_items, $user_role);
apply_filters('hvac_dashboard_widgets', $widgets, $user_id);
apply_filters('hvac_date_format', $format);

// Query filters
apply_filters('hvac_events_query_args', $args, $context);
apply_filters('hvac_trainers_query_args', $args);
```

## AJAX Endpoints

### Event Management

```javascript
// Create event
{
    action: 'hvac_create_event',
    nonce: hvac_ajax.nonce,
    event_data: {
        title: 'Event Title',
        start_date: '2025-08-15',
        venue_id: 123,
        capacity: 50
    }
}

// Update event
{
    action: 'hvac_update_event',
    nonce: hvac_ajax.nonce,
    event_id: 456,
    event_data: {
        title: 'Updated Title'
    }
}

// Delete event
{
    action: 'hvac_delete_event',
    nonce: hvac_ajax.nonce,
    event_id: 456
}
```

### Profile Management

```javascript
// Get profile data
{
    action: 'hvac_get_profile',
    nonce: hvac_ajax.nonce,
    user_id: 789 // Optional, defaults to current user
}

// Update profile
{
    action: 'hvac_update_profile',
    nonce: hvac_ajax.nonce,
    profile_data: {
        bio: 'Updated bio',
        certifications: ['NATE', 'EPA'],
        website: 'https://example.com'
    }
}

// Upload profile photo
{
    action: 'hvac_upload_photo',
    nonce: hvac_ajax.nonce,
    photo: File // File object from input
}
```

### Certificate Generation

```javascript
// Generate single certificate
{
    action: 'hvac_generate_certificate',
    nonce: hvac_ajax.nonce,
    event_id: 456,
    attendee_id: 789
}

// Generate bulk certificates
{
    action: 'hvac_generate_bulk_certificates',
    nonce: hvac_ajax.nonce,
    event_id: 456,
    attendee_ids: [789, 790, 791]
}
```

## Shortcodes

### Display Shortcodes

```php
// Trainer dashboard
[hvac_trainer_dashboard]

// Event list
[hvac_event_list trainer_id="123" limit="10" status="upcoming"]

// Profile view
[hvac_trainer_profile_view user_id="123"]

// Profile edit form
[hvac_trainer_profile_edit]

// Certificate reports
[hvac_certificate_reports]

// Event creation form
[hvac_event_form]

// Venue management
[hvac_venue_list]
[hvac_venue_form]

// Organizer management
[hvac_organizer_list]
[hvac_organizer_form]
```

### Shortcode Parameters

```php
// Event list parameters
[hvac_event_list 
    trainer_id=""      // Trainer ID (default: current user)
    limit="10"         // Number of events
    status="upcoming"  // upcoming|past|all
    orderby="date"     // date|title|capacity
    order="ASC"        // ASC|DESC
]

// Profile view parameters
[hvac_trainer_profile_view 
    user_id=""         // User ID (default: current user)
    show_stats="true"  // Show statistics
    show_events="true" // Show event list
]
```

## Database Schema

### Post Meta (Events)

```sql
-- Event-specific meta keys
_EventStartDate         -- Event start datetime
_EventEndDate          -- Event end datetime
_EventVenueID          -- Venue post ID
_EventOrganizerID      -- Organizer post ID
_EventTrainerID        -- Trainer user ID
_EventCapacity         -- Maximum attendees
_EventRegisteredCount  -- Current registration count
_EventCertificateTemplate -- Certificate template ID
```

### User Meta (Trainers)

```sql
-- Profile information
role                   -- User's HVAC industry role (technician, installer, etc.)
hvac_bio               -- Trainer biography
hvac_certifications    -- Serialized array of certifications
hvac_trainer_photo     -- Attachment ID of profile photo
hvac_website           -- Trainer website URL
hvac_location          -- Trainer location
hvac_phone             -- Contact phone

-- Certification information (admin/master trainer editable only)
date_certified         -- Date when trainer was certified (YYYY-MM-DD)
certification_type     -- Type of certification ('Certified measureQuick Trainer', 'Certified measureQuick Champion')
certification_status   -- Current certification status ('Active', 'Expired', 'Pending', 'Disabled')

-- Training preferences
hvac_training_formats  -- Serialized array of formats
hvac_training_audience -- Target audience
hvac_training_topics   -- Specialized topics

-- Statistics (cached)
hvac_total_events      -- Total events created
hvac_total_students    -- Total students trained
hvac_total_revenue     -- Total revenue generated
```

### Options Table

```sql
-- Plugin settings
hvac_plugin_version    -- Current plugin version
hvac_settings          -- Serialized settings array
hvac_email_templates   -- Email template configurations
hvac_certificate_settings -- Certificate generation settings

-- Feature flags
hvac_enable_zoho       -- Zoho CRM integration
hvac_enable_analytics  -- Analytics tracking
hvac_maintenance_mode  -- Maintenance mode flag
```

## Error Codes

### Event Errors
- `HVAC001` - Invalid event data
- `HVAC002` - Event not found
- `HVAC003` - Insufficient permissions to manage event
- `HVAC004` - Event capacity exceeded

### User Errors
- `HVAC101` - User not found
- `HVAC102` - Invalid user role
- `HVAC103` - Insufficient permissions
- `HVAC104` - Profile update failed

### Certificate Errors
- `HVAC201` - Certificate generation failed
- `HVAC202` - Invalid attendee data
- `HVAC203` - Template not found
- `HVAC204` - PDF library error

### System Errors
- `HVAC901` - Database connection error
- `HVAC902` - File system error
- `HVAC903` - Third-party API error
- `HVAC904` - Unknown error

## Response Formats

### Success Response
```json
{
    "success": true,
    "data": {
        "id": 123,
        "message": "Operation completed successfully",
        "additional_data": {}
    }
}
```

### Error Response
```json
{
    "success": false,
    "data": {
        "code": "HVAC001",
        "message": "Invalid event data",
        "details": {
            "field": "event_date",
            "error": "Date must be in the future"
        }
    }
}
```