Building a Propstack API Integration Plugin for WordPress: A Developer's Guide

class PropstackIntegration {
    private $api_key;

    public function __construct() {
        // Load API key from WordPress options
        $this->api_key = get_option('propstack_api_key');

        // WordPress Action Hooks
        add_action('init', array($this, 'init_plugin')); // Changed from 'init' to avoid conflict
        add_action('wp_enqueue_scripts', array($this, 'enqueue_assets')); // Changed for clarity
        add_action('admin_menu', array($this, 'add_admin_menu_page')); // Changed for clarity
        add_action('admin_init', array($this, 'register_plugin_settings')); // Changed for clarity

        // Shortcode
        add_shortcode('propstack_listings', array($this, 'display_listings_shortcode'));

        // AJAX Actions for frontend and admin
        add_action('wp_ajax_load_more_properties', array($this, 'ajax_load_more_properties')); // Changed
        add_action('wp_ajax_nopriv_load_more_properties', array($this, 'ajax_load_more_properties')); // Changed
        add_action('wp_ajax_test_propstack_connection', array($this, 'ajax_test_api_connection')); // Changed
    }

    public function init_plugin() {
        // Future initializations, like custom post types if needed
    }

    // ... other methods will be discussed below ...
}

// Initialize the plugin
new PropstackIntegration();

    public function enqueue_assets() {
        // Enqueue stylesheet
        wp_enqueue_style(
            'propstack-css',
            PROPSTACK_PLUGIN_URL . 'assets/propstack.css',
            array(),
            '1.0.0'
        );

        // Enqueue JavaScript (jQuery dependency, loaded in footer)
        wp_enqueue_script(
            'propstack-js',
            PROPSTACK_PLUGIN_URL . 'assets/propstack.js',
            array('jquery'),
            '1.0.0',
            true // Load in footer
        );

        // Pass data to JavaScript (e.g., AJAX URL, nonce for security)
        wp_localize_script('propstack-js', 'propstack_ajax', array(
            'ajax_url' => admin_url('admin-ajax.php'),
            'nonce'    => wp_create_nonce('propstack_nonce') // For general AJAX
        ));
    }

    public function add_admin_menu_page() {
        add_options_page(
            'Propstack Settings',       // Page Title
            'Propstack',                // Menu Title
            'manage_options',           // Capability required
            'propstack-settings',       // Menu Slug
            array($this, 'render_settings_page_html') // Callback to render HTML
        );
    }

    public function register_plugin_settings() {
        // Register a setting group
        register_setting('propstack_settings_group', 'propstack_api_key'); // Sanitize callback can be added
        register_setting('propstack_settings_group', 'propstack_properties_per_page', 'intval');
        register_setting('propstack_settings_group', 'propstack_default_image', 'esc_url_raw');

        // Add a settings section
        add_settings_section(
            'propstack_api_section',
            'API Configuration',
            null, // Optional callback for section description
            'propstack-settings' // Page slug
        );

        // Add fields to the section
        add_settings_field(
            'propstack_api_key',
            'API Key',
            array($this, 'render_api_key_field'),
            'propstack-settings',
            'propstack_api_section'
        );
        // ... similar add_settings_field calls for properties_per_page and default_image ...
    }

    public function render_settings_page_html() {
        ?>
        <div class="wrap">
            <h1>Propstack Settings</h1>
            <form action="options.php" method="post">
                <?php
                settings_fields('propstack_settings_group'); // Matches register_setting
                do_settings_sections('propstack-settings'); // Matches add_settings_section
                submit_button();
                ?>
            </form>

            <?php if (!empty($this->api_key)): ?>
            <div class="propstack-test-connection" style="margin-top: 20px;">
                <h2>API Connection Test</h2>
                <button type="button" id="test-propstack-connection" class="button button-secondary">Test API Connection</button>
                <div id="propstack-test-results" style="margin-top: 10px;"></div>
                <script>
                // Inline JS for the test button (simplified here for brevity)
                // Ideally, this would also be in an enqueued JS file
                document.getElementById('test-propstack-connection').addEventListener('click', function() {
                    // ... (Fetch API call to our test_api_connection AJAX action) ...
                    // Uses a unique nonce for this action, e.g., wp_create_nonce('propstack_test_nonce')
                });
                </script>
            </div>
            <?php endif; ?>
             <h2>Usage</h2>
             <p>Use the shortcode <code>[propstack_listings]</code> to display property listings.</p>
             </div>
        <?php
    }

    private function make_api_request($endpoint, $params = array()) {
        if (empty($this->api_key)) {
            return new WP_Error('no_api_key', 'Propstack API key not configured.');
        }

        $url = PROPSTACK_API_BASE_URL . '/' . ltrim($endpoint, '/');
        // Propstack might require API key in headers or as a query param.
        // This example assumes it's primarily in headers.
        // Adjust $params as needed if API key is also a query param for GET.

        $response = wp_remote_get(add_query_arg($params, $url), array(
            'timeout' => 30,
            'headers' => array(
                'X-API-KEY' => $this->api_key // Common way to send API key
            )
        ));

        if (is_wp_error($response)) {
            return $response;
        }

        $body = wp_remote_retrieve_body($response);
        $data = json_decode($body, true);

        if (wp_remote_retrieve_response_code($response) !== 200) {
            return new WP_Error('api_error', 'API Request Failed: ' . ($data['message'] ?? $body));
        }
        return $data;
    }

    public function get_properties($params = array()) {
        $default_params = array(
            'page'     => 1,
            'per_page' => get_option('propstack_properties_per_page', 12),
            'with_meta'=> 1 // Assuming Propstack uses this for metadata
        );
        $params = wp_parse_args($params, $default_params);

        // Create a unique cache key based on parameters
        $cache_key = 'propstack_units_' . md5(serialize($params));
        $cached_data = get_transient($cache_key);

        if (false !== $cached_data) {
            return $cached_data; // Return cached data if available
        }

        // 'units' is assumed to be the Propstack endpoint for listings
        $response = $this->make_api_request('units', $params);

        if (!is_wp_error($response)) {
            // Cache successful response for 5 minutes
            set_transient($cache_key, $response, 5 * MINUTE_IN_SECONDS);
        }
        return $response;
    }

    public function display_listings_shortcode($atts) {
        $atts = shortcode_atts(array(
            'limit'             => get_option('propstack_properties_per_page', 12),
            'columns'           => 3,
            'show_pagination'   => 'true',
            'property_type'     => '', // For filtering
            'page'              => 1    // Initial page for shortcode
        ), $atts, 'propstack_listings');

        $params = array(
            'per_page' => intval($atts['limit']),
            'page'     => intval($atts['page'])
        );
        if (!empty($atts['property_type'])) {
            $params['type'] = sanitize_text_field($atts['property_type']);
        }

        $properties_data = $this->get_properties($params);

        if (is_wp_error($properties_data)) {
            return '<div class="propstack-error">Error: ' . esc_html($properties_data->get_error_message()) . '</div>';
        }

        ob_start();
        // Pass $properties_data (API response) and $atts (shortcode attributes)
        $this->render_properties_grid($properties_data, $atts);
        return ob_get_clean();
    }

    private function render_properties_grid($api_response, $shortcode_atts) {
        $properties = isset($api_response['data']) ? $api_response['data'] : array();
        $meta = isset($api_response['meta']) ? $api_response['meta'] : array(); // For pagination
        // Propstack's API might provide total count differently, e.g., $meta['total_count'] or $meta['total']
        $total_properties = $meta['total_count'] ?? ($meta['total'] ?? count($properties));


        if (empty($properties)) {
            echo '<div class="propstack-no-results"><p>Keine Immobilien gefunden.</p></div>';
            return;
        }

        // Data attributes for AJAX pagination in JS
        echo '<div class="propstack-listings-container"
                     data-limit="' . esc_attr($shortcode_atts['limit']) . '"
                     data-columns="' . esc_attr($shortcode_atts['columns']) . '"
                     data-property-type="' . esc_attr($shortcode_atts['property_type']) . '"
                     data-show-pagination="' . esc_attr($shortcode_atts['show_pagination']) . '">';
        echo '<div class="propstack-grid propstack-columns-' . esc_attr($shortcode_atts['columns']) . '">';
        foreach ($properties as $property) {
            // Column class can be handled purely by CSS grid, or calculated in PHP if needed
            echo '<div class="propstack-property-card-wrapper">'; // Wrapper for column class
            $this->render_property_card($property);
            echo '</div>';
        }
        echo '</div>'; // .propstack-grid

        if ($shortcode_atts['show_pagination'] === 'true') {
            $current_page = intval($shortcode_atts['page']);
            $per_page = intval($shortcode_atts['limit']);
            $last_page = ceil($total_properties / $per_page);
            if ($last_page > 1) {
                 $this->render_pagination($current_page, $last_page, $shortcode_atts);
            }
        }
        echo '</div>'; // .propstack-listings-container
    }

    private function render_property_card($property) {
        // Extract data: $title, $image_url, $address, $price, $status etc.
        // Handle missing data gracefully and use esc_attr(), esc_html(), esc_url() for security.
        // Example for image:
        $default_image_url = get_option('propstack_default_image', PROPSTACK_PLUGIN_URL . 'assets/default-property.jpg');
        $image_url = $default_image_url;
        if (!empty($property['images']) && is_array($property['images'])) {
            $first_image = $property['images'][0];
            // Propstack API might offer different image sizes
            $image_url = $first_image['medium'] ?? $first_image['big'] ?? $first_image['original'] ?? $default_image_url;
        }
        // ... HTML for the card structure (see your CSS for class names) ...
    }

    private function render_pagination($current_page, $last_page, $shortcode_atts) {
        // ... HTML for pagination links, using data-page attributes for JS ...
    }

    public function ajax_load_more_properties() {
        // Security check: Verify nonce
        check_ajax_referer('propstack_nonce', 'nonce');

        $page = isset($_POST['page']) ? intval($_POST['page']) : 1;
        $limit = isset($_POST['limit']) ? intval($_POST['limit']) : get_option('propstack_properties_per_page', 12);
        $property_type = isset($_POST['property_type']) ? sanitize_text_field($_POST['property_type']) : '';
        // Get columns to pass it back to render_properties_grid if necessary or handle it via JS
        $columns = isset($_POST['columns']) ? intval($_POST['columns']) : 3;


        $params = ['page' => $page, 'per_page' => $limit];
        if (!empty($property_type)) {
            $params['type'] = $property_type;
        }

        $api_response = $this->get_properties($params);

        if (is_wp_error($api_response)) {
            wp_send_json_error($api_response->get_error_message());
        }

        // We need to reconstruct the shortcode attributes for render_properties_grid
        $shortcode_atts_for_render = [
            'limit' => $limit,
            'columns' => $columns, // Assuming you might need this in render_properties_grid
            'property_type' => $property_type,
            'page' => $page, // Current page being loaded
            'show_pagination' => 'true' // Or get this from POST if it can change
        ];

        ob_start();
        // Re-use render_properties_grid to generate the HTML for the new set of properties
        // but only the grid part, not the full container and pagination controls.
        // So, we might need a more specific rendering function here, or adjust render_properties_grid.

        // For simplicity, let's assume we render just the cards.
        // A better approach would be to have render_properties_grid output only the grid
        // and then call a separate render_pagination function.
        // The JS would then replace only the grid and update pagination separately.

        $html_content = '';
        $properties = isset($api_response['data']) ? $api_response['data'] : array();
        if (!empty($properties)) {
            foreach ($properties as $property) {
                ob_start();
                $this->render_property_card($property); // Render individual card
                $html_content .= ob_get_clean();
            }
        } else {
             $html_content = '<div class="propstack-no-results"><p>Keine weiteren Immobilien gefunden.</p></div>';
        }


        // Determine if there are more pages
        $meta = $api_response['meta'] ?? [];
        $total_properties = $meta['total_count'] ?? ($meta['total'] ?? 0);
        $has_more = ($page * $limit) < $total_properties;

        wp_send_json_success(array(
            'html'      => $html_content, // Send back only the new property cards
            'has_more'  => $has_more,     // Let JS know if there are more pages
            // Optionally, send back new pagination HTML if you regenerate it here
        ));
    }

    public function ajax_test_api_connection() {
        // Use a specific nonce for this admin-only action
        check_ajax_referer('propstack_test_nonce', 'nonce'); // Ensure this nonce is generated and passed in JS

        if (!current_user_can('manage_options')) {
            wp_send_json_error('Insufficient permissions.');
        }

        // Make a minimal API request, e.g., get 1 property
        $response = $this->make_api_request('units', array('per_page' => 1, 'with_meta' => 1));

        if (is_wp_error($response)) {
            wp_send_json_error($response->get_error_message());
        }

        // Check response structure and content
        $count = $response['meta']['total'] ?? ($response['meta']['total_count'] ?? 0);
        $first_property_info = 'N/A';
        if (!empty($response['data']) && is_array($response['data'])) {
             $first_prop = $response['data'][0];
             $first_property_info = ($first_prop['title'] ?? $first_prop['name'] ?? 'Unknown') . ' (ID: ' . ($first_prop['id'] ?? 'N/A') . ')';
        }

        wp_send_json_success(array(
            'message' => 'Connection successful!',
            'count' => $count,
            'first_property' => $first_property_info
            // 'raw_response' => $response // For debugging, but be careful with sensitive data
        ));
    }