<?php
/**
 * Admin Chat Box Firebase Service
 *
 * This class handles Firebase authentication and real-time database operations
 *
 * @package ACB\Inc
 */

namespace ACB\Inc;

defined('ABSPATH') || die('Hey, what are you doing here? You silly human!');

/**
 * ACB_FirebaseService Class
 *
 * @since 1.0.0
 */
class ACB_FirebaseService {
	
	/**
	 * Firebase configuration
	 *
	 * @var array
	 */
	private $firebase_config;
	
	/**
	 * Construct method.
	 *
	 * @since 1.0.0
	 */
	public function __construct() {
		$this->firebase_config = $this->get_firebase_config();
		add_action('wp_ajax_acb_firebase_auth', [$this, 'handle_firebase_auth']);
		add_action('wp_ajax_nopriv_acb_firebase_auth', [$this, 'handle_firebase_auth']);
		add_action('wp_ajax_acb_save_message', [$this, 'save_message']);
		add_action('wp_ajax_nopriv_acb_save_message', [$this, 'save_message']);
		add_action('wp_ajax_acb_get_messages', [$this, 'get_messages']);
		add_action('wp_ajax_nopriv_acb_get_messages', [$this, 'get_messages']);
		add_action('wp_ajax_acb_save_firebase_config', [$this, 'save_firebase_config']);
	}
	
	/**
	 * Get Firebase configuration
	 *
	 * @return array
	 */
	public function get_firebase_config() {
		$config = get_option('acb_firebase_authentication_value', '');
		
		if (empty($config)) {
			return [];
		}
		
		$decoded_config = json_decode($config, true);
		
		// Validate JSON decode
		if (json_last_error() !== JSON_ERROR_NONE) {
			error_log('ACB Firebase Service - Invalid JSON in stored config: ' . json_last_error_msg());
			return [];
		}
		
		return is_array($decoded_config) ? $decoded_config : [];
	}
	
	/**
	 * Save Firebase configuration
	 *
	 * @since 1.0.0
	 */
	public function save_firebase_config() {
		// Verify nonce
		if (!wp_verify_nonce($_POST['nonce'] ?? '', 'acb_firebase_nonce')) {
			wp_send_json_error('Security check failed');
		}
		
		// Check user permissions
		if (!current_user_can('manage_options')) {
			wp_send_json_error('Insufficient permissions');
		}
		
		// Validate POST data exists
		if (!isset($_POST['config']) || empty($_POST['config'])) {
			wp_send_json_error('Configuration data is required');
		}
		
		// Sanitize and unslash config data
		$config = wp_unslash($_POST['config']);
		$config = sanitize_textarea_field($config);
		$config_array = json_decode($config, true);
		
		// Validate JSON decode
		if (json_last_error() !== JSON_ERROR_NONE) {
			wp_send_json_error('Invalid configuration format: ' . json_last_error_msg());
		}
		
		if (!is_array($config_array)) {
			wp_send_json_error('Configuration must be a valid JSON object');
		}
		
		// Validate required fields
		$required_fields = ['apiKey', 'authDomain', 'projectId'];
		foreach ($required_fields as $field) {
			if (!isset($config_array[$field]) || empty(trim($config_array[$field]))) {
				wp_send_json_error("Missing or empty required field: $field");
			}
		}
		
		// Sanitize configuration values
		$sanitized_config = [];
		foreach ($config_array as $key => $value) {
			$sanitized_key = sanitize_key($key);
			$sanitized_value = sanitize_text_field($value);
			
			if (!empty($sanitized_key) && !empty($sanitized_value)) {
				$sanitized_config[$sanitized_key] = $sanitized_value;
			}
		}
		
		// Validate sanitized config still has required fields
		foreach ($required_fields as $field) {
			if (!isset($sanitized_config[$field]) || empty($sanitized_config[$field])) {
				wp_send_json_error("Invalid data for required field: $field");
			}
		}
		
		// Save configuration
		$result = update_option('acb_firebase_authentication_value', wp_json_encode($sanitized_config));
		
		if ($result) {
			// Update internal config
			$this->firebase_config = $sanitized_config;
			wp_send_json_success('Firebase configuration saved successfully');
		} else {
			wp_send_json_error('Failed to save configuration');
		}
	}
	
	/**
	 * Handle Firebase authentication
	 *
	 * @since 1.0.0
	 */
	public function handle_firebase_auth() {
		// Verify nonce
		if (!wp_verify_nonce($_POST['nonce'] ?? '', 'acb_firebase_nonce')) {
			wp_send_json_error('Security check failed');
		}
		
		// Validate required fields exist
		$required_fields = ['firebase_uid', 'user_name', 'user_email'];
		foreach ($required_fields as $field) {
			if (!isset($_POST[$field]) || empty(trim($_POST[$field]))) {
				wp_send_json_error("Missing required field: $field");
			}
		}
		
		// Sanitize and validate input data
		$firebase_uid = sanitize_text_field(wp_unslash($_POST['firebase_uid']));
		$user_name = sanitize_text_field(wp_unslash($_POST['user_name']));
		$user_email = sanitize_email(wp_unslash($_POST['user_email']));
		$user_avatar = isset($_POST['user_avatar']) ? esc_url_raw(wp_unslash($_POST['user_avatar'])) : '';
		$auth_provider = isset($_POST['auth_provider']) ? sanitize_text_field(wp_unslash($_POST['auth_provider'])) : 'firebase';
		
		// Validate email format
		if (!is_email($user_email)) {
			wp_send_json_error('Invalid email format');
		}
		
		// Validate sanitized data
		if (empty($firebase_uid) || empty($user_name) || empty($user_email)) {
			wp_send_json_error('Invalid data provided');
		}
		
		$user_id = $this->create_or_update_user($firebase_uid, $user_name, $user_email, $user_avatar, $auth_provider);
		
		if ($user_id) {
			wp_send_json_success([
				'user_id' => absint($user_id),
				'message' => 'Authentication successful'
			]);
		} else {
			wp_send_json_error('Failed to authenticate user');
		}
	}
	
	/**
	 * Create or update user in database
	 *
	 * @param string $firebase_uid
	 * @param string $user_name
	 * @param string $user_email
	 * @param string $user_avatar
	 * @param string $auth_provider
	 * @return int|false
	 */
	private function create_or_update_user($firebase_uid, $user_name, $user_email, $user_avatar, $auth_provider) {
		global $wpdb;
		$table_users = $wpdb->prefix . 'acb_users';
		
		// Validate table exists
		if ($wpdb->get_var($wpdb->prepare("SHOW TABLES LIKE %s", $table_users)) !== $table_users) {
			error_log('ACB Firebase Service - Table does not exist: ' . $table_users);
			return false;
		}
		
		// Check if user exists
		$existing_user = $wpdb->get_row(
			$wpdb->prepare(
				"SELECT * FROM $table_users WHERE firebase_uid = %s OR user_email = %s",
				$firebase_uid,
				$user_email
			)
		);
		
		if ($existing_user) {
			// Update existing user
			$result = $wpdb->update(
				$table_users,
				[
					'firebase_uid' => $firebase_uid,
					'user_name' => $user_name,
					'user_email' => $user_email,
					'user_avatar' => $user_avatar,
					'auth_provider' => $auth_provider,
					'last_seen' => current_time('mysql'),
					'updated_at' => current_time('mysql')
				],
				['id' => $existing_user->id],
				['%s', '%s', '%s', '%s', '%s', '%s', '%s'],
				['%d']
			);
			
			return $result !== false ? $existing_user->id : false;
		} else {
			// Create new user
			$result = $wpdb->insert(
				$table_users,
				[
					'firebase_uid' => $firebase_uid,
					'user_name' => $user_name,
					'user_email' => $user_email,
					'user_avatar' => $user_avatar,
					'auth_provider' => $auth_provider,
					'is_admin' => 0,
					'created_at' => current_time('mysql'),
					'updated_at' => current_time('mysql')
				],
				['%s', '%s', '%s', '%s', '%s', '%d', '%s', '%s']
			);
			
			return $result !== false ? $wpdb->insert_id : false;
		}
	}
	
	/**
	 * Save message to database
	 *
	 * @since 1.0.0
	 */
	public function save_message() {
		// Verify nonce
		if (!wp_verify_nonce($_POST['nonce'] ?? '', 'acb_message_nonce')) {
			wp_send_json_error('Security check failed');
		}
		
		// Validate required fields exist
		$required_fields = ['user_id', 'user_name', 'message'];
		foreach ($required_fields as $field) {
			if (!isset($_POST[$field]) || empty(trim($_POST[$field]))) {
				wp_send_json_error("Missing required field: $field");
			}
		}
		
		// Sanitize and validate input data
		$user_id = sanitize_text_field(wp_unslash($_POST['user_id']));
		$user_name = sanitize_text_field(wp_unslash($_POST['user_name']));
		$user_email = isset($_POST['user_email']) ? sanitize_email(wp_unslash($_POST['user_email'])) : '';
		$user_avatar = isset($_POST['user_avatar']) ? esc_url_raw(wp_unslash($_POST['user_avatar'])) : '';
		$message = wp_kses_post(wp_unslash($_POST['message'])); // Allow safe HTML for messages
		$message_type = isset($_POST['message_type']) ? sanitize_text_field(wp_unslash($_POST['message_type'])) : 'text';
		$file_url = isset($_POST['file_url']) ? esc_url_raw(wp_unslash($_POST['file_url'])) : '';
		
		// Validate email if provided
		if (!empty($user_email) && !is_email($user_email)) {
			wp_send_json_error('Invalid email format');
		}
		
		// Validate sanitized data
		if (empty($user_id) || empty($user_name) || empty($message)) {
			wp_send_json_error('Invalid data provided');
		}
		
		$message_id = $this->insert_message($user_id, $user_name, $user_email, $user_avatar, $message, $message_type, $file_url);
		
		if ($message_id) {
			wp_send_json_success([
				'message_id' => absint($message_id),
				'message' => 'Message saved successfully'
			]);
		} else {
			wp_send_json_error('Failed to save message');
		}
	}
	
	/**
	 * Insert message into database
	 *
	 * @param string $user_id
	 * @param string $user_name
	 * @param string $user_email
	 * @param string $user_avatar
	 * @param string $message
	 * @param string $message_type
	 * @param string $file_url
	 * @return int|false
	 */
	private function insert_message($user_id, $user_name, $user_email, $user_avatar, $message, $message_type, $file_url) {
		global $wpdb;
		$table_messages = $wpdb->prefix . 'acb_messages';
		
		// Validate table exists
		if ($wpdb->get_var($wpdb->prepare("SHOW TABLES LIKE %s", $table_messages)) !== $table_messages) {
			error_log('ACB Firebase Service - Table does not exist: ' . $table_messages);
			return false;
		}
		
		$result = $wpdb->insert(
			$table_messages,
			[
				'user_id' => $user_id,
				'user_name' => $user_name,
				'user_email' => $user_email,
				'user_avatar' => $user_avatar,
				'message' => $message,
				'message_type' => $message_type,
				'file_url' => $file_url,
				'created_at' => current_time('mysql'),
				'updated_at' => current_time('mysql')
			],
			['%s', '%s', '%s', '%s', '%s', '%s', '%s', '%s', '%s']
		);
		
		return $result !== false ? $wpdb->insert_id : false;
	}
	
	/**
	 * Get messages from database
	 *
	 * @since 1.0.0
	 */
	public function get_messages() {
		// Verify nonce
		if (!wp_verify_nonce($_POST['nonce'] ?? '', 'acb_message_nonce')) {
			wp_send_json_error('Security check failed');
		}
		
		// Sanitize and validate pagination parameters
		$limit = isset($_POST['limit']) ? absint($_POST['limit']) : 50;
		$offset = isset($_POST['offset']) ? absint($_POST['offset']) : 0;
		
		// Set reasonable limits
		$limit = min($limit, 100); // Max 100 messages per request
		$limit = max($limit, 1);   // Min 1 message per request
		
		global $wpdb;
		$table_messages = $wpdb->prefix . 'acb_messages';
		
		// Validate table exists
		if ($wpdb->get_var($wpdb->prepare("SHOW TABLES LIKE %s", $table_messages)) !== $table_messages) {
			wp_send_json_error('Messages table does not exist');
		}
		
		$messages = $wpdb->get_results(
			$wpdb->prepare(
				"SELECT * FROM $table_messages ORDER BY created_at DESC LIMIT %d OFFSET %d",
				$limit,
				$offset
			)
		);
		
		if ($messages === false) {
			wp_send_json_error('Failed to retrieve messages');
		}
		
		$formatted_messages = [];
		foreach ($messages as $message) {
			$formatted_messages[] = [
				'id' => absint($message->id),
				'user_id' => esc_html($message->user_id),
				'user_name' => esc_html($message->user_name),
				'user_email' => esc_html($message->user_email),
				'user_avatar' => esc_url($message->user_avatar),
				'message' => wp_kses_post($message->message), // Allow safe HTML for display
				'message_type' => esc_html($message->message_type),
				'file_url' => esc_url($message->file_url),
				'created_at' => esc_html($message->created_at),
				'formatted_time' => esc_html(date('M d, Y > h:i A', strtotime($message->created_at)))
			];
		}
		
		wp_send_json_success([
			'messages' => array_reverse($formatted_messages),
			'total' => count($formatted_messages)
		]);
	}
	
	/**
	 * Get user by Firebase UID
	 *
	 * @param string $firebase_uid
	 * @return object|null
	 */
	public function get_user_by_firebase_uid($firebase_uid) {
		global $wpdb;
		$table_users = $wpdb->prefix . 'acb_users';
		
		// Sanitize input
		$firebase_uid = sanitize_text_field($firebase_uid);
		
		if (empty($firebase_uid)) {
			return null;
		}
		
		// Validate table exists
		if ($wpdb->get_var($wpdb->prepare("SHOW TABLES LIKE %s", $table_users)) !== $table_users) {
			error_log('ACB Firebase Service - Table does not exist: ' . $table_users);
			return null;
		}
		
		return $wpdb->get_row(
			$wpdb->prepare(
				"SELECT * FROM $table_users WHERE firebase_uid = %s",
				$firebase_uid
			)
		);
	}
	
	/**
	 * Update user last seen
	 *
	 * @param string $firebase_uid
	 * @return bool
	 */
	public function update_user_last_seen($firebase_uid) {
		global $wpdb;
		$table_users = $wpdb->prefix . 'acb_users';
		
		// Sanitize input
		$firebase_uid = sanitize_text_field($firebase_uid);
		
		if (empty($firebase_uid)) {
			return false;
		}
		
		// Validate table exists
		if ($wpdb->get_var($wpdb->prepare("SHOW TABLES LIKE %s", $table_users)) !== $table_users) {
			error_log('ACB Firebase Service - Table does not exist: ' . $table_users);
			return false;
		}
		
		$result = $wpdb->update(
			$table_users,
			['last_seen' => current_time('mysql')],
			['firebase_uid' => $firebase_uid],
			['%s'],
			['%s']
		);
		
		return $result !== false;
	}
}