<?php
/**
 * Admin Chat Box Firebase Service
 *
 * This class handles Firebase authentication and real-time database operations
 *
 * @package ACB\Inc
 */

namespace ACB\Inc;

defined( 'ABSPATH' ) || exit;

/**
 * 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() {
		// Issue Part C: Removed duplicate wp_ajax_acb_firebase_auth hooks — ACB_AjaxHandler registers first.
		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_get_users', [ $this, 'get_users' ] );
		add_action( 'wp_ajax_acb_save_firebase_config', [ $this, 'save_firebase_config' ] );
	}
	
	
	/**
	 * Save Firebase configuration
	 *
	 * @since 1.0.0
	 */
	public function save_firebase_config() {
		// Verify nonce
		if ( ! isset( $_POST['nonce'] ) || ! wp_verify_nonce( sanitize_text_field( wp_unslash( $_POST['nonce'] ) ), 'acb_nonce' ) ) {
			wp_send_json_error( [ 'message' => __( 'Security check failed.','admin-chat-box' ) ] );
			wp_die();
		}

		// Check user permissions
		if ( ! current_user_can( 'manage_options' ) ) {
			wp_send_json_error( [ 'message' => __( 'Insufficient permissions.','admin-chat-box' ) ] );
			wp_die();
		}

		// Validate POST data exists
		if ( ! isset( $_POST['config'] ) || empty( $_POST['config'] ) ) {
			wp_send_json_error( [ 'message' => __( 'Configuration data is required.','admin-chat-box' ) ] );
			wp_die();
		}

		// 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( [ 'message' => __( 'Invalid configuration format.','admin-chat-box' ) ] );
			wp_die();
		}

		if ( ! is_array( $config_array ) ) {
			wp_send_json_error( [ 'message' => __( 'Configuration must be a valid JSON object.','admin-chat-box' ) ] );
			wp_die();
		}

		// Validate required fields
		$required_fields = [ 'apiKey', 'authDomain', 'projectId' ];
		foreach ( $required_fields as $field ) {
			if ( ! isset( $config_array[ $field ] ) || '' === trim( $config_array[ $field ] ) ) {
				wp_send_json_error( [ 'message' => sprintf( __( 'Missing or empty required field: %s','admin-chat-box' ), esc_html( $field ) ) ] );
				wp_die();
			}
		}

		// Issue 4.4: Use allowlist instead of sanitize_key() which destroys camelCase keys.
		$allowed_keys     = [ 'apiKey', 'authDomain', 'projectId', 'storageBucket', 'messagingSenderId', 'appId' ];
		$sanitized_config = [];
		foreach ( $allowed_keys as $allowed_key ) {
			if ( isset( $config_array[ $allowed_key ] ) ) {
				$sanitized_config[ $allowed_key ] = sanitize_text_field( wp_unslash( $config_array[ $allowed_key ] ) );
			}
		}

		// 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( [ 'message' => sprintf( __( 'Invalid data for required field: %s','admin-chat-box' ), esc_html( $field ) ) ] );
				wp_die();
			}
		}

		// Save configuration
		$result = update_option( 'acb_firebase_authentication_value', wp_json_encode( $sanitized_config ) );

		if ( $result ) {
			$this->firebase_config = $sanitized_config;
			wp_send_json_success( [ 'message' => __( 'Firebase configuration saved successfully.','admin-chat-box' ) ] );
		} else {
			wp_send_json_error( [ 'message' => __( 'Failed to save configuration.','admin-chat-box' ) ] );
		}
		wp_die();
	}
	
	/**
	 * Handle Firebase authentication
	 *
	 * @since 1.0.0
	 */
	
	/**
	 * 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) {
			if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
				// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
				error_log( 'ACB Firebase Service - Table does not exist: ' . esc_attr( $table_users ) );
			}
			return false;
		}
		
		// Check if user exists by Firebase UID first, then by email
		$existing_user = $wpdb->get_row(
			$wpdb->prepare(
				"SELECT * FROM {$wpdb->prefix}acb_users WHERE firebase_uid = %s",
				$firebase_uid
			)
		);
		
		// If not found by Firebase UID, check by email
		if (!$existing_user) {
			$existing_user = $wpdb->get_row(
				$wpdb->prepare(
					"SELECT * FROM {$wpdb->prefix}acb_users WHERE user_email = %s",
					$user_email
				)
			);
		}
		
		if ($existing_user) {
			// Update existing user with latest information
			$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']
			);
			
			if ($result !== false) {
				return $existing_user->id;
			} else {
				if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
					// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
					error_log( 'ACB Firebase Service - Failed to update user: ' . esc_attr( $user_email ) );
				}
				return false;
			}
		} else {
			// Create new user - this is where new users should be immediately visible
			$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,
					'last_seen' => current_time('mysql'),
					'created_at' => current_time('mysql'),
					'updated_at' => current_time('mysql')
				],
				['%s', '%s', '%s', '%s', '%s', '%d', '%s', '%s', '%s']
			);
			
			if ($result !== false) {
				$new_user_id = $wpdb->insert_id;
				// Immediately make this user available to other users by triggering a refresh
				$this->notify_user_list_update();
				return $new_user_id;
			} else {
				if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
					// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
					error_log( 'ACB Firebase Service - Failed to create user: ' . esc_attr( $user_email ) . ' Error: ' . esc_attr( $wpdb->last_error ) );
				}
				return false;
			}
		}
	}
	
	/**
	 * Notify that user list should be updated (for real-time updates)
	 */
	private function notify_user_list_update() {
		set_transient( 'acb_user_list_updated', time(), 60 );
	}
	
	/**
	 * Save message to database
	 *
	 * @since 1.0.0
	 */
	public function save_message() {
		if ( ! isset( $_POST['nonce'] ) || ! wp_verify_nonce( sanitize_text_field( wp_unslash( $_POST['nonce'] ) ), 'acb_nonce' ) ) {
			wp_send_json_error( [ 'message' => __( 'Security check failed.','admin-chat-box' ) ] );
			wp_die();
		}

		$required_fields = [ 'user_id', 'user_name', 'message' ];
		foreach ( $required_fields as $field ) {
			if ( ! isset( $_POST[ $field ] ) || '' === trim( $_POST[ $field ] ) ) {
				wp_send_json_error( [ 'message' => sprintf( __( 'Missing required field: %s','admin-chat-box' ), esc_html( $field ) ) ] );
				wp_die();
			}
		}

		$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'] ) );
		$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'] ) ) : '';

		if ( ! empty( $user_email ) && ! is_email( $user_email ) ) {
			wp_send_json_error( [ 'message' => __( 'Invalid email format.','admin-chat-box' ) ] );
			wp_die();
		}

		if ( empty( $user_id ) || empty( $user_name ) || empty( $message ) ) {
			wp_send_json_error( [ 'message' => __( 'Invalid data provided.','admin-chat-box' ) ] );
			wp_die();
		}

		$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.','admin-chat-box' ),
			] );
		} else {
			wp_send_json_error( [ 'message' => __( 'Failed to save message.','admin-chat-box' ) ] );
		}
		wp_die();
	}
	
	/**
	 * 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) {
			if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
				// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
				error_log( 'ACB Firebase Service - Table does not exist: ' . esc_attr( $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() {
		if ( ! isset( $_POST['nonce'] ) || ! wp_verify_nonce( sanitize_text_field( wp_unslash( $_POST['nonce'] ) ), 'acb_nonce' ) ) {
			wp_send_json_error( [ 'message' => __( 'Security check failed.','admin-chat-box' ) ] );
			wp_die();
		}

		$limit  = isset( $_POST['limit'] ) ? absint( $_POST['limit'] ) : 50;
		$offset = isset( $_POST['offset'] ) ? absint( $_POST['offset'] ) : 0;
		$limit  = min( max( $limit, 1 ), 100 );

		global $wpdb;
		$table_messages = $wpdb->prefix . 'acb_messages';

		if ( $wpdb->get_var( $wpdb->prepare( 'SHOW TABLES LIKE %s', $table_messages ) ) !== $table_messages ) {
			wp_send_json_error( [ 'message' => __( 'Messages table does not exist.','admin-chat-box' ) ] );
			wp_die();
		}

		$messages = $wpdb->get_results(
			$wpdb->prepare(
				"SELECT * FROM {$wpdb->prefix}acb_messages ORDER BY created_at DESC LIMIT %d OFFSET %d",
				$limit,
				$offset
			)
		);

		if ( false === $messages ) {
			wp_send_json_error( [ 'message' => __( 'Failed to retrieve messages.','admin-chat-box' ) ] );
			wp_die();
		}

		$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 ),
				'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( wp_date( 'M d, Y > h:i A', strtotime( $message->created_at ) ) ),
			];
		}

		wp_send_json_success( [
			'messages' => array_reverse( $formatted_messages ),
			'total'    => count( $formatted_messages ),
		] );
		wp_die();
	}

	/**
	 * Get users from database
	 *
	 * @since 1.0.0
	 */
	public function get_users() {
		if ( ! isset( $_POST['nonce'] ) || ! wp_verify_nonce( sanitize_text_field( wp_unslash( $_POST['nonce'] ) ), 'acb_nonce' ) ) {
			wp_send_json_error( [ 'message' => __( 'Security check failed.','admin-chat-box' ) ] );
			wp_die();
		}

		global $wpdb;
		$table_users = $wpdb->prefix . 'acb_users';

		if ( $wpdb->get_var( $wpdb->prepare( 'SHOW TABLES LIKE %s', $table_users ) ) !== $table_users ) {
			wp_send_json_error( [ 'message' => __( 'Users table does not exist.','admin-chat-box' ) ] );
			wp_die();
		}

		$current_user_uid = isset( $_POST['current_user_uid'] ) ? sanitize_text_field( wp_unslash( $_POST['current_user_uid'] ) ) : '';

		if ( ! empty( $current_user_uid ) ) {
			$users = $wpdb->get_results(
				$wpdb->prepare(
					"SELECT * FROM {$wpdb->prefix}acb_users WHERE firebase_uid != %s ORDER BY last_seen DESC",
					$current_user_uid
				)
			);
		} else {
			$users = $wpdb->get_results(
				"SELECT * FROM {$wpdb->prefix}acb_users ORDER BY last_seen DESC"
			);
		}

		if ( false === $users ) {
			wp_send_json_error( [ 'message' => __( 'Failed to retrieve users.','admin-chat-box' ) ] );
			wp_die();
		}

		$formatted_users = [];
		foreach ( $users as $user ) {
			$last_seen_time  = strtotime( $user->last_seen );
			$is_online       = ( time() - $last_seen_time ) < 120;

			$formatted_users[] = [
				'id'           => absint( $user->id ),
				'firebase_uid' => esc_html( $user->firebase_uid ),
				'user_name'    => esc_html( $user->user_name ),
				'user_email'   => esc_html( $user->user_email ),
				'user_avatar'  => esc_url( $user->user_avatar ),
				'auth_provider' => esc_html( $user->auth_provider ),
				'is_admin'     => (bool) $user->is_admin,
				'is_online'    => $is_online,
				'last_seen'    => esc_html( $user->last_seen ),
				'created_at'   => esc_html( $user->created_at ),
				'formatted_last_seen' => esc_html( wp_date( 'M d, Y > h:i A', strtotime( $user->last_seen ) ) )
			];
		}
		
		wp_send_json_success( [
			'users'     => $formatted_users,
			'total'     => count( $formatted_users ),
			'timestamp' => time(),
		] );
		wp_die();
	}

	/**
	 * 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) {
			if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
				// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
				error_log( 'ACB Firebase Service - Table does not exist: ' . esc_attr( $table_users ) );
			}
			return null;
		}
		
		return $wpdb->get_row(
			$wpdb->prepare(
				"SELECT * FROM {$wpdb->prefix}acb_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) {
			if ( defined( 'WP_DEBUG' ) && WP_DEBUG ) {
				// phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
				error_log( 'ACB Firebase Service - Table does not exist: ' . esc_attr( $table_users ) );
			}
			return false;
		}
		
		$result = $wpdb->update(
			$table_users,
			['last_seen' => current_time('mysql')],
			['firebase_uid' => $firebase_uid],
			['%s'],
			['%s']
		);
		
		return $result !== false;
	}
}