<?php
defined( 'ABSPATH' ) || exit;

/**
 * Class AISP_Customer_Activity_Tracker
 *
 * Handles login time, page activity tracking, and cart summary.
 * A customer is shown if cart > 0, regardless of online status.
 */
class AISP_Customer_Activity_Tracker {

	/** Transient key for active customers cache. */
	const TRANSIENT_KEY = 'aisp_ca_active_customers';

	/** Transient lifetime in seconds. */
	const TRANSIENT_TTL = 60;

	public static function init() {
		add_action( 'wp_login', [ __CLASS__, 'on_login' ], 10, 2 );
		add_action( 'wp',       [ __CLASS__, 'track_activity' ] );
		add_action( 'admin_post_aisp_customer_activity_hide', [ __CLASS__, 'hide_customer_callback' ] );

		// Invalidate transient when cart changes.
		add_action( 'woocommerce_cart_updated',         [ __CLASS__, 'invalidate_cache' ] );
		add_action( 'woocommerce_add_to_cart',          [ __CLASS__, 'invalidate_cache' ] );
		add_action( 'woocommerce_cart_item_removed',    [ __CLASS__, 'invalidate_cache' ] );
		add_action( 'woocommerce_cart_emptied',         [ __CLASS__, 'invalidate_cache' ] );

		// Invalidate dormant cache when order status changes.
		add_action( 'woocommerce_order_status_changed', [ __CLASS__, 'invalidate_dormant_cache' ] );
		add_action( 'woocommerce_new_order',            [ __CLASS__, 'invalidate_dormant_cache' ] );
	}

	// -------------------------------------------------------------------------
	// Cache
	// -------------------------------------------------------------------------

	public static function invalidate_cache() {
		delete_transient( self::TRANSIENT_KEY );
	}

	/**
	 * Invalidate the dormant customers cache (called on order changes).
	 *
	 * @since 1.1.0
	 */
	public static function invalidate_dormant_cache() {
		AISP_Customer_Activity_Dormant::invalidate_cache();
	}

	// -------------------------------------------------------------------------
	// Helpers
	// -------------------------------------------------------------------------

	/**
	 * True if the user has at least one tracked role and is not an administrator.
	 */
	private static function is_trackable_user( WP_User $user ): bool {
		$roles         = (array) $user->roles;
		$tracked_roles = AISP_Customer_Activity_Settings::get_tracked_roles();

		if ( in_array( 'administrator', $roles, true ) ) {
			return false;
		}

		return ! empty( array_intersect( $roles, $tracked_roles ) );
	}

	// -------------------------------------------------------------------------
	// 1. Login
	// -------------------------------------------------------------------------

	public static function on_login( string $user_login, WP_User $user ) {
		if ( ! self::is_trackable_user( $user ) ) {
			return;
		}
		$now = current_time( 'timestamp' );
		update_user_meta( $user->ID, 'aisp_ca_last_login',    $now );
		update_user_meta( $user->ID, 'aisp_ca_last_activity', $now );
		self::invalidate_cache();
	}

	// -------------------------------------------------------------------------
	// 2. Page activity + cart
	// -------------------------------------------------------------------------

	public static function track_activity() {
		if ( ! is_user_logged_in() ) {
			return;
		}
		$user = wp_get_current_user();
		if ( ! self::is_trackable_user( $user ) ) {
			return;
		}

		$now           = current_time( 'timestamp' );
		$last_activity = (int) get_user_meta( $user->ID, 'aisp_ca_last_activity', true );

		// Throttle DB writes — update only if older than 60 s.
		if ( ! $last_activity || ( $now - $last_activity ) >= 60 ) {
			update_user_meta( $user->ID, 'aisp_ca_last_activity', $now );
			self::invalidate_cache();
		}

		self::update_cart_summary( $user->ID, $now );
	}

	// -------------------------------------------------------------------------
	// 3. Cart summary
	// -------------------------------------------------------------------------

	public static function update_cart_summary( int $user_id, int $now = 0 ) {
		if ( ! function_exists( 'WC' ) || ! WC()->cart ) {
			return;
		}
		$now = $now ?: current_time( 'timestamp' );

		update_user_meta( $user_id, 'aisp_ca_cart_count',   absint( WC()->cart->get_cart_contents_count() ) );
		update_user_meta( $user_id, 'aisp_ca_cart_total',   wc_format_decimal( WC()->cart->get_cart_contents_total() ) );
		update_user_meta( $user_id, 'aisp_ca_cart_updated', $now );
	}

	// -------------------------------------------------------------------------
	// 4. Manual hide
	// -------------------------------------------------------------------------

	public static function hide_customer_callback() {
		if ( ! current_user_can( 'manage_woocommerce' ) ) {
			wp_die( esc_html__( 'Permission denied.', 'aisp-customer-activity' ) );
		}

		$user_id = isset( $_GET['user_id'] ) ? absint( $_GET['user_id'] ) : 0;

		if ( ! $user_id ) {
			wp_safe_redirect( admin_url() );
			exit;
		}

		check_admin_referer( 'aisp_ca_hide_' . $user_id );
		self::delete_user_metas( $user_id );
		self::invalidate_cache();

		$redirect = ! empty( $_GET['redirect'] ) ? esc_url_raw( wp_unslash( $_GET['redirect'] ) ) : admin_url();
		wp_safe_redirect( $redirect );
		exit;
	}

	// -------------------------------------------------------------------------
	// 5. Meta cleanup
	// -------------------------------------------------------------------------

	public static function delete_user_metas( int $user_id ) {
		foreach ( self::get_meta_keys() as $key ) {
			delete_user_meta( $user_id, $key );
		}
	}

	public static function get_meta_keys(): array {
		return [
			'aisp_ca_last_login',
			'aisp_ca_last_activity',
			'aisp_ca_cart_count',
			'aisp_ca_cart_total',
			'aisp_ca_cart_updated',
		];
	}

	// -------------------------------------------------------------------------
	// 6. Query helpers
	// -------------------------------------------------------------------------

	/**
	 * Return customers active within $hours who have cart > 0.
	 * If $hours === 0, all customers with a cart are returned (no time limit).
	 * Results are cached in a transient for TRANSIENT_TTL seconds.
	 */
	public static function get_active_customers( int $hours, int $limit ): array {
		$cached = get_transient( self::TRANSIENT_KEY );

		if ( false === $cached ) {
			$cached = self::query_active_customers();
			set_transient( self::TRANSIENT_KEY, $cached, self::TRANSIENT_TTL );
		}

		// Apply time filter after cache (cache stores all, filter on read).
		if ( $hours > 0 ) {
			$limit_time = current_time( 'timestamp' ) - ( $hours * HOUR_IN_SECONDS );
			$cached = array_values( array_filter( $cached, function( $user ) use ( $limit_time ) {
				$last = (int) get_user_meta( $user->ID, 'aisp_ca_last_activity', true );
				return $last >= $limit_time;
			} ) );
		}

		return array_slice( $cached, 0, $limit );
	}

	/**
	 * Raw DB query — all tracked customers with cart > 0, ordered by last activity DESC.
	 * Called only when transient is expired or invalidated.
	 */
	private static function query_active_customers(): array {
		$tracked_roles = AISP_Customer_Activity_Settings::get_tracked_roles();

		if ( empty( $tracked_roles ) ) {
			return [];
		}

		$users = get_users( [
			'role__in'     => $tracked_roles,
			'meta_key'     => 'aisp_ca_last_activity', // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_key
			'meta_compare' => 'EXISTS',
			'orderby'      => 'meta_value_num',
			'order'        => 'DESC',
			'number'       => 2000,
			'fields'       => [ 'ID', 'display_name', 'user_email' ],
		] );

		// Filter: cart > 0 only.
		return array_values( array_filter( $users, function ( $user ) {
			return (int) get_user_meta( $user->ID, 'aisp_ca_cart_count', true ) > 0;
		} ) );
	}

	/**
	 * Is the customer currently online?
	 * Uses aisp_ca_online_minutes (default 5).
	 */
	public static function is_online( int $user_id ): bool {
		$last    = (int) get_user_meta( $user_id, 'aisp_ca_last_activity', true );
		$minutes = (int) get_option( 'aisp_ca_online_minutes', 5 );
		return $last && ( current_time( 'timestamp' ) - $last ) <= ( $minutes * 60 );
	}

	/**
	 * Build a nonce-protected hide URL.
	 */
	public static function hide_url( int $user_id, string $redirect = '' ): string {
		$args = [
			'action'  => 'aisp_customer_activity_hide',
			'user_id' => $user_id,
		];
		if ( $redirect ) {
			$args['redirect'] = $redirect;
		}
		return wp_nonce_url(
			admin_url( 'admin-post.php?' . http_build_query( $args ) ),
			'aisp_ca_hide_' . $user_id
		);
	}
}