<?php
/**
 * GDPR Compliance Handler for Agentorie Chat.
 *
 * Handles data privacy operations:
 * - Data retention (purge old conversations)
 * - Data export (GDPR portability)
 * - Data erasure (right to be forgotten)
 *
 * @package    Agentorie_Chat
 * @subpackage Agentorie_Chat/includes
 * @since      1.0.0
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Class Agentorie_GDPR
 *
 * Provides GDPR compliance functionality for the plugin.
 *
 * @since 1.0.0
 */
class Agentorie_GDPR {

	/**
	 * Initialize GDPR hooks.
	 *
	 * @since 1.0.0
	 * @return void
	 */
	public static function init() {
		// Admin POST handlers.
		add_action( 'admin_post_agentorie_chat_purge_old_data', array( __CLASS__, 'handle_purge_old_data' ) );
		add_action( 'admin_post_agentorie_chat_export_visitor_data', array( __CLASS__, 'handle_export_visitor_data' ) );
		add_action( 'admin_post_agentorie_chat_delete_visitor_data', array( __CLASS__, 'handle_delete_visitor_data' ) );

		// WordPress Privacy hooks (for Tools > Export/Erase Personal Data).
		add_filter( 'wp_privacy_personal_data_exporters', array( __CLASS__, 'register_data_exporter' ) );
		add_filter( 'wp_privacy_personal_data_erasers', array( __CLASS__, 'register_data_eraser' ) );
	}

	/**
	 * Handle purge old data form submission.
	 *
	 * Deletes conversations older than specified number of days.
	 *
	 * @since 1.0.0
	 * @return void
	 */
	public static function handle_purge_old_data() {
		// Verify nonce.
		if ( ! isset( $_POST['_wpnonce'] ) || ! wp_verify_nonce( sanitize_text_field( wp_unslash( $_POST['_wpnonce'] ) ), 'agentorie_chat_purge_old_data' ) ) {
			wp_die( esc_html__( 'Security check failed.', 'agentorie-chat' ), 403 );
		}

		// Check capabilities.
		if ( ! current_user_can( 'manage_options' ) ) {
			wp_die( esc_html__( 'You do not have permission to perform this action.', 'agentorie-chat' ), 403 );
		}

		// Get retention days.
		$retention_days = isset( $_POST['retention_days'] ) ? absint( wp_unslash( $_POST['retention_days'] ) ) : 90;
		$allowed_days   = array( 30, 60, 90, 180, 365 );

		if ( ! in_array( $retention_days, $allowed_days, true ) ) {
			$retention_days = 90;
		}

		// Perform purge.
		$deleted_count = self::purge_old_data( $retention_days );

		// Redirect back with result.
		$redirect_url = add_query_arg(
			array(
				'page'    => 'agentorie-chat-conversations',
				'tab'     => 'conversations',
				'deleted' => $deleted_count,
			),
			admin_url( 'admin.php' )
		);

		wp_safe_redirect( $redirect_url );
		exit;
	}

	/**
	 * Handle export visitor data form submission.
	 *
	 * Exports all data for a specific visitor as JSON download.
	 *
	 * @since 1.0.0
	 * @return void
	 */
	public static function handle_export_visitor_data() {
		// Verify nonce.
		if ( ! isset( $_POST['_wpnonce'] ) || ! wp_verify_nonce( sanitize_text_field( wp_unslash( $_POST['_wpnonce'] ) ), 'agentorie_chat_export_visitor_data' ) ) {
			wp_die( esc_html__( 'Security check failed.', 'agentorie-chat' ), 403 );
		}

		// Check capabilities.
		if ( ! current_user_can( 'manage_options' ) ) {
			wp_die( esc_html__( 'You do not have permission to perform this action.', 'agentorie-chat' ), 403 );
		}

		// Get visitor identifier.
		$identifier = isset( $_POST['visitor_identifier'] ) ? sanitize_text_field( wp_unslash( $_POST['visitor_identifier'] ) ) : '';

		if ( empty( $identifier ) ) {
			self::redirect_with_error( 'invalid_identifier' );
		}

		// Get visitor data.
		$data = self::get_visitor_data( $identifier );

		if ( empty( $data['sessions'] ) && empty( $data['contacts'] ) ) {
			self::redirect_with_error( 'no_data_found' );
		}

		// Generate JSON export.
		$export = array(
			'export_date'        => current_time( 'c' ),
			'export_site'        => get_bloginfo( 'name' ),
			'visitor_identifier' => $identifier,
			'data'               => $data,
		);

		$filename = 'agentorie-visitor-data-' . sanitize_file_name( $identifier ) . '-' . gmdate( 'Y-m-d' ) . '.json';

		// Send JSON file.
		header( 'Content-Type: application/json; charset=utf-8' );
		header( 'Content-Disposition: attachment; filename="' . $filename . '"' );
		header( 'Pragma: no-cache' );
		header( 'Expires: 0' );

		echo wp_json_encode( $export, JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE );
		exit;
	}

	/**
	 * Handle delete visitor data form submission.
	 *
	 * Permanently deletes all data for a specific visitor.
	 *
	 * @since 1.0.0
	 * @return void
	 */
	public static function handle_delete_visitor_data() {
		// Verify nonce.
		if ( ! isset( $_POST['_wpnonce'] ) || ! wp_verify_nonce( sanitize_text_field( wp_unslash( $_POST['_wpnonce'] ) ), 'agentorie_chat_delete_visitor_data' ) ) {
			wp_die( esc_html__( 'Security check failed.', 'agentorie-chat' ), 403 );
		}

		// Check capabilities.
		if ( ! current_user_can( 'manage_options' ) ) {
			wp_die( esc_html__( 'You do not have permission to perform this action.', 'agentorie-chat' ), 403 );
		}

		// Get visitor identifier.
		$identifier = isset( $_POST['visitor_identifier'] ) ? sanitize_text_field( wp_unslash( $_POST['visitor_identifier'] ) ) : '';

		if ( empty( $identifier ) ) {
			self::redirect_with_error( 'invalid_identifier' );
		}

		// Perform deletion.
		$deleted_count = self::delete_visitor_data( $identifier );

		if ( 0 === $deleted_count ) {
			self::redirect_with_error( 'no_data_found' );
		}

		// Redirect back with result.
		$redirect_url = add_query_arg(
			array(
				'page'       => 'agentorie-chat-conversations',
				'tab'        => 'conversations',
				'anonymized' => $deleted_count,
			),
			admin_url( 'admin.php' )
		);

		wp_safe_redirect( $redirect_url );
		exit;
	}

	/**
	 * Purge conversations older than specified days.
	 *
	 * @since 1.0.0
	 * @param int $days Number of days to retain.
	 * @return int Number of deleted conversations.
	 */
	public static function purge_old_data( $days ) {
		global $wpdb;

		$sessions_table = Agentorie_Database::sessions_table();
		$messages_table = Agentorie_Database::messages_table();
		$contacts_table = Agentorie_Database::contacts_table();

		$cutoff_date = wp_date( 'Y-m-d H:i:s', strtotime( "-{$days} days" ) );

		// Get session IDs to delete.
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, PluginCheck.Security.DirectDB.UnescapedDBParameter
		$session_ids = $wpdb->get_col(
			$wpdb->prepare(
				"SELECT session_id FROM {$sessions_table} WHERE created_at < %s", // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter
				$cutoff_date
			)
		);

		if ( empty( $session_ids ) ) {
			return 0;
		}

		$count = count( $session_ids );

		// Delete messages for these sessions.
		$placeholders = implode( ',', array_fill( 0, $count, '%s' ) );

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, PluginCheck.Security.DirectDB.UnescapedDBParameter
		$wpdb->query(
			$wpdb->prepare(
				"DELETE FROM {$messages_table} WHERE session_id IN ({$placeholders})", // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared, WordPress.DB.PreparedSQLPlaceholders.UnfinishedPrepare, PluginCheck.Security.DirectDB.UnescapedDBParameter -- Dynamic placeholders
				$session_ids
			)
		);

		// Delete contacts for these sessions.
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, PluginCheck.Security.DirectDB.UnescapedDBParameter
		$wpdb->query(
			$wpdb->prepare(
				"DELETE FROM {$contacts_table} WHERE session_id IN ({$placeholders})", // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared, WordPress.DB.PreparedSQLPlaceholders.UnfinishedPrepare, PluginCheck.Security.DirectDB.UnescapedDBParameter -- Dynamic placeholders
				$session_ids
			)
		);

		// Delete sessions.
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, PluginCheck.Security.DirectDB.UnescapedDBParameter
		$wpdb->query(
			$wpdb->prepare(
				"DELETE FROM {$sessions_table} WHERE created_at < %s", // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter
				$cutoff_date
			)
		);

		return $count;
	}

	/**
	 * Get all data for a specific visitor.
	 *
	 * @since 1.0.0
	 * @param string $identifier Visitor ID or email.
	 * @return array Visitor data including sessions, messages, and contacts.
	 */
	public static function get_visitor_data( $identifier ) {
		global $wpdb;

		$sessions_table = Agentorie_Database::sessions_table();
		$messages_table = Agentorie_Database::messages_table();
		$contacts_table = Agentorie_Database::contacts_table();

		$data = array(
			'sessions' => array(),
			'contacts' => array(),
		);

		// Find sessions by visitor_id or by email in contacts.
		// phpcs:disable WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, WordPress.DB.PreparedSQL.InterpolatedNotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter -- Table names from internal methods
		$sessions = $wpdb->get_results(
			$wpdb->prepare(
				"SELECT s.* FROM {$sessions_table} s
				LEFT JOIN {$contacts_table} c ON s.session_id = c.session_id
				WHERE s.visitor_id = %s OR s.session_id = %s OR c.email = %s
				GROUP BY s.session_id
				ORDER BY s.created_at DESC",
				$identifier,
				$identifier,
				$identifier
			),
			ARRAY_A
		);
		// phpcs:enable WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, WordPress.DB.PreparedSQL.InterpolatedNotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter

		if ( empty( $sessions ) ) {
			return $data;
		}

		foreach ( $sessions as $session ) {
			$session_id = $session['session_id'];

			// Get messages for this session.
			// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, PluginCheck.Security.DirectDB.UnescapedDBParameter
			$messages = $wpdb->get_results(
				$wpdb->prepare(
					"SELECT role, message, created_at FROM {$messages_table} WHERE session_id = %s ORDER BY created_at ASC", // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter
					$session_id
				),
				ARRAY_A
			);

			$data['sessions'][] = array(
				'session_id' => $session_id,
				'visitor_id' => $session['visitor_id'],
				'started_at' => $session['created_at'],
				'messages'   => $messages,
			);
		}

		// Get contacts.
		$session_ids  = wp_list_pluck( $sessions, 'session_id' );
		$placeholders = implode( ',', array_fill( 0, count( $session_ids ), '%s' ) );

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, PluginCheck.Security.DirectDB.UnescapedDBParameter
		$contacts = $wpdb->get_results(
			$wpdb->prepare(
				"SELECT name, email, phone, message, created_at FROM {$contacts_table} WHERE session_id IN ({$placeholders}) OR email = %s", // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter
				array_merge( $session_ids, array( $identifier ) )
			),
			ARRAY_A
		);

		$data['contacts'] = $contacts ? $contacts : array();

		return $data;
	}

	/**
	 * Delete all data for a specific visitor.
	 *
	 * @since 1.0.0
	 * @param string $identifier Visitor ID or email.
	 * @return int Number of deleted sessions.
	 */
	public static function delete_visitor_data( $identifier ) {
		global $wpdb;

		$sessions_table = Agentorie_Database::sessions_table();
		$messages_table = Agentorie_Database::messages_table();
		$contacts_table = Agentorie_Database::contacts_table();

		// Find session IDs.
		// phpcs:disable WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, WordPress.DB.PreparedSQL.InterpolatedNotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter -- Table names from internal methods
		$session_ids = $wpdb->get_col(
			$wpdb->prepare(
				"SELECT DISTINCT s.session_id FROM {$sessions_table} s
				LEFT JOIN {$contacts_table} c ON s.session_id = c.session_id
				WHERE s.visitor_id = %s OR s.session_id = %s OR c.email = %s",
				$identifier,
				$identifier,
				$identifier
			)
		);
		// phpcs:enable WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, WordPress.DB.PreparedSQL.InterpolatedNotPrepared, PluginCheck.Security.DirectDB.UnescapedDBParameter

		if ( empty( $session_ids ) ) {
			// Also check contacts directly by email.
			// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, PluginCheck.Security.DirectDB.UnescapedDBParameter
			$deleted = $wpdb->delete(
				$contacts_table,
				array( 'email' => $identifier ),
				array( '%s' )
			);

			return $deleted ? 1 : 0;
		}

		$count        = count( $session_ids );
		$placeholders = implode( ',', array_fill( 0, $count, '%s' ) );

		// Delete messages.
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, PluginCheck.Security.DirectDB.UnescapedDBParameter
		$wpdb->query(
			$wpdb->prepare(
				"DELETE FROM {$messages_table} WHERE session_id IN ({$placeholders})", // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared, WordPress.DB.PreparedSQLPlaceholders.UnfinishedPrepare, PluginCheck.Security.DirectDB.UnescapedDBParameter -- Dynamic placeholders
				$session_ids
			)
		);

		// Delete contacts.
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, PluginCheck.Security.DirectDB.UnescapedDBParameter
		$wpdb->query(
			$wpdb->prepare(
				"DELETE FROM {$contacts_table} WHERE session_id IN ({$placeholders}) OR email = %s", // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared, WordPress.DB.PreparedSQLPlaceholders.UnfinishedPrepare, PluginCheck.Security.DirectDB.UnescapedDBParameter -- Dynamic placeholders
				array_merge( $session_ids, array( $identifier ) )
			)
		);

		// Delete sessions.
		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, PluginCheck.Security.DirectDB.UnescapedDBParameter
		$wpdb->query(
			$wpdb->prepare(
				"DELETE FROM {$sessions_table} WHERE session_id IN ({$placeholders})", // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared, WordPress.DB.PreparedSQLPlaceholders.UnfinishedPrepare, PluginCheck.Security.DirectDB.UnescapedDBParameter -- Dynamic placeholders
				$session_ids
			)
		);

		return $count;
	}

	/**
	 * Register data exporter for WordPress Privacy tools.
	 *
	 * Integrates with Tools > Export Personal Data.
	 *
	 * @since 1.0.0
	 * @param array $exporters Registered exporters.
	 * @return array Modified exporters array.
	 */
	public static function register_data_exporter( $exporters ) {
		$exporters['agentorie-chat'] = array(
			'exporter_friendly_name' => __( 'Agentorie Chat Data', 'agentorie-chat' ),
			'callback'               => array( __CLASS__, 'wp_privacy_exporter' ),
		);

		return $exporters;
	}

	/**
	 * Register data eraser for WordPress Privacy tools.
	 *
	 * Integrates with Tools > Erase Personal Data.
	 *
	 * @since 1.0.0
	 * @param array $erasers Registered erasers.
	 * @return array Modified erasers array.
	 */
	public static function register_data_eraser( $erasers ) {
		$erasers['agentorie-chat'] = array(
			'eraser_friendly_name' => __( 'Agentorie Chat Data', 'agentorie-chat' ),
			'callback'             => array( __CLASS__, 'wp_privacy_eraser' ),
		);

		return $erasers;
	}

	/**
	 * WordPress Privacy exporter callback.
	 *
	 * Called by WordPress when exporting personal data.
	 *
	 * @since 1.0.0
	 * @param string $email_address User email address.
	 * @param int    $page          Page number for pagination.
	 * @return array Export data array.
	 */
	public static function wp_privacy_exporter( $email_address, $page = 1 ) { // phpcs:ignore Generic.CodeAnalysis.UnusedFunctionParameter.FoundAfterLastUsed -- Required by WordPress privacy exporter callback.
		$export_items = array();

		$data = self::get_visitor_data( $email_address );

		// Export sessions and messages.
		foreach ( $data['sessions'] as $session ) {
			$messages_text = array();
			foreach ( $session['messages'] as $msg ) {
				$messages_text[] = sprintf( '[%s] %s: %s', $msg['created_at'], $msg['role'], $msg['message'] );
			}

			$export_items[] = array(
				'group_id'          => 'agentorie-chat-conversations',
				'group_label'       => __( 'Chat Conversations', 'agentorie-chat' ),
				'group_description' => __( 'Conversations with the Agentorie chatbot.', 'agentorie-chat' ),
				'item_id'           => 'session-' . $session['session_id'],
				'data'              => array(
					array(
						'name'  => __( 'Session ID', 'agentorie-chat' ),
						'value' => $session['session_id'],
					),
					array(
						'name'  => __( 'Started', 'agentorie-chat' ),
						'value' => $session['started_at'],
					),
					array(
						'name'  => __( 'Messages', 'agentorie-chat' ),
						'value' => implode( "\n", $messages_text ),
					),
				),
			);
		}

		// Export contacts.
		foreach ( $data['contacts'] as $contact ) {
			$export_items[] = array(
				'group_id'          => 'agentorie-contacts',
				'group_label'       => __( 'Contact Requests', 'agentorie-chat' ),
				'group_description' => __( 'Contact information submitted via chatbot.', 'agentorie-chat' ),
				'item_id'           => 'contact-' . md5( $contact['email'] . $contact['created_at'] ),
				'data'              => array(
					array(
						'name'  => __( 'Name', 'agentorie-chat' ),
						'value' => isset( $contact['name'] ) ? $contact['name'] : '',
					),
					array(
						'name'  => __( 'Email', 'agentorie-chat' ),
						'value' => isset( $contact['email'] ) ? $contact['email'] : '',
					),
					array(
						'name'  => __( 'Phone', 'agentorie-chat' ),
						'value' => isset( $contact['phone'] ) ? $contact['phone'] : '',
					),
					array(
						'name'  => __( 'Message', 'agentorie-chat' ),
						'value' => isset( $contact['message'] ) ? $contact['message'] : '',
					),
					array(
						'name'  => __( 'Date', 'agentorie-chat' ),
						'value' => isset( $contact['created_at'] ) ? $contact['created_at'] : '',
					),
				),
			);
		}

		return array(
			'data' => $export_items,
			'done' => true,
		);
	}

	/**
	 * WordPress Privacy eraser callback.
	 *
	 * Called by WordPress when erasing personal data.
	 *
	 * @since 1.0.0
	 * @param string $email_address User email address.
	 * @param int    $page          Page number for pagination.
	 * @return array Eraser result array.
	 */
	public static function wp_privacy_eraser( $email_address, $page = 1 ) { // phpcs:ignore Generic.CodeAnalysis.UnusedFunctionParameter.FoundAfterLastUsed -- Required by WordPress privacy eraser callback.
		$deleted = self::delete_visitor_data( $email_address );

		return array(
			'items_removed'  => $deleted > 0,
			'items_retained' => false,
			'messages'       => array(),
			'done'           => true,
		);
	}

	/**
	 * Redirect back to conversations page with error.
	 *
	 * @since 1.0.0
	 * @param string $error Error code.
	 * @return void
	 */
	private static function redirect_with_error( $error ) {
		$redirect_url = add_query_arg(
			array(
				'page'  => 'agentorie-chat-conversations',
				'tab'   => 'conversations',
				'error' => $error,
			),
			admin_url( 'admin.php' )
		);

		wp_safe_redirect( $redirect_url );
		exit;
	}
}