<?php
/**
 * Plugin settings: defaults, access and sanitization. One option array, three groups.
 *
 * @package Enrollment_Verifier_Logger
 */

defined( 'ABSPATH' ) || exit;

/**
 * Settings storage. Option shape: array( 'email' => array(...), 'logging' => array(...), 'privacy' => array(...) ).
 */
final class EVLFL_Settings {

	const OPTION = 'evlfl_settings';

	/**
	 * Allowed retention periods in days (0 = keep forever).
	 *
	 * @return int[]
	 */
	public static function retention_choices() {
		return array( 0, 30, 90, 180, 365, 730 );
	}

	/**
	 * Notification triggers. A event matches when ANY ticked trigger matches ("all" matches everything).
	 *
	 * @return array<string,string> key => label.
	 */
	public static function notify_choices() {
		return array(
			'all'        => __( 'All events', 'accesstrace-for-learndash' ),
			'invalid'    => __( 'Invalid events (conflicts worth investigating)', 'accesstrace-for-learndash' ),
			'unenrolled' => __( 'Unenrollments', 'accesstrace-for-learndash' ),
			'enrolled'   => __( 'Enrollments', 'accesstrace-for-learndash' ),
			'unknown'    => __( 'Unknown-status events', 'accesstrace-for-learndash' ),
		);
	}

	/**
	 * Default values. Subject and body default to '' meaning "use the built-in translatable text".
	 *
	 * @return array<string,array<string,mixed>>
	 */
	public static function defaults() {
		return array(
			'email'   => array(
				'enabled'            => 0,
				'recipients'         => '',
				'notify_on'          => array( 'invalid' ),
				'sources'            => array(),
				'delivery'           => 'immediate',
				'rate_limit'         => 20,
				'subject'            => '',
				'body'               => '',
				'include_user_email' => 0,
				'format'             => 'plain',
				'from_name'          => '',
				'from_email'         => '',
			),
			'logging' => array(
				'enabled'         => 1,
				'record_enrolled' => 1,
				'record_unenrolled' => 1,
				'retention_days'  => 0,
				'ignore_courses'  => '',
			),
			'privacy' => array(
				'delete_on_uninstall'    => 0,
				'erase_on_user_delete'   => 0,
			),
		);
	}

	/**
	 * All settings merged over the defaults.
	 *
	 * @return array<string,array<string,mixed>>
	 */
	public static function all() {
		$stored = get_option( self::OPTION, array() );
		$stored = is_array( $stored ) ? $stored : array();
		$out    = self::defaults();
		foreach ( $out as $group => $values ) {
			if ( isset( $stored[ $group ] ) && is_array( $stored[ $group ] ) ) {
				$out[ $group ] = array_merge( $values, array_intersect_key( $stored[ $group ], $values ) );
			}
		}
		return $out;
	}

	/**
	 * One value.
	 *
	 * @param string $group Group.
	 * @param string $key   Key.
	 * @return mixed
	 */
	public static function get( $group, $key ) {
		$all = self::all();
		return isset( $all[ $group ][ $key ] ) ? $all[ $group ][ $key ] : null;
	}

	/**
	 * Whether an event should be written to the log.
	 *
	 * @param array $event Normalized event.
	 * @return bool
	 */
	public static function should_log( array $event ) {
		$log = self::all()['logging'];
		if ( empty( $log['enabled'] ) ) {
			return false;
		}
		if ( EVLFL_Event::ACTION_ENROLLED === $event['action'] && empty( $log['record_enrolled'] ) ) {
			return false;
		}
		if ( EVLFL_Event::ACTION_UNENROLLED === $event['action'] && empty( $log['record_unenrolled'] ) ) {
			return false;
		}
		return ! in_array( (int) $event['course_id'], self::ids_from_csv( (string) $log['ignore_courses'] ), true );
	}

	/**
	 * Parse "1, 2,3" into unique positive ints.
	 *
	 * @param string $csv Comma-separated list.
	 * @return int[]
	 */
	public static function ids_from_csv( $csv ) {
		$ids = array();
		foreach ( explode( ',', (string) $csv ) as $part ) {
			$n = absint( trim( $part ) );
			if ( $n > 0 ) {
				$ids[ $n ] = $n;
			}
		}
		return array_values( $ids );
	}

	/**
	 * Settings API sanitize callback. Only the groups present in $input are replaced, so saving
	 * one tab never resets the others.
	 *
	 * @param mixed $input Submitted value (already unslashed by options.php).
	 * @return array
	 */
	public static function sanitize( $input ) {
		$stored = get_option( self::OPTION, array() );
		$out    = is_array( $stored ) ? $stored : array();
		if ( ! is_array( $input ) ) {
			return $out;
		}
		if ( isset( $input['email'] ) && is_array( $input['email'] ) ) {
			$out['email'] = self::sanitize_email_group( $input['email'] );
		}
		if ( isset( $input['logging'] ) && is_array( $input['logging'] ) ) {
			$out['logging'] = self::sanitize_logging_group( $input['logging'] );
		}
		if ( isset( $input['privacy'] ) && is_array( $input['privacy'] ) ) {
			$out['privacy'] = self::sanitize_privacy_group( $input['privacy'] );
		}
		return $out;
	}

	/**
	 * Email tab.
	 *
	 * @param array $in Input.
	 * @return array
	 */
	private static function sanitize_email_group( array $in ) {
		$defaults = self::defaults()['email'];

		$valid   = array();
		$invalid = array();
		foreach ( explode( ',', isset( $in['recipients'] ) && is_scalar( $in['recipients'] ) ? (string) $in['recipients'] : '' ) as $candidate ) {
			$candidate = trim( $candidate );
			if ( '' === $candidate ) {
				continue;
			}
			$address = sanitize_email( $candidate );
			if ( is_email( $address ) ) {
				if ( ! isset( $valid[ strtolower( $address ) ] ) ) {
					$valid[ strtolower( $address ) ] = $address;
				}
			} else {
				$invalid[] = $candidate;
			}
		}
		if ( $invalid ) {
			add_settings_error(
				self::OPTION,
				'evlfl_bad_recipients',
				sprintf(
					/* translators: %s: list of rejected email addresses. */
					__( 'These recipients are not valid email addresses and were removed: %s', 'accesstrace-for-learndash' ),
					esc_html( implode( ', ', array_map( 'sanitize_text_field', $invalid ) ) )
				),
				'warning'
			);
		}

		$notify_on = self::pick_many( isset( $in['notify_on'] ) ? $in['notify_on'] : array(), self::notify_choices() );
		$enabled   = ! empty( $in['enabled'] ) ? 1 : 0;
		if ( $enabled && ! $notify_on ) {
			add_settings_error(
				self::OPTION,
				'evlfl_no_triggers',
				__( 'Admin emails are on, but no event type is ticked, so no email will be sent.', 'accesstrace-for-learndash' ),
				'warning'
			);
		}

		$delivery = isset( $in['delivery'] ) && is_scalar( $in['delivery'] ) ? sanitize_key( (string) $in['delivery'] ) : '';
		$format   = isset( $in['format'] ) && is_scalar( $in['format'] ) ? sanitize_key( (string) $in['format'] ) : '';
		$limit    = isset( $in['rate_limit'] ) && is_scalar( $in['rate_limit'] ) ? absint( $in['rate_limit'] ) : $defaults['rate_limit'];

		$from_name = isset( $in['from_name'] ) && is_scalar( $in['from_name'] ) ? sanitize_text_field( (string) $in['from_name'] ) : '';
		$from_name = trim( str_replace( array( '<', '>', '"' ), '', $from_name ) );
		$from_mail = isset( $in['from_email'] ) && is_scalar( $in['from_email'] ) ? sanitize_email( (string) $in['from_email'] ) : '';

		return array(
			'enabled'            => $enabled,
			'recipients'         => implode( ', ', array_slice( array_values( $valid ), 0, 10 ) ),
			'notify_on'          => $notify_on,
			'sources'            => self::pick_many( isset( $in['sources'] ) ? $in['sources'] : array(), EVLFL_Event::get_sources() ),
			'delivery'           => in_array( $delivery, array( 'immediate', 'hourly', 'daily' ), true ) ? $delivery : $defaults['delivery'],
			'rate_limit'         => min( 500, max( 1, $limit ) ),
			'subject'            => isset( $in['subject'] ) && is_scalar( $in['subject'] ) ? substr( sanitize_text_field( (string) $in['subject'] ), 0, 200 ) : '',
			'body'               => isset( $in['body'] ) && is_scalar( $in['body'] ) ? substr( sanitize_textarea_field( (string) $in['body'] ), 0, 5000 ) : '',
			'include_user_email' => ! empty( $in['include_user_email'] ) ? 1 : 0,
			'format'             => in_array( $format, array( 'plain', 'html' ), true ) ? $format : $defaults['format'],
			'from_name'          => substr( $from_name, 0, 100 ),
			'from_email'         => is_email( $from_mail ) ? $from_mail : '',
		);
	}

	/**
	 * Logging tab.
	 *
	 * @param array $in Input.
	 * @return array
	 */
	private static function sanitize_logging_group( array $in ) {
		$days = isset( $in['retention_days'] ) && is_scalar( $in['retention_days'] ) ? absint( $in['retention_days'] ) : 0;
		$ids  = self::ids_from_csv( isset( $in['ignore_courses'] ) && is_scalar( $in['ignore_courses'] ) ? (string) $in['ignore_courses'] : '' );

		return array(
			'enabled'           => ! empty( $in['enabled'] ) ? 1 : 0,
			'record_enrolled'   => ! empty( $in['record_enrolled'] ) ? 1 : 0,
			'record_unenrolled' => ! empty( $in['record_unenrolled'] ) ? 1 : 0,
			'retention_days'    => in_array( $days, self::retention_choices(), true ) ? $days : 0,
			'ignore_courses'    => implode( ', ', array_slice( $ids, 0, 200 ) ),
		);
	}

	/**
	 * Privacy tab.
	 *
	 * @param array $in Input.
	 * @return array
	 */
	private static function sanitize_privacy_group( array $in ) {
		return array(
			'delete_on_uninstall'  => ! empty( $in['delete_on_uninstall'] ) ? 1 : 0,
			'erase_on_user_delete' => ! empty( $in['erase_on_user_delete'] ) ? 1 : 0,
		);
	}

	/**
	 * Keep only allowlisted keys.
	 *
	 * @param mixed $values  Submitted list.
	 * @param array $allowed Allowlist (key => label).
	 * @return string[]
	 */
	private static function pick_many( $values, array $allowed ) {
		$out = array();
		foreach ( (array) $values as $value ) {
			$value = is_scalar( $value ) ? sanitize_key( (string) $value ) : '';
			if ( isset( $allowed[ $value ] ) ) {
				$out[ $value ] = $value;
			}
		}
		return array_values( $out );
	}
}