<?php
/**
 * Per-user preferences.
 *
 * @package ShiftSnap
 */

declare( strict_types=1 );

namespace ShiftSnap;

defined( 'ABSPATH' ) || exit;

/**
 * Reads, validates and stores each user's clipboard preferences (user meta).
 */
final class Preferences {

	/**
	 * User meta key.
	 */
	public const META_KEY = 'shiftsnap_prefs';

	/**
	 * Accepted values of `copy_mode`.
	 */
	public const COPY_MODES = array( 'replace', 'append' );

	/**
	 * Preference names and default values.
	 */
	public const DEFAULTS = array(
		'copy_mode'       => 'replace',
		'hide_cut'        => false,
		'hide_copy_add'   => false,
		'hide_transfer'   => false,
		'section_content' => false,
	);

	/**
	 * Preferences of a user, defaults filled in.
	 *
	 * @param int $user_id User ID.
	 * @return array<string, mixed>
	 */
	public static function get( int $user_id ): array {
		$stored = get_user_meta( $user_id, self::META_KEY, true );

		return self::sanitize( is_array( $stored ) ? $stored : array() );
	}

	/**
	 * Whether a user ever saved preferences.
	 *
	 * @param int $user_id User ID.
	 */
	public static function exists( int $user_id ): bool {
		return metadata_exists( 'user', $user_id, self::META_KEY );
	}

	/**
	 * Merges changes into a user's preferences and saves them.
	 *
	 * @param int                  $user_id User ID.
	 * @param array<string, mixed> $changes Preferences to change; unknown keys are ignored.
	 * @return array<string, mixed> Saved preferences.
	 */
	public static function update( int $user_id, array $changes ): array {
		$prefs = self::sanitize( array_merge( self::get( $user_id ), $changes ) );

		update_user_meta( $user_id, self::META_KEY, $prefs );

		return $prefs;
	}

	/**
	 * Keeps known keys only, with valid values; anything else falls back to the default.
	 *
	 * @param array<string, mixed> $input Raw preferences.
	 * @return array<string, mixed>
	 */
	public static function sanitize( array $input ): array {
		$prefs = self::DEFAULTS;

		if ( isset( $input['copy_mode'] ) && in_array( $input['copy_mode'], self::COPY_MODES, true ) ) {
			$prefs['copy_mode'] = $input['copy_mode'];
		}

		foreach ( array( 'hide_cut', 'hide_copy_add', 'hide_transfer', 'section_content' ) as $key ) {
			if ( isset( $input[ $key ] ) ) {
				$prefs[ $key ] = (bool) filter_var( $input[ $key ], FILTER_VALIDATE_BOOLEAN );
			}
		}

		return $prefs;
	}

	/**
	 * JSON schema of the preferences, for the REST route.
	 *
	 * @return array<string, mixed>
	 */
	public static function schema(): array {
		return array(
			'copy_mode'       => array(
				'type' => 'string',
				'enum' => self::COPY_MODES,
			),
			'hide_cut'        => array( 'type' => 'boolean' ),
			'hide_copy_add'   => array( 'type' => 'boolean' ),
			'hide_transfer'   => array( 'type' => 'boolean' ),
			'section_content' => array( 'type' => 'boolean' ),
		);
	}
}