<?php
/**
 * Plugin state that isn't a setting.
 *
 * @package StandChat
 */

namespace StandChat;

defined( 'ABSPATH' ) || exit;

/**
 * Setup progress, the AI assistant and knowledge base this site uses, the last
 * installation check, and dismissed notices. Not autoloaded.
 */
final class State {

	const OPTION = 'stand_chat_state';

	/**
	 * Everything stored.
	 *
	 * @return array<string, mixed>
	 */
	public static function all(): array {
		$state = get_option( self::OPTION, array() );
		return is_array( $state ) ? $state : array();
	}

	/**
	 * One value.
	 *
	 * @param string $key      Key.
	 * @param mixed  $fallback Returned when the key is missing.
	 * @return mixed
	 */
	public static function get( string $key, $fallback = null ) {
		$state = self::all();
		return array_key_exists( $key, $state ) ? $state[ $key ] : $fallback;
	}

	/**
	 * Stores one value.
	 *
	 * @param string $key   Key.
	 * @param mixed  $value Value.
	 */
	public static function set( string $key, $value ): void {
		// Built on what's stored now, so a key another request just stored stays.
		Option_Queue::change(
			self::OPTION,
			static function ( array $state ) use ( $key, $value ): array {
				$state[ $key ] = $value;
				return $state;
			}
		);
	}

	/**
	 * Changes one value from what's stored now, so what another request
	 * changes in it meanwhile isn't lost.
	 *
	 * @param string   $key    Key.
	 * @param callable $change Gets the stored value, null when there's none,
	 *                         and returns the new one. It may run more than
	 *                         once; its last run counts.
	 */
	public static function change( string $key, callable $change ): void {
		Option_Queue::change(
			self::OPTION,
			static function ( array $state ) use ( $key, $change ): array {
				$state[ $key ] = $change( $state[ $key ] ?? null );
				return $state;
			}
		);
	}

	/**
	 * Removes values.
	 *
	 * @param string ...$keys Keys.
	 */
	public static function forget( string ...$keys ): void {
		Option_Queue::change(
			self::OPTION,
			static function ( array $state ) use ( $keys ): array {
				foreach ( $keys as $key ) {
					unset( $state[ $key ] );
				}
				return $state;
			}
		);
	}

	/**
	 * Setup progress for the three-step checklist.
	 *
	 * @return array{account: bool, brief: bool, live: bool}
	 */
	public static function setup(): array {
		$setup = self::get( 'setup', array() );
		$setup = is_array( $setup ) ? $setup : array();
		return array(
			'account' => ! empty( $setup['account'] ),
			'brief'   => ! empty( $setup['brief'] ),
			'live'    => ! empty( $setup['live'] ),
		);
	}

	/**
	 * Marks one setup step done (or not).
	 *
	 * @param string $step One of account, brief, live.
	 * @param bool   $done Done.
	 */
	public static function mark_setup( string $step, bool $done = true ): void {
		self::change(
			'setup',
			static function ( $setup ) use ( $step, $done ): array {
				$setup          = is_array( $setup ) ? $setup : array();
				$setup[ $step ] = $done;
				return $setup;
			}
		);
	}

	/**
	 * Whether a notice is dismissed right now.
	 *
	 * @param string $notice Notice ID.
	 */
	public static function is_dismissed( string $notice ): bool {
		$dismissed = self::get( 'dismissed', array() );
		if ( ! is_array( $dismissed ) || ! isset( $dismissed[ $notice ] ) ) {
			return false;
		}
		$until = (int) $dismissed[ $notice ];
		return 0 === $until || $until > time();
	}

	/**
	 * Dismisses a notice, optionally until a time.
	 *
	 * @param string $notice Notice ID.
	 * @param int    $until  Unix time; 0 means for good.
	 */
	public static function dismiss( string $notice, int $until = 0 ): void {
		self::change(
			'dismissed',
			static function ( $dismissed ) use ( $notice, $until ): array {
				$dismissed            = is_array( $dismissed ) ? $dismissed : array();
				$dismissed[ $notice ] = $until;
				return $dismissed;
			}
		);
	}
}