<?php
/**
 * Settings store.
 *
 * One autoloaded option holding every feature's settings, keyed by feature id. One row, not forty.
 *
 * @package Adminkeep
 */

namespace Adminkeep;

defined( 'ABSPATH' ) || exit;

/**
 * Reads and writes the plugin's single option.
 */
class Settings {

	/**
	 * Option name.
	 */
	const OPTION = 'adminkeep_settings';

	/**
	 * Schema version. 1 stamped the v1 cleanup; 2 moved "Hide unused features" from user meta into
	 * this option (1.8.1).
	 */
	const SCHEMA_VERSION = 2;

	/**
	 * The user meta 1.8.0 kept "Hide unused features" in. Read by the schema-2 step only.
	 */
	const LEGACY_HIDE_UNUSED_META = 'adminkeep_hide_unused';

	/**
	 * Keys written by v1 (the AI chat plugin). It used the option name 1.1.0 also used, so they
	 * reach this option through LegacyNames.
	 *
	 * v1 sold zero licences, but any install that ran it still has these rows — including an
	 * encrypted API key that is now dead weight. They are removed on first boot.
	 *
	 * @var string[]
	 */
	const LEGACY_V1_KEYS = array( 'mode', 'model', 'api_key_encrypted', 'api_key_iv' );

	/**
	 * Runtime cache of the decoded option.
	 *
	 * @var array|null
	 */
	private static $cache = null;

	/**
	 * Get every stored setting.
	 *
	 * A corrupt or non-array option degrades to an empty array rather than fataling.
	 *
	 * @return array
	 */
	public static function all() {
		if ( null === self::$cache ) {
			$stored = get_option( self::OPTION, array() );

			self::$cache = is_array( $stored ) ? $stored : array();
		}

		return self::$cache;
	}

	/**
	 * Get one feature's settings.
	 *
	 * @param string $feature_id Feature id.
	 * @return array
	 */
	public static function get( $feature_id ) {
		$all = self::all();

		if ( ! isset( $all[ $feature_id ] ) || ! is_array( $all[ $feature_id ] ) ) {
			return array();
		}

		return $all[ $feature_id ];
	}

	/**
	 * Whether a feature is enabled. Features are off until switched on.
	 *
	 * @param string $feature_id Feature id.
	 * @return bool
	 */
	public static function is_enabled( $feature_id ) {
		$settings = self::get( $feature_id );

		return ! empty( $settings['enabled'] );
	}

	/**
	 * Replace one feature's settings.
	 *
	 * @param string $feature_id Feature id.
	 * @param array  $values     Settings for that feature.
	 * @return void
	 */
	public static function update( $feature_id, array $values ) {
		$all = self::all();

		$all[ $feature_id ]     = $values;
		$all['_schema_version'] = self::SCHEMA_VERSION;

		self::$cache = $all;

		update_option( self::OPTION, $all, true );
	}

	/**
	 * Bring a stored option up to the current schema, one step per version.
	 *
	 * Step 1 clears out v1's leftovers: its AI settings arrive here through the LegacyNames rename.
	 * Only the four known v1 keys are touched, and unknown keys from any *future* schema are left
	 * alone, so a downgrade cannot destroy data it does not understand.
	 *
	 * Step 2 moves "Hide unused features" from per-user meta to this option: on if any user who can
	 * open the settings screen had it on, then the meta goes for everyone.
	 *
	 * An install that never stored the option has nothing to migrate and nothing is written.
	 *
	 * @return bool Whether any data changed (a bare schema stamp does not count).
	 */
	public static function maybe_migrate() {
		$stored = get_option( self::OPTION, null );

		if ( ! is_array( $stored ) ) {
			return false;
		}

		$version = isset( $stored['_schema_version'] ) ? (int) $stored['_schema_version'] : 0;

		if ( $version >= self::SCHEMA_VERSION ) {
			return false;
		}

		$changed = false;

		if ( $version < 1 ) {
			foreach ( self::LEGACY_V1_KEYS as $legacy_key ) {
				if ( array_key_exists( $legacy_key, $stored ) ) {
					unset( $stored[ $legacy_key ] );
					$changed = true;
				}
			}
		}

		if ( $version < 2 && self::migrate_hide_unused() ) {
			$stored[ PluginSettings::KEY ] = array( 'hide_unused' => true );
			$changed                       = true;
		}

		$stored['_schema_version'] = self::SCHEMA_VERSION;

		self::$cache = $stored;

		update_option( self::OPTION, $stored, true );

		return $changed;
	}

	/**
	 * Schema step 2: read and delete 1.8.0's per-user meta.
	 *
	 * @return bool Whether any user who can open the settings screen had the view switched on.
	 */
	private static function migrate_hide_unused() {
		$user_ids = get_users(
			array(
				'meta_key'   => self::LEGACY_HIDE_UNUSED_META, // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_key
				'meta_value' => '1', // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_value
				'fields'     => 'ID',
				'number'     => -1,
			)
		);

		$hide = false;

		foreach ( $user_ids as $user_id ) {
			if ( user_can( (int) $user_id, Admin\SettingsPage::CAPABILITY ) ) {
				$hide = true;
				break;
			}
		}

		if ( $user_ids ) {
			delete_metadata( 'user', 0, self::LEGACY_HIDE_UNUSED_META, '', true );
		}

		return $hide;
	}

	/**
	 * Drop the runtime cache. Test seam.
	 *
	 * @return void
	 */
	public static function flush_cache() {
		self::$cache = null;
	}
}