//
//  TunnelSettingsStrategy.swift
//  MullvadSettings
//
//  Created by Mojgan on 2024-08-09.
//  Copyright © 2025 Mullvad VPN AB. All rights reserved.
//

import Foundation

public protocol TunnelSettingsStrategyProtocol: Sendable {
    func shouldReconnectToNewRelay(oldSettings: LatestTunnelSettings, newSettings: LatestTunnelSettings) -> Bool
    func getReconnectionStrategy(
        oldSettings: LatestTunnelSettings,
        newSettings: LatestTunnelSettings
    ) -> TunnelSettingsReconnectionStrategy
}

public struct TunnelSettingsStrategy: TunnelSettingsStrategyProtocol, Sendable {
    public init() {}

    public func shouldReconnectToNewRelay(
        oldSettings: LatestTunnelSettings,
        newSettings: LatestTunnelSettings
    ) -> Bool {
        getReconnectionStrategy(
            oldSettings: oldSettings,
            newSettings: newSettings
        ) != .currentRelayReconnect
    }

    public func getReconnectionStrategy(
        oldSettings: LatestTunnelSettings,
        newSettings: LatestTunnelSettings
    ) -> TunnelSettingsReconnectionStrategy {
        if oldSettings.localNetworkSharing != newSettings.localNetworkSharing
            || oldSettings.includeAllNetworks != newSettings.includeAllNetworks
        {
            return .hardReconnect
        }
        switch (oldSettings, newSettings) {
        case let (old, new) where old != new:
            return .newRelayReconnect
        default:
            return .currentRelayReconnect
        }
    }
}

/// This enum representes reconnection strategies.
/// > Warning: `hardReconnect` will disconnect and reconnect which
/// > potentially leads to traffic leaking outside the tunnel.
public enum TunnelSettingsReconnectionStrategy {
    case currentRelayReconnect
    case newRelayReconnect
    case hardReconnect
}