// SPDX-License-Identifier: MIT
// Copyright © 2018 WireGuard LLC. All Rights Reserved.

import NetworkExtension

enum PacketTunnelProviderError: String, Error {
    case savedProtocolConfigurationIsInvalid
    case dnsResolutionFailure
    case couldNotStartBackend
    case couldNotDetermineFileDescriptor
    case couldNotSetNetworkSettings
}

extension NETunnelProviderProtocol {

    enum Keys: String {
        case wgQuickConfig = "WgQuickConfig"
    }

    convenience init?(tunnelConfiguration: TunnelConfiguration) {
        self.init()

        let appId = Bundle.main.bundleIdentifier!
        providerBundleIdentifier = "\(appId).network-extension"
        providerConfiguration = [Keys.wgQuickConfig.rawValue: tunnelConfiguration.asWgQuickConfig()]

        let endpoints = tunnelConfiguration.peers.compactMap { $0.endpoint }
        if endpoints.count == 1 {
            serverAddress = endpoints[0].stringRepresentation
        } else if endpoints.isEmpty {
            serverAddress = "Unspecified"
        } else {
            serverAddress = "Multiple endpoints"
        }

        //TODO(roopc): Why are we doing this? Just for kicks? Is it useful? Seems needless.
        username = tunnelConfiguration.name
    }

    func asTunnelConfiguration(called name: String? = nil) -> TunnelConfiguration? {
        migrateConfigurationIfNeeded()
        guard let serializedConfig = providerConfiguration?[Keys.wgQuickConfig.rawValue] as? String else { return nil }
        return try? TunnelConfiguration(fromWgQuickConfig: serializedConfig, called: name)
    }

}