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

import Foundation

@available(OSX 10.14, iOS 12.0, *)
final class TunnelConfiguration: Codable {
    var interface: InterfaceConfiguration
    let peers: [PeerConfiguration]

    static let keyLength: Int = 32

    init(interface: InterfaceConfiguration, peers: [PeerConfiguration]) {
        self.interface = interface
        self.peers = peers

        let peerPublicKeysArray = peers.map { $0.publicKey }
        let peerPublicKeysSet = Set<Data>(peerPublicKeysArray)
        if peerPublicKeysArray.count != peerPublicKeysSet.count {
            fatalError("Two or more peers cannot have the same public key")
        }
    }
}

@available(OSX 10.14, iOS 12.0, *)
struct InterfaceConfiguration: Codable {
    var name: String
    var privateKey: Data
    var addresses: [IPAddressRange] = []
    var listenPort: UInt16?
    var mtu: UInt16?
    var dns: [DNSServer] = []

    init(name: String, privateKey: Data) {
        self.name = name
        self.privateKey = privateKey
        if name.isEmpty {
            fatalError("Empty name")
        }
        if privateKey.count != TunnelConfiguration.keyLength {
            fatalError("Invalid private key")
        }
    }
}

@available(OSX 10.14, iOS 12.0, *)
struct PeerConfiguration: Codable {
    var publicKey: Data
    var preSharedKey: Data? {
        didSet(value) {
            if let value = value {
                if value.count != TunnelConfiguration.keyLength {
                    fatalError("Invalid preshared key")
                }
            }
        }
    }
    var allowedIPs: [IPAddressRange] = []
    var endpoint: Endpoint?
    var persistentKeepAlive: UInt16?

    init(publicKey: Data) {
        self.publicKey = publicKey
        if publicKey.count != TunnelConfiguration.keyLength {
            fatalError("Invalid public key")
        }
    }
}