/*
 * Copyright (c) 2026 Proton AG
 *
 * This file is part of ProtonVPN.
 *
 * ProtonVPN is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * ProtonVPN is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with ProtonVPN.  If not, see <https://www.gnu.org/licenses/>.
 */

using System;
using System.Collections.Generic;
using ProtonVPN.Common.Core.Dns;
using ProtonVPN.Common.Core.Extensions;
using ProtonVPN.Common.Core.Networking;

namespace ProtonVPN.Common.Legacy.Vpn;

public class VpnConfig
{
    public IReadOnlyDictionary<VpnProtocol, IReadOnlyCollection<int>> Ports { get; }
    public IReadOnlyCollection<string> CustomDns { get; }
    public SplitTunnelMode SplitTunnelMode { get; }
    public IReadOnlyCollection<string> SplitTunnelIPs { get; }
    public OpenVpnAdapter OpenVpnAdapter { get; set; }
    public VpnProtocol VpnProtocol { get; private set; }
    public IList<VpnProtocol> PreferredProtocols { get; }
    public int NetShieldMode { get; }
    public bool SplitTcp { get; }
    public bool PortForwarding { get; }
    public bool IsIpv6Enabled { get; }
    public DnsBlockMode DnsBlockMode { get; }
    public bool ShouldDisableWeakHostSetting { get; }
    public bool IsWireGuardServerRouteEnabled { get; }

    public bool ModerateNat { get; }
    public TimeSpan WireGuardConnectionTimeout { get; }

    public VpnConfig(VpnConfigParameters parameters)
    {
        AssertPortsValid(parameters.Ports);
        AssertCustomDnsValid(parameters.CustomDns);

        Ports = parameters.Ports;
        CustomDns = parameters.CustomDns ?? new List<string>();
        SplitTunnelMode = parameters.SplitTunnelMode;
        SplitTunnelIPs = parameters.SplitTunnelIPs ?? new List<string>();
        OpenVpnAdapter = parameters.OpenVpnAdapter;
        VpnProtocol = parameters.VpnProtocol;
        PreferredProtocols = parameters.PreferredProtocols;
        NetShieldMode = parameters.NetShieldMode;
        SplitTcp = parameters.SplitTcp;
        ModerateNat = parameters.ModerateNat;
        PortForwarding = parameters.PortForwarding;
        IsIpv6Enabled = parameters.IsIpv6Enabled;
        WireGuardConnectionTimeout = parameters.WireGuardConnectionTimeout;
        DnsBlockMode = parameters.DnsBlockMode;
        ShouldDisableWeakHostSetting = parameters.ShouldDisableWeakHostSetting;
        IsWireGuardServerRouteEnabled = parameters.IsWireGuardServerRouteEnabled;
    }

    public void UpdateVpnProtocol(VpnProtocol protocol)
    {
        VpnProtocol = protocol;
    }

    private void AssertPortsValid(IReadOnlyDictionary<VpnProtocol, IReadOnlyCollection<int>> ports)
    {
        foreach (KeyValuePair<VpnProtocol, IReadOnlyCollection<int>> item in ports)
        {
            foreach (int port in item.Value)
            {
                if (port < 1 || port > 65535)
                {
                    throw new ArgumentException($"Invalid OpenVPN port: {port}");
                }
            }
        }
    }

    private void AssertCustomDnsValid(IReadOnlyCollection<string> customDns)
    {
        if (customDns == null)
        {
            return;
        }

        foreach (string dns in customDns)
        {
            if (!dns.IsValidIpAddressFormat())
            {
                throw new ArgumentException($"Invalid DNS address: {dns}");
            }
        }
    }
}