/*
 * Copyright (c) 2025 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.Networking;
using ProtonVPN.Common.Legacy.Helpers;
using ProtonVPN.Common.Legacy.KillSwitch;
using ProtonVPN.ProcessCommunication.Contracts.Entities.Settings;
using ProtonVPN.ProcessCommunication.Contracts.Entities.Vpn;
using ProtonVPN.Service.Firewall;

namespace ProtonVPN.Service.Settings;

public class ServiceSettings : IServiceSettings
{
    private readonly ISettingsFileStorage _storage;

    private MainSettingsIpcEntity _settings;
    private IpFilter _ipFilter;

    public event EventHandler<MainSettingsIpcEntity> SettingsChanged;

    public ServiceSettings(ISettingsFileStorage storage, IpFilter ipFilter)
    {
        _storage = storage;
        _ipFilter = ipFilter;
    }

    public KillSwitchMode KillSwitchMode
    {
        get
        {
            Load();
            return (KillSwitchMode)_settings.KillSwitchMode;
        }
    }

    public SplitTunnelSettingsIpcEntity SplitTunnelSettings
    {
        get
        {
            Load();
            return _settings.SplitTunnel ??= new SplitTunnelSettingsIpcEntity();
        }
    }

    public bool Ipv6LeakProtection
    {
        get
        {
            Load();
            return _settings.Ipv6LeakProtection;
        }
    }

    public bool IsIpv6Enabled
    {
        get
        {
            Load();
            return _settings.IsIpv6Enabled;
        }
    }

    public List<string> Ipv6Fragments
    {
        get
        {
            Load();
            return _settings.Ipv6Fragments ??= [];
        }
    }

    public bool IsShareCrashReportsEnabled
    {
        get
        {
            Load();
            return _settings.IsShareCrashReportsEnabled;
        }
    }

    public bool IsLocalAreaNetworkAccessEnabled
    {
        get
        {
            Load();
            return _settings.IsLocalAreaNetworkAccessEnabled;
        }
    }

    public VpnProtocol VpnProtocol
    {
        get
        {
            Load();
            return (VpnProtocol)_settings.VpnProtocol;
        }
    }

    public OpenVpnAdapter OpenVpnAdapter
    {
        get
        {
            Load();
            return (OpenVpnAdapter)_settings.OpenVpnAdapter;
        }
    }

    public DnsBlockMode DnsBlockMode
    {
        get
        {
            Load();
            return (DnsBlockMode)_settings.DnsBlockMode;
        }
    }

    public void Apply(MainSettingsIpcEntity settings)
    {
        Ensure.NotNull(settings, nameof(settings));

        _settings = settings;
        Save();

        SettingsChanged?.Invoke(this, settings);
    }

    private void Load()
    {
        if (_settings == null)
        {
            _settings = _storage.Get() ?? new MainSettingsIpcEntity();
            if (_ipFilter.PermanentSublayer.GetFilterCount() > 0)
            {
                _settings.KillSwitchMode = KillSwitchModeIpcEntity.Hard;
            }
        }
    }

    private void Save()
    {
        _storage.Set(_settings);
    }
}