/*
 * 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.Extensions;
using ProtonVPN.Common.Core.Networking;

namespace ProtonVPN.Vpn.Management;

/// <summary>
/// Maps OpenVPN state received over management interface to VPN status.
/// </summary>
public class ManagementState
{
    private static readonly Dictionary<string, VpnStatus> _statusMapping = new(StringComparer.OrdinalIgnoreCase)
    {
        ["TCP_CONNECT"] = VpnStatus.Connecting,
        ["WAIT"] = VpnStatus.Waiting,
        ["AUTH"] = VpnStatus.Authenticating,
        ["GET_CONFIG"] = VpnStatus.RetrievingConfiguration,
        ["ASSIGN_IP"] = VpnStatus.AssigningIp,
        ["ADD_ROUTES"] = VpnStatus.AssigningIp,
        ["CONNECTING"] = VpnStatus.Connecting,
        ["CONNECTED"] = VpnStatus.Connected,
        ["DISCONNECTED"] = VpnStatus.Disconnecting,
        ["EXITING"] = VpnStatus.Disconnecting,
        ["RECONNECTING"] = VpnStatus.Reconnecting,
    };

    private readonly string? _state;
    private readonly string? _status;

    public ManagementState(string? stateMessage, string? statusMessage, string? localIpAddress, string? remoteAddress)
    {
        _state = stateMessage;
        _status = statusMessage;
        LocalIpAddress = localIpAddress;
        RemoteIpAddress = remoteAddress;
    }

    public VpnStatus Status => GetStatus();

    public bool HasStatus => GetStatus() != default(VpnStatus);

    public bool HasError => Status == VpnStatus.Connected && _status is not null && _status.EqualsIgnoringCase("ERROR")
                            || HasTlsError();

    public VpnError Error => HasTlsError() ? VpnError.TlsError : VpnError.None;

    public static ManagementState Null => new(null, null, null, null);

    public string? LocalIpAddress { get; }

    public string? RemoteIpAddress { get; }

    private VpnStatus GetStatus()
    {
        return _state is not null && _statusMapping.TryGetValue(_state, out VpnStatus status)
            ? status
            : default(VpnStatus);
    }

    private bool HasTlsError()
    {
        return Status == VpnStatus.Reconnecting && _status is not null && _status.EqualsIgnoringCase("tls-error");
    }
}