using CliWrap;
using CliWrap.Buffered;
using InnovEnergy.Lib.Utils;
using static InnovEnergy.App.BmsTunnel.CliPrograms;

namespace InnovEnergy.App.BmsTunnel;

using Nodes = IReadOnlyList<Byte>;

public readonly struct BatteryConnection
{
    public String Tty   { get; }
    public Nodes  Nodes { get; }

    private BatteryConnection(String tty, Nodes nodes)
    {
        Tty   = tty;
        Nodes = nodes;
    }
    
    private BatteryConnection(String tty, params Byte[] nodes) : this(tty, (Nodes) nodes)
    {
    }


    public static async Task<BatteryConnection?> Connect(SshHost? host = null)
    {
        Console.WriteLine("searching battery connection...");

        return await GetConnectionFromDBus(host) 
            ?? await GetConnectionFromDevTty(host);
    }

    private static async Task<BatteryConnection?> GetConnectionFromDevTty(SshHost? host)
    {
        var fs = FileSystem.OnHost(host);

        var ttys = await fs.GetFiles("/dev", FileType.CharacterDevice);
        
        var candidateTtys = ttys
                           .Where(f => f.StartsWith("ttyUSB"))
                           .Select(t => t.Split("/").LastOrDefault())
                           .NotNull()
                           .ToList();

        if (!candidateTtys.Any())
        {
            Console.WriteLine("no USB converter cable attached!");
            return null;
        }

        var userSelectedTty = "Select TTY:".ChooseFrom(candidateTtys);

        return userSelectedTty != null
             ? new BatteryConnection(userSelectedTty)
             : null;
    }

    private static async Task<BatteryConnection?> GetConnectionFromDBus(SshHost? host)
    {
        var tty = await LsDBus
                       .OnHost(host)
                       .ExecuteBufferedAsync()
                       .Select(ParseBatteryTty);

        if (tty == null)
            return null;
        
        Console.WriteLine("found battery on DBus");
        
        var availableNodes = await GetNodes(tty, host);
        return new BatteryConnection(tty, availableNodes);
    }

    private static CommandTask<Nodes> GetNodes(String tty, SshHost? host = null)
    {
        const String defaultArgs = "--system --print-reply --type=method_call / com.victronenergy.BusItem.GetValue";
        
        return DBusSend
              .OnHost(host)
              .AppendArgument($"--dest=com.victronenergy.battery.{tty}")  
              .AppendArgument(defaultArgs)  
              .ExecuteBufferedAsync()
              .Select(ParseBatteryNodes);
    }

    private static Nodes ParseBatteryNodes(BufferedCommandResult result)
    {
        return result
              .StandardOutput
              .Split(Environment.NewLine)
              .Where(l => l.Contains("_Battery/"))
              .Select(l => l.Split('/')[1])
              .Where(n => Byte.TryParse(n, out _))
              .Select(Byte.Parse)
              .Distinct()
              .OrderBy(n => n)
              .ToList();
    }

    private static String? ParseBatteryTty(BufferedCommandResult result)
    {
        return result
              .StandardOutput
              .Split(Environment.NewLine)
              .Where(l => l.Contains("com.victronenergy.battery."))
              .SelectMany(l => l.Split('.'))
              .LastOrDefault();
    }

}