using System.Diagnostics;
using System.Text;
using ZA.CoreService.ESBCertificateManager.Models;

namespace ZA.CoreService.ESBCertificateManager.Services;

/// <summary>
/// Neustart über Sonic-Server-Scripts:
///   stopcontainer.bat / startcontainer.bat
/// Diese liegen nur in einer vollen MQ/ESB-Server-Installation – nicht in einer
/// reinen Sonic Management Console (SMC/Client).
/// </summary>
public sealed class SonicBinRestartExecutor
{
    private readonly SonicConnection _connection;

    public SonicBinRestartExecutor(SonicConnection connection)
    {
        _connection = connection;
    }

    public (bool Ok, string? Error, string? Detail) Probe()
    {
        string sonicHome = _connection.SonicHome?.Trim() ?? string.Empty;
        if (string.IsNullOrWhiteSpace(sonicHome))
        {
            return (false, "SonicHome ist leer – in appsettings setzen.", null);
        }

        if (!Directory.Exists(sonicHome))
        {
            return (false, $"SonicHome existiert nicht: '{sonicHome}'", null);
        }

        (string? stop, string? start, string searchNote) = LocateContainerScripts(sonicHome);
        if (stop is null || start is null)
        {
            string binDir = Path.Combine(sonicHome, "bin");
            string binListing = DescribeDirectory(binDir);
            bool looksLikeSmcOnly = Directory.Exists(Path.Combine(sonicHome, "lib"))
                && !File.Exists(Path.Combine(binDir, "stopcontainer.bat"));

            string why = looksLikeSmcOnly
                ? "Das sieht nach einer Sonic Management Console / Client-Installation aus "
                  + "(lib vorhanden, aber keine Server-Scripts). "
                  + "stopcontainer.bat gibt es nur auf dem Sonic-SERVER, nicht in der reinen SMC."
                : "Server-Scripts wurden unter SonicHome nicht gefunden.";

            return (false,
                why + $" Gesucht unter '{sonicHome}'.",
                $"{searchNote}\nInhalt von bin: {binListing}\n"
                + "Lösung A: SonicHome auf den Server-Installationspfad setzen (dort wo stopcontainer.bat liegt).\n"
                + "Lösung B: App lässt automatisch MfApi/SMC-Verbindung versuchen (ConnectionUrl + Login).");
        }

        return (true, null, $"stop={stop}; start={start}");
    }

    public async Task<(bool Success, string Status, string? Detail)> RestartAsync(
        string containerName,
        CancellationToken cancellationToken = default)
    {
        (bool probeOk, string? probeError, string? probeDetail) = Probe();
        if (!probeOk)
        {
            return (false, "Neustart fehlgeschlagen (SonicBin)",
                $"{probeError}\n{probeDetail}");
        }

        string sonicHome = _connection.SonicHome.Trim();
        (string? stopBat, string? startBat, _) = LocateContainerScripts(sonicHome);
        string bin = Path.GetDirectoryName(stopBat!)!;

        string shortName = containerName.Contains('.')
            ? containerName[(containerName.IndexOf('.') + 1)..]
            : containerName;
        string fullName = containerName.Contains('.')
            ? containerName
            : $"{_connection.DomainName}.{containerName}";

        StringBuilder log = new();
        log.AppendLine($"SonicHome={sonicHome}");
        log.AppendLine($"stop={stopBat}");
        log.AppendLine($"start={startBat}");
        log.AppendLine($"Container={fullName} (kurz={shortName})");

        (bool stopOk, string stopOut, string stopErr, int stopCode) =
            await RunBatAsync(stopBat!, fullName, bin, cancellationToken);
        log.AppendLine($"STOP ExitCode={stopCode}");
        if (stopOut.Length > 0) log.AppendLine("STOP out: " + Truncate(stopOut));
        if (stopErr.Length > 0) log.AppendLine("STOP err: " + Truncate(stopErr));

        await Task.Delay(TimeSpan.FromSeconds(5), cancellationToken);

        (bool startOk, string startOut, string startErr, int startCode) =
            await RunBatAsync(startBat!, fullName, bin, cancellationToken);
        log.AppendLine($"START ExitCode={startCode}");
        if (startOut.Length > 0) log.AppendLine("START out: " + Truncate(startOut));
        if (startErr.Length > 0) log.AppendLine("START err: " + Truncate(startErr));

        if (startCode != 0
            && !string.Equals(shortName, fullName, StringComparison.OrdinalIgnoreCase))
        {
            log.AppendLine($"Retry START mit Kurzname '{shortName}'…");
            (_, startOut, startErr, startCode) =
                await RunBatAsync(startBat!, shortName, bin, cancellationToken);
            log.AppendLine($"START(short) ExitCode={startCode}");
            if (startOut.Length > 0) log.AppendLine("START out: " + Truncate(startOut));
            if (startErr.Length > 0) log.AppendLine("START err: " + Truncate(startErr));
        }

        await Task.Delay(
            TimeSpan.FromSeconds(Math.Clamp(_connection.PostRestartDelaySeconds, 0, 120)),
            cancellationToken);

        if (startCode != 0)
        {
            return (false, "Neustart fehlgeschlagen (SonicBin)",
                $"startcontainer ExitCode={startCode} (stop ExitCode={stopCode}).\n{log}");
        }

        return (true, $"Container '{fullName}' neugestartet (SonicBin)", log.ToString());
    }

    /// <summary>
    /// Sucht stop/startcontainer.bat unter SonicHome\bin und rekursiv (max. Tiefe 4).
    /// </summary>
    public static (string? StopBat, string? StartBat, string Note) LocateContainerScripts(string sonicHome)
    {
        List<string> candidates = [];

        void AddDir(string? dir)
        {
            if (!string.IsNullOrWhiteSpace(dir) && Directory.Exists(dir) && !candidates.Contains(dir))
            {
                candidates.Add(dir);
            }
        }

        AddDir(Path.Combine(sonicHome, "bin"));
        AddDir(Path.Combine(sonicHome, "MQ_HOME", "bin"));
        AddDir(Path.Combine(sonicHome, "MQ", "bin"));

        try
        {
            string? parent = Directory.GetParent(sonicHome)?.FullName;
            if (parent is not null)
            {
                foreach (string child in Directory.EnumerateDirectories(parent))
                {
                    AddDir(Path.Combine(child, "bin"));
                }
            }
        }
        catch
        {
            // ignore
        }

        // Rekursiv nach Dateinamen suchen
        try
        {
            foreach (string file in Directory.EnumerateFiles(sonicHome, "stopcontainer.bat", SearchOption.AllDirectories)
                         .Take(20))
            {
                AddDir(Path.GetDirectoryName(file));
            }
        }
        catch
        {
            // ignore permission issues
        }

        foreach (string dir in candidates)
        {
            string stop = Path.Combine(dir, "stopcontainer.bat");
            string start = Path.Combine(dir, "startcontainer.bat");
            if (File.Exists(stop) && File.Exists(start))
            {
                return (stop, start, $"Scripts gefunden in '{dir}'");
            }
        }

        return (null, null, $"Keine Scripts in {candidates.Count} geprüften bin-Ordnern.");
    }

    private static string DescribeDirectory(string dir)
    {
        if (!Directory.Exists(dir))
        {
            return "(Ordner existiert nicht)";
        }

        try
        {
            string[] names = Directory.GetFileSystemEntries(dir)
                .Select(Path.GetFileName)
                .Where(n => n is not null)
                .Cast<string>()
                .OrderBy(n => n)
                .Take(25)
                .ToArray();
            return names.Length == 0 ? "(leer)" : string.Join(", ", names);
        }
        catch (Exception ex)
        {
            return $"(nicht lesbar: {ex.Message})";
        }
    }

    private static async Task<(bool Started, string StdOut, string StdErr, int ExitCode)> RunBatAsync(
        string batPath,
        string argument,
        string workingDirectory,
        CancellationToken cancellationToken)
    {
        ProcessStartInfo psi = new()
        {
            FileName = "cmd.exe",
            Arguments = $"/c \"\"{batPath}\" \"{argument}\"\"",
            WorkingDirectory = workingDirectory,
            UseShellExecute = false,
            RedirectStandardOutput = true,
            RedirectStandardError = true,
            CreateNoWindow = true,
            StandardOutputEncoding = Encoding.UTF8,
            StandardErrorEncoding = Encoding.UTF8
        };

        using Process process = new() { StartInfo = psi };
        if (!process.Start())
        {
            return (false, string.Empty, "cmd.exe konnte nicht gestartet werden.", -1);
        }

        Task<string> stdoutTask = process.StandardOutput.ReadToEndAsync(cancellationToken);
        Task<string> stderrTask = process.StandardError.ReadToEndAsync(cancellationToken);

        await process.WaitForExitAsync(cancellationToken);
        return (true, (await stdoutTask).Trim(), (await stderrTask).Trim(), process.ExitCode);
    }

    private static string Truncate(string value, int max = 500)
        => value.Length <= max ? value : value[..max] + "…";
}