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

namespace ZA.CoreService.ESBCertificateManager.Services;

/// <summary>
/// Führt Sonic-Container-Operationen über die offizielle MF Management Runtime API aus
/// (JMSConnectorClient + MFProxyFactory + IAgentProxy.restart), per Java-Hilfsprogramm
/// und Client-JARs unter SonicHome/lib bzw. MfClientLibPath.
/// Nutzt ConnectionUrl + Username/Password aus appsettings (SMC / Domain Manager).
/// </summary>
public sealed class SonicMfApiExecutor
{
    private readonly SonicConnection _connection;

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

    public Task<(bool Success, string? Error)> TestConnectionAsync(CancellationToken cancellationToken = default)
        => RunAsync("ping", container: null, cancellationToken);

    public async Task<(bool Success, IReadOnlyList<string> Containers, string? Error)> ListContainersAsync(
        CancellationToken cancellationToken = default)
    {
        (bool ok, string? output, string? error) = await RunRawAsync("list", null, cancellationToken);
        if (!ok)
        {
            return (false, [], error ?? output);
        }

        List<string> names = (output ?? string.Empty)
            .Split(['\r', '\n'], StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries)
            .Where(l => !l.StartsWith("OK:", StringComparison.OrdinalIgnoreCase))
            .Where(l => !l.StartsWith("INFO:", StringComparison.OrdinalIgnoreCase))
            .Where(l => !l.StartsWith("ERROR:", StringComparison.OrdinalIgnoreCase))
            .Where(l => !l.StartsWith("WARN:", StringComparison.OrdinalIgnoreCase))
            .Where(l => !l.StartsWith("Usage:", StringComparison.OrdinalIgnoreCase))
            .ToList();

        return (true, names, null);
    }

    public async Task<(bool Success, string? Output, string? Error)> RestartAsync(
        string containerName,
        CancellationToken cancellationToken = default)
    {
        (bool ok, string? output, string? error) = await RunRawAsync("restart", containerName, cancellationToken);
        if (!ok)
        {
            return (false, output, error);
        }

        bool invoked = (output ?? string.Empty)
            .Contains("OK:RestartInvoked", StringComparison.OrdinalIgnoreCase);
        return invoked
            ? (true, output, error)
            : (false, output, error ?? "Kein OK:RestartInvoked von SonicMfContainerTool.");
    }

    private async Task<(bool Success, string? Error)> RunAsync(
        string command,
        string? container,
        CancellationToken cancellationToken)
    {
        (bool ok, string? output, string? error) = await RunRawAsync(command, container, cancellationToken);
        if (ok)
        {
            return (true, null);
        }

        return (false, error ?? output);
    }

    private async Task<(bool Success, string? Output, string? Error)> RunRawAsync(
        string command,
        string? container,
        CancellationToken cancellationToken)
    {
        (bool prepared, string? javaExe, string? classDir, string? classpath, string? prepareError) =
            await PrepareToolAsync(cancellationToken);
        if (!prepared)
        {
            return (false, null, prepareError);
        }

        List<string> args =
        [
            "-cp", Quote(classpath!),
            "SonicMfContainerTool",
            command,
            "--domain", _connection.DomainName,
            "--url", _connection.ConnectionUrl,
            "--user", _connection.Username,
            "--timeout", Math.Clamp(_connection.TimeoutSeconds, 5, 600).ToString()
        ];

        if (!string.IsNullOrWhiteSpace(container))
        {
            args.Add("--container");
            args.Add(container);
        }

        ProcessStartInfo psi = new()
        {
            FileName = javaExe!,
            Arguments = string.Join(" ", args.Select(EscapeArg)),
            UseShellExecute = false,
            RedirectStandardOutput = true,
            RedirectStandardError = true,
            CreateNoWindow = true,
            StandardOutputEncoding = Encoding.UTF8,
            StandardErrorEncoding = Encoding.UTF8,
            WorkingDirectory = classDir!
        };

        psi.Environment["ESB_SONIC_PASSWORD"] = _connection.Password ?? string.Empty;

        using Process process = new() { StartInfo = psi };
        if (!process.Start())
        {
            return (false, null, "Java-Prozess konnte nicht gestartet werden.");
        }

        using CancellationTokenSource timeoutCts =
            CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
        timeoutCts.CancelAfter(TimeSpan.FromSeconds(Math.Clamp(_connection.TimeoutSeconds, 10, 600)));

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

        try
        {
            await process.WaitForExitAsync(timeoutCts.Token);
        }
        catch (OperationCanceledException) when (!cancellationToken.IsCancellationRequested)
        {
            try { process.Kill(entireProcessTree: true); } catch { /* ignore */ }
            return (false, null, $"MfApi Timeout nach {_connection.TimeoutSeconds}s.");
        }

        string stdout = (await stdoutTask).Trim();
        string stderr = (await stderrTask).Trim();
        string combined = string.Join("\n", new[] { stdout, stderr }.Where(s => s.Length > 0));

        if (process.ExitCode == 0
            && !combined.Contains("ERROR:", StringComparison.OrdinalIgnoreCase))
        {
            return (true, combined, null);
        }

        string err = ExtractError(combined)
            ?? $"SonicMfContainerTool ExitCode={process.ExitCode}";
        return (false, combined.Length > 0 ? combined : null, err);
    }

    private async Task<(bool Ok, string? JavaExe, string? ClassDir, string? Classpath, string? Error)>
        PrepareToolAsync(CancellationToken cancellationToken)
    {
        string? javaExe = ResolveJavaExecutable();
        if (javaExe is null)
        {
            return (false, null, null, null,
                "Java nicht gefunden (JAVA_HOME/bin/java.exe oder PATH). " +
                "Für MfApi wird ein JRE/JDK benötigt.");
        }

        string? libDir = ResolveLibDirectory();
        if (libDir is null)
        {
            return (false, null, null, null,
                "Sonic-Client-JARs nicht gefunden. SonicHome\\lib oder MfClientLibPath setzen " +
                $"(aktuell SonicHome='{_connection.SonicHome}', MfClientLibPath='{_connection.MfClientLibPath}'). " +
                "Benötigt u.a. mgmt_client.jar / mfcontext.jar / sonic_Client.jar.");
        }

        string? sourcePath = ResolveToolSourcePath();
        if (sourcePath is null)
        {
            return (false, null, null, null,
                "Tools\\SonicMfContainerTool.java nicht gefunden (App-Ausgabeverzeichnis prüfen).");
        }

        string workDir = Path.Combine(Path.GetTempPath(), "esb-sonic-mf");
        Directory.CreateDirectory(workDir);

        string javaTarget = Path.Combine(workDir, "SonicMfContainerTool.java");
        string classFile = Path.Combine(workDir, "SonicMfContainerTool.class");

        File.Copy(sourcePath, javaTarget, overwrite: true);

        string classpath = BuildClasspath(libDir, workDir);
        bool needsCompile = !File.Exists(classFile)
            || File.GetLastWriteTimeUtc(classFile) < File.GetLastWriteTimeUtc(sourcePath);

        if (needsCompile)
        {
            string? javac = ResolveJavacExecutable(javaExe);
            if (javac is null)
            {
                return (false, null, null, null,
                    "javac nicht gefunden. JDK installieren (nicht nur JRE), " +
                    "damit SonicMfContainerTool.java kompiliert werden kann.");
            }

            ProcessStartInfo compilePsi = new()
            {
                FileName = javac,
                Arguments = $"-encoding UTF-8 -cp {Quote(BuildClasspath(libDir, null))} -d {Quote(workDir)} {Quote(javaTarget)}",
                UseShellExecute = false,
                RedirectStandardOutput = true,
                RedirectStandardError = true,
                CreateNoWindow = true,
                StandardOutputEncoding = Encoding.UTF8,
                StandardErrorEncoding = Encoding.UTF8
            };

            using Process compile = new() { StartInfo = compilePsi };
            if (!compile.Start())
            {
                return (false, null, null, null, "javac konnte nicht gestartet werden.");
            }

            string cOut = await compile.StandardOutput.ReadToEndAsync(cancellationToken);
            string cErr = await compile.StandardError.ReadToEndAsync(cancellationToken);
            await compile.WaitForExitAsync(cancellationToken);

            if (compile.ExitCode != 0 || !File.Exists(classFile))
            {
                return (false, null, null, null,
                    "Kompilieren von SonicMfContainerTool fehlgeschlagen.\n" +
                    Truncate((cErr + "\n" + cOut).Trim()) +
                    $"\nClasspath-Lib: {libDir}");
            }
        }

        return (true, javaExe, workDir, classpath, null);
    }

    private string? ResolveLibDirectory()
    {
        List<string> candidates = [];

        if (!string.IsNullOrWhiteSpace(_connection.MfClientLibPath))
        {
            candidates.Add(_connection.MfClientLibPath);
        }

        if (!string.IsNullOrWhiteSpace(_connection.SonicHome))
        {
            candidates.Add(Path.Combine(_connection.SonicHome, "lib"));
            candidates.Add(_connection.SonicHome);
        }

        foreach (string dir in candidates.Where(Directory.Exists))
        {
            if (Directory.EnumerateFiles(dir, "*.jar", SearchOption.TopDirectoryOnly).Any())
            {
                return dir;
            }
        }

        return null;
    }

    private static string BuildClasspath(string libDir, string? extraDir)
    {
        // Java-Classpath-Wildcard für alle JARs im Lib-Ordner
        string jars = Path.Combine(libDir, "*");
        return string.IsNullOrWhiteSpace(extraDir)
            ? jars
            : jars + Path.PathSeparator + extraDir;
    }

    private static string? ResolveToolSourcePath()
    {
        string[] candidates =
        [
            Path.Combine(AppContext.BaseDirectory, "Tools", "SonicMfContainerTool.java"),
            Path.Combine(Directory.GetCurrentDirectory(), "Tools", "SonicMfContainerTool.java"),
            Path.Combine(AppContext.BaseDirectory, "SonicMfContainerTool.java")
        ];

        return candidates.FirstOrDefault(File.Exists);
    }

    private static string? ResolveJavaExecutable()
    {
        string? javaHome = Environment.GetEnvironmentVariable("JAVA_HOME");
        if (!string.IsNullOrWhiteSpace(javaHome))
        {
            string candidate = Path.Combine(javaHome, "bin", "java.exe");
            if (File.Exists(candidate))
            {
                return candidate;
            }
        }

        return FindOnPath("java.exe") ?? FindOnPath("java");
    }

    private static string? ResolveJavacExecutable(string javaExe)
    {
        string? dir = Path.GetDirectoryName(javaExe);
        if (!string.IsNullOrWhiteSpace(dir))
        {
            string sibling = Path.Combine(dir, OperatingSystem.IsWindows() ? "javac.exe" : "javac");
            if (File.Exists(sibling))
            {
                return sibling;
            }
        }

        string? javaHome = Environment.GetEnvironmentVariable("JAVA_HOME");
        if (!string.IsNullOrWhiteSpace(javaHome))
        {
            string candidate = Path.Combine(javaHome, "bin",
                OperatingSystem.IsWindows() ? "javac.exe" : "javac");
            if (File.Exists(candidate))
            {
                return candidate;
            }
        }

        return FindOnPath("javac.exe") ?? FindOnPath("javac");
    }

    private static string? FindOnPath(string fileName)
    {
        string? pathEnv = Environment.GetEnvironmentVariable("PATH");
        if (string.IsNullOrWhiteSpace(pathEnv))
        {
            return null;
        }

        foreach (string dir in pathEnv.Split(Path.PathSeparator, StringSplitOptions.RemoveEmptyEntries))
        {
            try
            {
                string candidate = Path.Combine(dir.Trim('"'), fileName);
                if (File.Exists(candidate))
                {
                    return candidate;
                }
            }
            catch
            {
                // ignore bad PATH entries
            }
        }

        return null;
    }

    private static string? ExtractError(string combined)
    {
        foreach (string line in combined.Split(['\r', '\n'], StringSplitOptions.RemoveEmptyEntries))
        {
            if (line.StartsWith("ERROR:", StringComparison.OrdinalIgnoreCase))
            {
                return line["ERROR:".Length..].Trim();
            }
        }

        return string.IsNullOrWhiteSpace(combined) ? null : Truncate(combined);
    }

    private static string Quote(string value)
        => "\"" + value.Replace("\"", "\\\"") + "\"";

    private static string EscapeArg(string value)
    {
        if (value.Length == 0)
        {
            return "\"\"";
        }

        bool needsQuotes = value.Contains(' ') || value.Contains('\t') || value.Contains('"')
            || value.Contains('*') || value.Contains(';');
        if (!needsQuotes)
        {
            return value;
        }

        return "\"" + value.Replace("\"", "\\\"") + "\"";
    }

    private static string Truncate(string s, int max = 800)
        => s.Length <= max ? s : s[..max] + "…";
}