using System.Net;
using System.Net.Http.Headers;
using System.Text;
using System.Text.Json;
using ZA.CoreService.ESBCertificateManager.Models;

namespace ZA.CoreService.ESBCertificateManager.Services;

/// <summary>
/// Verwaltet Sonic ESB Container über die Management Console.
///
/// Modus = WinRm (Standard):
///   PowerShell Remoting (Invoke-Command) → CMD stop/startcontainer auf dem Sonic-Server.
///
/// Modus = LocalCmd:
///   Dieselbe CMD/PowerShell-Logik lokal (Test direkt auf dem Sonic-PC).
///
/// Modus = HttpApi:
///   HTTP REST API mit automatischer Pfad-Erkennung.
/// </summary>
public sealed class SonicManagementClient : IDisposable
{
    private readonly SonicConnection _connection;
    private readonly HttpClient? _http;
    private readonly WinRmExecutor? _scriptRunner;

    // Gecachter HTTP-Basis-Pfad (nur im HttpApi-Modus)
    private string? _resolvedContainerBasePath;

    private static readonly string[] CandidateContainerPaths =
    [
        "/mf/rest/v1/domains/{domain}/containers",
        "/api/v1/domains/{domain}/containers",
        "/sonic/management/domains/{domain}/containers",
        "/containers"
    ];

    private bool UsesScripts =>
        _connection.ManagementMode is SonicManagementMode.WinRm or SonicManagementMode.LocalCmd;

    public SonicManagementClient(SonicConnection connection)
    {
        _connection = connection;

        if (UsesScripts)
        {
            _scriptRunner = new WinRmExecutor(connection);
        }
        else
        {
            HttpClientHandler handler = new()
            {
                ServerCertificateCustomValidationCallback =
                    HttpClientHandler.DangerousAcceptAnyServerCertificateValidator
            };

            _http = new HttpClient(handler)
            {
                BaseAddress = BuildHttpBaseUri(connection.ConnectionUrl, connection.ManagementHttpPort),
                Timeout = TimeSpan.FromSeconds(Math.Clamp(connection.TimeoutSeconds, 5, 300))
            };

            string credentials = Convert.ToBase64String(
                Encoding.UTF8.GetBytes($"{connection.Username}:{connection.Password}"));
            _http.DefaultRequestHeaders.Authorization =
                new AuthenticationHeaderValue("Basic", credentials);
            _http.DefaultRequestHeaders.Accept.Add(
                new MediaTypeWithQualityHeaderValue("application/json"));
        }
    }

    // ---------------------------------------------------------------
    // Öffentliche API
    // ---------------------------------------------------------------

    /// <summary>
    /// Prüft die Verbindung zur Management Console.
    /// WinRm: TCP-Ping auf WinRM-Port + Test-PSSession.
    /// Http:  Probe gegen bekannte API-Pfade.
    /// </summary>
    public async Task<(bool Success, string? Error, string? ResolvedPath)> CheckConnectionAsync(
        CancellationToken cancellationToken = default)
    {
        if (UsesScripts)
        {
            (bool ok, string? error) = await _scriptRunner!.TestConnectionAsync(cancellationToken);
            string modeLabel = _connection.ManagementMode == SonicManagementMode.LocalCmd
                ? $"LocalCmd (SonicHome={_connection.SonicHome})"
                : $"WinRM auf {ExtractHost(_connection.ConnectionUrl)}:{_connection.WinRmPort}";
            return (ok, error, ok ? modeLabel : null);
        }

        try
        {
            string? path = await ResolveContainerBasePathAsync(cancellationToken);
            if (path is null)
            {
                return (false,
                    $"Keine Sonic HTTP-API unter {_http!.BaseAddress} gefunden.\n" +
                    $"Geprüfte Pfade: {string.Join(", ", GetCandidatePaths())}\n" +
                    $"Tipp: ManagementMode auf 'WinRm' setzen falls kein HTTP-API vorhanden.",
                    null);
            }

            return (true, null, path);
        }
        catch (TaskCanceledException) when (!cancellationToken.IsCancellationRequested)
        {
            return (false,
                $"HTTP-Timeout nach {_connection.TimeoutSeconds}s – Port {_connection.ManagementHttpPort} nicht erreichbar.\n" +
                $"Tipp: ManagementMode auf 'WinRm' setzen.",
                null);
        }
        catch (Exception ex)
        {
            return (false, ex.Message, null);
        }
    }

    /// <summary>
    /// Listet alle Container der Domain auf.
    /// </summary>
    public async Task<(bool Success, IReadOnlyList<string> ContainerNames, string? Error)> GetContainersAsync(
        CancellationToken cancellationToken = default)
    {
        if (UsesScripts)
        {
            return await GetContainersViaScriptAsync(cancellationToken);
        }

        return await GetContainersViaHttpAsync(cancellationToken);
    }

    /// <summary>
    /// Startet den Container neu.
    /// </summary>
    public async Task<(bool Success, string Status, string? Detail)> RestartContainerAsync(
        string containerName,
        CancellationToken cancellationToken = default)
    {
        if (UsesScripts)
        {
            return await RestartViaScriptAsync(containerName, cancellationToken);
        }

        return await RestartViaHttpAsync(containerName, cancellationToken);
    }

    /// <summary>
    /// Importiert XApi-Ressourcen und startet den Container neu.
    /// </summary>
    public async Task<(bool Success, string Status, string? Detail)> ImportXapiAndRestartAsync(
        string containerName,
        string xapiSourcePath,
        CancellationToken cancellationToken = default)
    {
        if (UsesScripts)
        {
            return await ImportXapiViaScriptAsync(containerName, xapiSourcePath, cancellationToken);
        }

        return await ImportXapiViaHttpAsync(containerName, xapiSourcePath, cancellationToken);
    }

    // ---------------------------------------------------------------
    // Script-Implementierungen (WinRM / LocalCmd)
    // ---------------------------------------------------------------

    private async Task<(bool, IReadOnlyList<string>, string?)> GetContainersViaScriptAsync(
        CancellationToken cancellationToken)
    {
        string script = WinRmExecutor.ApplyScriptTemplate(
            _connection.ResolveContainerListScript(),
            containerName: string.Empty,
            domainName: _connection.DomainName,
            sonicHome: _connection.SonicHome,
            connectionUrl: _connection.ConnectionUrl,
            username: _connection.Username,
            password: _connection.Password);

        (bool ok, string? output, string? error) =
            await _scriptRunner!.RunScriptAsync(script, cancellationToken);

        if (!ok)
        {
            return (false, [], $"Container-Liste fehlgeschlagen ({_connection.ManagementMode}): {error}");
        }

        List<string> names = (output ?? string.Empty)
            .Split(['\r', '\n'], StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries)
            .Where(l => l.Length > 0)
            .Where(l => !l.StartsWith("WARNING:", StringComparison.OrdinalIgnoreCase))
            .ToList();

        // INFO:/WARN:-Zeilen aus dem Script bewusst durchreichen (Diagnose in Discovery)
        return (true, names, null);
    }

    private async Task<(bool, string, string?)> RestartViaScriptAsync(
        string containerName, CancellationToken cancellationToken)
    {
        string script = WinRmExecutor.ApplyScriptTemplate(
            _connection.ResolveRestartScript(),
            containerName,
            _connection.DomainName,
            _connection.SonicHome,
            connectionUrl: _connection.ConnectionUrl,
            username: _connection.Username,
            password: _connection.Password);

        (bool ok, string? output, string? error) =
            await _scriptRunner!.RunScriptAsync(script, cancellationToken);

        string mode = _connection.ManagementMode.ToString();
        bool verified = (output ?? string.Empty)
            .Contains("OK:ContainerRestartVerified", StringComparison.OrdinalIgnoreCase);

        if (!ok || !verified)
        {
            return (false, $"Neustart fehlgeschlagen ({mode})",
                $"Kein verifizierter Prozess-Neustart für Container '{containerName}' " +
                $"(Domain '{_connection.DomainName}').\n" +
                $"Fehler: {error}\nAusgabe: {output}\nSonicHome={_connection.SonicHome}");
        }

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

        return (true, $"Container '{containerName}' neugestartet ({mode})",
            $"Domain={_connection.DomainName}; verifiziert.\n{output}");
    }

    private async Task<(bool, string, string?)> ImportXapiViaScriptAsync(
        string containerName, string xapiSourcePath, CancellationToken cancellationToken)
    {
        if (string.IsNullOrWhiteSpace(_connection.WinRmXapiImportScript))
        {
            return (false, "XApi-Import fehlgeschlagen",
                "WinRmXapiImportScript ist nicht konfiguriert.");
        }

        string script = WinRmExecutor.ApplyScriptTemplate(
            _connection.WinRmXapiImportScript,
            containerName,
            _connection.DomainName,
            _connection.SonicHome,
            xapiSourcePath,
            _connection.ConnectionUrl,
            _connection.Username,
            _connection.Password);

        (bool importOk, string? importOut, string? importErr) =
            await _scriptRunner!.RunScriptAsync(script, cancellationToken);

        if (!importOk)
        {
            return (false, "XApi-Import fehlgeschlagen", importErr ?? importOut);
        }

        (bool restartOk, string restartStatus, string? restartDetail) =
            await RestartViaScriptAsync(containerName, cancellationToken);

        return restartOk
            ? (true, "XApi importiert + Container neugestartet",
                $"Import: {importOut} | Restart: {restartDetail}")
            : (false, restartStatus, restartDetail);
    }

    // ---------------------------------------------------------------
    // HTTP-Implementierungen
    // ---------------------------------------------------------------

    private async Task<(bool, IReadOnlyList<string>, string?)> GetContainersViaHttpAsync(
        CancellationToken cancellationToken)
    {
        try
        {
            string? basePath = await ResolveContainerBasePathAsync(cancellationToken);
            if (basePath is null)
            {
                return (false, [], "Kein HTTP-API-Pfad gefunden. ManagementMode auf 'WinRm' setzen?");
            }

            using HttpResponseMessage response = await _http!.GetAsync(basePath, cancellationToken);
            if (!response.IsSuccessStatusCode)
            {
                return (false, [], $"HTTP {(int)response.StatusCode}: {response.ReasonPhrase}");
            }

            string json = await response.Content.ReadAsStringAsync(cancellationToken);
            return (true, ParseContainerNames(json), null);
        }
        catch (Exception ex) when (ex is not OperationCanceledException)
        {
            return (false, [], ex.Message);
        }
    }

    private async Task<(bool, string, string?)> RestartViaHttpAsync(
        string containerName, CancellationToken cancellationToken)
    {
        string encoded = Uri.EscapeDataString(containerName);

        try
        {
            string? basePath = await ResolveContainerBasePathAsync(cancellationToken);
            if (basePath is null)
            {
                return (false, "Neustart fehlgeschlagen",
                    "Kein HTTP-API-Pfad gefunden. ManagementMode auf 'WinRm' setzen.");
            }

            if (!string.IsNullOrWhiteSpace(_connection.ContainerRestartPath))
            {
                string customPath = ApplyTemplate(_connection.ContainerRestartPath, encoded);
                (bool ok, _, string? d) = await PostAsync(customPath, cancellationToken);
                if (ok) { await DelayAsync(cancellationToken); return (true, "Container neugestartet", d); }
            }

            (bool r1Ok, _, string? r1d) = await PostAsync($"{basePath}/{encoded}/restart", cancellationToken);
            if (r1Ok) { await DelayAsync(cancellationToken); return (true, "Container neugestartet", r1d); }

            (bool r2Ok, _, string? r2d) = await PutStateAsync(basePath, encoded, "running", cancellationToken);
            if (r2Ok) { await DelayAsync(cancellationToken); return (true, "Container neugestartet (State-API)", r2d); }

            return await StopThenStartAsync(basePath, encoded, cancellationToken);
        }
        catch (OperationCanceledException) { throw; }
        catch (Exception ex) { return (false, "Neustart fehlgeschlagen", ex.Message); }
    }

    private async Task<(bool, string, string?)> ImportXapiViaHttpAsync(
        string containerName, string xapiSourcePath, CancellationToken cancellationToken)
    {
        if (!File.Exists(xapiSourcePath))
        {
            return (false, "XApi-Import fehlgeschlagen", $"Quelldatei nicht gefunden: {xapiSourcePath}");
        }

        string encoded = Uri.EscapeDataString(containerName);
        string? basePath = await ResolveContainerBasePathAsync(cancellationToken);
        if (basePath is null) return (false, "XApi-Import fehlgeschlagen", "Kein HTTP-API-Pfad.");

        string path = $"{basePath}/{encoded}/xapi/import";
        await using FileStream fs = File.OpenRead(xapiSourcePath);
        string mt = xapiSourcePath.EndsWith(".zip", StringComparison.OrdinalIgnoreCase) ? "application/zip" : "application/xml";
        using StreamContent content = new(fs);
        content.Headers.ContentType = new MediaTypeHeaderValue(mt);
        using HttpResponseMessage rsp = await _http!.PostAsync(path, content, cancellationToken);

        if (!rsp.IsSuccessStatusCode)
        {
            string body = await rsp.Content.ReadAsStringAsync(cancellationToken);
            return (false, "XApi-Import fehlgeschlagen", $"HTTP {(int)rsp.StatusCode}: {Truncate(body)}");
        }

        (bool restartOk, string rs, string? rd) = await RestartViaHttpAsync(containerName, cancellationToken);
        return restartOk
            ? (true, "XApi importiert + Container neugestartet", rd)
            : (false, rs, rd);
    }

    // ---------------------------------------------------------------
    // HTTP-Pfad-Erkennung
    // ---------------------------------------------------------------

    private async Task<string?> ResolveContainerBasePathAsync(CancellationToken cancellationToken)
    {
        if (_resolvedContainerBasePath is not null) return _resolvedContainerBasePath;

        foreach (string p in GetCandidatePaths())
        {
            try
            {
                using HttpResponseMessage r = await _http!.GetAsync(p, cancellationToken);
                if (r.IsSuccessStatusCode || r.StatusCode == HttpStatusCode.Unauthorized)
                {
                    _resolvedContainerBasePath = p;
                    return p;
                }
            }
            catch (HttpRequestException) { }
            catch (TaskCanceledException) when (!cancellationToken.IsCancellationRequested) { }
        }

        return null;
    }

    private IEnumerable<string> GetCandidatePaths()
    {
        if (!string.IsNullOrWhiteSpace(_connection.ContainerListPath))
            yield return ApplyTemplate(_connection.ContainerListPath, string.Empty).TrimEnd('/');

        if (!string.IsNullOrWhiteSpace(_connection.ApiBasePath))
        {
            string d = Uri.EscapeDataString(_connection.DomainName);
            yield return $"{_connection.ApiBasePath.TrimEnd('/')}/domains/{d}/containers";
        }

        foreach (string pattern in CandidateContainerPaths)
            yield return pattern.Replace("{domain}", Uri.EscapeDataString(_connection.DomainName), StringComparison.OrdinalIgnoreCase);
    }

    // ---------------------------------------------------------------
    // HTTP-Aktions-Helfer
    // ---------------------------------------------------------------

    private async Task<(bool, string, string?)> PostAsync(string path, CancellationToken ct)
    {
        using HttpResponseMessage r = await _http!.PostAsync(path, null, ct);
        if (r.IsSuccessStatusCode)
            return (true, $"OK ({(int)r.StatusCode})", $"POST {path} → {(int)r.StatusCode}");
        string body = await r.Content.ReadAsStringAsync(ct);
        return (false, $"Fehler ({(int)r.StatusCode})", $"POST {path} → {(int)r.StatusCode}: {Truncate(body)}");
    }

    private async Task<(bool, string, string?)> PutStateAsync(
        string basePath, string encoded, string state, CancellationToken ct)
    {
        string path = $"{basePath}/{encoded}";
        using StringContent body = new($"{{\"state\":\"{state}\"}}", Encoding.UTF8, "application/json");
        using HttpResponseMessage r = await _http!.PutAsync(path, body, ct);
        if (r.IsSuccessStatusCode)
            return (true, $"State={state}", $"PUT {path} state={state} → {(int)r.StatusCode}");
        string b = await r.Content.ReadAsStringAsync(ct);
        return (false, "State fehlgeschlagen", $"PUT {path} → {(int)r.StatusCode}: {Truncate(b)}");
    }

    private async Task<(bool, string, string?)> StopThenStartAsync(
        string basePath, string encoded, CancellationToken ct)
    {
        string stopPath = string.IsNullOrWhiteSpace(_connection.ContainerStopPath)
            ? $"{basePath}/{encoded}/stop"
            : ApplyTemplate(_connection.ContainerStopPath, encoded);

        string startPath = string.IsNullOrWhiteSpace(_connection.ContainerStartPath)
            ? $"{basePath}/{encoded}/start"
            : ApplyTemplate(_connection.ContainerStartPath, encoded);

        (bool sOk, _, string? sd) = await PostAsync(stopPath, ct);
        if (!sOk) return (false, "Container-Stop fehlgeschlagen", sd);

        await Task.Delay(TimeSpan.FromSeconds(3), ct);

        (bool stOk, _, string? std) = await PostAsync(startPath, ct);
        if (!stOk) return (false, "Container-Start fehlgeschlagen", std);

        await DelayAsync(ct);
        return (true, "Container neugestartet (Stop+Start)", $"{sd} | {std}");
    }

    private async Task DelayAsync(CancellationToken ct)
    {
        int d = Math.Clamp(_connection.PostRestartDelaySeconds, 0, 120);
        if (d > 0) await Task.Delay(TimeSpan.FromSeconds(d), ct);
    }

    private string ApplyTemplate(string template, string encodedName)
        => template
            .Replace("{domain}", Uri.EscapeDataString(_connection.DomainName), StringComparison.OrdinalIgnoreCase)
            .Replace("{container}", encodedName, StringComparison.OrdinalIgnoreCase);

    private static Uri BuildHttpBaseUri(string connectionUrl, int httpPort)
    {
        try { return new Uri($"http://{new Uri(connectionUrl).Host}:{httpPort}"); }
        catch { return new Uri(connectionUrl); }
    }

    private static string ExtractHost(string connectionUrl)
    {
        try { return new Uri(connectionUrl).Host; }
        catch { return connectionUrl; }
    }

    private static List<string> ParseContainerNames(string json)
    {
        try
        {
            using JsonDocument doc = JsonDocument.Parse(json);
            JsonElement root = doc.RootElement;
            List<string> names = [];

            IEnumerable<JsonElement> elements = root.ValueKind == JsonValueKind.Array
                ? root.EnumerateArray()
                : root.ValueKind == JsonValueKind.Object
                    ? new[] { "containers", "data", "items", "result" }
                        .Where(k => root.TryGetProperty(k, out _))
                        .SelectMany(k =>
                        {
                            root.TryGetProperty(k, out JsonElement a);
                            return a.ValueKind == JsonValueKind.Array
                                ? a.EnumerateArray()
                                : Enumerable.Empty<JsonElement>();
                        })
                    : [];

            foreach (JsonElement el in elements)
            {
                string? name = el.ValueKind == JsonValueKind.String
                    ? el.GetString()
                    : new[] { "name", "containerName", "id", "configId" }
                        .Where(k => el.TryGetProperty(k, out _))
                        .Select(k => { el.TryGetProperty(k, out JsonElement p); return p.GetString(); })
                        .FirstOrDefault();
                if (name is not null) names.Add(name);
            }

            return names;
        }
        catch { return []; }
    }

    private static string Truncate(string v, int max = 400)
        => v.Length <= max ? v : v[..max] + "…";

    public void Dispose()
    {
        _http?.Dispose();
    }
}