using log4net;
using log4net.Config;
using Microsoft.Extensions.Configuration;
using RestSharp;
using RestSharp.Authenticators;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Text.Json;
using System.Text.Json.Nodes;
using System.Text.RegularExpressions;

internal class Program
{
    private static readonly ILog Log = LogManager.GetLogger(typeof(Program));

    static int Main(string[] args)
    {
        Console.OutputEncoding = Encoding.UTF8;
        Console.InputEncoding = Encoding.UTF8;
        ConfigureLogging();

        AppDomain.CurrentDomain.UnhandledException += (_, e) =>
            Log.Fatal("Unhandled exception", e.ExceptionObject as Exception);

        try
        {
            var baseDir = AppContext.BaseDirectory;
            var appSettingsPath = Path.Combine(baseDir, "appsettings.json");
            var config = LoadConfig(baseDir);

            var apiBase = (config["Crewbrain:ApiBase"] ?? "").TrimEnd('/');
            if (string.IsNullOrWhiteSpace(apiBase))
                throw new Exception("Missing config 'Crewbrain:ApiBase' (e.g. https://vt-media.crewbrain.com/api)");

            // Paths
            var angebotPath = config["Paths:Angebot"] ?? "";
            var auftragPath = config["Paths:Auftrag"] ?? "";
            var lieferscheinPath = config["Paths:Lieferschein"] ?? "";

            // Upload settings (3 unterschiedliche TypeIDs / Flags)
            var settingsAngebot = UploadSettings.FromConfig(config, "Crewbrain:Upload:Angebot");
            var settingsAuftrag = UploadSettings.FromConfig(config, "Crewbrain:Upload:Auftrag");
            var settingsLieferschein = UploadSettings.FromConfig(config, "Crewbrain:Upload:Lieferschein");

            Log.Info("=== EPI2CrewbrainFile.Console started ===");
            Log.Info($"Config path: {appSettingsPath}");
            Log.Info($"Crewbrain ApiBase: {apiBase}");

            Log.Info($"AngebotPath: {angebotPath} | TypeId={settingsAngebot.TypeId} | OverwriteSingleDocument={settingsAngebot.OverwriteSingleDocument}");
            Log.Info($"AuftragPath: {auftragPath} | TypeId={settingsAuftrag.TypeId} | OverwriteSingleDocument={settingsAuftrag.OverwriteSingleDocument}");
            Log.Info($"LieferscheinPath: {lieferscheinPath} | TypeId={settingsLieferschein.TypeId} | OverwriteSingleDocument={settingsLieferschein.OverwriteSingleDocument}");

            // Access token (prompt once, store)
            var accessToken = TokenAuthHelper.EnsureAccessToken(
                config: config,
                appSettingsPath: appSettingsPath,
                log: Log,
                apiBase: apiBase
            );

            Log.Info($"TokenAuth: AccessToken loaded (len={accessToken.Length})");

            // Uploader service
            var service = new UploaderService(apiBase, accessToken, appSettingsPath, Log);

            // Process
            ProcessFolder(folder: angebotPath, uploader: service, tag: "Angebot", settings: settingsAngebot);
            ProcessFolder(folder: auftragPath, uploader: service, tag: "Auftrag", settings: settingsAuftrag);
            ProcessFolder(folder: lieferscheinPath, uploader: service, tag: "Lieferschein", settings: settingsLieferschein);

            Log.Info("=== EPI2CrewbrainFile.Console finished successfully ===");
            return 0;
        }
        catch (Exception ex)
        {
            Log.Fatal("Fatal error", ex);
            return 1;
        }
        finally
        {
            LogManager.Shutdown();
        }
    }

    private static IConfigurationRoot LoadConfig(string baseDir)
        => new ConfigurationBuilder()
            .SetBasePath(baseDir)
            .AddJsonFile("appsettings.json", optional: false, reloadOnChange: false)
            .Build();

    private static void ConfigureLogging()
    {
        Directory.CreateDirectory(Path.Combine(AppContext.BaseDirectory, "logs"));
        var configFile = Path.Combine(AppContext.BaseDirectory, "log4net.config");
        XmlConfigurator.Configure(LogManager.GetRepository(Assembly.GetEntryAssembly()!), new FileInfo(configFile));
    }

    private static void ProcessFolder(string folder, UploaderService uploader, string tag, UploadSettings settings)
    {
        if (string.IsNullOrWhiteSpace(folder) || !Directory.Exists(folder))
        {
            Log.Warn($"[{tag}] Folder missing: {folder}");
            return;
        }

        var pdfs = new DirectoryInfo(folder).GetFiles("*.pdf");
        Log.Info($"[{tag}] Found {pdfs.Length} PDF(s) in {folder}");

        foreach (var file in pdfs)
        {
            try
            {
                var eventIdManual = ExtractEventIdManual(file.Name);
                if (string.IsNullOrWhiteSpace(eventIdManual))
                {
                    Log.Warn($"[{tag}] Could not extract EventIDManual from filename: {file.Name} (skip)");
                    continue;
                }

                Log.Info($"[{tag}] File '{file.Name}' -> EventIDManual={eventIdManual}");

                var eventId = uploader.ResolveCrewbrainEventIdByManualId(eventIdManual);
                if (eventId == null)
                {
                    Log.Warn($"[{tag}] No CrewBrain event found for EventIDManual={eventIdManual}. File not moved.");
                    continue;
                }

                Log.Info($"[{tag}] Resolved EventIDManual={eventIdManual} -> CrewBrain ID={eventId}");

                var filenameWithoutExt = Path.GetFileNameWithoutExtension(file.Name);
                var ok = uploader.UploadDocumentToEvent(
                    eventId: eventId.Value,
                    typeId: settings.TypeId,
                    overwriteSingleDocument: settings.OverwriteSingleDocument,
                    fullPath: file.FullName,
                    filename: filenameWithoutExt,
                    filetype: file.Extension.TrimStart('.')
                );

                if (ok)
                {
                    MoveToUploaded(folder, file.Name, tag);
                }
                else
                {
                    Log.Warn($"[{tag}] Upload failed -> file NOT moved. ({file.Name})");
                }
            }
            catch (Exception ex)
            {
                Log.Error($"[{tag}] Error processing '{file.FullName}'", ex);
            }
        }
    }

    /// <summary>
    /// Robust: findet 3- bis 5-stellige IDs im Format NNN-NN / NNNN-NN / NNNNN-NN.
    /// Wenn mehrere Treffer existieren, nimmt er den längsten (also bevorzugt 5-stellig vor 4-stellig vor 3-stellig).
    /// </summary>
    private static string ExtractEventIdManual(string fileName)
    {
        // Match: 3..5 digits - 2 digits, nicht Teil einer größeren Zahl
        var matches = Regex.Matches(fileName, @"(?<!\d)(\d{3,5}-\d{2})(?!\d)");
        if (matches.Count == 0) return "";

        return matches
            .Select(m => m.Groups[1].Value)
            .OrderByDescending(s => s.Length)   // bevorzugt 12345-01
            .First();
    }

    private static void MoveToUploaded(string baseFolder, string fileName, string tag)
    {
        var uploadedDir = Path.Combine(baseFolder, "Uploaded");
        Directory.CreateDirectory(uploadedDir);

        var source = Path.Combine(baseFolder, fileName);
        if (!File.Exists(source))
        {
            Log.Warn($"[{tag}] Move: source missing: {source}");
            return;
        }

        var nameNoExt = Path.GetFileNameWithoutExtension(fileName);
        var ext = Path.GetExtension(fileName); // inkl ".pdf"
        if (string.IsNullOrWhiteSpace(ext)) ext = "";

        var dest = Path.Combine(uploadedDir, fileName);
        if (File.Exists(dest))
        {
            var stamp = DateTime.Now.ToString("yyyyMMddHHmmssffff");
            var newName = $"{nameNoExt}_{stamp}{ext}";
            dest = Path.Combine(uploadedDir, newName);
        }

        File.Move(source, dest);
        Log.Info($"[{tag}] Moved to '{dest}'");
    }

    private sealed record UploadSettings(int TypeId, bool OverwriteSingleDocument)
    {
        public static UploadSettings FromConfig(IConfiguration cfg, string prefix)
        {
            int typeId = 0;
            bool overwrite = false;

            int.TryParse(cfg[$"{prefix}:TypeId"], out typeId);
            bool.TryParse(cfg[$"{prefix}:OverwriteSingleDocument"], out overwrite);

            return new UploadSettings(typeId, overwrite);
        }
    }
}

internal static class TokenAuthHelper
{
    public static string EnsureAccessToken(IConfiguration config, string appSettingsPath, ILog log, string apiBase)
    {
        apiBase = (apiBase ?? "").TrimEnd('/');

        var token = (config["Crewbrain:TokenAuth:AccessToken"] ?? "").Trim();
        if (!string.IsNullOrWhiteSpace(token))
        {
            log.Info("TokenAuth: Using stored AccessToken from appsettings.json");
            return token;
        }

        log.Warn("TokenAuth: No AccessToken stored. Prompting for username/password to request one-time token...");

        Console.Write("CrewBrain Username: ");
        var user = (Console.ReadLine() ?? "").Trim();

        var pass = ReadPassword("CrewBrain Password: ");

        if (string.IsNullOrWhiteSpace(user) || string.IsNullOrWhiteSpace(pass))
            throw new Exception("TokenAuth: Missing username/password; cannot request access token.");

        var fetched = FetchAccessToken(apiBase, user, pass, log);
        SaveAccessToken(appSettingsPath, fetched, log);

        log.Info("TokenAuth: AccessToken saved to appsettings.json");
        return fetched;
    }

    public static void ClearStoredToken(string appSettingsPath, ILog log)
    {
        try
        {
            var json = File.Exists(appSettingsPath) ? File.ReadAllText(appSettingsPath) : "";
            var root = (JsonNode.Parse(json) as JsonObject) ?? new JsonObject();

            var crew = root["Crewbrain"] as JsonObject;
            var tokenAuth = crew?["TokenAuth"] as JsonObject;
            if (tokenAuth == null) return;

            tokenAuth["AccessToken"] = "";
            tokenAuth["ClearedAtUtc"] = DateTime.UtcNow.ToString("o");

            File.WriteAllText(appSettingsPath, root.ToJsonString(new JsonSerializerOptions { WriteIndented = true }));
            log.Warn("TokenAuth: Stored token cleared in appsettings.json (will re-prompt next time).");
        }
        catch (Exception ex)
        {
            log.Warn("TokenAuth: Failed to clear token from appsettings.json", ex);
        }
    }

    private static string FetchAccessToken(string apiBase, string user, string pass, ILog log)
    {
        var options = new RestClientOptions(apiBase.TrimEnd('/') + "/")
        {
            Authenticator = new HttpBasicAuthenticator(user, pass),
            FollowRedirects = true
        };
        var client = new RestClient(options);

        var req = new RestRequest("accesstoken", Method.Get);
        req.AddHeader("Accept", "application/json");

        var resp = client.Execute(req);

        log.Info($"GET /accesstoken -> {(int)resp.StatusCode} {resp.StatusCode}");
        if (!resp.IsSuccessful)
            throw new Exception($"AccessToken request failed: {(int)resp.StatusCode} {resp.StatusCode} Body={resp.Content}");

        var body = resp.Content ?? "";
        var node = JsonNode.Parse(body) as JsonObject
            ?? throw new Exception($"AccessToken response not a JSON object: {body}");

        var token = (node["Accesstoken"]?.GetValue<string>() ?? "").Trim();
        if (string.IsNullOrWhiteSpace(token))
            throw new Exception($"TokenAuth: 'Accesstoken' missing in response: {body}");

        log.Info($"TokenAuth: token received (len={token.Length})");
        return token;
    }

    private static void SaveAccessToken(string appSettingsPath, string accessToken, ILog log)
    {
        JsonObject root;
        try
        {
            var json = File.Exists(appSettingsPath) ? File.ReadAllText(appSettingsPath) : "";
            root = (JsonNode.Parse(json) as JsonObject) ?? new JsonObject();
        }
        catch (Exception ex)
        {
            if (File.Exists(appSettingsPath))
            {
                var backupPath = appSettingsPath + ".broken_" + DateTime.Now.ToString("yyyyMMddHHmmss");
                File.Copy(appSettingsPath, backupPath, overwrite: true);
                log.Warn($"TokenAuth: appsettings.json invalid JSON. Backed up to: {backupPath}", ex);
            }
            root = new JsonObject();
        }

        var crew = root["Crewbrain"] as JsonObject ?? new JsonObject();
        root["Crewbrain"] = crew;

        var tokenAuth = crew["TokenAuth"] as JsonObject ?? new JsonObject();
        crew["TokenAuth"] = tokenAuth;

        tokenAuth["AccessToken"] = accessToken;
        tokenAuth["SavedAtUtc"] = DateTime.UtcNow.ToString("o");

        File.WriteAllText(appSettingsPath, root.ToJsonString(new JsonSerializerOptions { WriteIndented = true }));
    }

    private static string ReadPassword(string prompt)
    {
        Console.Write(prompt);
        var sb = new StringBuilder();

        while (true)
        {
            var key = Console.ReadKey(intercept: true);

            if (key.Key == ConsoleKey.Enter)
            {
                Console.WriteLine();
                break;
            }

            if (key.Key == ConsoleKey.Backspace)
            {
                if (sb.Length > 0)
                {
                    sb.Length--;
                    Console.Write("\b \b");
                }
                continue;
            }

            if (!char.IsControl(key.KeyChar))
            {
                sb.Append(key.KeyChar);
                Console.Write("*");
            }
        }

        return sb.ToString();
    }
}

internal class UploaderService
{
    private static readonly ILog Log = LogManager.GetLogger(typeof(UploaderService));

    private readonly string _baseUrl;           // https://.../api/
    private string _accessToken;               // X-API-KEY
    private readonly string _appSettingsPath;   // for clearing token on 401/403
    private readonly ILog _rootLog;

    public UploaderService(string apiBase, string accessToken, string appSettingsPath, ILog rootLog)
    {
        _baseUrl = (apiBase ?? "").TrimEnd('/') + "/";
        _accessToken = (accessToken ?? "").Trim();
        _appSettingsPath = appSettingsPath;
        _rootLog = rootLog;
    }

    public int? ResolveCrewbrainEventIdByManualId(string eventIdManual)
        => ResolveCrewbrainEventIdByManualIdInternal(eventIdManual, allowTokenRetry: true);

    private int? ResolveCrewbrainEventIdByManualIdInternal(string eventIdManual, bool allowTokenRetry)
    {
        try
        {
            var client = new RestClient(new RestClientOptions(_baseUrl) { FollowRedirects = true });

            var req = new RestRequest("v2/events", Method.Get);
            req.AddHeader("Accept", "application/json");
            req.AddHeader("X-API-KEY", _accessToken);
            req.AddQueryParameter("EventIDManual", eventIdManual);

            DebugLogRawRequest(client, req, bodyPreview: null);

            var resp = client.Execute(req);
            Log.Info($"GET v2/events?EventIDManual={eventIdManual} -> {(int)resp.StatusCode} {resp.StatusCode}");

            if ((int)resp.StatusCode == 401 || (int)resp.StatusCode == 403)
            {
                Log.Error("Resolve: unauthorized/forbidden. Token might be invalid/expired.");

                if (allowTokenRetry && TryReAuthToken())
                    return ResolveCrewbrainEventIdByManualIdInternal(eventIdManual, allowTokenRetry: false);

                return null;
            }

            if (!resp.IsSuccessful)
            {
                var b = resp.Content ?? "";
                if (b.Length > 1200) b = b.Substring(0, 1200) + "...(truncated)";
                Log.Warn($"Resolve event failed: {(int)resp.StatusCode} {resp.StatusCode} Body={b}");
                return null;
            }

            var body = resp.Content ?? "";
            var root = JsonNode.Parse(body) as JsonObject;
            var data = root?["data"] as JsonArray;

            if (data == null || data.Count == 0)
            {
                Log.Warn($"Resolve event: no items for EventIDManual={eventIdManual}");
                return null;
            }

            if (data.Count > 1)
                Log.Warn($"Resolve event: multiple items ({data.Count}) for EventIDManual={eventIdManual}. Using first.");

            var first = data[0] as JsonObject;
            var idNode = first?["ID"];
            if (idNode == null)
            {
                Log.Warn($"Resolve event: 'ID' missing in first item for EventIDManual={eventIdManual}");
                return null;
            }

            return idNode.GetValue<int>();
        }
        catch (Exception ex)
        {
            Log.Error($"ResolveCrewbrainEventIdByManualId failed (EventIDManual={eventIdManual})", ex);
            return null;
        }
    }

    public bool UploadDocumentToEvent(int eventId, int typeId, bool overwriteSingleDocument, string fullPath, string filename, string filetype)
        => UploadDocumentToEventInternal(eventId, typeId, overwriteSingleDocument, fullPath, filename, filetype, allowTokenRetry: true);

    private bool UploadDocumentToEventInternal(int eventId, int typeId, bool overwriteSingleDocument, string fullPath, string filename, string filetype, bool allowTokenRetry)
    {
        try
        {
            filename = (filename ?? "").Trim();
            filetype = (filetype ?? "").Trim().TrimStart('.');

            if (string.IsNullOrWhiteSpace(filename))
                filename = Path.GetFileNameWithoutExtension(fullPath) ?? "";
            if (string.IsNullOrWhiteSpace(filename))
                throw new Exception("UploadDocumentToEvent: filename is empty.");

            if (string.IsNullOrWhiteSpace(filetype))
                filetype = "pdf";

            var bytes = File.ReadAllBytes(fullPath);
            var base64 = Convert.ToBase64String(bytes);

            // API fordert "Filename" mandatory → wir geben hier den kompletten Dateinamen inkl. Extension mit,
            // aber lassen dein "filename" (ohne Ext) drin lesbar.
            var filenameWithExt = filename.EndsWith("." + filetype, StringComparison.OrdinalIgnoreCase)
                ? filename
                : $"{filename}.{filetype}";

            var payload = new
            {
                Base64String = base64,
                Filename = filenameWithExt,
                Filetype = filetype
            };

            var client = new RestClient(new RestClientOptions(_baseUrl) { FollowRedirects = true });

            var req = new RestRequest($"v2/events/{eventId}/additionalDatas/{typeId}/addDocument", Method.Put);
            req.AddHeader("Accept", "application/json");
            req.AddHeader("Content-Type", "application/json");
            req.AddHeader("X-API-KEY", _accessToken);

            if (overwriteSingleDocument)
                req.AddQueryParameter("overwriteSingleDocument", "true");

            var jsonBody = JsonSerializer.Serialize(payload);
            req.AddStringBody(jsonBody, DataFormat.Json);

            // DEBUG Raw Request (ohne Base64)
            var bodyPreview = JsonSerializer.Serialize(new
            {
                Base64String = $"<base64 len={base64.Length} bytes={bytes.Length}>",
                Filename = filenameWithExt,
                Filetype = filetype
            });
            DebugLogRawRequest(client, req, bodyPreview);

            var resp = client.Execute(req);
            Log.Info($"PUT v2/events/{eventId}/additionalDatas/{typeId}/addDocument -> {(int)resp.StatusCode} {resp.StatusCode}");

            if ((int)resp.StatusCode == 401 || (int)resp.StatusCode == 403)
            {
                Log.Error("Upload: unauthorized/forbidden. Token might be invalid/expired.");

                // NOTE: Bei euch kommt 403 auch für Validierungsfehler (z.B. Filename fehlt)
                // Darum: ReAuth nur dann, wenn Response "wirklich" nach Auth aussieht.
                // Wir machen es pragmatisch: wenn allowTokenRetry -> einmal neu Token holen und retry,
                // ABER nur wenn message NICHT nach Feldvalidierung klingt.
                var content = resp.Content ?? "";
                if (allowTokenRetry && LooksLikeAuthFailure(content) && TryReAuthToken())
                    return UploadDocumentToEventInternal(eventId, typeId, overwriteSingleDocument, fullPath, filename, filetype, allowTokenRetry: false);
            }

            if (!resp.IsSuccessful)
            {
                var body = resp.Content ?? "";
                if (body.Length > 2000) body = body.Substring(0, 2000) + "...(truncated)";
                Log.Warn($"Upload failed: {(int)resp.StatusCode} {resp.StatusCode} Body={body}");
                return false;
            }

            return true;
        }
        catch (Exception ex)
        {
            Log.Error($"UploadDocumentToEvent failed (EventID={eventId}, File={fullPath})", ex);
            return false;
        }
    }

    private bool TryReAuthToken()
    {
        try
        {
            // Token leeren, dann per EnsureAccessToken neu holen (Prompt)
            TokenAuthHelper.ClearStoredToken(_appSettingsPath, _rootLog);

            // Config neu laden, damit EnsureAccessToken die aktuelle Datei sieht
            var baseDir = AppContext.BaseDirectory;
            var cfg = new ConfigurationBuilder()
                .SetBasePath(baseDir)
                .AddJsonFile("appsettings.json", optional: false, reloadOnChange: false)
                .Build();

            var apiBase = (cfg["Crewbrain:ApiBase"] ?? "").TrimEnd('/');
            var newToken = TokenAuthHelper.EnsureAccessToken(cfg, _appSettingsPath, _rootLog, apiBase);

            if (string.IsNullOrWhiteSpace(newToken))
                return false;

            _accessToken = newToken.Trim();
            _rootLog.Warn("TokenAuth: Re-auth succeeded, token replaced in memory.");
            return true;
        }
        catch (Exception ex)
        {
            _rootLog.Warn("TokenAuth: Re-auth failed.", ex);
            return false;
        }
    }

    private static bool LooksLikeAuthFailure(string body)
    {
        if (string.IsNullOrWhiteSpace(body)) return true;

        // Wenn es klar nach Validierungsfehler aussieht (Missing mandatory field etc.), NICHT reauthen
        var b = body.ToLowerInvariant();
        if (b.Contains("missing mandatory field")) return false;
        if (b.Contains("\"field\"")) return false;

        // Auth-typische Signale
        if (b.Contains("unauthorized")) return true;
        if (b.Contains("forbidden")) return true;
        if (b.Contains("invalid token")) return true;
        if (b.Contains("not authorized")) return true;

        // default: lieber einmal reauthen als endlos scheitern
        return true;
    }

    private static void DebugLogRawRequest(RestClient client, RestRequest req, string? bodyPreview)
    {
        if (!Log.IsDebugEnabled) return;

        try
        {
            var baseUrl = client.Options.BaseUrl?.ToString() ?? "(null)";
            var resource = req.Resource ?? "";
            var method = req.Method.ToString();

            var fullUrl = CombineUrl(baseUrl, resource);
            var headers = new List<string>();
            var query = new List<string>();

            foreach (var p in req.Parameters)
            {
                if (p.Type == ParameterType.HttpHeader)
                {
                    var val = p.Value?.ToString() ?? "";
                    if (p.Name != null && p.Name.Equals("X-API-KEY", StringComparison.OrdinalIgnoreCase))
                    {
                        val = Mask(val);
                    }
                    headers.Add($"{p.Name}: {val}");
                }
                else if (p.Type == ParameterType.QueryString)
                {
                    query.Add($"{p.Name}={p.Value}");
                }
            }

            Log.Debug("----- RAW REQUEST -----");
            Log.Debug($"{method} {fullUrl}");
            if (query.Count > 0) Log.Debug("Query: " + string.Join("&", query));
            if (headers.Count > 0)
            {
                Log.Debug("Headers:");
                foreach (var h in headers) Log.Debug("  " + h);
            }

            if (!string.IsNullOrWhiteSpace(bodyPreview))
            {
                Log.Debug("Body (preview):");
                Log.Debug(bodyPreview);
            }
            Log.Debug("-----------------------");
        }
        catch (Exception ex)
        {
            Log.Debug("Failed to build raw request debug log.", ex);
        }
    }

    private static string CombineUrl(string baseUrl, string resource)
    {
        baseUrl = (baseUrl ?? "").TrimEnd('/');
        resource = (resource ?? "").TrimStart('/');
        return baseUrl + "/" + resource;
    }

    private static string Mask(string s)
    {
        s = s ?? "";
        if (s.Length <= 6) return new string('*', s.Length);
        return s.Substring(0, 3) + "***" + s.Substring(s.Length - 3) + $" (len={s.Length})";
    }
}