using System.Text;
using System.Text.Json;
using ClawdDotNet.Core.Config;
using ClawdDotNet.Core.Organisation;
using ClawdDotNet.Core.Storage;
using ClawdDotNet.Core.Tools;
using FluentFTP;
using Microsoft.Extensions.Logging;

namespace ClawdDotNet.Tools.FTP;

public sealed class FTPTool : IAgentTool
{
    public string Name => "FTP";

    /// <summary>#715: Brings text from outside into the context — files from outside servers.</summary>
    public bool ReadsForeignContent => true;

    public string Description => """
        Allows file transfer between the local workspace and a remote FTP/FTPS server.

        For localPath, the same workspace prefixes as in the FileRW tool are supported:
        - "personal:website/index.html" → file in the agent's personal workspace
        - "shared:website/index.html" → file in the shared SharedWorkspace
        - "unit:report.pdf" → your unit's workspace; "<workspace id>:file" → a workspace you are a member of
        - Without prefix, the personal workspace is used.
        Uploading from a workspace needs read access to it, downloading into one needs write access.

        Example upload: { "action": "upload", "localPath": "shared:website/index.html", "remotePath": "/index.html" }
        """;

    public JsonElement InputSchema { get; } = JsonDocument.Parse("""
        {
            "type": "object",
            "properties": {
                "action": {
                    "type": "string",
                    "enum": ["upload", "download", "list", "delete"],
                    "description": "The action to perform"
                },
                "localPath": {
                    "type": "string",
                    "description": "Path to local file with optional workspace prefix: 'personal:file.txt' (default), 'shared:file.txt' for the SharedWorkspace, 'unit:file.txt' for your unit's workspace or '<workspace id>:file.txt'. Without prefix, personal workspace is used."
                },
                "remotePath": {
                    "type": "string",
                    "description": "Path on the FTP server"
                }
            },
            "required": ["action"]
        }
        """).RootElement.Clone();

    public async Task<ToolResult> ExecuteAsync(
        JsonElement input,
        AgentToolContext context,
        CancellationToken ct)
    {
        var action = input.GetProperty("action").GetString()
            ?? throw new ArgumentException("'action' is required");

        var config = context.ToolConfig;
        var host = config.TryGetValue("host", out var h) ? h?.ToString() : null;
        var username = config.TryGetValue("username", out var u) ? u?.ToString() : null;
        var password = config.TryGetValue("password", out var p) ? p?.ToString() : null;
        var port = 21;
        if (config.TryGetValue("port", out var po) && po is JsonElement portElement)
            port = portElement.TryGetInt32(out var p32) ? p32 : 21;

        if (string.IsNullOrWhiteSpace(host))
        {
            return ToolResult.Fail("Configuration error: 'host' is required.");
        }

        // SSL/TLS-Modus aus Config lesen (Standard: true)
        var useSsl = true;
        if (config.TryGetValue("useSsl", out var sslVal))
        {
            if (sslVal is JsonElement sslElem) useSsl = sslElem.GetBoolean();
            else if (sslVal is bool sslBool) useSsl = sslBool;
        }

        using var ftpClient = new AsyncFtpClient(host, username, password, port);

        if (useSsl)
        {
            ftpClient.Config.EncryptionMode = FtpEncryptionMode.Explicit;
            ftpClient.Config.ValidateAnyCertificate = true;
        }

        try
        {
            await ftpClient.Connect(ct);

            return action switch
            {
                "upload" => await HandleUploadAsync(ftpClient, input, context, ct),
                "download" => await HandleDownloadAsync(ftpClient, input, context, ct),
                "list" => await HandleListAsync(ftpClient, input, context, ct),
                "delete" => await HandleDeleteAsync(ftpClient, input, context, ct),
                _ => ToolResult.Fail($"Unknown action: {action}")
            };
        }
        catch (Exception ex)
        {
            context.Logger.LogError(ex, "Error during FTP action {Action} on {Host}", action, host);
            return ToolResult.Fail($"Error: {ex.Message}");
        }
        finally
        {
            if (ftpClient.IsConnected) await ftpClient.Disconnect(ct);
        }
    }

    /// <summary>
    /// Löst einen localPath mit optionalem Workspace-Prefix auf.
    /// "shared:website/index.html" → SharedWorkspace + "website/index.html"
    /// "personal:datei.txt" → persönlicher Workspace + "datei.txt"
    /// "datei.txt" → persönlicher Workspace + "datei.txt" (Standard)
    /// </summary>
    /// <param name="write">
    /// #718: The file is written into the workspace (download). A workspace with a member list
    /// then needs Write; reading from it (upload) needs Read.
    /// </param>
    internal static (string fullPath, string workspaceLabel) ResolveLocalPath(string localPath, AgentToolContext context, bool write)
    {
        string basePath;
        var (label, relativePath) = NamedWorkspaces.Split(localPath);

        if (label == WorkspaceLayout.Shared)
        {
            basePath = context.SharedWorkspacePath
                ?? throw new ArgumentException("No SharedWorkspace configured.");
        }
        else if (label == WorkspaceLayout.Personal)
        {
            basePath = context.WorkspacePath
                ?? throw new ArgumentException("No personal workspace configured.");
        }
        else
        {
            // #718: "unit:" or a workspace id. Unknown and not allowed answer the same.
            var named = NamedWorkspaces.Resolve(label, context.AgentId, context.Organisation, context.SharedWorkspacePath);
            if (named is null || named.Access < (write ? WorkspaceAccess.Write : WorkspaceAccess.Read))
                throw new ArgumentException(named is null
                    ? NamedWorkspaces.Unknown(label, context.AgentId, context.Organisation, withShared: true)
                    : $"Access denied: this agent may not {(write ? "write to" : "read from")} workspace '{named.Workspace.Id}'.");
            basePath = named.Root;
            label = named.Workspace.Id;
            if (write)
                Directory.CreateDirectory(basePath);
        }

        // Config-rootPath als Override (nur wenn kein Prefix verwendet)
        if (label == "personal" && !localPath.Contains(':'))
        {
            if (context.ToolConfig.TryGetValue("rootPath", out var rp) && !string.IsNullOrWhiteSpace(rp?.ToString()))
            {
                basePath = rp.ToString()!;
            }
        }

        basePath = Path.GetFullPath(basePath);
        var fullPath = Path.GetFullPath(Path.Combine(basePath, relativePath));

        // Sicherheitsprüfung: Kein Ausbruch aus dem Workspace.
        //
        // PathBoundary statt eines Zeichenketten-Präfixes: Es vergleicht auf
        // Verzeichnisgrenzen (sonst gälte "…/Workspace-Backup" als Teil von
        // "…/Workspace"), berücksichtigt die Groß-/Kleinschreibung des Dateisystems
        // und löst symbolische Verknüpfungen auf.
        if (!PathBoundary.IsInside(fullPath, basePath))
        {
            throw new UnauthorizedAccessException(
                $"Access outside the {label} workspace directory denied.");
        }

        return (fullPath, label);
    }

    private async Task<ToolResult> HandleUploadAsync(IAsyncFtpClient client, JsonElement input, AgentToolContext context, CancellationToken ct)
    {
        var localRel = input.TryGetProperty("localPath", out var lp) ? lp.GetString() : null;
        var remote = input.TryGetProperty("remotePath", out var rp) ? rp.GetString() : null;

        if (string.IsNullOrWhiteSpace(localRel) || string.IsNullOrWhiteSpace(remote))
        {
            return ToolResult.Fail("'localPath' and 'remotePath' are required for upload.");
        }

        try
        {
            var (localFull, wsLabel) = ResolveLocalPath(localRel, context, write: false);

            if (!File.Exists(localFull))
                return ToolResult.Fail($"Local file not found: {localRel} (resolved: {localFull})");

            var status = await client.UploadFile(localFull, remote, FtpRemoteExists.Overwrite, true, FtpVerify.None, null, ct);
            if (status != FtpStatus.Success)
                return ToolResult.Fail($"Upload failed: {status}");

            // Bei HTML/CSS/JS-Uploads: .htaccess für UTF-8 sicherstellen
            var extra = "";
            if (IsWebFile(remote))
            {
                var htaccessDeployed = await EnsureHtaccessAsync(client, remote, context.Logger, ct);
                if (htaccessDeployed)
                    extra = " (.htaccess for UTF-8 encoding was automatically created)";
            }

            return ToolResult.Ok($"[{wsLabel} Workspace] File successfully uploaded: {localRel} → {remote}{extra}");
        }
        catch (ArgumentException ex)
        {
            return ToolResult.Fail(ex.Message);
        }
        catch (UnauthorizedAccessException ex)
        {
            return ToolResult.Fail(ex.Message);
        }
    }

    private static bool IsWebFile(string remotePath)
    {
        var ext = Path.GetExtension(remotePath).ToLowerInvariant();
        return ext is ".html" or ".htm" or ".css" or ".js" or ".json" or ".xml" or ".svg";
    }

    private const string HtaccessCharsetMarker = "# ClawdDotNet-UTF8-Charset";
    private const string HtaccessCharsetBlock = $"""

        {HtaccessCharsetMarker}
        AddDefaultCharset UTF-8
        <IfModule mod_mime.c>
            AddCharset UTF-8 .html .htm .css .js .json .xml .svg .txt
        </IfModule>
        """;

    /// <summary>
    /// Stellt sicher, dass im Zielverzeichnis eine .htaccess mit UTF-8 Charset existiert.
    /// - Existiert keine .htaccess: Neue mit nur den Charset-Regeln erstellen.
    /// - Existiert eine .htaccess: Charset-Block anhängen, falls der Marker noch nicht drin ist.
    ///   Der bestehende Inhalt (z.B. Zugriffsschutz, Rewrite-Regeln) bleibt IMMER unangetastet.
    /// </summary>
    private async Task<bool> EnsureHtaccessAsync(IAsyncFtpClient client, string remotePath, ILogger logger, CancellationToken ct)
    {
        try
        {
            var remoteDir = Path.GetDirectoryName(remotePath)?.Replace('\\', '/') ?? "/";
            if (string.IsNullOrWhiteSpace(remoteDir)) remoteDir = "/";
            var htaccessPath = remoteDir.TrimEnd('/') + "/.htaccess";

            if (await client.FileExists(htaccessPath, ct))
            {
                // .htaccess existiert — lesen und prüfen ob UTF-8-Block schon drin ist
                using var downloadStream = new MemoryStream();
                if (!await client.DownloadStream(downloadStream, htaccessPath, token: ct))
                    return false; // Download fehlgeschlagen → nichts tun

                downloadStream.Position = 0;
                var existingContent = Encoding.UTF8.GetString(downloadStream.ToArray());

                // Wenn unser Marker bereits enthalten ist → nichts tun
                if (existingContent.Contains(HtaccessCharsetMarker, StringComparison.Ordinal))
                    return false;

                // Wenn bereits AddDefaultCharset gesetzt ist → nicht einmischen
                if (existingContent.Contains("AddDefaultCharset", StringComparison.OrdinalIgnoreCase))
                    return false;

                // Charset-Block an bestehenden Inhalt anhängen
                var newContent = existingContent.TrimEnd() + "\n" + HtaccessCharsetBlock;
                var bytes = Encoding.UTF8.GetBytes(newContent);
                using var uploadStream = new MemoryStream(bytes);
                var status = await client.UploadStream(uploadStream, htaccessPath, FtpRemoteExists.Overwrite, true, null, ct);

                if (status == FtpStatus.Success)
                {
                    logger.LogInformation("UTF-8 charset block appended to existing .htaccess: {Path}", htaccessPath);
                    return true;
                }
            }
            else
            {
                // Keine .htaccess vorhanden → neue erstellen (nur Charset-Regeln)
                var content = HtaccessCharsetMarker + "\nAddDefaultCharset UTF-8\n\n<IfModule mod_mime.c>\n    AddCharset UTF-8 .html .htm .css .js .json .xml .svg .txt\n</IfModule>\n";
                var bytes = Encoding.UTF8.GetBytes(content);
                using var stream = new MemoryStream(bytes);
                var status = await client.UploadStream(stream, htaccessPath, FtpRemoteExists.Skip, true, null, ct);

                if (status == FtpStatus.Success)
                {
                    logger.LogInformation("New UTF-8 .htaccess created: {Path}", htaccessPath);
                    return true;
                }
            }
        }
        catch (Exception ex)
        {
            logger.LogWarning(ex, "Could not automatically adjust .htaccess (non-critical)");
        }

        return false;
    }

    private async Task<ToolResult> HandleDownloadAsync(IAsyncFtpClient client, JsonElement input, AgentToolContext context, CancellationToken ct)
    {
        var localRel = input.TryGetProperty("localPath", out var lp) ? lp.GetString() : null;
        var remote = input.TryGetProperty("remotePath", out var rp) ? rp.GetString() : null;

        if (string.IsNullOrWhiteSpace(localRel) || string.IsNullOrWhiteSpace(remote))
        {
            return ToolResult.Fail("'localPath' and 'remotePath' are required for download.");
        }

        try
        {
            var (localFull, wsLabel) = ResolveLocalPath(localRel, context, write: true);

            var localDir = Path.GetDirectoryName(localFull);
            if (localDir != null && !Directory.Exists(localDir)) Directory.CreateDirectory(localDir);

            var status = await client.DownloadFile(localFull, remote, FtpLocalExists.Overwrite, FtpVerify.None, null, ct);
            return status == FtpStatus.Success
                ? ToolResult.Ok($"[{wsLabel} Workspace] File successfully downloaded: {remote} → {localRel}")
                : ToolResult.Fail($"Download failed: {status}");
        }
        catch (ArgumentException ex)
        {
            return ToolResult.Fail(ex.Message);
        }
        catch (UnauthorizedAccessException ex)
        {
            return ToolResult.Fail(ex.Message);
        }
    }

    private async Task<ToolResult> HandleListAsync(IAsyncFtpClient client, JsonElement input, AgentToolContext context, CancellationToken ct)
    {
        var remote = input.TryGetProperty("remotePath", out var rp) ? rp.GetString() : "/";
        var items = await client.GetListing(remote, FtpListOption.Recursive, ct);

        var result = items.Select(i => new
        {
            i.Name,
            i.FullName,
            Type = i.Type.ToString(),
            Size = i.Size,
            Modified = i.Modified
        }).ToList();

        return ToolResult.Ok(JsonSerializer.Serialize(result, new JsonSerializerOptions { WriteIndented = true }));
    }

    private async Task<ToolResult> HandleDeleteAsync(IAsyncFtpClient client, JsonElement input, AgentToolContext context, CancellationToken ct)
    {
        var remote = input.TryGetProperty("remotePath", out var rp) ? rp.GetString() : null;
        if (string.IsNullOrWhiteSpace(remote)) return ToolResult.Fail("'remotePath' is required for delete.");

        await client.DeleteFile(remote, ct);
        return ToolResult.Ok($"File/directory deleted: {remote}");
    }
}