gott/Services/DatabaseService.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using Dapper;
using Gott.Models;
using Microsoft.Data.Sqlite;
using SixLabors.ImageSharp;
using SixLabors.ImageSharp.Formats.Webp;
using SixLabors.ImageSharp.Processing;

namespace Gott.Services;

public class DatabaseService
{
    private readonly string _connectionString;

    public DatabaseService(string dbPath)
    {
        _connectionString = $"Data Source={dbPath}";
        InitializeDatabase();
    }

    private SqliteConnection CreateConnection()
    {
        var conn = new SqliteConnection(_connectionString);
        conn.Open();
        return conn;
    }

    private void InitializeDatabase()
    {
        using var conn = CreateConnection();

        Dapper.DefaultTypeMap.MatchNamesWithUnderscores = true;

        conn.Execute(@"
            CREATE TABLE IF NOT EXISTS sessions (
                id            INTEGER PRIMARY KEY AUTOINCREMENT,
                session_id    TEXT NOT NULL UNIQUE,
                name          TEXT,
                created_at    TEXT NOT NULL,
                updated_at    TEXT NOT NULL
            );

            CREATE TABLE IF NOT EXISTS archives (
                id            INTEGER PRIMARY KEY AUTOINCREMENT,
                archive_id    TEXT NOT NULL UNIQUE,
                session_id    TEXT NOT NULL,
                name          TEXT,
                chain_count   INTEGER NOT NULL DEFAULT 0,
                message_count INTEGER NOT NULL DEFAULT 0,
                created_at    TEXT NOT NULL
            );

            CREATE TABLE IF NOT EXISTS chains (
                id            INTEGER PRIMARY KEY AUTOINCREMENT,
                chain_id      TEXT NOT NULL UNIQUE,
                session_id    TEXT,
                archive_id    TEXT,
                model         TEXT NOT NULL,
                system_prompt TEXT,
                input_tokens  INTEGER NOT NULL DEFAULT 0,
                output_tokens INTEGER NOT NULL DEFAULT 0,
                iterations    INTEGER NOT NULL DEFAULT 0,
                stop_reason   TEXT,
                duration_ms   INTEGER NOT NULL DEFAULT 0,
                created_at    TEXT NOT NULL
            );

            CREATE TABLE IF NOT EXISTS messages (
                id            INTEGER PRIMARY KEY AUTOINCREMENT,
                chain_id      TEXT NOT NULL,
                role          TEXT NOT NULL,
                type          TEXT NOT NULL,
                content       TEXT,
                tool_name     TEXT,
                tool_call_id  TEXT,
                is_error      INTEGER NOT NULL DEFAULT 0,
                iteration     INTEGER NOT NULL DEFAULT 0,
                created_at    TEXT NOT NULL,
                FOREIGN KEY (chain_id) REFERENCES chains(chain_id)
            );

            CREATE TABLE IF NOT EXISTS agents (
                id            INTEGER PRIMARY KEY AUTOINCREMENT,
                agent_id      TEXT NOT NULL UNIQUE,
                name          TEXT NOT NULL,
                avatar        TEXT,
                description   TEXT,
                model         TEXT NOT NULL DEFAULT 'sonnet',
                persona       TEXT,
                instructions  TEXT,
                is_deleted    INTEGER NOT NULL DEFAULT 0,
                created_at    TEXT NOT NULL,
                updated_at    TEXT NOT NULL
            );

            CREATE INDEX IF NOT EXISTS idx_chains_session ON chains(session_id);
            CREATE INDEX IF NOT EXISTS idx_chains_archive ON chains(archive_id);
            CREATE INDEX IF NOT EXISTS idx_messages_chain ON messages(chain_id);
        ");

        conn.Execute(@"
            CREATE TABLE IF NOT EXISTS attachments (
                id            INTEGER PRIMARY KEY AUTOINCREMENT,
                message_id    INTEGER NOT NULL,
                type          TEXT NOT NULL,
                media_type    TEXT NOT NULL,
                file_name     TEXT,
                data          TEXT NOT NULL,
                created_at    TEXT NOT NULL,
                FOREIGN KEY (message_id) REFERENCES messages(id)
            );

            CREATE INDEX IF NOT EXISTS idx_attachments_message ON attachments(message_id);
        ");

        // Migrations
        TryAddColumn(conn, "sessions", "agent_id", "TEXT");
        TryAddColumn(conn, "sessions", "description", "TEXT");
        TryAddColumn(conn, "sessions", "image", "TEXT");
        TryAddColumn(conn, "sessions", "workspace", "TEXT");
        TryAddColumn(conn, "sessions", "context", "TEXT");
        TryAddColumn(conn, "sessions", "is_deleted", "INTEGER NOT NULL DEFAULT 0");
        TryAddColumn(conn, "sessions", "custom_commands", "TEXT");
        TryAddColumn(conn, "chains", "agent_id", "TEXT");
        TryAddColumn(conn, "chains", "cache_creation_tokens", "INTEGER NOT NULL DEFAULT 0");
        TryAddColumn(conn, "chains", "cache_read_tokens", "INTEGER NOT NULL DEFAULT 0");
        TryAddColumn(conn, "chains", "tool_choice", "TEXT");
        TryAddColumn(conn, "chains", "tool_names", "TEXT");
        TryAddColumn(conn, "messages", "attachment_count", "INTEGER NOT NULL DEFAULT 0");
        TryAddColumn(conn, "messages", "attachment_names", "TEXT");
        TryAddColumn(conn, "agents", "tool_choice", "TEXT DEFAULT 'any'");
        TryAddColumn(conn, "agents", "custom_commands", "TEXT");
        TryAddColumn(conn, "messages", "is_marked", "INTEGER NOT NULL DEFAULT 0");
        TryAddColumn(conn, "agents", "auto_commit", "INTEGER NOT NULL DEFAULT 0");

        // Migration: auto_commit von INTEGER (0/1) zu TEXT ("", "mention", "forbid")
        try
        {
            conn.Execute("UPDATE agents SET auto_commit = '' WHERE auto_commit = '0' OR auto_commit = 0");
            conn.Execute("UPDATE agents SET auto_commit = 'enforce' WHERE auto_commit = '1' OR auto_commit = 1");
        }
        catch { /* already migrated */ }
        TryAddColumn(conn, "chains", "stream_error_info", "TEXT");
        TryAddColumn(conn, "agents", "use_soul", "INTEGER NOT NULL DEFAULT 1");
        TryAddColumn(conn, "agents", "use_identity", "INTEGER NOT NULL DEFAULT 1");
        TryAddColumn(conn, "agents", "use_user_info", "INTEGER NOT NULL DEFAULT 1");
        TryAddColumn(conn, "agents", "use_memory", "INTEGER NOT NULL DEFAULT 1");
        TryAddColumn(conn, "agents", "use_auto_context", "INTEGER NOT NULL DEFAULT 1");

        TryAddColumn(conn, "messages", "deleted_on", "TEXT");
        TryAddColumn(conn, "agents", "use_web_search", "INTEGER NOT NULL DEFAULT 0");
        TryAddColumn(conn, "agents", "web_search_version", "TEXT DEFAULT ''");

        // Migration: use_web_search (bool) → web_search_version (text)
        try
        {
            conn.Execute("UPDATE agents SET web_search_version = 'web_search_20260209' WHERE use_web_search = 1 AND (web_search_version IS NULL OR web_search_version = '')");
        }
        catch { /* already migrated */ }

        // User-Zuordnung
        TryAddColumn(conn, "sessions", "user_id", "TEXT");
        TryAddColumn(conn, "sessions", "telegram_bot_token", "TEXT");
        TryAddColumn(conn, "sessions", "telegram_webhook_secret", "TEXT");
        TryAddColumn(conn, "sessions", "telegram_chat_id", "TEXT");
        TryAddColumn(conn, "sessions", "telegram_allowed_chat_ids", "TEXT");
        TryAddColumn(conn, "sessions", "telegram_bot_id", "TEXT");
        TryAddColumn(conn, "agents", "user_id", "TEXT");
        TryAddColumn(conn, "users", "is_admin", "INTEGER NOT NULL DEFAULT 0");
        TryAddColumn(conn, "users", "persona", "TEXT");
        TryAddColumn(conn, "users", "settings", "TEXT");
        TryAddColumn(conn, "users", "default_path", "TEXT");
        TryAddColumn(conn, "sessions", "avatar_scale", "REAL NOT NULL DEFAULT 1.0");
        TryAddColumn(conn, "agents", "avatar_scale", "REAL NOT NULL DEFAULT 1.0");
        TryAddColumn(conn, "cronjobs", "notify_session_id", "TEXT");
        TryAddColumn(conn, "sessions", "review_agent_id", "TEXT");
        TryAddColumn(conn, "sessions", "max_review_iterations", "INTEGER NOT NULL DEFAULT 3");
        TryAddColumn(conn, "sessions", "avatar_offset_x", "REAL NOT NULL DEFAULT 0");
        TryAddColumn(conn, "sessions", "avatar_offset_y", "REAL NOT NULL DEFAULT 0");
        TryAddColumn(conn, "agents", "avatar_offset_x", "REAL NOT NULL DEFAULT 0");
        TryAddColumn(conn, "agents", "avatar_offset_y", "REAL NOT NULL DEFAULT 0");
        TryAddColumn(conn, "sessions", "finalizer_agent_id", "TEXT");
        TryAddColumn(conn, "agents", "allow_user_choice", "INTEGER NOT NULL DEFAULT 1");
        TryAddColumn(conn, "agents", "task_instruction", "TEXT");
        TryAddColumn(conn, "chains", "plan_mode", "INTEGER NOT NULL DEFAULT 0");
        TryAddColumn(conn, "sessions", "preparer_agent_id", "TEXT");
        TryAddColumn(conn, "messages", "tag", "TEXT");

        conn.Execute(@"
            CREATE TABLE IF NOT EXISTS agent_skills (
                id            INTEGER PRIMARY KEY AUTOINCREMENT,
                agent_id      TEXT NOT NULL,
                skill_slug    TEXT NOT NULL,
                created_at    TEXT NOT NULL,
                UNIQUE(agent_id, skill_slug)
            );
            CREATE INDEX IF NOT EXISTS idx_agent_skills_agent ON agent_skills(agent_id);
        ");

        conn.Execute(@"
            CREATE TABLE IF NOT EXISTS users (
                id            INTEGER PRIMARY KEY AUTOINCREMENT,
                user_id       TEXT NOT NULL UNIQUE,
                username      TEXT NOT NULL UNIQUE COLLATE NOCASE,
                password_hash TEXT NOT NULL,
                display_name  TEXT,
                is_admin      INTEGER NOT NULL DEFAULT 0,
                persona       TEXT,
                settings      TEXT,
                default_path  TEXT,
                created_at    TEXT NOT NULL,
                updated_at    TEXT NOT NULL
            );
        ");

        conn.Execute(@"
            CREATE TABLE IF NOT EXISTS telegram_links (
                id               INTEGER PRIMARY KEY AUTOINCREMENT,
                telegram_chat_id INTEGER NOT NULL,
                user_id          TEXT NOT NULL,
                session_id       TEXT NOT NULL,
                agent_id         TEXT,
                link_code        TEXT,
                expires_at       TEXT,
                created_at       TEXT NOT NULL,
                updated_at       TEXT NOT NULL,
                UNIQUE(telegram_chat_id)
            );
            CREATE INDEX IF NOT EXISTS idx_telegram_links_code ON telegram_links(link_code);
        ");

        conn.Execute(@"
            CREATE TABLE IF NOT EXISTS telegram_bots (
                id              INTEGER PRIMARY KEY AUTOINCREMENT,
                bot_id          TEXT NOT NULL UNIQUE,
                user_id         TEXT NOT NULL,
                name            TEXT NOT NULL,
                bot_token       TEXT NOT NULL,
                webhook_secret  TEXT NOT NULL,
                created_at      TEXT NOT NULL,
                updated_at      TEXT NOT NULL
            );
            CREATE INDEX IF NOT EXISTS idx_telegram_bots_user ON telegram_bots(user_id);
        ");

        TryAddColumn(conn, "telegram_bots", "is_public", "INTEGER NOT NULL DEFAULT 0");

        // Migration: Bestehende Session-Telegram-Daten in telegram_bots überführen
        MigrateTelegramBotsFromSessions(conn);

        conn.Execute(@"
            CREATE TABLE IF NOT EXISTS cronjobs (
                id               INTEGER PRIMARY KEY AUTOINCREMENT,
                cronjob_id       TEXT NOT NULL UNIQUE,
                user_id          TEXT NOT NULL,
                session_id       TEXT NOT NULL,
                name             TEXT NOT NULL,
                cron_expression  TEXT NOT NULL,
                prompt           TEXT NOT NULL,
                notify_session_id TEXT,
                is_enabled       INTEGER NOT NULL DEFAULT 1,
                last_run_at      TEXT,
                next_run_at      TEXT,
                last_run_status  TEXT,
                last_run_error   TEXT,
                created_at       TEXT NOT NULL,
                updated_at       TEXT NOT NULL
            );
            CREATE INDEX IF NOT EXISTS idx_cronjobs_user ON cronjobs(user_id);
            CREATE INDEX IF NOT EXISTS idx_cronjobs_next_run ON cronjobs(next_run_at);
        ");

        conn.Execute(@"
            CREATE TABLE IF NOT EXISTS shared_messages (
                id               INTEGER PRIMARY KEY AUTOINCREMENT,
                share_token      TEXT NOT NULL UNIQUE,
                message_id       INTEGER NOT NULL,
                user_id          TEXT NOT NULL,
                include_context  INTEGER NOT NULL DEFAULT 0,
                expires_at       TEXT,
                created_at       TEXT NOT NULL
            );
            CREATE INDEX IF NOT EXISTS idx_shared_messages_token ON shared_messages(share_token);
            CREATE INDEX IF NOT EXISTS idx_shared_messages_message ON shared_messages(message_id);
        ");

        TryAddColumn(conn, "agents", "avatar_small", "TEXT");
        TryAddColumn(conn, "agents", "is_public", "INTEGER NOT NULL DEFAULT 0");
        TryAddColumn(conn, "sessions", "image_small", "TEXT");

        // Migration: Bestehende PNG/JPEG-Avatare/Images zu WebP konvertieren
        MigrateImagesToWebP(conn);

        // Migration: Small-Thumbnails für bestehende Bilder generieren
        MigrateImageThumbnails(conn);
    }

    private void MigrateImagesToWebP(SqliteConnection conn)
    {
        const int webPQuality = 80;

        // Agent Avatare
        var agentImages = conn.Query<(string AgentId, string Avatar)>(
            "SELECT agent_id, avatar FROM agents WHERE avatar IS NOT NULL AND avatar != '' AND avatar NOT LIKE 'data:image/webp%'")
            .ToList();

        foreach (var (agentId, avatar) in agentImages)
        {
            var converted = ConvertDataUrlToWebP(avatar, webPQuality);
            if (converted != null)
                conn.Execute("UPDATE agents SET avatar = @converted WHERE agent_id = @agentId", new { converted, agentId });
        }

        // Session Images
        var sessionImages = conn.Query<(string SessionId, string Image)>(
            "SELECT session_id, image FROM sessions WHERE image IS NOT NULL AND image != '' AND image NOT LIKE 'data:image/webp%'")
            .ToList();

        foreach (var (sessionId, image) in sessionImages)
        {
            var converted = ConvertDataUrlToWebP(image, webPQuality);
            if (converted != null)
                conn.Execute("UPDATE sessions SET image = @converted WHERE session_id = @sessionId", new { converted, sessionId });
        }

        if (agentImages.Count > 0 || sessionImages.Count > 0)
            Console.WriteLine($"[Migration] Converted {agentImages.Count} agent avatars and {sessionImages.Count} session images to WebP");
    }

    private void MigrateImageThumbnails(SqliteConnection conn)
    {
        const int smallSize = 256;
        const int smallQuality = 70;

        // Agent Avatare ohne Thumbnail
        var agentsWithoutThumb = conn.Query<(string AgentId, string Avatar)>(
            "SELECT agent_id, avatar FROM agents WHERE avatar IS NOT NULL AND avatar != '' AND (avatar_small IS NULL OR avatar_small = '')")
            .ToList();

        foreach (var (agentId, avatar) in agentsWithoutThumb)
        {
            var small = ConvertDataUrlToWebP(avatar, smallQuality, maxSide: smallSize);
            if (small != null)
                conn.Execute("UPDATE agents SET avatar_small = @small WHERE agent_id = @agentId", new { small, agentId });
        }

        // Session Images ohne Thumbnail
        var sessionsWithoutThumb = conn.Query<(string SessionId, string Image)>(
            "SELECT session_id, image FROM sessions WHERE image IS NOT NULL AND image != '' AND (image_small IS NULL OR image_small = '')")
            .ToList();

        foreach (var (sessionId, image) in sessionsWithoutThumb)
        {
            var small = ConvertDataUrlToWebP(image, smallQuality, maxSide: smallSize);
            if (small != null)
                conn.Execute("UPDATE sessions SET image_small = @small WHERE session_id = @sessionId", new { small, sessionId });
        }

        if (agentsWithoutThumb.Count > 0 || sessionsWithoutThumb.Count > 0)
            Console.WriteLine($"[Migration] Generated {agentsWithoutThumb.Count} agent thumbnails and {sessionsWithoutThumb.Count} session thumbnails");
    }

    /// <summary>
    /// Konvertiert ein DataUrl-Bild zu WebP. Optional Resize wenn maxSide > 0.
    /// </summary>
    private static string ConvertDataUrlToWebP(string dataUrl, int quality, int maxSide = 0)
    {
        try
        {
            var commaIndex = dataUrl.IndexOf(',');
            if (commaIndex < 0) return null;

            var base64 = dataUrl.Substring(commaIndex + 1);
            var bytes = Convert.FromBase64String(base64);

            using var image = Image.Load(bytes);
            if (maxSide > 0 && (image.Width > maxSide || image.Height > maxSide))
            {
                image.Mutate(x => x.Resize(new ResizeOptions
                {
                    Size = new Size(maxSide, maxSide),
                    Mode = ResizeMode.Max
                }));
            }

            using var ms = new MemoryStream();
            image.Save(ms, new WebpEncoder { Quality = quality });

            return "data:image/webp;base64," + Convert.ToBase64String(ms.ToArray());
        }
        catch
        {
            return null;
        }
    }

    private void TryAddColumn(SqliteConnection conn, string table, string column, string type)
    {
        try { conn.Execute($"ALTER TABLE {table} ADD COLUMN {column} {type}"); }
        catch { /* column already exists */ }
    }

    // ── Shared Messages ──

    public async Task<SharedMessageRecord> CreateSharedMessage(long messageId, string userId, bool includeContext, string expiresAt = null)
    {
        using var conn = CreateConnection();
        var record = new SharedMessageRecord
        {
            ShareToken = Guid.NewGuid().ToString("N"),
            MessageId = messageId,
            UserId = userId,
            IncludeContext = includeContext,
            ExpiresAt = expiresAt,
            CreatedAt = DateTime.UtcNow.ToString("o")
        };
        await conn.ExecuteAsync(@"
            INSERT INTO shared_messages (share_token, message_id, user_id, include_context, expires_at, created_at)
            VALUES (@ShareToken, @MessageId, @UserId, @IncludeContext, @ExpiresAt, @CreatedAt)
        ", record);
        return record;
    }

    public async Task<SharedMessageRecord> GetSharedMessage(string shareToken)
    {
        using var conn = CreateConnection();
        return await conn.QuerySingleOrDefaultAsync<SharedMessageRecord>(
            "SELECT * FROM shared_messages WHERE share_token = @shareToken", new { shareToken });
    }

    public async Task<IEnumerable<SharedMessageRecord>> GetSharedMessagesByUser(string userId)
    {
        using var conn = CreateConnection();
        return await conn.QueryAsync<SharedMessageRecord>(
            "SELECT * FROM shared_messages WHERE user_id = @userId ORDER BY created_at DESC", new { userId });
    }

    public async Task DeleteSharedMessage(string shareToken, string userId)
    {
        using var conn = CreateConnection();
        await conn.ExecuteAsync(
            "DELETE FROM shared_messages WHERE share_token = @shareToken AND user_id = @userId",
            new { shareToken, userId });
    }

    public async Task<MessageRecord> GetMessage(long messageId)
    {
        using var conn = CreateConnection();
        return await conn.QuerySingleOrDefaultAsync<MessageRecord>(
            "SELECT * FROM messages WHERE id = @messageId", new { messageId });
    }

    public async Task<List<MessageRecord>> GetChainMessagesUpTo(string chainId, long messageId)
    {
        using var conn = CreateConnection();
        var result = await conn.QueryAsync<MessageRecord>(
            "SELECT * FROM messages WHERE chain_id = @chainId AND id <= @messageId ORDER BY id ASC",
            new { chainId, messageId });
        return result.AsList();
    }

    // ── Agents ──

    public async Task<AgentRecord> CreateAgent(AgentRecord agent)
    {
        using var conn = CreateConnection();
        var now = DateTime.UtcNow.ToString("o");
        agent.AgentId = Guid.NewGuid().ToString("N");
        agent.CreatedAt = now;
        agent.UpdatedAt = now;
        await conn.ExecuteAsync(@"
            INSERT INTO agents (agent_id, user_id, name, avatar, avatar_small, description, model, tool_choice, custom_commands, auto_commit, use_soul, use_identity, use_user_info, use_memory, use_auto_context, use_web_search, web_search_version, allow_user_choice, task_instruction, avatar_scale, avatar_offset_x, avatar_offset_y, is_deleted, created_at, updated_at)
            VALUES (@AgentId, @UserId, @Name, @Avatar, @AvatarSmall, @Description, @Model, @ToolChoice, @CustomCommands, @AutoCommit, @UseSoul, @UseIdentity, @UseUserInfo, @UseMemory, @UseAutoContext, @UseWebSearch, @WebSearchVersion, @AllowUserChoice, @TaskInstruction, @AvatarScale, @AvatarOffsetX, @AvatarOffsetY, 0, @CreatedAt, @UpdatedAt)
        ", agent);
        return agent;
    }

    public async Task<IEnumerable<AgentRecord>> GetAgents(string userId)
    {
        using var conn = CreateConnection();
        return await conn.QueryAsync<AgentRecord>(
            "SELECT * FROM agents WHERE user_id = @userId AND is_deleted = 0 ORDER BY name", new { userId });
    }

    public async Task<IEnumerable<AgentRecord>> GetAvailableAgents(string userId)
    {
        using var conn = CreateConnection();
        return await conn.QueryAsync<AgentRecord>(
            "SELECT * FROM agents WHERE (user_id = @userId OR is_public = 1) AND is_deleted = 0 ORDER BY name", new { userId });
    }

    public async Task<AgentRecord> GetAgent(string agentId)
    {
        using var conn = CreateConnection();
        return await conn.QuerySingleOrDefaultAsync<AgentRecord>(
            "SELECT * FROM agents WHERE agent_id = @agentId AND is_deleted = 0", new { agentId });
    }

    public async Task UpdateAgent(AgentRecord agent)
    {
        using var conn = CreateConnection();
        agent.UpdatedAt = DateTime.UtcNow.ToString("o");
        await conn.ExecuteAsync(@"
            UPDATE agents SET name = @Name, avatar = @Avatar, avatar_small = @AvatarSmall, description = @Description,
                model = @Model, tool_choice = @ToolChoice,
                custom_commands = @CustomCommands, auto_commit = @AutoCommit,
                use_soul = @UseSoul, use_identity = @UseIdentity, use_user_info = @UseUserInfo, use_memory = @UseMemory, use_auto_context = @UseAutoContext, use_web_search = @UseWebSearch, web_search_version = @WebSearchVersion,
                allow_user_choice = @AllowUserChoice, task_instruction = @TaskInstruction,
                avatar_scale = @AvatarScale, avatar_offset_x = @AvatarOffsetX, avatar_offset_y = @AvatarOffsetY,
                is_public = @IsPublic, updated_at = @UpdatedAt
            WHERE agent_id = @AgentId AND user_id = @UserId
        ", agent);
    }

    public async Task DeleteAgent(string agentId, string userId)
    {
        using var conn = CreateConnection();
        await conn.ExecuteAsync(
            "UPDATE agents SET is_deleted = 1, updated_at = @now WHERE agent_id = @agentId AND user_id = @userId",
            new { agentId, userId, now = DateTime.UtcNow.ToString("o") });
    }

    // ── Sessions ──

    public async Task<SessionRecord> CreateSession(string userId, string name = null, string description = null, string image = null, string imageSmall = null, string agentId = null, string workspace = null, string context = null, string customCommands = null, double avatarScale = 1.0, double avatarOffsetX = 0, double avatarOffsetY = 0, string reviewAgentId = null, int maxReviewIterations = 3, string finalizerAgentId = null, string preparerAgentId = null)
    {
        using var conn = CreateConnection();
        var now = DateTime.UtcNow.ToString("o");
        var session = new SessionRecord
        {
            SessionId = Guid.NewGuid().ToString("N"),
            UserId = userId,
            Name = name,
            Description = description,
            Image = image,
            ImageSmall = imageSmall,
            AgentId = agentId,
            Workspace = workspace,
            Context = context,
            CustomCommands = customCommands,
            AvatarScale = avatarScale,
            AvatarOffsetX = avatarOffsetX,
            AvatarOffsetY = avatarOffsetY,
            ReviewAgentId = reviewAgentId,
            MaxReviewIterations = maxReviewIterations,
            FinalizerAgentId = finalizerAgentId,
            PreparerAgentId = preparerAgentId,
            CreatedAt = now,
            UpdatedAt = now
        };
        await conn.ExecuteAsync(@"
            INSERT INTO sessions (session_id, user_id, name, description, image, image_small, agent_id, workspace, context, custom_commands, avatar_scale, avatar_offset_x, avatar_offset_y, review_agent_id, max_review_iterations, finalizer_agent_id, preparer_agent_id, created_at, updated_at)
            VALUES (@SessionId, @UserId, @Name, @Description, @Image, @ImageSmall, @AgentId, @Workspace, @Context, @CustomCommands, @AvatarScale, @AvatarOffsetX, @AvatarOffsetY, @ReviewAgentId, @MaxReviewIterations, @FinalizerAgentId, @PreparerAgentId, @CreatedAt, @UpdatedAt)
        ", session);
        return session;
    }

    public async Task<List<SessionWithStats>> GetSessionsWithStats(string userId)
    {
        using var conn = CreateConnection();
        var sessions = await conn.QueryAsync<SessionRecord>(
            "SELECT * FROM sessions WHERE user_id = @userId AND is_deleted = 0 ORDER BY updated_at DESC", new { userId });

        var results = new List<SessionWithStats>();
        foreach (var s in sessions)
        {
            var activeCount = await conn.ExecuteScalarAsync<int>(@"
                SELECT COUNT(*) FROM messages m
                JOIN chains c ON m.chain_id = c.chain_id
                WHERE c.session_id = @sessionId AND c.archive_id IS NULL AND m.type = 'text'",
                new { sessionId = s.SessionId });

            var totalCount = await conn.ExecuteScalarAsync<int>(@"
                SELECT COUNT(*) FROM messages m
                JOIN chains c ON m.chain_id = c.chain_id
                WHERE c.session_id = @sessionId AND m.type = 'text'",
                new { sessionId = s.SessionId });

            results.Add(new SessionWithStats
            {
                Session = s,
                MessageCount = activeCount,
                ArchiveMessageCount = totalCount - activeCount,
                TotalMessageCount = totalCount,
                TelegramConfigured = !string.IsNullOrEmpty(s.TelegramBotId),
                TelegramLinked = !string.IsNullOrEmpty(s.TelegramChatId)
            });
        }
        return results;
    }

    public async Task<SessionRecord> GetSession(string sessionId)
    {
        using var conn = CreateConnection();
        return await conn.QuerySingleOrDefaultAsync<SessionRecord>(
            "SELECT * FROM sessions WHERE session_id = @sessionId AND is_deleted = 0", new { sessionId });
    }

    public async Task UpdateSessionTimestamp(string sessionId)
    {
        using var conn = CreateConnection();
        await conn.ExecuteAsync(
            "UPDATE sessions SET updated_at = @now WHERE session_id = @sessionId",
            new { sessionId, now = DateTime.UtcNow.ToString("o") });
    }

    public async Task UpdateSession(string sessionId, System.Text.Json.JsonElement body, ImageService imageService = null)
    {
        using var conn = CreateConnection();
        var sets = new List<string> { "updated_at = @now" };
        var p = new Dapper.DynamicParameters();
        p.Add("sessionId", sessionId);
        p.Add("now", DateTime.UtcNow.ToString("o"));

        if (body.TryGetProperty("name", out var n)) { sets.Add("name = @name"); p.Add("name", n.GetString()); }
        if (body.TryGetProperty("description", out var d)) { sets.Add("description = @desc"); p.Add("desc", d.GetString()); }
        if (body.TryGetProperty("image", out var img))
        {
            var imageData = img.GetString();
            if (imageService != null)
            {
                sets.Add("image_small = @imageSmall");
                p.Add("imageSmall", imageService.ResizeDataUrlSmall(imageData));
                imageData = imageService.ResizeDataUrl(imageData);
            }
            sets.Add("image = @image");
            p.Add("image", imageData);
        }
        if (body.TryGetProperty("agentId", out var a)) { sets.Add("agent_id = @agentId2"); p.Add("agentId2", a.GetString()); }
        if (body.TryGetProperty("workspace", out var w)) { sets.Add("workspace = @workspace"); p.Add("workspace", w.GetString()); }
        if (body.TryGetProperty("context", out var ctx)) { sets.Add("context = @context"); p.Add("context", ctx.GetString()); }
        if (body.TryGetProperty("customCommands", out var cc)) { sets.Add("custom_commands = @customCommands"); p.Add("customCommands", cc.ValueKind == System.Text.Json.JsonValueKind.Null ? null : cc.GetRawText()); }
        if (body.TryGetProperty("avatarScale", out var asc)) { sets.Add("avatar_scale = @avatarScale"); p.Add("avatarScale", asc.GetDouble()); }
        if (body.TryGetProperty("avatarOffsetX", out var aox)) { sets.Add("avatar_offset_x = @avatarOffsetX"); p.Add("avatarOffsetX", aox.GetDouble()); }
        if (body.TryGetProperty("avatarOffsetY", out var aoy)) { sets.Add("avatar_offset_y = @avatarOffsetY"); p.Add("avatarOffsetY", aoy.GetDouble()); }
        if (body.TryGetProperty("reviewAgentId", out var ra)) { sets.Add("review_agent_id = @reviewAgentId"); p.Add("reviewAgentId", ra.ValueKind == System.Text.Json.JsonValueKind.Null ? null : ra.GetString()); }
        if (body.TryGetProperty("maxReviewIterations", out var mri)) { sets.Add("max_review_iterations = @maxReviewIterations"); p.Add("maxReviewIterations", mri.GetInt32()); }
        if (body.TryGetProperty("finalizerAgentId", out var fa)) { sets.Add("finalizer_agent_id = @finalizerAgentId"); p.Add("finalizerAgentId", fa.ValueKind == System.Text.Json.JsonValueKind.Null ? null : fa.GetString()); }
        if (body.TryGetProperty("preparerAgentId", out var pa)) { sets.Add("preparer_agent_id = @preparerAgentId"); p.Add("preparerAgentId", pa.ValueKind == System.Text.Json.JsonValueKind.Null ? null : pa.GetString()); }

        await conn.ExecuteAsync($"UPDATE sessions SET {string.Join(", ", sets)} WHERE session_id = @sessionId", p);
    }

    public async Task DeleteSession(string sessionId, string userId)
    {
        using var conn = CreateConnection();
        await conn.ExecuteAsync(
            "UPDATE sessions SET is_deleted = 1, updated_at = @now WHERE session_id = @sessionId AND user_id = @userId",
            new { sessionId, userId, now = DateTime.UtcNow.ToString("o") });
    }

    // ── Archives ──

    public async Task<ArchiveRecord> CreateArchive(string sessionId, string name = null)
    {
        using var conn = CreateConnection();

        var chainCount = await conn.ExecuteScalarAsync<int>(
            "SELECT COUNT(*) FROM chains WHERE archive_id IS NULL AND session_id = @sessionId",
            new { sessionId });
        if (chainCount == 0) return null;

        var messageCount = await conn.ExecuteScalarAsync<int>(@"
            SELECT COUNT(*) FROM messages
            WHERE type = 'text' AND chain_id IN (SELECT chain_id FROM chains WHERE archive_id IS NULL AND session_id = @sessionId)",
            new { sessionId });

        var archive = new ArchiveRecord
        {
            ArchiveId = Guid.NewGuid().ToString("N"),
            SessionId = sessionId,
            Name = name,
            ChainCount = chainCount,
            MessageCount = messageCount,
            CreatedAt = DateTime.UtcNow.ToString("o")
        };

        await conn.ExecuteAsync(@"
            INSERT INTO archives (archive_id, session_id, name, chain_count, message_count, created_at)
            VALUES (@ArchiveId, @SessionId, @Name, @ChainCount, @MessageCount, @CreatedAt)
        ", archive);

        await conn.ExecuteAsync(
            "UPDATE chains SET archive_id = @archiveId WHERE archive_id IS NULL AND session_id = @sessionId",
            new { archiveId = archive.ArchiveId, sessionId });

        return archive;
    }

    public async Task<IEnumerable<ArchiveRecord>> GetArchives(string sessionId)
    {
        using var conn = CreateConnection();
        return await conn.QueryAsync<ArchiveRecord>(
            "SELECT * FROM archives WHERE session_id = @sessionId ORDER BY id DESC",
            new { sessionId });
    }

    public async Task<IEnumerable<ChainRecord>> GetArchiveChains(string archiveId)
    {
        using var conn = CreateConnection();
        return await conn.QueryAsync<ChainRecord>(
            "SELECT * FROM chains WHERE archive_id = @archiveId ORDER BY id",
            new { archiveId });
    }

    // ── Chains ──

    public async Task CreateChain(ChainRecord chain)
    {
        using var conn = CreateConnection();
        chain.CreatedAt = DateTime.UtcNow.ToString("o");
        await conn.ExecuteAsync(@"
            INSERT INTO chains (chain_id, session_id, archive_id, agent_id, model, system_prompt, tool_choice, tool_names, input_tokens, output_tokens, iterations, stop_reason, duration_ms, plan_mode, created_at)
            VALUES (@ChainId, @SessionId, @ArchiveId, @AgentId, @Model, @SystemPrompt, @ToolChoice, @ToolNames, @InputTokens, @OutputTokens, @Iterations, @StopReason, @DurationMs, @PlanMode, @CreatedAt)
        ", chain);
    }

    public async Task UpdateChain(ChainRecord chain)
    {
        using var conn = CreateConnection();
        await conn.ExecuteAsync(@"
            UPDATE chains SET
                input_tokens = @InputTokens,
                output_tokens = @OutputTokens,
                cache_creation_tokens = @CacheCreationTokens,
                cache_read_tokens = @CacheReadTokens,
                iterations = @Iterations,
                stop_reason = @StopReason,
                stream_error_info = @StreamErrorInfo,
                duration_ms = @DurationMs
            WHERE chain_id = @ChainId
        ", chain);
    }

    public async Task<ChainRecord> GetChain(string chainId)
    {
        using var conn = CreateConnection();
        return await conn.QuerySingleOrDefaultAsync<ChainRecord>(
            "SELECT * FROM chains WHERE chain_id = @chainId", new { chainId }
        );
    }

    public async Task<IEnumerable<ChainRecord>> GetActiveChains(string sessionId)
    {
        using var conn = CreateConnection();
        return await conn.QueryAsync<ChainRecord>(
            "SELECT * FROM chains WHERE session_id = @sessionId AND archive_id IS NULL ORDER BY id DESC",
            new { sessionId });
    }

    // ── Messages ──

    public async Task<long> SaveMessage(MessageRecord record)
    {
        using var conn = CreateConnection();
        record.CreatedAt = DateTime.UtcNow.ToString("o");
        return await conn.ExecuteScalarAsync<long>(@"
            INSERT INTO messages (chain_id, role, type, content, tool_name, tool_call_id, is_error, iteration, attachment_count, tag, created_at)
            VALUES (@ChainId, @Role, @Type, @Content, @ToolName, @ToolCallId, @IsError, @Iteration, @AttachmentCount, @Tag, @CreatedAt);
            SELECT last_insert_rowid();
        ", record);
    }

    /// <summary>
    /// Speichert Message + Attachments in einer Transaktion (1x fsync statt N+1).
    /// </summary>
    public async Task<long> SaveMessageWithAttachments(MessageRecord record, List<AttachmentRecord> attachments)
    {
        using var conn = CreateConnection();
        using var tx = conn.BeginTransaction();

        record.CreatedAt = DateTime.UtcNow.ToString("o");
        record.AttachmentCount = attachments?.Count ?? 0;
        if (attachments != null && attachments.Count > 0)
        {
            var names = attachments.Select(a => a.FileName ?? "").ToArray();
            record.AttachmentNames = System.Text.Json.JsonSerializer.Serialize(names);
        }
        var messageId = await conn.ExecuteScalarAsync<long>(@"
            INSERT INTO messages (chain_id, role, type, content, tool_name, tool_call_id, is_error, iteration, attachment_count, attachment_names, tag, created_at)
            VALUES (@ChainId, @Role, @Type, @Content, @ToolName, @ToolCallId, @IsError, @Iteration, @AttachmentCount, @AttachmentNames, @Tag, @CreatedAt);
            SELECT last_insert_rowid();
        ", record, tx);

        if (attachments != null)
        {
            var now = DateTime.UtcNow.ToString("o");
            foreach (var att in attachments)
            {
                att.MessageId = messageId;
                att.CreatedAt = now;
                await conn.ExecuteAsync(@"
                    INSERT INTO attachments (message_id, type, media_type, file_name, data, created_at)
                    VALUES (@MessageId, @Type, @MediaType, @FileName, @Data, @CreatedAt)
                ", att, tx);
            }
        }

        tx.Commit();
        return messageId;
    }

    // ── OpenClaw Import ──

    public async Task CreateChainForImport(string chainId, string sessionId, string agentId, string model, int inputTokens, int outputTokens, int cacheCreationTokens, int cacheReadTokens, string createdAt)
    {
        using var conn = CreateConnection();
        await conn.ExecuteAsync(@"
            INSERT INTO chains (chain_id, session_id, agent_id, model, input_tokens, output_tokens, cache_creation_tokens, cache_read_tokens, iterations, stop_reason, duration_ms, plan_mode, created_at)
            VALUES (@chainId, @sessionId, @agentId, @model, @inputTokens, @outputTokens, @cacheCreationTokens, @cacheReadTokens, 0, 'end_turn', 0, 0, @createdAt)
        ", new { chainId, sessionId, agentId, model, inputTokens, outputTokens, cacheCreationTokens, cacheReadTokens, createdAt });
    }

    public async Task CreateMessageForImport(string chainId, string role, string type, string content, string createdAt, string tag)
    {
        using var conn = CreateConnection();
        await conn.ExecuteAsync(@"
            INSERT INTO messages (chain_id, role, type, content, is_error, iteration, attachment_count, tag, created_at)
            VALUES (@chainId, @role, @type, @content, 0, 0, 0, @tag, @createdAt)
        ", new { chainId, role, type, content, tag, createdAt });
    }

    public async Task DeleteOpenClawImport(string sessionId)
    {
        using var conn = CreateConnection();
        using var tx = conn.BeginTransaction();

        // Get all chain_ids that belong to this session and have imported messages
        var importedChainIds = (await conn.QueryAsync<string>(@"
            SELECT DISTINCT c.chain_id
            FROM chains c
            INNER JOIN messages m ON m.chain_id = c.chain_id
            WHERE c.session_id = @sessionId AND m.tag = 'openclaw-import'
        ", new { sessionId }, tx)).ToList();

        if (importedChainIds.Count > 0)
        {
            // Delete messages for these chains
            await conn.ExecuteAsync(
                "DELETE FROM messages WHERE chain_id IN @chainIds",
                new { chainIds = importedChainIds }, tx);

            // Delete the chains themselves
            await conn.ExecuteAsync(
                "DELETE FROM chains WHERE chain_id IN @chainIds",
                new { chainIds = importedChainIds }, tx);
        }

        tx.Commit();
    }

    // ── Attachments ──

    public async Task<IEnumerable<AttachmentRecord>> GetAttachments(long messageId)
    {
        using var conn = CreateConnection();
        return await conn.QueryAsync<AttachmentRecord>(
            "SELECT * FROM attachments WHERE message_id = @messageId ORDER BY id",
            new { messageId });
    }

    public async Task<IEnumerable<AttachmentRecord>> GetAttachmentsForMessages(IEnumerable<long> messageIds)
    {
        using var conn = CreateConnection();
        return await conn.QueryAsync<AttachmentRecord>(
            "SELECT * FROM attachments WHERE message_id IN @messageIds ORDER BY id",
            new { messageIds });
    }

    public async Task<IEnumerable<MessageRecord>> GetChainMessages(string chainId, bool includeDeleted = false)
    {
        using var conn = CreateConnection();
        var deletedFilter = includeDeleted ? "" : " AND deleted_on IS NULL";
        return await conn.QueryAsync<MessageRecord>(
            $"SELECT * FROM messages WHERE chain_id = @chainId{deletedFilter} ORDER BY id", new { chainId }
        );
    }

    public async Task<int> GetActiveMessageCount(string sessionId, bool includeDeleted = false)
    {
        using var conn = CreateConnection();
        var deletedFilter = includeDeleted ? "" : "AND m.deleted_on IS NULL";
        return await conn.ExecuteScalarAsync<int>($@"
            SELECT COUNT(*) FROM messages m
            JOIN chains c ON m.chain_id = c.chain_id
            WHERE c.archive_id IS NULL AND c.session_id = @sessionId AND m.type = 'text' {deletedFilter}",
            new { sessionId });
    }

    public async Task<List<MessageRecord>> GetLatestActiveMessages(string sessionId, int limit, bool includeDeleted = false)
    {
        using var conn = CreateConnection();
        var deletedFilter = includeDeleted ? "" : "AND m.deleted_on IS NULL";
        var messages = await conn.QueryAsync<MessageRecord>($@"
            SELECT m.*, (CASE WHEN m.tag = 'openclaw-import' THEN m.id - 10000000000 ELSE m.id END) AS sort_key FROM messages m
            JOIN chains c ON m.chain_id = c.chain_id
            WHERE c.archive_id IS NULL AND c.session_id = @sessionId {deletedFilter}
            ORDER BY sort_key DESC LIMIT @limit",
            new { sessionId, limit });
        return messages.Reverse().ToList();
    }

    public async Task<int> GetActiveMessageCountBeforeSortKey(string sessionId, long beforeSortKey, bool includeDeleted = false)
    {
        using var conn = CreateConnection();
        var deletedFilter = includeDeleted ? "" : "AND m.deleted_on IS NULL";
        return await conn.ExecuteScalarAsync<int>($@"
            SELECT COUNT(*) FROM messages m
            JOIN chains c ON m.chain_id = c.chain_id
            WHERE (CASE WHEN m.tag = 'openclaw-import' THEN m.id - 10000000000 ELSE m.id END) < @beforeSortKey AND c.archive_id IS NULL AND c.session_id = @sessionId AND m.type = 'text' {deletedFilter}",
            new { sessionId, beforeSortKey });
    }

    public async Task<List<MessageRecord>> GetActiveMessagesBeforeSortKey(string sessionId, long beforeSortKey, int limit, bool includeDeleted = false)
    {
        using var conn = CreateConnection();
        var deletedFilter = includeDeleted ? "" : "AND m.deleted_on IS NULL";
        var messages = await conn.QueryAsync<MessageRecord>($@"
            SELECT m.*, (CASE WHEN m.tag = 'openclaw-import' THEN m.id - 10000000000 ELSE m.id END) AS sort_key FROM messages m
            JOIN chains c ON m.chain_id = c.chain_id
            WHERE (CASE WHEN m.tag = 'openclaw-import' THEN m.id - 10000000000 ELSE m.id END) < @beforeSortKey AND c.archive_id IS NULL AND c.session_id = @sessionId {deletedFilter}
            ORDER BY sort_key DESC LIMIT @limit",
            new { sessionId, beforeSortKey, limit });
        return messages.Reverse().ToList();
    }

    public async Task<IEnumerable<MessageRecord>> GetActiveMessagesAfterSortKey(string sessionId, long afterSortKey, int limit = 200, bool includeDeleted = false)
    {
        using var conn = CreateConnection();
        var deletedFilter = includeDeleted ? "" : "AND m.deleted_on IS NULL";
        return await conn.QueryAsync<MessageRecord>($@"
            SELECT m.*, (CASE WHEN m.tag = 'openclaw-import' THEN m.id - 10000000000 ELSE m.id END) AS sort_key FROM messages m
            JOIN chains c ON m.chain_id = c.chain_id
            WHERE (CASE WHEN m.tag = 'openclaw-import' THEN m.id - 10000000000 ELSE m.id END) > @afterSortKey AND c.archive_id IS NULL AND c.session_id = @sessionId {deletedFilter}
            ORDER BY sort_key LIMIT @limit",
            new { sessionId, afterSortKey, limit });
    }

    // ── Message Marking ──

    public async Task<bool> ToggleMessageMark(long messageId)
    {
        using var conn = CreateConnection();
        await conn.ExecuteAsync(
            "UPDATE messages SET is_marked = CASE WHEN is_marked = 1 THEN 0 ELSE 1 END WHERE id = @messageId",
            new { messageId });
        return await conn.ExecuteScalarAsync<bool>(
            "SELECT is_marked FROM messages WHERE id = @messageId",
            new { messageId });
    }

    // ── Message Deletion ──

    public async Task<string> ToggleMessageDelete(long messageId)
    {
        using var conn = CreateConnection();
        var current = await conn.ExecuteScalarAsync<string>(
            "SELECT deleted_on FROM messages WHERE id = @messageId", new { messageId });
        string newValue;
        if (current == null)
        {
            newValue = DateTime.UtcNow.ToString("o");
            await conn.ExecuteAsync(
                "UPDATE messages SET deleted_on = @newValue WHERE id = @messageId",
                new { messageId, newValue });
        }
        else
        {
            newValue = null;
            await conn.ExecuteAsync(
                "UPDATE messages SET deleted_on = NULL WHERE id = @messageId",
                new { messageId });
        }
        return newValue;
    }

    public async Task<IEnumerable<MessageRecord>> GetMarkedMessages(string sessionId)
    {
        using var conn = CreateConnection();
        return await conn.QueryAsync<MessageRecord>(@"
            SELECT m.* FROM messages m
            JOIN chains c ON m.chain_id = c.chain_id
            WHERE c.session_id = @sessionId AND m.is_marked = 1
            ORDER BY m.id",
            new { sessionId });
    }

    // ── Agent Skills ──

    public async Task<IEnumerable<string>> GetAgentSkills(string agentId)
    {
        using var conn = CreateConnection();
        return await conn.QueryAsync<string>(
            "SELECT skill_slug FROM agent_skills WHERE agent_id = @agentId ORDER BY skill_slug",
            new { agentId });
    }

    public async Task SetAgentSkills(string agentId, IEnumerable<string> skillSlugs)
    {
        using var conn = CreateConnection();
        using var tx = conn.BeginTransaction();

        await conn.ExecuteAsync("DELETE FROM agent_skills WHERE agent_id = @agentId", new { agentId }, tx);

        var now = DateTime.UtcNow.ToString("o");
        foreach (var slug in skillSlugs)
        {
            await conn.ExecuteAsync(@"
                INSERT INTO agent_skills (agent_id, skill_slug, created_at)
                VALUES (@agentId, @slug, @now)",
                new { agentId, slug, now }, tx);
        }

        tx.Commit();
    }

    public async Task AddAgentSkill(string agentId, string skillSlug)
    {
        using var conn = CreateConnection();
        var now = DateTime.UtcNow.ToString("o");
        await conn.ExecuteAsync(@"
            INSERT OR IGNORE INTO agent_skills (agent_id, skill_slug, created_at)
            VALUES (@agentId, @skillSlug, @now)",
            new { agentId, skillSlug, now });
    }

    public async Task RemoveAgentSkill(string agentId, string skillSlug)
    {
        using var conn = CreateConnection();
        await conn.ExecuteAsync(
            "DELETE FROM agent_skills WHERE agent_id = @agentId AND skill_slug = @skillSlug",
            new { agentId, skillSlug });
    }

    // ── Users ──

    public void EnsureDefaultUser(AuthService auth)
    {
        using var conn = CreateConnection();
        var count = conn.ExecuteScalar<int>("SELECT COUNT(*) FROM users");
        string adminUserId;
        if (count == 0)
        {
            adminUserId = Guid.NewGuid().ToString("N");
            var now = DateTime.UtcNow.ToString("o");
            conn.Execute(@"
                INSERT INTO users (user_id, username, password_hash, display_name, is_admin, created_at, updated_at)
                VALUES (@userId, @username, @hash, @displayName, 1, @now, @now)",
                new
                {
                    userId = adminUserId,
                    username = "admin",
                    hash = auth.HashPassword("admin"),
                    displayName = "Admin",
                    now
                });
        }
        else
        {
            adminUserId = conn.ExecuteScalar<string>("SELECT user_id FROM users ORDER BY id LIMIT 1");
        }

        // Bestehende Sessions/Agents ohne User dem ersten User zuweisen
        conn.Execute("UPDATE sessions SET user_id = @userId WHERE user_id IS NULL", new { userId = adminUserId });
        conn.Execute("UPDATE agents SET user_id = @userId WHERE user_id IS NULL", new { userId = adminUserId });

        // Erster User ist immer Admin
        conn.Execute("UPDATE users SET is_admin = 1 WHERE user_id = @userId AND is_admin = 0", new { userId = adminUserId });
    }

    public async Task<UserRecord> GetUserByUsername(string username)
    {
        using var conn = CreateConnection();
        return await conn.QuerySingleOrDefaultAsync<UserRecord>(
            "SELECT * FROM users WHERE username = @username COLLATE NOCASE",
            new { username });
    }

    public async Task<UserRecord> GetUser(string userId)
    {
        using var conn = CreateConnection();
        return await conn.QuerySingleOrDefaultAsync<UserRecord>(
            "SELECT * FROM users WHERE user_id = @userId",
            new { userId });
    }

    public async Task<IEnumerable<UserRecord>> GetUsers()
    {
        using var conn = CreateConnection();
        return await conn.QueryAsync<UserRecord>(
            "SELECT * FROM users ORDER BY username");
    }

    public async Task UpdateUserPassword(string userId, string passwordHash)
    {
        using var conn = CreateConnection();
        await conn.ExecuteAsync(
            "UPDATE users SET password_hash = @passwordHash, updated_at = @now WHERE user_id = @userId",
            new { userId, passwordHash, now = DateTime.UtcNow.ToString("o") });
    }

    public async Task UpdateUserProfile(string userId, string displayName, string persona)
    {
        using var conn = CreateConnection();
        await conn.ExecuteAsync(
            "UPDATE users SET display_name = @displayName, persona = @persona, updated_at = @now WHERE user_id = @userId",
            new { userId, displayName, persona, now = DateTime.UtcNow.ToString("o") });
    }

    public async Task<string> GetUserSettings(string userId)
    {
        using var conn = CreateConnection();
        return await conn.QuerySingleOrDefaultAsync<string>(
            "SELECT settings FROM users WHERE user_id = @userId",
            new { userId });
    }

    public async Task UpdateUserSettings(string userId, string settings)
    {
        using var conn = CreateConnection();
        await conn.ExecuteAsync(
            "UPDATE users SET settings = @settings, updated_at = @now WHERE user_id = @userId",
            new { userId, settings, now = DateTime.UtcNow.ToString("o") });
    }

    public async Task<UserRecord> CreateUser(string username, string passwordHash, string displayName, bool isAdmin, string defaultPath = null)
    {
        using var conn = CreateConnection();
        var now = DateTime.UtcNow.ToString("o");
        var userId = Guid.NewGuid().ToString("N");
        await conn.ExecuteAsync(@"
            INSERT INTO users (user_id, username, password_hash, display_name, is_admin, default_path, created_at, updated_at)
            VALUES (@userId, @username, @passwordHash, @displayName, @isAdmin, @defaultPath, @now, @now)",
            new { userId, username, passwordHash, displayName, isAdmin, defaultPath, now });
        return await GetUser(userId);
    }

    public async Task UpdateUserAdmin(string userId, string username, string displayName, bool isAdmin, string defaultPath)
    {
        using var conn = CreateConnection();
        await conn.ExecuteAsync(
            "UPDATE users SET username = @username, display_name = @displayName, is_admin = @isAdmin, default_path = @defaultPath, updated_at = @now WHERE user_id = @userId",
            new { userId, username, displayName, isAdmin, defaultPath, now = DateTime.UtcNow.ToString("o") });
    }

    public async Task DeleteUser(string userId)
    {
        using var conn = CreateConnection();
        await conn.ExecuteAsync("DELETE FROM tokens WHERE user_id = @userId", new { userId });
        await conn.ExecuteAsync("DELETE FROM shared_messages WHERE user_id = @userId", new { userId });
        await conn.ExecuteAsync("DELETE FROM users WHERE user_id = @userId", new { userId });
    }

    // ── Telegram Bots ──

    private void MigrateTelegramBotsFromSessions(SqliteConnection conn)
    {
        // Prüfe ob es Sessions mit bot_token gibt, die noch kein telegram_bot_id haben
        var sessions = conn.Query<dynamic>(
            "SELECT session_id, user_id, name, telegram_bot_token, telegram_webhook_secret FROM sessions WHERE telegram_bot_token IS NOT NULL AND telegram_bot_token != '' AND (telegram_bot_id IS NULL OR telegram_bot_id = '')").ToList();

        if (sessions.Count == 0) return;

        var now = DateTime.UtcNow.ToString("o");
        foreach (var s in sessions)
        {
            string token = s.telegram_bot_token;
            string userId = s.user_id ?? "";
            string sessionName = s.name ?? "Unbenannt";
            string secret = s.telegram_webhook_secret ?? Guid.NewGuid().ToString("N");

            // Prüfe ob für diesen Token bereits ein Bot existiert
            var existing = conn.QuerySingleOrDefault<dynamic>(
                "SELECT bot_id FROM telegram_bots WHERE bot_token = @token", new { token });

            string botId;
            if (existing != null)
            {
                botId = existing.bot_id;
            }
            else
            {
                botId = Guid.NewGuid().ToString();
                conn.Execute(@"
                    INSERT INTO telegram_bots (bot_id, user_id, name, bot_token, webhook_secret, created_at, updated_at)
                    VALUES (@botId, @userId, @name, @token, @secret, @now, @now)",
                    new { botId, userId, name = $"Bot von {sessionName}", token, secret, now });
            }

            conn.Execute(
                "UPDATE sessions SET telegram_bot_id = @botId, updated_at = @now WHERE session_id = @sessionId",
                new { botId, sessionId = (string)s.session_id, now });
        }
    }

    public async Task<IEnumerable<TelegramBotRecord>> GetTelegramBots(string userId)
    {
        using var conn = CreateConnection();
        return await conn.QueryAsync<TelegramBotRecord>(
            "SELECT * FROM telegram_bots WHERE user_id = @userId ORDER BY created_at DESC",
            new { userId });
    }

    public async Task<IEnumerable<TelegramBotRecord>> GetAvailableTelegramBots(string userId)
    {
        using var conn = CreateConnection();
        return await conn.QueryAsync<TelegramBotRecord>(
            "SELECT * FROM telegram_bots WHERE user_id = @userId OR is_public = 1 ORDER BY created_at DESC",
            new { userId });
    }

    public async Task<TelegramBotRecord> GetTelegramBot(string botId)
    {
        using var conn = CreateConnection();
        return await conn.QuerySingleOrDefaultAsync<TelegramBotRecord>(
            "SELECT * FROM telegram_bots WHERE bot_id = @botId",
            new { botId });
    }

    public async Task<TelegramBotRecord> CreateTelegramBot(string userId, string name, string botToken)
    {
        using var conn = CreateConnection();
        var botId = Guid.NewGuid().ToString();
        var secret = Guid.NewGuid().ToString("N");
        var now = DateTime.UtcNow.ToString("o");
        await conn.ExecuteAsync(@"
            INSERT INTO telegram_bots (bot_id, user_id, name, bot_token, webhook_secret, created_at, updated_at)
            VALUES (@botId, @userId, @name, @botToken, @secret, @now, @now)",
            new { botId, userId, name, botToken, secret, now });
        return await GetTelegramBot(botId);
    }

    public async Task UpdateTelegramBot(string botId, string name, string botToken, bool isPublic)
    {
        using var conn = CreateConnection();
        var now = DateTime.UtcNow.ToString("o");
        await conn.ExecuteAsync(@"
            UPDATE telegram_bots SET name = @name, bot_token = @botToken, is_public = @isPublic, updated_at = @now
            WHERE bot_id = @botId",
            new { botId, name, botToken, isPublic, now });
    }

    public async Task DeleteTelegramBot(string botId)
    {
        using var conn = CreateConnection();
        var now = DateTime.UtcNow.ToString("o");
        // Erst alle Session-Verknüpfungen entfernen
        await conn.ExecuteAsync(
            "UPDATE sessions SET telegram_bot_id = NULL, updated_at = @now WHERE telegram_bot_id = @botId",
            new { botId, now });
        await conn.ExecuteAsync("DELETE FROM telegram_bots WHERE bot_id = @botId", new { botId });
    }

    public async Task<int> GetTelegramBotSessionCount(string botId)
    {
        using var conn = CreateConnection();
        return await conn.ExecuteScalarAsync<int>(
            "SELECT COUNT(*) FROM sessions WHERE telegram_bot_id = @botId AND is_deleted = 0",
            new { botId });
    }

    public async Task SetSessionTelegramBot(string sessionId, string botId)
    {
        using var conn = CreateConnection();
        var now = DateTime.UtcNow.ToString("o");
        await conn.ExecuteAsync(
            "UPDATE sessions SET telegram_bot_id = @botId, updated_at = @now WHERE session_id = @sessionId",
            new { sessionId, botId = (object)botId ?? DBNull.Value, now });
    }

    public async Task UpdateSessionTelegramChat(string sessionId, string chatId)
    {
        using var conn = CreateConnection();
        var now = DateTime.UtcNow.ToString("o");
        await conn.ExecuteAsync(@"
            UPDATE sessions SET telegram_chat_id = @chatId, updated_at = @now
            WHERE session_id = @sessionId",
            new { sessionId, chatId, now });
    }

    public async Task<IEnumerable<SessionRecord>> GetSessionsByTelegramBot(string botId)
    {
        using var conn = CreateConnection();
        return await conn.QueryAsync<SessionRecord>(
            "SELECT * FROM sessions WHERE telegram_bot_id = @botId AND is_deleted = 0",
            new { botId });
    }

    public async Task<SessionRecord> FindSessionForTelegramChat(string botId, long chatId)
    {
        using var conn = CreateConnection();
        var chatIdStr = chatId.ToString();
        return await conn.QuerySingleOrDefaultAsync<SessionRecord>(
            "SELECT * FROM sessions WHERE telegram_bot_id = @botId AND telegram_chat_id = @chatIdStr AND is_deleted = 0",
            new { botId, chatIdStr });
    }

    public async Task<IEnumerable<SessionRecord>> FindUnlinkedSessionsForBot(string botId)
    {
        using var conn = CreateConnection();
        return await conn.QueryAsync<SessionRecord>(
            "SELECT * FROM sessions WHERE telegram_bot_id = @botId AND (telegram_chat_id IS NULL OR telegram_chat_id = '') AND is_deleted = 0",
            new { botId });
    }

    // ── Cronjobs ──

    public async Task<CronjobRecord> CreateCronjob(CronjobRecord cronjob)
    {
        using var conn = CreateConnection();
        var now = DateTime.UtcNow.ToString("o");
        cronjob.CronjobId = Guid.NewGuid().ToString("N");
        cronjob.CreatedAt = now;
        cronjob.UpdatedAt = now;
        await conn.ExecuteAsync(@"
            INSERT INTO cronjobs (cronjob_id, user_id, session_id, name, cron_expression, prompt, notify_session_id, is_enabled, next_run_at, created_at, updated_at)
            VALUES (@CronjobId, @UserId, @SessionId, @Name, @CronExpression, @Prompt, @NotifySessionId, @IsEnabled, @NextRunAt, @CreatedAt, @UpdatedAt)
        ", cronjob);
        return cronjob;
    }

    public async Task<IEnumerable<CronjobRecord>> GetCronjobs(string userId)
    {
        using var conn = CreateConnection();
        return await conn.QueryAsync<CronjobRecord>(@"
            SELECT c.*, s.name AS session_name, ns.name AS notify_session_name
            FROM cronjobs c
            LEFT JOIN sessions s ON c.session_id = s.session_id
            LEFT JOIN sessions ns ON c.notify_session_id = ns.session_id
            WHERE c.user_id = @userId
            ORDER BY c.name",
            new { userId });
    }

    public async Task<CronjobRecord> GetCronjob(string cronjobId)
    {
        using var conn = CreateConnection();
        return await conn.QuerySingleOrDefaultAsync<CronjobRecord>(@"
            SELECT c.*, s.name AS session_name, ns.name AS notify_session_name
            FROM cronjobs c
            LEFT JOIN sessions s ON c.session_id = s.session_id
            LEFT JOIN sessions ns ON c.notify_session_id = ns.session_id
            WHERE c.cronjob_id = @cronjobId",
            new { cronjobId });
    }

    public async Task UpdateCronjob(CronjobRecord cronjob)
    {
        using var conn = CreateConnection();
        cronjob.UpdatedAt = DateTime.UtcNow.ToString("o");
        await conn.ExecuteAsync(@"
            UPDATE cronjobs SET name = @Name, session_id = @SessionId, cron_expression = @CronExpression,
                prompt = @Prompt, notify_session_id = @NotifySessionId, is_enabled = @IsEnabled, next_run_at = @NextRunAt, updated_at = @UpdatedAt
            WHERE cronjob_id = @CronjobId AND user_id = @UserId",
            cronjob);
    }

    public async Task DeleteCronjob(string cronjobId, string userId)
    {
        using var conn = CreateConnection();
        await conn.ExecuteAsync(
            "DELETE FROM cronjobs WHERE cronjob_id = @cronjobId AND user_id = @userId",
            new { cronjobId, userId });
    }

    public async Task UpdateCronjobRun(string cronjobId, string status, string error, string nextRunAt)
    {
        using var conn = CreateConnection();
        await conn.ExecuteAsync(@"
            UPDATE cronjobs SET last_run_at = @now, last_run_status = @status,
                last_run_error = @error, next_run_at = @nextRunAt, updated_at = @now
            WHERE cronjob_id = @cronjobId",
            new { cronjobId, status, error, nextRunAt, now = DateTime.UtcNow.ToString("o") });
    }

    public async Task<IEnumerable<CronjobRecord>> GetDueCronjobs()
    {
        using var conn = CreateConnection();
        var now = DateTime.UtcNow.ToString("o");
        return await conn.QueryAsync<CronjobRecord>(@"
            SELECT c.*, s.name AS session_name, ns.name AS notify_session_name
            FROM cronjobs c
            LEFT JOIN sessions s ON c.session_id = s.session_id
            LEFT JOIN sessions ns ON c.notify_session_id = ns.session_id
            WHERE c.is_enabled = 1 AND c.next_run_at IS NOT NULL AND c.next_run_at <= @now",
            new { now });
    }
}