nexus/backend/Services/AgentConfigService.cs

using Nexus.Api.Helpers;

namespace Nexus.Api.Services;

public sealed class AgentConfigService : IAgentConfigService
{
    private static readonly HashSet<string> AllowedFiles = new(StringComparer.OrdinalIgnoreCase)
    {
        "IDENTITY.md", "SOUL.md", "AGENTS.md", "TOOLS.md", "HEARTBEAT.md", "USER.md", "MEMORY.md"
    };

    public IReadOnlyList<AgentConfigFileInfo> GetConfigFiles(string agentId)
    {
        var workspacePath = $"/mnt/workspace-{agentId}";
        if (!Directory.Exists(workspacePath))
            return Array.Empty<AgentConfigFileInfo>();

        return Directory.GetFiles(workspacePath, "*.md")
            .Select(f => new FileInfo(f))
            .Where(f => AllowedFiles.Contains(f.Name))
            .OrderBy(f => f.Name)
            .Select(f => new AgentConfigFileInfo(f.Name, f.Length, f.LastWriteTimeUtc))
            .ToList();
    }

    public async Task<AgentConfigFileContent?> GetConfigFileAsync(string agentId, string fileName, CancellationToken ct = default)
    {
        if (!PathSecurityHelper.IsValidConfigFileName(fileName))
            return null;

        var workspacePath = $"/mnt/workspace-{agentId}";
        if (!PathSecurityHelper.TryResolveSafePath(workspacePath, fileName, out var safePath) || !File.Exists(safePath))
            return null;

        var content = await File.ReadAllTextAsync(safePath!, ct);
        var fi = new FileInfo(safePath!);
        return new AgentConfigFileContent(fileName, content, fi.Length, fi.LastWriteTimeUtc);
    }

    public async Task<AgentConfigFileSaveResult?> SaveConfigFileAsync(string agentId, string fileName, string content, CancellationToken ct = default)
    {
        if (!PathSecurityHelper.IsValidConfigFileName(fileName))
            return null;

        var workspacePath = $"/mnt/workspace-{agentId}";
        if (!PathSecurityHelper.TryResolveSafePath(workspacePath, fileName, out var safePath))
            return null;

        var tempPath = safePath + ".tmp";
        try
        {
            await File.WriteAllTextAsync(tempPath, content, ct);
            File.Move(tempPath, safePath!, overwrite: true);
        }
        catch
        {
            if (File.Exists(tempPath)) File.Delete(tempPath);
            throw;
        }

        var fi = new FileInfo(safePath!);
        return new AgentConfigFileSaveResult(fileName, fi.Length, fi.LastWriteTimeUtc);
    }
}