refactor(repl): Topic-based navigation model

- Replace flat path string with CurrentTopic + CurrentSubPath
- SlugRelative() strips topic prefix for relative name resolution
- FoldersInView() returns topics at root, slug sub-segments within topic
- NotesInView() filters by topic and subpath
- NavigateTo() / NavigateUp() for cd navigation
- ResolveSlug() / ResolveNewSlug() for command argument resolution

NozCli/Repl/ReplContext.cs

@@ -1,54 +1,157 @@
 using NozCli.Core.Client;
+using NozCli.Core.Config;
 using NozCli.Core.Models;
 
 namespace NozCli.Repl;
 
 /// Shared mutable state across the REPL session.
+/// Navigation model:
+///   ~                       → root, FoldersInView() returns distinct topics
+///   ~/psychologie           → topic view, notes filtered by topic
+///   ~/biosysteme/subfolder  → slug subfolder within a topic
 public class ReplContext
 {
-    public NozApiClient          Api         { get; }
+    public NozApiClient   Api          { get; }
-    public string                CurrentPath { get; set; } = "~";
+    public LocalConfig    Config       { get; }
-    public List<NoteInfo>        NoteCache   { get; set; } = [];
+    public List<NoteInfo> NoteCache    { get; set; } = [];
-    public bool                  Running     { get; set; } = true;
+    public bool           Running      { get; set; } = true;
 
-    public ReplContext(NozApiClient api) => Api = api;
+    // Navigation state
+    public string? CurrentTopic   { get; set; } = null;  // null = root
+    public string? CurrentSubPath { get; set; } = null;  // sub-path within topic
 
-    /// Returns the topic/folder prefix implied by CurrentPath, or null if at root.
+    public string CurrentPath =>
-    public string? PathPrefix()
+        CurrentTopic is null    ? "~" :
-    {
+        CurrentSubPath is null  ? $"~/{CurrentTopic}" :
-        if (CurrentPath is "~" or "~/noosphere") return null;
+                                  $"~/{CurrentTopic}/{CurrentSubPath}";
-        var stripped = CurrentPath.Replace("~/noosphere/", "").Replace("~/noosphere", "");
-        return string.IsNullOrEmpty(stripped) ? null : stripped;
-    }
 
-    /// Notes visible at the current path level.
+    public ReplContext(NozApiClient api, LocalConfig config) { Api = api; Config = config; }
+
+    /// Notes filtered to the current topic (all notes at root).
     public IEnumerable<NoteInfo> NotesInView()
     {
-        var prefix = PathPrefix();
+        if (CurrentTopic is null) return NoteCache;
-        return prefix is null
+
-            ? NoteCache
+        var topicNotes = NoteCache.Where(n =>
-            : NoteCache.Where(n => n.Slug.StartsWith(prefix + "/"));
+            string.Equals(n.Topic, CurrentTopic, StringComparison.OrdinalIgnoreCase));
+
+        if (CurrentSubPath is null) return topicNotes;
+
+        // Within a subfolder: filter by the slug sub-path relative to topic root
+        return topicNotes.Where(n =>
+        {
+            var rel = SlugRelative(n.Slug);
+            return rel.StartsWith(CurrentSubPath + "/") || rel == CurrentSubPath;
+        });
     }
 
-    /// Resolves a short name (e.g. "hydroponik") to a full slug using the current path as prefix.
+    /// Slug of a note relative to the topic root folder.
-    public string ResolveSlug(string nameOrSlug)
+    /// "biosysteme/bio-regenerative-systeme/hydroponik" under topic "biosysteme"
+    /// → "bio-regenerative-systeme/hydroponik"
+    public string SlugRelative(string slug)
     {
-        // Already a full slug
+        if (CurrentTopic is null) return slug;
-        if (NoteCache.Any(n => n.Slug == nameOrSlug)) return nameOrSlug;
+        var prefix = CurrentTopic + "/";
-        var prefix = PathPrefix();
+        return slug.StartsWith(prefix, StringComparison.OrdinalIgnoreCase)
-        var candidate = prefix is null ? nameOrSlug : $"{prefix}/{nameOrSlug}";
+            ? slug[prefix.Length..]
-        return NoteCache.Any(n => n.Slug == candidate) ? candidate : nameOrSlug;
+            : slug;
     }
 
-    /// Immediate sub-segments (topics or subfolders) at current path.
+    /// Immediate sub-folders at the current navigation level.
+    /// At root: returns distinct topic names.
+    /// Within a topic: returns slug sub-segments one level below CurrentSubPath.
     public IEnumerable<string> FoldersInView()
     {
-        var prefix = PathPrefix();
+        if (CurrentTopic is null)
-        var depth  = prefix is null ? 0 : prefix.Split('/').Length;
+            return NoteCache
-        return NoteCache
+                .Select(n => n.Topic)
-            .Where(n => prefix is null || n.Slug.StartsWith(prefix + "/"))
+                .Where(t => !string.IsNullOrEmpty(t))
-            .Select(n => n.Slug.Split('/').ElementAtOrDefault(depth))
+                .Distinct(StringComparer.OrdinalIgnoreCase)!;
+
+        var depth = CurrentSubPath is null ? 0 : CurrentSubPath.Split('/').Length;
+        return NotesInView()
+            .Select(n => SlugRelative(n.Slug).Split('/').ElementAtOrDefault(depth))
             .Where(s => s is not null)
             .Distinct(StringComparer.OrdinalIgnoreCase)!;
     }
+
+    /// Navigate into a topic or sub-folder segment.
+    public bool NavigateTo(string segment)
+    {
+        if (CurrentTopic is null)
+        {
+            // At root: segment must be a known topic
+            var topic = NoteCache
+                .Select(n => n.Topic)
+                .FirstOrDefault(t => string.Equals(t, segment, StringComparison.OrdinalIgnoreCase));
+            if (topic is null) return false;
+            CurrentTopic   = topic;
+            CurrentSubPath = null;
+            return true;
+        }
+
+        // Within a topic: segment must be a valid slug sub-folder
+        var newSub = CurrentSubPath is null ? segment : $"{CurrentSubPath}/{segment}";
+        var hasNotes = NoteCache
+            .Where(n => string.Equals(n.Topic, CurrentTopic, StringComparison.OrdinalIgnoreCase))
+            .Any(n =>
+            {
+                var rel = SlugRelative(n.Slug);
+                return rel.StartsWith(newSub + "/") || rel == newSub;
+            });
+
+        if (!hasNotes) return false;
+        CurrentSubPath = newSub;
+        return true;
+    }
+
+    /// Navigate up one level.
+    public void NavigateUp()
+    {
+        if (CurrentSubPath is not null)
+        {
+            var parts = CurrentSubPath.Split('/');
+            CurrentSubPath = parts.Length > 1 ? string.Join('/', parts[..^1]) : null;
+        }
+        else
+        {
+            CurrentTopic = null;
+        }
+    }
+
+    /// Resolve a short name to a full slug for note commands (cat, edit, rm).
+    public string ResolveSlug(string nameOrSlug)
+    {
+        nameOrSlug = nameOrSlug.TrimEnd('/');
+        // Already a full known slug
+        if (NoteCache.Any(n => n.Slug == nameOrSlug)) return nameOrSlug;
+
+        if (CurrentTopic is null) return nameOrSlug;
+
+        // Try reconstructing the full slug from relative name
+        var topicPrefix = CurrentTopic + "/";
+        var sub = CurrentSubPath is null ? nameOrSlug : $"{CurrentSubPath}/{nameOrSlug}";
+        var full = topicPrefix + sub;
+        if (NoteCache.Any(n => n.Slug == full)) return full;
+
+        // Slug without topic prefix (note stored at root of noosphere)
+        if (NoteCache.Any(n => n.Slug == sub)) return sub;
+
+        return nameOrSlug;
+    }
+
+    /// Build a slug for a NEW note that doesn't exist yet.
+    public string ResolveNewSlug(string nameOrSlug)
+    {
+        nameOrSlug = nameOrSlug.TrimEnd('/');
+        if (nameOrSlug.EndsWith(".md", StringComparison.OrdinalIgnoreCase))
+            nameOrSlug = nameOrSlug[..^3];
+
+        if (nameOrSlug.Contains('/')) return nameOrSlug;
+
+        if (CurrentTopic is null) return nameOrSlug;
+
+        var sub = CurrentSubPath is null ? nameOrSlug : $"{CurrentSubPath}/{nameOrSlug}";
+        return CurrentTopic + "/" + sub;
+    }
 }