From a6c1863f57b9be37747576b6669dac39f0de1c2e Mon Sep 17 00:00:00 2001
From: mow <wolfgang.morawetz@mailbox.org>
Date: Sun, 8 Mar 2026 17:41:05 +0100
Subject: [PATCH] refactor(core): reorganize module structure

---
 core/examples/cli.rs                          | 10 ++--
 core/src/document/command.rs                  | 50 ++--------------
 core/src/document/format.rs                   | 38 -------------
 core/src/document/loader.rs                   | 57 +++++++++++++++----
 core/src/document/mod.rs                      | 21 +++----
 core/src/document/model/mod.rs                | 12 ++++
 core/src/document/{ => model}/portable.rs     |  4 +-
 core/src/document/{ => model}/raster.rs       |  2 +-
 core/src/document/{ => model}/vector.rs       |  4 +-
 core/src/document/session/command.rs          | 45 +++++++++++++++
 .../document/{session.rs => session/data.rs}  |  8 ++-
 core/src/document/session/mod.rs              | 11 ++++
 core/src/document/{ => session}/store.rs      | 24 ++++++--
 core/src/document/types/image.rs              | 17 ++++++
 .../src/document/{core.rs => types/layout.rs} | 29 +++-------
 core/src/document/types/mod.rs                | 12 ++++
 core/src/document/types/viewbox.rs            | 16 ++++++
 core/src/{error/kinds.rs => error.rs}         | 14 ++---
 core/src/error/mod.rs                         |  8 ---
 core/src/lib.rs                               |  8 ++-
 core/src/render/mod.rs                        |  1 -
 core/src/render/page.rs                       |  4 --
 22 files changed, 231 insertions(+), 164 deletions(-)
 delete mode 100644 core/src/document/format.rs
 create mode 100644 core/src/document/model/mod.rs
 rename core/src/document/{ => model}/portable.rs (76%)
 rename core/src/document/{ => model}/raster.rs (87%)
 rename core/src/document/{ => model}/vector.rs (76%)
 create mode 100644 core/src/document/session/command.rs
 rename core/src/document/{session.rs => session/data.rs} (92%)
 create mode 100644 core/src/document/session/mod.rs
 rename core/src/document/{ => session}/store.rs (70%)
 create mode 100644 core/src/document/types/image.rs
 rename core/src/document/{core.rs => types/layout.rs} (63%)
 create mode 100644 core/src/document/types/mod.rs
 create mode 100644 core/src/document/types/viewbox.rs
 rename core/src/{error/kinds.rs => error.rs} (74%)
 delete mode 100644 core/src/error/mod.rs
 delete mode 100644 core/src/render/page.rs

diff --git a/core/examples/cli.rs b/core/examples/cli.rs
index 4d45b5c..cf4304e 100644
--- a/core/examples/cli.rs
+++ b/core/examples/cli.rs
@@ -4,9 +4,9 @@
 // CLI test harness for the noctua_core document foundation.
 
 use clap::{ArgGroup, Parser};
-use noctua_core::document::command::SessionCommand;
 use noctua_core::document::manager::{DocumentManager, DocumentState};
-use noctua_core::document::session::CollectionKind;
+use noctua_core::document::session::command::SessionCommand;
+use noctua_core::document::session::data::CollectionKind;
 use std::path::PathBuf;
 
 // ── ANSI helpers ──
@@ -139,7 +139,7 @@ fn main() {
 
         exec(
             &mut mgr,
-            &format!("New session '{session_name}'"),
+            &format!("New browser session '{session_name}'"),
             SessionCommand::New {
                 name: session_name.clone(),
                 kind: CollectionKind::DirectoryBrowser,
@@ -154,7 +154,7 @@ fn main() {
         );
         exec(
             &mut mgr,
-            &format!("Scan directory {}", dir.display()),
+            &format!("Add directory {}", dir.display()),
             SessionCommand::AddDirectory { dir },
         );
         exec(
@@ -186,7 +186,7 @@ fn main() {
         );
         exec(
             &mut mgr,
-            &format!("Scan directory {}", path.display()),
+            &format!("Add directory {}", path.display()),
             SessionCommand::AddDirectory { dir: path },
         );
     }
diff --git a/core/src/document/command.rs b/core/src/document/command.rs
index 01ce88e..7fe0ee1 100644
--- a/core/src/document/command.rs
+++ b/core/src/document/command.rs
@@ -1,51 +1,13 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
 // src/document/command.rs
 //
-// Command enums for session management and document operations.
+// Commands that operate on the active document itself.
 
-use crate::document::session::CollectionKind;
-use std::path::PathBuf;
-
-/// Commands operating on sessions and their document collections.
-/// All collection-mutating commands operate on the active session
-/// unless they explicitly name a session.
-#[derive(Debug, Clone)]
-pub enum SessionCommand {
-    // -- Lifecycle --
-    /// Create a new empty session of the given kind.
-    New { name: String, kind: CollectionKind },
-    /// Open sessions from an existing .ron file.
-    Open { path: PathBuf },
-    /// Switch the active session by name.
-    Select { name: String },
-
-    // -- Collection management --
-    /// Scan a directory and replace the active session's items.
-    AddDirectory { dir: PathBuf },
-    /// Add a single document to the active session.
-    AddDocument { path: PathBuf },
-    /// Copy a document from one session to another.
-    CopyDocument {
-        source: String,
-        target: String,
-        source_index: usize,
-        target_index: usize,
-    },
-    /// Remove a document by index from the active session.
-    RemoveDocument { index: usize },
-
-    // -- Navigation --
-    /// Navigate to the next document in the active session.
-    NextDocument,
-    /// Navigate to the previous document in the active session.
-    PreviousDocument,
-    /// Select a document by index in the active session.
-    SelectDocument { index: usize },
-}
-
-/// Commands operating on the active document itself.
-/// Reserved for future use (rotate, flip, zoom, export, …).
+/// Commands operating on the active document (zoom, export, annotate, …).
+///
+/// The `DocumentManager` dispatches these after resolving which document is
+/// active – the UI never needs to know the underlying format.
 #[derive(Debug, Clone)]
 pub enum DocumentCommand {
-    // Future: Rotate, Flip, Zoom, Export, ...
+    // Reserved for future use: Rotate, Flip, Zoom, Export, Annotate, …
 }
diff --git a/core/src/document/format.rs b/core/src/document/format.rs
deleted file mode 100644
index 1303f6f..0000000
--- a/core/src/document/format.rs
+++ /dev/null
@@ -1,38 +0,0 @@
-// SPDX-License-Identifier: GPL-3.0-or-later
-// src/document/format.rs
-//
-// Single source of truth for document format detection.
-
-use std::path::Path;
-
-/// The three document formats Noctua understands.
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub enum DocumentFormat {
-    /// Raster images – anything libcosmic's image crate can decode.
-    Raster,
-    /// Vector graphics (SVG).
-    Vector,
-    /// Portable documents (PDF).
-    Portable,
-}
-
-/// Detects the document format from the file extension.
-///
-/// Returns `None` for unknown extensions so directory scans can skip
-/// unsupported files early. At load time the underlying library
-/// (ImageReader, usvg, pdfium) is the final authority.
-pub fn detect_format(path: &Path) -> Option<DocumentFormat> {
-    match path
-        .extension()
-        .and_then(|e| e.to_str())
-        .map(|e| e.to_lowercase())
-        .as_deref()
-    {
-        Some("pdf") => Some(DocumentFormat::Portable),
-        Some("svg") => Some(DocumentFormat::Vector),
-        Some("png" | "jpg" | "jpeg" | "webp" | "gif" | "bmp" | "tiff" | "tif") => {
-            Some(DocumentFormat::Raster)
-        }
-        _ => None,
-    }
-}
diff --git a/core/src/document/loader.rs b/core/src/document/loader.rs
index 90f0a48..c94dc31 100644
--- a/core/src/document/loader.rs
+++ b/core/src/document/loader.rs
@@ -1,21 +1,56 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
 // src/document/loader.rs
 //
-// Document loading: format dispatch and directory scanning.
+// Document loading: format detection, format dispatch, and directory scanning.
 
-use crate::document::format::{detect_format, DocumentFormat};
-use crate::document::portable::PortableModel;
-use crate::document::raster::RasterModel;
-use crate::document::session::{SessionData, SessionItem};
-use crate::document::vector::VectorModel;
-use crate::document::{core::PageLayout, DocumentContent};
+use crate::document::model::{PortableModel, RasterModel, VectorModel};
+use crate::document::session::data::{SessionData, SessionItem};
+use crate::document::types::PageLayout;
+use crate::document::DocumentContent;
 use crate::error::{Error, Result};
 use std::path::Path;
 
+/// The three document formats Noctua understands.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub(crate) enum DocumentFormat {
+    /// Raster images – anything the image crate can decode.
+    Raster,
+    /// Vector graphics (SVG).
+    Vector,
+    /// Portable documents (PDF).
+    Portable,
+}
+
+/// Detects the document format from the file extension.
+///
+/// Returns `None` for unknown extensions so directory scans can skip
+/// unsupported files early. At load time the underlying library
+/// (`ImageReader`, `usvg`, `pdfium`) is the final authority.
+fn detect_format(path: &Path) -> Option<DocumentFormat> {
+    match path
+        .extension()
+        .and_then(|e| e.to_str())
+        .map(str::to_lowercase)
+        .as_deref()
+    {
+        Some("pdf") => Some(DocumentFormat::Portable),
+        Some("svg") => Some(DocumentFormat::Vector),
+        Some("png" | "jpg" | "jpeg" | "webp" | "gif" | "bmp" | "tiff" | "tif") => {
+            Some(DocumentFormat::Raster)
+        }
+        _ => None,
+    }
+}
+
 /// Loads a document from a path and returns its content.
-pub fn load_document(path: &Path) -> Result<DocumentContent> {
+///
+/// # Errors
+///
+/// Returns [`Error::NotFound`] if the path does not exist.
+/// Returns [`Error::Unsupported`] if the file extension is not recognised.
+pub(crate) fn load_document(path: &Path) -> Result<DocumentContent> {
     if !path.exists() {
-        return Err(Error::NotFound(format!("{:?}", path)));
+        return Err(Error::NotFound(format!("{}", path.display())));
     }
 
     match detect_format(path) {
@@ -51,10 +86,10 @@ pub fn load_document(path: &Path) -> Result<DocumentContent> {
 }
 
 /// Scans a directory for supported files and populates the session.
-pub fn scan_directory_into(session: &mut SessionData, dir: &Path) {
+pub(crate) fn scan_directory_into(session: &mut SessionData, dir: &Path) {
     if let Ok(entries) = std::fs::read_dir(dir) {
         let mut paths: Vec<_> = entries
-            .filter_map(|e| e.ok())
+            .filter_map(std::result::Result::ok)
             .map(|e| e.path())
             .filter(|p| p.is_file() && detect_format(p).is_some())
             .collect();
diff --git a/core/src/document/mod.rs b/core/src/document/mod.rs
index 5954763..c719136 100644
--- a/core/src/document/mod.rs
+++ b/core/src/document/mod.rs
@@ -1,25 +1,22 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
 // src/document/mod.rs
 //
-// Document abstraction and format definitions.
+// Document abstraction – the public surface of the document subsystem.
 
 pub mod command;
-pub mod core;
-pub mod format;
 pub mod loader;
 pub mod manager;
-pub mod portable;
-pub mod raster;
+pub mod model;
 pub mod session;
-pub mod store;
-pub mod vector;
+pub mod types;
 
-use self::portable::PortableModel;
-use self::raster::RasterModel;
-use self::vector::VectorModel;
+use self::model::{PortableModel, RasterModel, VectorModel};
 
-/// Represents the physical content of a loaded document.
-#[derive(Debug, Clone)]
+/// The decoded content of a loaded document.
+///
+/// This enum is internal to `noctua_core`. The UI only ever sees a `RawImage`
+/// produced by the render subsystem – it never matches on this type.
+#[derive(Debug)]
 pub enum DocumentContent {
     Raster(RasterModel),
     Vector(VectorModel),
diff --git a/core/src/document/model/mod.rs b/core/src/document/model/mod.rs
new file mode 100644
index 0000000..7ede092
--- /dev/null
+++ b/core/src/document/model/mod.rs
@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+// src/document/model/mod.rs
+//
+// The three concrete document models Noctua understands.
+
+pub mod portable;
+pub mod raster;
+pub mod vector;
+
+pub use portable::PortableModel;
+pub use raster::RasterModel;
+pub use vector::VectorModel;
diff --git a/core/src/document/portable.rs b/core/src/document/model/portable.rs
similarity index 76%
rename from core/src/document/portable.rs
rename to core/src/document/model/portable.rs
index e7ef528..cdcdc43 100644
--- a/core/src/document/portable.rs
+++ b/core/src/document/model/portable.rs
@@ -1,9 +1,9 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
-// src/document/portable.rs
+// src/document/model/portable.rs
 //
 // Portable document format model (PDF).
 
-use crate::document::core::PageLayout;
+use crate::document::types::PageLayout;
 use std::path::PathBuf;
 
 #[derive(Clone, Debug)]
diff --git a/core/src/document/raster.rs b/core/src/document/model/raster.rs
similarity index 87%
rename from core/src/document/raster.rs
rename to core/src/document/model/raster.rs
index 5000acd..83228bc 100644
--- a/core/src/document/raster.rs
+++ b/core/src/document/model/raster.rs
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
-// src/document/raster.rs
+// src/document/model/raster.rs
 //
 // Raster image document model (JPEG, PNG, etc.).
 
diff --git a/core/src/document/vector.rs b/core/src/document/model/vector.rs
similarity index 76%
rename from core/src/document/vector.rs
rename to core/src/document/model/vector.rs
index 5c29ad3..15e9bf9 100644
--- a/core/src/document/vector.rs
+++ b/core/src/document/model/vector.rs
@@ -1,9 +1,9 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
-// src/document/vector.rs
+// src/document/model/vector.rs
 //
 // Vector image document model (SVG).
 
-use crate::document::core::ViewBox;
+use crate::document::types::ViewBox;
 use std::path::PathBuf;
 
 #[derive(Clone, Debug)]
diff --git a/core/src/document/session/command.rs b/core/src/document/session/command.rs
new file mode 100644
index 0000000..0b141e4
--- /dev/null
+++ b/core/src/document/session/command.rs
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+// src/document/session/command.rs
+//
+// Commands that operate on sessions and their document collections.
+
+use crate::document::session::data::CollectionKind;
+use std::path::PathBuf;
+
+/// Commands operating on sessions and their document collections.
+///
+/// All collection-mutating commands operate on the active session
+/// unless they explicitly name a session.
+#[derive(Debug, Clone)]
+pub enum SessionCommand {
+    // Lifecycle
+    /// Create a new empty session of the given kind.
+    New { name: String, kind: CollectionKind },
+    /// Open sessions from an existing .ron file.
+    Open { path: PathBuf },
+    /// Switch the active session by name.
+    Select { name: String },
+
+    // Collection management
+    /// Scan a directory and replace the active session's items.
+    AddDirectory { dir: PathBuf },
+    /// Add a single document to the active session.
+    AddDocument { path: PathBuf },
+    /// Copy a document from one session to another.
+    CopyDocument {
+        source: String,
+        target: String,
+        source_index: usize,
+        target_index: usize,
+    },
+    /// Remove a document by index from the active session.
+    RemoveDocument { index: usize },
+
+    // Navigation
+    /// Navigate to the next document in the active session.
+    NextDocument,
+    /// Navigate to the previous document in the active session.
+    PreviousDocument,
+    /// Select a document by index in the active session.
+    SelectDocument { index: usize },
+}
diff --git a/core/src/document/session.rs b/core/src/document/session/data.rs
similarity index 92%
rename from core/src/document/session.rs
rename to core/src/document/session/data.rs
index 8dd49e9..157982e 100644
--- a/core/src/document/session.rs
+++ b/core/src/document/session/data.rs
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
-// src/document/session.rs
+// src/document/session/data.rs
 //
 // A session is the unit of work in Noctua. It groups a set of document items
 // under a name and tracks which item is currently active.
@@ -42,6 +42,7 @@ pub struct SessionItem {
 }
 
 impl SessionItem {
+    #[must_use]
     pub fn new(path: PathBuf, page_index: usize) -> Self {
         Self { path, page_index }
     }
@@ -52,8 +53,8 @@ impl SessionItem {
 pub struct SessionData {
     pub name: String,
     pub kind: CollectionKind,
-    /// For DirectoryBrowser: the source directory to scan.
-    /// For DocumentCollection: None (items are managed individually).
+    /// For `DirectoryBrowser`: the source directory to scan.
+    /// For `DocumentCollection`: None (items are managed individually).
     /// The .ron session file path is tracked separately.
     #[serde(default)]
     pub path: Option<PathBuf>,
@@ -63,6 +64,7 @@ pub struct SessionData {
 }
 
 impl SessionData {
+    #[must_use]
     pub fn new(
         name: &str,
         kind: CollectionKind,
diff --git a/core/src/document/session/mod.rs b/core/src/document/session/mod.rs
new file mode 100644
index 0000000..1e82946
--- /dev/null
+++ b/core/src/document/session/mod.rs
@@ -0,0 +1,11 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+// src/document/session/mod.rs
+//
+// Session subsystem: data model, commands, and persistence.
+
+pub mod command;
+pub mod data;
+pub mod store;
+
+pub use command::SessionCommand;
+pub use data::{CollectionKind, SessionData, SessionItem};
diff --git a/core/src/document/store.rs b/core/src/document/session/store.rs
similarity index 70%
rename from core/src/document/store.rs
rename to core/src/document/session/store.rs
index 70049c6..480728f 100644
--- a/core/src/document/store.rs
+++ b/core/src/document/session/store.rs
@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
-// src/document/store.rs
+// src/document/session/store.rs
 //
 // RON-based persistence for session data: load and save session lists.
 //
@@ -27,23 +27,37 @@
 //     ),
 // ]
 
-use crate::document::session::SessionData;
+use crate::document::session::data::SessionData;
 use crate::error::{Error, Result};
 use std::path::Path;
 
 /// Loads all sessions from a RON file.
+///
+/// # Errors
+///
+/// Returns [`Error::Io`] if the file cannot be read.
+/// Returns [`Error::Session`] if the file cannot be parsed.
 pub fn load_sessions(path: &Path) -> Result<Vec<SessionData>> {
     let content = std::fs::read_to_string(path).map_err(Error::Io)?;
 
-    ron::from_str(&content)
-        .map_err(|e| Error::Session(format!("Failed to parse session file {:?}: {}", path, e)))
+    ron::from_str(&content).map_err(|e| {
+        Error::Session(format!(
+            "Failed to parse session file {}: {e}",
+            path.display()
+        ))
+    })
 }
 
 /// Saves all sessions to a RON file.
+///
+/// # Errors
+///
+/// Returns [`Error::Session`] if the sessions cannot be serialized.
+/// Returns [`Error::Io`] if the file cannot be written.
 #[allow(dead_code)]
 pub fn save_sessions(path: &Path, sessions: &[SessionData]) -> Result<()> {
     let content = ron::ser::to_string_pretty(sessions, ron::ser::PrettyConfig::default())
-        .map_err(|e| Error::Session(format!("Failed to serialize sessions: {}", e)))?;
+        .map_err(|e| Error::Session(format!("Failed to serialize sessions: {e}")))?;
 
     std::fs::write(path, content).map_err(Error::Io)
 }
diff --git a/core/src/document/types/image.rs b/core/src/document/types/image.rs
new file mode 100644
index 0000000..3791631
--- /dev/null
+++ b/core/src/document/types/image.rs
@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+// src/document/types/image.rs
+//
+// Raw pixel buffer passed from the render subsystem to the UI.
+
+use std::sync::Arc;
+
+/// A decoded, format-independent pixel buffer ready for display.
+///
+/// The UI receives this type from the `DocumentManager` and never needs to
+/// know which document format (PDF, SVG, raster) produced it.
+#[derive(Clone, Debug)]
+pub struct RawImage {
+    pub data: Arc<Vec<u8>>,
+    pub width: u32,
+    pub height: u32,
+}
diff --git a/core/src/document/core.rs b/core/src/document/types/layout.rs
similarity index 63%
rename from core/src/document/core.rs
rename to core/src/document/types/layout.rs
index 9782d18..e86628d 100644
--- a/core/src/document/core.rs
+++ b/core/src/document/types/layout.rs
@@ -1,17 +1,13 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
-// src/document/core.rs
+// src/document/types/layout.rs
 //
-// Core domain models for document representation.
-
-use std::sync::Arc;
-
-#[derive(Clone, Debug)]
-pub struct RawImage {
-    pub data: Arc<Vec<u8>>,
-    pub width: u32,
-    pub height: u32,
-}
+// PageLayout – describes the vertical arrangement of pages in a document.
 
+/// The computed layout of all pages in a multi-page document.
+///
+/// Stores absolute y-offsets for each page so the render subsystem can
+/// determine which pages are visible at a given scroll position without
+/// iterating the full list on every frame.
 #[derive(Clone, Debug)]
 pub struct PageLayout {
     pub page_starts: Vec<f64>,
@@ -21,15 +17,8 @@ pub struct PageLayout {
     pub max_width: f64,
 }
 
-#[derive(Clone, Debug)]
-pub struct ViewBox {
-    pub x: f64,
-    pub y: f64,
-    pub width: f64,
-    pub height: f64,
-}
-
 impl PageLayout {
+    #[must_use]
     pub fn new(page_sizes: Vec<(f64, f64)>, gap: f64) -> Self {
         let mut page_starts = Vec::with_capacity(page_sizes.len());
         let mut y = 0.0_f64;
@@ -43,7 +32,7 @@ impl PageLayout {
             }
         }
 
-        let total_height = if !page_sizes.is_empty() { y - gap } else { 0.0 };
+        let total_height = if page_sizes.is_empty() { 0.0 } else { y - gap };
 
         Self {
             page_starts,
diff --git a/core/src/document/types/mod.rs b/core/src/document/types/mod.rs
new file mode 100644
index 0000000..eae29b1
--- /dev/null
+++ b/core/src/document/types/mod.rs
@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+// src/document/types/mod.rs
+//
+// Shared domain primitives used across the document and render subsystems.
+
+pub mod image;
+pub mod layout;
+pub mod viewbox;
+
+pub use image::RawImage;
+pub use layout::PageLayout;
+pub use viewbox::ViewBox;
diff --git a/core/src/document/types/viewbox.rs b/core/src/document/types/viewbox.rs
new file mode 100644
index 0000000..45715c6
--- /dev/null
+++ b/core/src/document/types/viewbox.rs
@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+// src/document/types/viewbox.rs
+//
+// ViewBox – describes the visible coordinate space of a vector document.
+
+/// The coordinate space declared by an SVG `viewBox` attribute.
+///
+/// Used by the render subsystem to map document coordinates to screen pixels
+/// without exposing SVG internals to the UI.
+#[derive(Clone, Debug)]
+pub struct ViewBox {
+    pub x: f64,
+    pub y: f64,
+    pub width: f64,
+    pub height: f64,
+}
diff --git a/core/src/error/kinds.rs b/core/src/error.rs
similarity index 74%
rename from core/src/error/kinds.rs
rename to core/src/error.rs
index 8f11344..c17566b 100644
--- a/core/src/error/kinds.rs
+++ b/core/src/error.rs
@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
-// src/error/kinds.rs
+// src/error.rs
 //
-// Central error types for Noctua.
+// Central error and result types for noctua_core.
 
 use std::fmt;
 
@@ -24,11 +24,11 @@ pub enum Error {
 impl fmt::Display for Error {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
-            Error::NotFound(msg) => write!(f, "Not found: {}", msg),
-            Error::Unsupported(msg) => write!(f, "Unsupported: {}", msg),
-            Error::Render(msg) => write!(f, "Render error: {}", msg),
-            Error::Session(msg) => write!(f, "Session error: {}", msg),
-            Error::Io(err) => write!(f, "I/O error: {}", err),
+            Error::NotFound(msg) => write!(f, "Not found: {msg}"),
+            Error::Unsupported(msg) => write!(f, "Unsupported: {msg}"),
+            Error::Render(msg) => write!(f, "Render error: {msg}"),
+            Error::Session(msg) => write!(f, "Session error: {msg}"),
+            Error::Io(err) => write!(f, "I/O error: {err}"),
         }
     }
 }
diff --git a/core/src/error/mod.rs b/core/src/error/mod.rs
deleted file mode 100644
index c488562..0000000
--- a/core/src/error/mod.rs
+++ /dev/null
@@ -1,8 +0,0 @@
-// SPDX-License-Identifier: GPL-3.0-or-later
-// src/error/mod.rs
-//
-// Central error module – re-exports the shared Error and Result types.
-
-mod kinds;
-
-pub use kinds::{Error, Result};
diff --git a/core/src/lib.rs b/core/src/lib.rs
index 9a4f59b..b337937 100644
--- a/core/src/lib.rs
+++ b/core/src/lib.rs
@@ -3,6 +3,12 @@
 //
 // Public API of the noctua_core library.
 
-pub mod document;
 pub mod error;
+
+pub mod document;
 pub mod render;
+
+pub use document::command::DocumentCommand;
+pub use document::manager::DocumentManager;
+pub use document::session::SessionCommand;
+pub use document::types::RawImage;
diff --git a/core/src/render/mod.rs b/core/src/render/mod.rs
index 9424162..c13e7ba 100644
--- a/core/src/render/mod.rs
+++ b/core/src/render/mod.rs
@@ -4,5 +4,4 @@
 // Rendering subsystem: converts document content into displayable output.
 
 pub mod converter;
-pub mod page;
 pub mod thumbnail;
diff --git a/core/src/render/page.rs b/core/src/render/page.rs
deleted file mode 100644
index 5242cbe..0000000
--- a/core/src/render/page.rs
+++ /dev/null
@@ -1,4 +0,0 @@
-// SPDX-License-Identifier: GPL-3.0-or-later
-// src/render/page.rs
-//
-// Page layout and rendering primitives (scaffold – not yet implemented).