First batch of smart stuff

notes-domain/src/entities.rs

@@ -204,6 +204,27 @@ impl NoteVersion {
     }
 }
 
+/// A derived link between two notes, typically generated by semantic similarity.
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
+pub struct NoteLink {
+    pub source_note_id: Uuid,
+    pub target_note_id: Uuid,
+    /// Similarity score (0.0 to 1.0)
+    pub score: f32,
+    pub created_at: DateTime<Utc>,
+}
+
+impl NoteLink {
+    pub fn new(source_note_id: Uuid, target_note_id: Uuid, score: f32) -> Self {
+        Self {
+            source_note_id,
+            target_note_id,
+            score,
+            created_at: Utc::now(),
+        }
+    }
+}
+
 /// Filter options for querying notes
 #[derive(Debug, Clone, Default, Serialize, Deserialize)]
 pub struct NoteFilter {

notes-domain/src/errors.rs

@@ -47,6 +47,10 @@ pub enum DomainError {
     /// A repository/infrastructure error occurred
     #[error("Repository error: {0}")]
     RepositoryError(String),
+
+    /// An infrastructure adapter error occurred
+    #[error("Infrastructure error: {0}")]
+    InfrastructureError(String),
 }
 
 impl DomainError {

notes-domain/src/lib.rs

@@ -10,6 +10,7 @@
 
 pub mod entities;
 pub mod errors;
+pub mod ports;
 pub mod repositories;
 pub mod services;
 

notes-domain/src/ports.rs

@@ -0,0 +1,36 @@
+use async_trait::async_trait;
+use uuid::Uuid;
+
+use crate::entities::NoteLink;
+use crate::errors::DomainResult;
+
+/// Defines how to generate vector embeddings from text.
+#[async_trait]
+pub trait EmbeddingGenerator: Send + Sync {
+    /// Generate a vector embedding for the given text.
+    async fn generate_embedding(&self, text: &str) -> DomainResult<Vec<f32>>;
+}
+
+/// Defines how to store and retrieve vectors.
+#[async_trait]
+pub trait VectorStore: Send + Sync {
+    /// Upsert a vector for a given note ID.
+    async fn upsert(&self, id: Uuid, vector: &[f32]) -> DomainResult<()>;
+
+    /// Find similar items to the given vector.
+    /// Returns a list of (NoteID, Score) tuples.
+    async fn find_similar(&self, vector: &[f32], limit: usize) -> DomainResult<Vec<(Uuid, f32)>>;
+}
+
+/// Defines how to persist note links.
+#[async_trait]
+pub trait LinkRepository: Send + Sync {
+    /// Save a batch of generated links.
+    async fn save_links(&self, links: &[NoteLink]) -> DomainResult<()>;
+
+    /// Delete existing links for a specific source note (e.g., before regenerating).
+    async fn delete_links_for_source(&self, source_note_id: Uuid) -> DomainResult<()>;
+
+    /// Get links for a specific source note.
+    async fn get_links_for_note(&self, source_note_id: Uuid) -> DomainResult<Vec<NoteLink>>;
+}

notes-domain/src/services.rs

@@ -356,6 +356,66 @@ impl UserService {
     }
 }
 
+/// Service for Smart Features (Embeddings, Vector Search, Linking)
+pub struct SmartNoteService {
+    embedding_generator: Arc<dyn crate::ports::EmbeddingGenerator>,
+    vector_store: Arc<dyn crate::ports::VectorStore>,
+    link_repo: Arc<dyn crate::ports::LinkRepository>,
+}
+
+impl SmartNoteService {
+    pub fn new(
+        embedding_generator: Arc<dyn crate::ports::EmbeddingGenerator>,
+        vector_store: Arc<dyn crate::ports::VectorStore>,
+        link_repo: Arc<dyn crate::ports::LinkRepository>,
+    ) -> Self {
+        Self {
+            embedding_generator,
+            vector_store,
+            link_repo,
+        }
+    }
+
+    /// Process a note to generate embeddings and find similar notes
+    pub async fn process_note(&self, note: &Note) -> DomainResult<()> {
+        // 1. Generate embedding
+        let embedding = self
+            .embedding_generator
+            .generate_embedding(&note.content)
+            .await?;
+
+        // 2. Upsert to vector store
+        self.vector_store.upsert(note.id, &embedding).await?;
+
+        // 3. Find similar notes
+        // TODO: Make limit configurable
+        let similar = self.vector_store.find_similar(&embedding, 5).await?;
+
+        // 4. Create links
+        let links: Vec<crate::entities::NoteLink> = similar
+            .into_iter()
+            .filter(|(id, _)| *id != note.id) // Exclude self
+            .map(|(target_id, score)| crate::entities::NoteLink::new(note.id, target_id, score))
+            .collect();
+
+        // 5. Save links (replacing old ones)
+        if !links.is_empty() {
+            self.link_repo.delete_links_for_source(note.id).await?;
+            self.link_repo.save_links(&links).await?;
+        }
+
+        Ok(())
+    }
+
+    /// Get related notes for a given note ID
+    pub async fn get_related_notes(
+        &self,
+        note_id: Uuid,
+    ) -> DomainResult<Vec<crate::entities::NoteLink>> {
+        self.link_repo.get_links_for_note(note_id).await
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;