feat(chat): persistance bornee du brouillon custom chat par projet/layout (#182)

crates/application/src/chat_drafts.rs

@@ -0,0 +1,157 @@
+//! Custom chat draft use cases.
+
+use std::sync::Arc;
+
+use domain::ports::{ChatDraftStore, Clock, ProjectStore};
+use domain::{ChatDraft, ChatDraftKey, LayoutId, NodeId, Project, ProjectId};
+
+use crate::AppError;
+
+/// Input identifying one draft scope.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct ChatDraftScopeInput {
+    /// Project owning the layout.
+    pub project_id: ProjectId,
+    /// Named layout containing the chat cell.
+    pub layout_id: LayoutId,
+    /// Layout node hosting the chat cell.
+    pub node_id: NodeId,
+}
+
+impl ChatDraftScopeInput {
+    fn key(self) -> ChatDraftKey {
+        ChatDraftKey::new(self.project_id, self.layout_id, self.node_id)
+    }
+}
+
+/// Output of [`ReadChatDraft`].
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct ReadChatDraftOutput {
+    /// Restored draft text, or `None` when no draft exists.
+    pub text: Option<String>,
+    /// Last update time when a draft exists.
+    pub updated_at_ms: Option<u64>,
+}
+
+/// Input for [`SaveChatDraft`].
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct SaveChatDraftInput {
+    /// Draft scope.
+    pub scope: ChatDraftScopeInput,
+    /// Text to persist. Empty text clears the draft.
+    pub text: String,
+}
+
+/// Reads a persisted custom chat draft.
+pub struct ReadChatDraft {
+    projects: Arc<dyn ProjectStore>,
+    drafts: Arc<dyn ChatDraftStore>,
+}
+
+impl ReadChatDraft {
+    /// Builds the use case.
+    #[must_use]
+    pub fn new(projects: Arc<dyn ProjectStore>, drafts: Arc<dyn ChatDraftStore>) -> Self {
+        Self { projects, drafts }
+    }
+
+    /// Executes the read.
+    pub async fn execute(
+        &self,
+        input: ChatDraftScopeInput,
+    ) -> Result<ReadChatDraftOutput, AppError> {
+        let project = self.load_project(input.project_id).await?;
+        let draft = self.drafts.read(&project.root, input.key()).await?;
+        Ok(ReadChatDraftOutput {
+            text: draft.as_ref().map(|draft| draft.text.clone()),
+            updated_at_ms: draft.map(|draft| draft.updated_at_ms),
+        })
+    }
+
+    async fn load_project(&self, project_id: ProjectId) -> Result<Project, AppError> {
+        self.projects
+            .load_project(project_id)
+            .await
+            .map_err(AppError::from)
+    }
+}
+
+/// Saves a persisted custom chat draft.
+pub struct SaveChatDraft {
+    projects: Arc<dyn ProjectStore>,
+    drafts: Arc<dyn ChatDraftStore>,
+    clock: Arc<dyn Clock>,
+}
+
+impl SaveChatDraft {
+    /// Builds the use case.
+    #[must_use]
+    pub fn new(
+        projects: Arc<dyn ProjectStore>,
+        drafts: Arc<dyn ChatDraftStore>,
+        clock: Arc<dyn Clock>,
+    ) -> Self {
+        Self {
+            projects,
+            drafts,
+            clock,
+        }
+    }
+
+    /// Executes the save. Empty text clears the draft.
+    pub async fn execute(&self, input: SaveChatDraftInput) -> Result<(), AppError> {
+        let project = self.load_project(input.scope.project_id).await?;
+        let key = input.scope.key();
+        if input.text.is_empty() {
+            return self
+                .drafts
+                .clear(&project.root, key)
+                .await
+                .map_err(AppError::from);
+        }
+        let updated_at_ms = u64::try_from(self.clock.now_millis()).unwrap_or(0);
+        let draft = ChatDraft::new(key, input.text, updated_at_ms)
+            .map_err(|err| AppError::Invalid(err.to_string()))?;
+        self.drafts
+            .save(&project.root, draft)
+            .await
+            .map_err(AppError::from)
+    }
+
+    async fn load_project(&self, project_id: ProjectId) -> Result<Project, AppError> {
+        self.projects
+            .load_project(project_id)
+            .await
+            .map_err(AppError::from)
+    }
+}
+
+/// Clears a persisted custom chat draft.
+pub struct ClearChatDraft {
+    projects: Arc<dyn ProjectStore>,
+    drafts: Arc<dyn ChatDraftStore>,
+}
+
+impl ClearChatDraft {
+    /// Builds the use case.
+    #[must_use]
+    pub fn new(projects: Arc<dyn ProjectStore>, drafts: Arc<dyn ChatDraftStore>) -> Self {
+        Self { projects, drafts }
+    }
+
+    /// Executes the clear.
+    pub async fn execute(&self, input: ChatDraftScopeInput) -> Result<(), AppError> {
+        let project = self.load_project(input.project_id).await?;
+        self.drafts
+            .clear(&project.root, input.key())
+            .await
+            .map_err(AppError::from)
+    }
+
+    async fn load_project(&self, project_id: ProjectId) -> Result<Project, AppError> {
+        self.projects
+            .load_project(project_id)
+            .await
+            .map_err(AppError::from)
+    }
+}