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

crates/infrastructure/src/chat_drafts.rs

@@ -0,0 +1,125 @@
+//! Filesystem custom chat draft store.
+//!
+//! Drafts are persisted per project under `<root>/.ideai/chat-drafts.json`.
+
+use std::path::PathBuf;
+
+use async_trait::async_trait;
+use serde::{Deserialize, Serialize};
+
+use domain::ports::{ChatDraftStore, StoreError};
+use domain::{ChatDraft, ChatDraftKey, ProjectPath};
+
+const IDEAI_DIR: &str = ".ideai";
+const CHAT_DRAFTS_FILE: &str = "chat-drafts.json";
+const CHAT_DRAFTS_TMP_FILE: &str = "chat-drafts.json.tmp";
+const CHAT_DRAFTS_VERSION: u32 = 1;
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+struct ChatDraftsDoc {
+    version: u32,
+    drafts: Vec<ChatDraft>,
+}
+
+impl Default for ChatDraftsDoc {
+    fn default() -> Self {
+        Self {
+            version: CHAT_DRAFTS_VERSION,
+            drafts: Vec::new(),
+        }
+    }
+}
+
+/// Filesystem-backed [`ChatDraftStore`].
+#[derive(Debug, Clone, Default)]
+pub struct FsChatDraftStore;
+
+impl FsChatDraftStore {
+    /// Builds a store.
+    #[must_use]
+    pub const fn new() -> Self {
+        Self
+    }
+}
+
+fn dir(root: &ProjectPath) -> PathBuf {
+    PathBuf::from(root.as_str()).join(IDEAI_DIR)
+}
+
+fn path(root: &ProjectPath) -> PathBuf {
+    dir(root).join(CHAT_DRAFTS_FILE)
+}
+
+fn tmp_path(root: &ProjectPath) -> PathBuf {
+    dir(root).join(CHAT_DRAFTS_TMP_FILE)
+}
+
+fn io_error(err: std::io::Error) -> StoreError {
+    StoreError::Io(err.to_string())
+}
+
+async fn read_doc(root: &ProjectPath) -> Result<ChatDraftsDoc, StoreError> {
+    match tokio::fs::read(path(root)).await {
+        Ok(bytes) => {
+            let doc: ChatDraftsDoc = serde_json::from_slice(&bytes)
+                .map_err(|err| StoreError::Serialization(err.to_string()))?;
+            if doc.version != CHAT_DRAFTS_VERSION {
+                return Err(StoreError::Invalid(format!(
+                    "unsupported chat drafts version {}",
+                    doc.version
+                )));
+            }
+            Ok(doc)
+        }
+        Err(err) if err.kind() == std::io::ErrorKind::NotFound => Ok(ChatDraftsDoc::default()),
+        Err(err) => Err(io_error(err)),
+    }
+}
+
+async fn write_doc(root: &ProjectPath, doc: &ChatDraftsDoc) -> Result<(), StoreError> {
+    let dir = dir(root);
+    tokio::fs::create_dir_all(&dir).await.map_err(io_error)?;
+    let bytes =
+        serde_json::to_vec_pretty(doc).map_err(|err| StoreError::Serialization(err.to_string()))?;
+    let tmp = tmp_path(root);
+    tokio::fs::write(&tmp, bytes).await.map_err(io_error)?;
+    tokio::fs::rename(tmp, path(root)).await.map_err(io_error)
+}
+
+#[async_trait]
+impl ChatDraftStore for FsChatDraftStore {
+    async fn read(
+        &self,
+        root: &ProjectPath,
+        key: ChatDraftKey,
+    ) -> Result<Option<ChatDraft>, StoreError> {
+        Ok(read_doc(root)
+            .await?
+            .drafts
+            .into_iter()
+            .find(|draft| draft.key == key))
+    }
+
+    async fn save(&self, root: &ProjectPath, draft: ChatDraft) -> Result<(), StoreError> {
+        let mut doc = read_doc(root).await?;
+        if let Some(slot) = doc
+            .drafts
+            .iter_mut()
+            .find(|existing| existing.key == draft.key)
+        {
+            *slot = draft;
+        } else {
+            doc.drafts.push(draft);
+        }
+        doc.drafts
+            .sort_by_key(|draft| (draft.key.project_id, draft.key.layout_id, draft.key.node_id));
+        write_doc(root, &doc).await
+    }
+
+    async fn clear(&self, root: &ProjectPath, key: ChatDraftKey) -> Result<(), StoreError> {
+        let mut doc = read_doc(root).await?;
+        doc.drafts.retain(|draft| draft.key != key);
+        write_doc(root, &doc).await
+    }
+}