revert: remove unused Agent PostgreSQL persistence

src/conversations/stateStore.ts

@@ -1,6 +1,12 @@
-import { type QueryResultRow } from "pg";
+import { join } from "node:path";
 
-import { AgentDatabase, getAgentDatabase } from "../db/index.js";
+import { config } from "../config.js";
+import {
+  atomicWriteJson,
+  ensureDirectory,
+  readJsonFile,
+  removeFileIfExists,
+} from "../utils/fileStore.js";
 
 export type ConversationStateRecord = {
   sessionId: string;
@@ -9,81 +15,27 @@ export type ConversationStateRecord = {
   branchGroups: unknown[];
 };
 
-type ConversationStateRow = QueryResultRow & {
-  session_id: string;
-  is_title_manually_edited: boolean;
-  messages: unknown[];
-  branch_groups: unknown[];
-};
-
 export class ConversationStateStore {
-  constructor(private readonly db: AgentDatabase = getAgentDatabase()) {}
+  constructor(private readonly baseDir = config.CONVERSATION_STATE_STORAGE_DIR) {}
 
   async initialize() {
-    await this.db.initialize();
+    await ensureDirectory(this.baseDir);
   }
 
-  async read(sessionId: string) {
-    const result = await this.db.query<ConversationStateRow>(
-      `
-        SELECT session_id, is_title_manually_edited, messages, branch_groups
-        FROM ${this.db.table("conversation_states")}
-        WHERE session_id = $1
-        LIMIT 1
-      `,
-      [sessionId],
-    );
-    return mapConversationStateRow(result.rows[0]);
+  async read(sessionScopeKey: string) {
+    return await readJsonFile<ConversationStateRecord>(this.filePath(sessionScopeKey));
   }
 
-  async write(sessionId: string, state: ConversationStateRecord) {
-    const result = await this.db.query<ConversationStateRow>(
-      `
-        INSERT INTO ${this.db.table("conversation_states")} (
-          session_id,
-          is_title_manually_edited,
-          messages,
-          branch_groups
-        )
-        VALUES ($1, $2, $3::jsonb, $4::jsonb)
-        ON CONFLICT (session_id)
-        DO UPDATE SET
-          is_title_manually_edited = EXCLUDED.is_title_manually_edited,
-          messages = EXCLUDED.messages,
-          branch_groups = EXCLUDED.branch_groups
-        RETURNING session_id, is_title_manually_edited, messages, branch_groups
-      `,
-      [
-        sessionId,
-        state.isTitleManuallyEdited ?? false,
-        JSON.stringify(state.messages),
-        JSON.stringify(state.branchGroups),
-      ],
-    );
-    return mapConversationStateRow(result.rows[0]) ?? state;
+  async write(sessionScopeKey: string, state: ConversationStateRecord) {
+    await atomicWriteJson(this.filePath(sessionScopeKey), state);
+    return state;
   }
 
-  async remove(sessionId: string) {
-    await this.db.query(
-      `
-        DELETE FROM ${this.db.table("conversation_states")}
-        WHERE session_id = $1
-      `,
-      [sessionId],
-    );
+  async remove(sessionScopeKey: string) {
+    await removeFileIfExists(this.filePath(sessionScopeKey));
+  }
+
+  private filePath(sessionScopeKey: string) {
+    return join(this.baseDir, `${sessionScopeKey}.json`);
   }
 }
-
-const mapConversationStateRow = (
-  row?: ConversationStateRow | null,
-): ConversationStateRecord | null => {
-  if (!row) {
-    return null;
-  }
-  return {
-    sessionId: row.session_id,
-    isTitleManuallyEdited: row.is_title_manually_edited,
-    messages: Array.isArray(row.messages) ? row.messages : [],
-    branchGroups: Array.isArray(row.branch_groups) ? row.branch_groups : [],
-  };
-};