feat(FN-4785): complete Step 1 — add batched task column lookup

Fusion-Task-Id: FN-4785
Fusion-Task-Lineage: be241ee7-9df0-433c-a00b-997bcd558862

packages/core/src/__tests__/store-get-task-columns.test.ts

@@ -0,0 +1,77 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import { createTaskStoreTestHarness } from "./store-test-helpers.js";
+
+describe("TaskStore.getTaskColumns", () => {
+  const harness = createTaskStoreTestHarness();
+
+  beforeEach(async () => {
+    await harness.beforeEach();
+  });
+
+  afterEach(async () => {
+    await harness.afterEach();
+  });
+
+  it("returns empty map for empty input", async () => {
+    const store = harness.store();
+    const prepareSpy = vi.spyOn((store as any).db, "prepare");
+
+    const result = await store.getTaskColumns([]);
+
+    expect(result.size).toBe(0);
+    expect(prepareSpy).not.toHaveBeenCalled();
+  });
+
+  it("returns columns for active tasks", async () => {
+    const store = harness.store();
+    const one = await harness.createTestTask();
+    const two = await harness.createTestTask();
+    await store.moveTask(two.id, "in-progress");
+
+    const result = await store.getTaskColumns([one.id, two.id]);
+
+    expect(result.get(one.id)).toBe("todo");
+    expect(result.get(two.id)).toBe("in-progress");
+  });
+
+  it("maps archived tasks to archived column", async () => {
+    const store = harness.store();
+    const task = await harness.createTestTask();
+    await store.moveTask(task.id, "done");
+    await store.archiveTask(task.id);
+
+    const result = await store.getTaskColumns([task.id]);
+
+    expect(result.get(task.id)).toBe("archived");
+  });
+
+  it("handles mixed active, archived, and unknown ids", async () => {
+    const store = harness.store();
+    const active = await harness.createTestTask();
+    const archived = await harness.createTestTask();
+    await store.moveTask(archived.id, "done");
+    await store.archiveTask(archived.id);
+
+    const result = await store.getTaskColumns([active.id, archived.id, "FN-DOES-NOT-EXIST"]);
+
+    expect(result.get(active.id)).toBe("todo");
+    expect(result.get(archived.id)).toBe("archived");
+    expect(result.has("FN-DOES-NOT-EXIST")).toBe(false);
+  });
+
+  it("queries live tasks once for large batches", async () => {
+    const store = harness.store();
+    const tasks = await Promise.all(Array.from({ length: 120 }, () => harness.createTestTask()));
+    const ids = tasks.map((task) => task.id);
+
+    const prepareSpy = vi.spyOn((store as any).db, "prepare");
+    const result = await store.getTaskColumns(ids);
+
+    const liveColumnQueryCalls = prepareSpy.mock.calls.filter(([sql]) =>
+      typeof sql === "string" && sql.includes('SELECT id, "column" FROM tasks WHERE id IN ('),
+    );
+
+    expect(result.size).toBe(ids.length);
+    expect(liveColumnQueryCalls).toHaveLength(1);
+  });
+});

packages/core/src/store.ts

@@ -3300,6 +3300,44 @@ export class TaskStore extends EventEmitter<TaskStoreEvents> {
     });
   }
 
+  async getTaskColumns(ids: string[]): Promise<Map<string, Column>> {
+    if (ids.length === 0) {
+      return new Map();
+    }
+
+    const uniqueIds = [...new Set(ids)];
+    const placeholders = uniqueIds.map(() => "?").join(",");
+    const rows = this.db
+      .prepare(`SELECT id, "column" FROM tasks WHERE id IN (${placeholders})`)
+      .all(...uniqueIds) as Array<{ id: string; column: Column }>;
+
+    const activeById = new Map<string, Column>();
+    for (const row of rows) {
+      activeById.set(row.id, row.column);
+    }
+
+    const missingIds: string[] = [];
+    for (const id of uniqueIds) {
+      if (!activeById.has(id)) {
+        missingIds.push(id);
+      }
+    }
+
+    const archivedSet = missingIds.length > 0 ? this.archiveDb.filterArchived(missingIds) : new Set<string>();
+
+    const result = new Map<string, Column>();
+    for (const id of uniqueIds) {
+      const activeColumn = activeById.get(id);
+      if (activeColumn !== undefined) {
+        result.set(id, activeColumn);
+      } else if (archivedSet.has(id)) {
+        result.set(id, "archived");
+      }
+    }
+
+    return result;
+  }
+
   async listTasks(options?: {
     limit?: number;
     offset?: number;