feat(layout): plan 01 — tile engine + view registry

1 files changed, 99 insertions, 0 deletions

diff --git a/src/features/layout/logic/seed.test.ts b/src/features/layout/logic/seed.test.ts
new file mode 100644
index 0000000..dfe166a
--- /dev/null
+++ b/src/features/layout/logic/seed.test.ts
@@ -0,0 +1,99 @@
+import { DEFAULT_LAYOUT, type LayoutTree, type SplitNode } from "@dispatch/layout-contract";
+import { describe, expect, it } from "vitest";
+import { DEFAULT_PANEL_VIEWS, overlaySidePanels, seedLayout } from "./seed";
+import { firstCollapsibleNodeId, firstPanelsNode } from "./tree-query";
+
+function sideViews(tree: LayoutTree): string[] {
+  const root = tree.root as SplitNode;
+  const side = root.children[1]?.node;
+  return side?.kind === "panels" ? side.panels.map((p) => p.view) : [];
+}
+
+describe("seedLayout", () => {
+  it("uses the default panels when nothing is stored", () => {
+    const tree = seedLayout(null, ["tabs", "model", "settings"]);
+    expect(sideViews(tree)).toEqual(DEFAULT_PANEL_VIEWS);
+  });
+
+  it("overlays the stored selection, dropping unknown/removed kinds", () => {
+    const tree = seedLayout(
+      ["extensions", "ghost-view", "model"],
+      ["tabs", "model", "extensions", "settings"],
+    );
+    expect(sideViews(tree)).toEqual(["extensions", "model"]);
+  });
+
+  it("falls back to the defaults when the stored selection is all-unknown or empty", () => {
+    expect(sideViews(seedLayout(["ghost"], ["tabs", "model"]))).toEqual(["tabs", "model"]);
+    expect(sideViews(seedLayout([], ["tabs", "model"]))).toEqual(["tabs", "model"]);
+  });
+
+  it("falls back to the defaults when the stored value is not a string array", () => {
+    expect(sideViews(seedLayout("junk", ["tabs", "model"]))).toEqual(["tabs", "model"]);
+    expect(sideViews(seedLayout([42], ["tabs", "model"]))).toEqual(["tabs", "model"]);
+    expect(sideViews(seedLayout({ a: 1 }, ["tabs", "model"]))).toEqual(["tabs", "model"]);
+  });
+
+  it("preserves the default tree's ids and the titlebar-unset invariant", () => {
+    const tree = seedLayout(["model"], ["tabs", "model"]);
+    expect((tree.root as SplitNode).id).toBe("root");
+    expect(tree.titlebar).toBeUndefined();
+  });
+});
+
+describe("overlaySidePanels", () => {
+  it("replaces only the side panels of the given base tree", () => {
+    const tree = overlaySidePanels(DEFAULT_LAYOUT, ["settings", "tasks"]);
+    expect(sideViews(tree)).toEqual(["settings", "tasks"]);
+    // The rest of the tree is untouched.
+    expect((tree.root as SplitNode).children[0]?.node).toEqual(
+      (DEFAULT_LAYOUT.root as SplitNode).children[0]?.node,
+    );
+  });
+});
+
+describe("tree queries", () => {
+  it("firstPanelsNode finds the side panels with its path", () => {
+    const tree = seedLayout(["model"], ["tabs", "model"]);
+    const found = firstPanelsNode(tree);
+    expect(found?.path).toEqual([1]);
+    expect(found?.node.panels.map((p) => p.view)).toEqual(["model"]);
+  });
+
+  it("firstCollapsibleNodeId returns the default tree's side node id", () => {
+    expect(firstCollapsibleNodeId(DEFAULT_LAYOUT)).toBe("side");
+  });
+
+  it("firstCollapsibleNodeId falls back to a path key when the node has no id", () => {
+    const tree: LayoutTree = {
+      version: 1,
+      root: {
+        kind: "split",
+        dir: "row",
+        children: [
+          { size: 1, node: { kind: "leaf", view: "chat" } },
+          {
+            size: 0,
+            basis: 320,
+            collapsible: true,
+            node: { kind: "panels", panels: [{ kind: "leaf", view: "tabs" }] },
+          },
+        ],
+      },
+    };
+    // The collapsible child sits at root path index 1 → key "1".
+    expect(firstCollapsibleNodeId(tree)).toBe("1");
+  });
+
+  it("firstCollapsibleNodeId returns null when nothing is collapsible", () => {
+    const tree: LayoutTree = {
+      version: 1,
+      root: {
+        kind: "split",
+        dir: "row",
+        children: [{ size: 1, node: { kind: "leaf", view: "chat" } }],
+      },
+    };
+    expect(firstCollapsibleNodeId(tree)).toBeNull();
+  });
+});