import { describe, expect, test } from "bun:test";
import type { Command } from "./command";
import { createInitialAppState } from "@editor/initial-state";
import { createAppStore } from "@editor/store";
import { commandIds } from "./ids";
import { createCommandRegistry } from "./registry";
import { viewportPanCommand } from "./viewport";

const noOpCommand: Command<unknown> = {
  id: "test.noop",
  name: "No-op",
  execute: ({ state }) => state,
};

describe("command dispatcher", () => {
  test("throws for unknown commands", () => {
    const store = createAppStore(createInitialAppState("Test"), createCommandRegistry([]));
    expect(() => store.dispatch("missing" as never, undefined as never)).toThrow("Unknown command: missing");
  });

  test("dispatch applies command result to store", () => {
    const store = createAppStore(createInitialAppState("Test"), createCommandRegistry([viewportPanCommand]));
    store.dispatch(commandIds.viewportPan, { delta: { x: 3, y: 7 } });
    expect(store.getState().editor.viewport.center).toEqual({ x: 3, y: 7 });
  });

  test("repeated no-op commands do not emit or record history", () => {
    const initialState = createInitialAppState("Test");
    const store = createAppStore(initialState, createCommandRegistry([noOpCommand]));
    let notificationCount = 0;
    store.subscribe(() => {
      notificationCount += 1;
    });

    const firstResult = store.dispatch("test.noop" as never, undefined as never);
    const secondResult = store.dispatch("test.noop" as never, undefined as never);

    expect(firstResult).toBe(initialState);
    expect(secondResult).toBe(initialState);
    expect(store.getState()).toBe(initialState);
    expect(store.getState().history.past).toHaveLength(0);
    expect(store.getState().history.future).toHaveLength(0);
    expect(notificationCount).toBe(0);
  });
});