import { describe, it, expect } from "vitest";
import { layoutGraph } from "./layout";
import type { ProcessStep, FlowEdge } from "../data/types";

const linearSteps: ProcessStep[] = [
  { id: "a", name: "A", kind: "start", owner: "system", governs: [], state: "done", actions: [] },
  { id: "b", name: "B", kind: "human", owner: "human", governs: [], state: "running", actions: [] },
  { id: "c", name: "C", kind: "end", owner: "system", governs: [], state: "idle", actions: [] },
];
const linearEdges: FlowEdge[] = [
  { id: "ab", source: "a", target: "b" },
  { id: "bc", source: "b", target: "c" },
];

describe("layoutGraph", () => {
  it("returns one position per step", () => {
    const positions = layoutGraph(linearSteps, linearEdges);
    expect(positions.length).toBe(linearSteps.length);
    expect(new Set(positions.map((p) => p.id))).toEqual(new Set(["a", "b", "c"]));
  });

  it("produces strictly-increasing x positions for a linear chain (LR layout)", () => {
    const positions = layoutGraph(linearSteps, linearEdges);
    const byId = Object.fromEntries(positions.map((p) => [p.id, p.position]));
    expect(byId.a.x).toBeLessThan(byId.b.x);
    expect(byId.b.x).toBeLessThan(byId.c.x);
  });

  it("handles disconnected nodes without crashing", () => {
    const positions = layoutGraph(
      [
        { id: "x", name: "X", kind: "start", owner: "system", governs: [], state: "idle", actions: [] },
        { id: "y", name: "Y", kind: "end", owner: "system", governs: [], state: "idle", actions: [] },
      ],
      [],
    );
    expect(positions.length).toBe(2);
  });
});