import { content } from "@deadhead/content";
import { describe, expect, it } from "vitest";
import { routeDistance } from "../src/index";

const earth = content.location("earth")!;
const moon = content.location("moon")!;
const mars = content.location("mars")!;

const start = Date.parse("2100-01-01T00:00:00Z");
const MS_PER_DAY = 86_400_000;
/** Game times sampled every ~30 days across two years. */
const monthly = Array.from({ length: 25 }, (_, i) => start + i * 30 * MS_PER_DAY);

describe("route distance", () => {
  it("keeps Earth→Moon under 1 million km at any time", () => {
    for (const t of monthly) {
      expect(routeDistance(earth, moon, t)).toBeLessThan(1);
    }
  });

  it("gives the same distance at every time (decision 0.5.93)", () => {
    const first = routeDistance(earth, mars, monthly[0]!);
    for (const t of monthly) expect(routeDistance(earth, mars, t)).toBe(first);
  });

  it("is symmetric", () => {
    for (const a of content.locations) {
      for (const b of content.locations) {
        expect(routeDistance(a, b, start)).toBe(routeDistance(b, a, start));
      }
    }
  });
});