import { describe, expect, it } from "vitest";
import { MAX_ZOOM, MIN_ZOOM } from "../src/map/camera";
import { backgroundRect } from "../src/map/layout";

const viewports = [
  { width: 390, height: 700 },
  { width: 1280, height: 720 },
  { width: 2560, height: 1440 },
  { width: 320, height: 2000 },
];
const pans = [-50_000, -800, -1, 0, 3, 640, 50_000];
const zooms = [MIN_ZOOM, 0.75, 1, 3, 12, MAX_ZOOM];
const images = [
  { width: 1254, height: 1254 },
  { width: 2048, height: 1024 },
];

describe("background placement (decision 0.5.40)", () => {
  it("always fully contains the viewport", () => {
    for (const view of viewports) {
      for (const image of images) {
        for (const panX of pans) {
          for (const panY of pans) {
            for (const zoom of zooms) {
              const r = backgroundRect(view, { zoom, panX, panY }, image);
              const where = JSON.stringify({ view, image, panX, panY, zoom, r });
              expect(r.x, where).toBeLessThanOrEqual(0);
              expect(r.y, where).toBeLessThanOrEqual(0);
              expect(r.x + r.width, where).toBeGreaterThanOrEqual(view.width - 1e-9);
              expect(r.y + r.height, where).toBeGreaterThanOrEqual(view.height - 1e-9);
            }
          }
        }
      }
    }
  });

  it("moves a fraction of the pan (parallax) and keeps its aspect ratio", () => {
    const view = { width: 1280, height: 720 };
    const image = { width: 1254, height: 1254 };
    const still = backgroundRect(view, { zoom: 1, panX: 0, panY: 0 }, image);
    const panned = backgroundRect(view, { zoom: 1, panX: 100, panY: -60 }, image);
    expect(panned.x - still.x).toBeCloseTo(15);
    expect(panned.y - still.y).toBeCloseTo(-9);
    expect(still.width / still.height).toBeCloseTo(1);
  });

  it("zooms only slightly with the map", () => {
    const view = { width: 1280, height: 720 };
    const image = { width: 1254, height: 1254 };
    const one = backgroundRect(view, { zoom: 1, panX: 0, panY: 0 }, image);
    const far = backgroundRect(view, { zoom: MAX_ZOOM, panX: 0, panY: 0 }, image);
    expect(far.width / one.width).toBeGreaterThan(1);
    expect(far.width / one.width).toBeLessThan(1.3);
  });
});