import { describe, expect, it } from "vitest";
import { beltMapRadii, beltRocks, placeRocks } from "../src/map/belt";
import { MAX_ZOOM, MIN_ZOOM, toScreen } from "../src/map/camera";
import { hitTest } from "../src/map/hitTest";
import { layoutScene, spriteScale } from "../src/map/layout";
import { buildScene } from "../src/map/scene";
import { mapStyle } from "../src/map/style";
import { samplePlayerState } from "./render";

const NOW = Date.parse("2100-01-01T00:00:00Z");
const views = [
  { width: 1280, height: 800 },
  { width: 390, height: 844 },
];
const zooms = [MIN_ZOOM, 1, 3, 12, MAX_ZOOM];
const scene = buildScene(samplePlayerState(), NOW);

describe("the belt's rocks (Step 16.7, decision 0.5.104)", () => {
  it("places the same rocks every time", () => {
    expect(beltRocks(6)).toEqual(beltRocks(6));
    expect(beltRocks(6)).toHaveLength(mapStyle.belt.rocks.count);
  });

  it("keeps every rock inside the band, denser toward its middle", () => {
    const { inner, outer } = beltMapRadii();
    const rocks = beltRocks(6);
    const middle = rocks.filter((r) => {
      const t = (Math.hypot(r.x, r.y) - inner) / (outer - inner);
      expect(t).toBeGreaterThanOrEqual(0);
      expect(t).toBeLessThanOrEqual(1);
      return t > 0.25 && t < 0.75;
    });
    // A uniform scatter would put half in the middle half; the falloff puts more there.
    expect(middle.length / rocks.length).toBeGreaterThan(0.6);
  });

  it("is mostly small rocks with a few larger ones, using every rock image", () => {
    const rocks = beltRocks(6);
    const { min, max } = mapStyle.belt.rocks.sizePx;
    const small = rocks.filter((r) => r.sizePx < min + (max - min) / 3).length;
    expect(small / rocks.length).toBeGreaterThan(0.6);
    expect(rocks.some((r) => r.sizePx > min + ((max - min) * 2) / 3)).toBe(true);
    expect(new Set(rocks.map((r) => r.piece)).size).toBe(6);
  });

  it("never draws a rock over Ceres, at any zoom or screen size", () => {
    const rocks = beltRocks(6);
    for (const view of views) {
      for (const zoom of zooms) {
        const camera = { zoom, panX: 0, panY: 0 };
        const layout = layoutScene(scene, view, camera);
        const ceres = layout.locations.find((l) => l.id === "ceres-station")!;
        const placed = placeRocks(rocks, view, camera, layout.scale, ceres);
        for (const { center, size } of placed) {
          const gap = Math.hypot(center.x - ceres.center.x, center.y - ceres.center.y);
          expect(gap).toBeGreaterThanOrEqual(ceres.size / 2 + mapStyle.belt.rocks.ceresMarginPx);
          expect(gap - size / 2).toBeGreaterThanOrEqual(ceres.size / 2);
        }
        // Rocks near Ceres were left out; the rest are drawn at the sprite scale.
        expect(placed.length).toBeLessThanOrEqual(rocks.length);
        for (const { rock, size } of placed) {
          expect(size).toBeCloseTo(rock.sizePx * spriteScale(zoom), 9);
        }
      }
    }
  });

  it("lets a tap on a rock reach whatever is beneath it", () => {
    const view = views[0]!;
    const camera = { zoom: 1, panX: 0, panY: 0 };
    const layout = layoutScene(scene, view, camera);
    const placed = placeRocks(beltRocks(6), view, camera, layout.scale, null);
    for (const { center } of placed) {
      const hit = hitTest(scene, center, view, camera);
      // Never the rock: empty map, or a location whose tap target is there.
      if (hit !== null) {
        expect(hit.kind).toBe("location");
        const loc = layout.locations.find((l) => hit.kind === "location" && l.id === hit.id)!;
        expect(Math.hypot(center.x - loc.center.x, center.y - loc.center.y)).toBeLessThanOrEqual(
          loc.tap / 2,
        );
      }
    }
    // And most rocks sit over empty map.
    expect(
      placed.filter(({ center }) => hitTest(scene, center, view, camera) === null).length,
    ).toBeGreaterThan(placed.length / 2);
    expect(toScreen({ x: 0, y: 0 }, view, camera)).toEqual(layout.sun.center);
  });
});