// ============ rendercheck.mjs — regression test for terrain culling ============
let fails = 0;
const ok = (cond, msg) => { console.log((cond ? '✔ ' : '✘ ') + msg); if (!cond) fails++; };

globalThis.window = globalThis;
globalThis.requestAnimationFrame = () => 0;
globalThis.document = {
  getElementById: () => null, createElement: () => ({ style: {}, classList: { add() {}, remove() {} }, addEventListener() {}, appendChild() {} }),
  addEventListener() {}, body: { appendChild() {} },
};
globalThis.localStorage = { getItem: () => null, setItem() {}, removeItem() {} };

const R = await import('../js/render/renderer.js');
const { visibleBounds, worldToScreen, screenToWorld } = R;
ok(typeof visibleBounds === 'function', 'visibleBounds exported');

// --- camera translation regression: panning MUST shift screen coords ---
const camA = { x: 20, y: 20, zoom: 1 };
const camB = { x: 30, y: 26, zoom: 1 };
const [ax] = worldToScreen(camA, 1280, 800, 10, 10);
const [bx] = worldToScreen(camB, 1280, 800, 10, 10);
ok(Math.abs(bx - ax) > 50, `worldToScreen shifts with cam.x (${ax.toFixed(0)} → ${bx.toFixed(0)})`);
const [, ay2] = worldToScreen(camA, 1280, 800, 10, 10);
const camC = { x: 20, y: 30, zoom: 1 };
const [, cy2] = worldToScreen(camC, 1280, 800, 10, 10);
ok(Math.abs(cy2 - ay2) > 50, `worldToScreen shifts with cam.y (${ay2.toFixed(0)} → ${cy2.toFixed(0)})`);

// --- roundtrip screen→world→screen identity ---
for (const cz of [0.5, 1, 1.7]) {
  const c = { x: 25.3, y: 41.8, zoom: cz };
  const [sx, sy] = worldToScreen(c, 1280, 800, 12.4, 33.9, 0);   // ground plane
  const [wx, wy] = screenToWorld(c, 1280, 800, sx, sy);
  ok(wx === 12 && wy === 33,
    `roundtrip zoom ${cz}: (${sx.toFixed(0)},${sy.toFixed(0)}) → (${wx},${wy}) expect (12,33)`);
}

// --- visibleBounds must follow the camera ---
const bA = visibleBounds({ x: 5, y: 5, zoom: 1 }, 1280, 800, 80);
const bB = visibleBounds({ x: 40, y: 40, zoom: 1 }, 1280, 800, 80);
ok(bB.x0 > bA.x0 + 10 && bB.y0 > bA.y0 + 10, `bounds track camera (x0 ${bA.x0}→${bB.x0}, y0 ${bA.y0}→${bB.y0})`);

const cases = [
  { name: 'center of 52-map, zoom 1', cam: { x: 26, y: 26, zoom: 1 }, cw: 1280, ch: 800 },
  { name: 'entrance area, zoom 1', cam: { x: 28, y: 44, zoom: 1 }, cw: 1280, ch: 800 },
  { name: 'zoomed out 0.5', cam: { x: 26, y: 26, zoom: 0.5 }, cw: 1280, ch: 800 },
  { name: 'zoomed in 2', cam: { x: 26, y: 26, zoom: 2 }, cw: 1920, ch: 1080 },
];
for (const c of cases) {
  const b = visibleBounds(c.cam, c.cw, c.ch, 80);
  const spanX = b.x1 - b.x0, spanY = b.y1 - b.y0;
  // exact iso-diamond coverage: ((cw+2p)/(TW2·z) + (ch+2p)/(TH2·z)) / 2 per axis
  const p = 80;
  const expectSpan = ((c.cw + 2 * p) / (32 * c.cam.zoom) + (c.ch + 2 * p) / (16 * c.cam.zoom)) / 2;
  ok(spanX >= expectSpan - 2 && spanY >= expectSpan - 2,
    `${c.name}: span ${spanX}×${spanY} tiles (expect ≈${Math.round(expectSpan)})`);
}

// the old bug produced a y-span of roughly 10 rows on a 1280×800 @zoom1 view
const b = visibleBounds({ x: 26, y: 26, zoom: 1 }, 1280, 800, 80);
ok(b.y1 - b.y0 > 40, `vertical coverage fixed (${b.y1 - b.y0} rows, was ~10 before)`);

console.log(fails ? `\n${fails} RENDER FAILURES` : '\nRENDER CULLING OK');
process.exit(fails ? 1 : 0);