perf: вычитать лестницы из площади пола только по запросу (#669)

Путь чистого пола строят четыре места рендера, а площадь читают только
подсказка комнаты и PDF. cleanFloorForRoom больше не вычитает лестницы при
построении пути: площадь считается при первом чтении и хранится в том же
закэшированном объекте. geometryMinusStairs передаёт в polyclip только
контуры лестниц, чей габарит пересекает вычитаемую геометрию, — результат
тот же, а комната на этаже с 250 лестницами больше не прогоняет все 250.

Issue: #669
User-Visible: no
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018qZfe7YS4rqEMKoVeS3GKd

test/clean-floor.test.mjs

@@ -0,0 +1,76 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+
+import { cleanFloorForRoom } from '../test-build/clean-floor.js';
+import { geometryAreaMinusStairs } from '../test-build/stairs.js';
+
+// #669: the four render paths read only `path`; the room tooltip and the PDF
+// read `area`. The stair subtraction behind `area` must wait for that read.
+const floor = [[100, 100], [500, 100], [500, 500], [100, 500]];
+const room = { id: 'room-a' };
+const stair = {
+  id: 'stair-a', kind: 'straight', x: 0.3, y: 0.3, angle: 0,
+  direction: 'forward', length: 0.1, width: 0.05, target_space_id: 'upper',
+};
+const column = [[400, 400], [440, 400], [440, 440], [400, 440]];
+const space = { id: 'space-a', rooms: [room], stairs: [stair] };
+
+const counting = () => {
+  const calls = { count: 0 };
+  const areaMinusStairs = (source, stairs) => {
+    calls.count += 1;
+    return geometryAreaMinusStairs(source, stairs);
+  };
+  return { calls, areaMinusStairs };
+};
+
+const build = (overrides = {}) => cleanFloorForRoom({
+  room, floor, space, configEpoch: 3, resizePreview: false, cache: new Map(),
+  physicalBodies: () => [column], ...overrides,
+});
+
+test('#669 AC1 a floor path does not subtract stairs until the area is read', () => {
+  const { calls, areaMinusStairs } = counting();
+  const cache = new Map();
+  const result = build({ cache, areaMinusStairs });
+  assert.ok(result.path.length > 0, 'the path is built from the floor minus the column');
+  assert.equal(calls.count, 0, 'building the path must not run the stair subtraction');
+
+  const area = result.area;
+  assert.equal(calls.count, 1, 'the first read subtracts once');
+  assert.equal(result.area, area);
+  assert.equal(calls.count, 1, 'a second read reuses the value');
+
+  const again = build({ cache, areaMinusStairs });
+  assert.equal(again, result, 'the cached result is returned');
+  assert.equal(again.area, area);
+  assert.equal(calls.count, 1, 'a cache hit does not subtract again');
+});
+
+test('#669 AC1 the lazy area equals the eager subtraction and still removes stairs', () => {
+  const result = build();
+  const expected = geometryAreaMinusStairs(result.geom, space.stairs);
+  assert.ok(Math.abs(result.area - expected) <= expected * 1e-9);
+  const withoutStairs = build({ space: { ...space, stairs: [] } }).area;
+  assert.ok(result.area < withoutStairs - 1, 'the stair footprint is subtracted');
+});
+
+test('#669 AC1 the resize preview is not cached and stays lazy', () => {
+  const { calls, areaMinusStairs } = counting();
+  const cache = new Map();
+  const preview = build({ cache, resizePreview: true, areaMinusStairs });
+  assert.equal(cache.size, 0);
+  assert.equal(calls.count, 0);
+  assert.ok(preview.area > 0);
+  assert.equal(calls.count, 1);
+});
+
+test('#669 AC1 a room without independent bodies subtracts stairs from the plain floor', () => {
+  const { calls, areaMinusStairs } = counting();
+  const result = build({ physicalBodies: () => [], areaMinusStairs });
+  assert.equal(result.geom, null);
+  assert.equal(calls.count, 0);
+  const plain = geometryAreaMinusStairs([[[...floor, floor[0]]]], space.stairs);
+  assert.ok(Math.abs(result.area - plain) <= plain * 1e-9);
+  assert.equal(calls.count, 1);
+});

test/stairs.test.mjs

@@ -8,8 +8,12 @@ import {
   geometryAreaMinusStairs,
   geometryMinusStairsSteps,
   isStair,
+  stairFootprintGeometry,
+  stairFootprintsTouching,
   stairRenderGeometry,
 } from '../test-build/stairs.js';
+import { geometryArea } from '../test-build/physical-geometry.js';
+import { difference } from 'polyclip-ts';
 import {
   convertStairKind,
   defaultStair,
@@ -207,3 +211,56 @@ test('#663 legacy-no-stairs-config never materializes an empty stair collection'
   assert.equal(Object.hasOwn(result.config.spaces[0], 'stairs'), false);
   assert.deepEqual(legacy, before, 'Optimize remains immutable for the caller');
 });
+
+// #669 AC2: the bounds filter must not change the subtraction it shortens.
+const unfilteredArea = (source, stairs) => {
+  const footprints = stairs.map((stair) => stairFootprintGeometry(stair));
+  return Math.max(0, geometryArea(footprints.length ? difference(source, ...footprints) : source));
+};
+
+test('#669 AC2 stair area with the bounds filter equals the unfiltered subtraction', () => {
+  const room = [[[[200, 200], [600, 200], [600, 600], [200, 600], [200, 200]]]];
+  const stairs = [
+    straight({ id: 'inside', x: 0.3, y: 0.3, length: 0.1, width: 0.05 }),
+    straight({ id: 'rotated', x: 0.45, y: 0.45, angle: 45, length: 0.12, width: 0.04 }),
+    straight({ id: 'edge', x: 0.6, y: 0.4, angle: 90, length: 0.1, width: 0.05 }),
+    straight({ id: 'corner', x: 0.2, y: 0.2, angle: 135, length: 0.08, width: 0.05 }),
+    spiral({ id: 'spiral-inside', x: 0.5, y: 0.3, radius: 0.04 }),
+    spiral({ id: 'spiral-edge', x: 0.4, y: 0.6, radius: 0.05 }),
+    straight({ id: 'overlap-a', x: 0.35, y: 0.5, length: 0.1, width: 0.06 }),
+    straight({ id: 'overlap-b', x: 0.36, y: 0.52, angle: 90, length: 0.1, width: 0.06 }),
+    straight({ id: 'far-a', x: 0.9, y: 0.9, length: 0.1, width: 0.05 }),
+    spiral({ id: 'far-b', x: 0.05, y: 0.9, radius: 0.03 }),
+  ];
+  const expected = unfilteredArea(room, stairs);
+  const actual = geometryAreaMinusStairs(room, stairs);
+  assert.ok(Math.abs(actual - expected) <= expected * 1e-9, `${actual} vs ${expected}`);
+  assert.ok(actual < 160_000, 'the touching stairs are subtracted');
+});
+
+test('#669 AC2 stairs whose bounds miss the room never reach polyclip', () => {
+  const room = [[[[200, 200], [600, 200], [600, 600], [200, 600], [200, 200]]]];
+  const stairs = [
+    straight({ id: 'inside', x: 0.3, y: 0.3, length: 0.1, width: 0.05 }),
+    spiral({ id: 'edge', x: 0.4, y: 0.6, radius: 0.05 }),
+    straight({ id: 'far-a', x: 0.9, y: 0.9, length: 0.1, width: 0.05 }),
+    spiral({ id: 'far-b', x: 0.05, y: 0.9, radius: 0.03 }),
+  ];
+  const touching = stairFootprintsTouching(room, stairs);
+  assert.equal(touching.length, 2, 'only the inside and the edge stair are passed on');
+  assert.deepEqual(stairFootprintsTouching([], stairs), [], 'an empty subject touches nothing');
+});
+
+test('#669 AC2 a maximum stair collection keeps the room area and passes a bounded subset', () => {
+  const stairs = Array.from({ length: 250 }, (_, index) => {
+    const common = { id: `grid-${index}`, x: 0.025 + (index % 25) * 0.039, y: 0.03 + Math.floor(index / 25) * 0.1,
+      angle: (index % 8) * 45 };
+    return index % 2 ? spiral({ ...common, radius: 0.05 }) : straight({ ...common, length: 0.12, width: 0.045 });
+  });
+  const room = [[[[100, 100], [300, 100], [300, 300], [100, 300], [100, 100]]]];
+  const touching = stairFootprintsTouching(room, stairs);
+  assert.ok(touching.length > 0 && touching.length < 50, `${touching.length} of 250 touch the room bounds`);
+  const expected = unfilteredArea(room, stairs);
+  const actual = geometryAreaMinusStairs(room, stairs);
+  assert.ok(Math.abs(actual - expected) <= Math.max(expected, 1) * 1e-9, `${actual} vs ${expected}`);
+});