SlabUploader/frontend/src/png/overlay.test.ts

import { test } from 'node:test';
import assert from 'node:assert/strict';
import {
  overlayWidthStations,
  pickBottomTowardTop,
  axisRightUnit,
  buildOverlayPlan,
  inventorySourceMap,
  type OverlayPlan,
} from './overlay.ts';
import { orientedRect, minAreaRect } from '../geometry/rect.ts';
import { axisEndpoints } from '../measure/measure.ts';

// --- Station math (#63) ---

test('overlayWidthStations: every 12 in from 6 while ≤ L−6 (#63)', () => {
  assert.deepEqual(overlayWidthStations(48), [6, 18, 30, 42]);
  assert.deepEqual(overlayWidthStations(40), [6, 18, 30]);
  assert.deepEqual(overlayWidthStations(12), [6]);
  assert.deepEqual(overlayWidthStations(18), [6]);
  assert.deepEqual(overlayWidthStations(19), [6]); // L−6=13 → 18 excluded
  assert.deepEqual(overlayWidthStations(11), []);
  assert.deepEqual(overlayWidthStations(10), []);
  assert.deepEqual(overlayWidthStations(6), []);
  assert.deepEqual(overlayWidthStations(24), [6, 18]);
  assert.deepEqual(overlayWidthStations(30), [6, 18]);
});

test('overlayWidthStations: never tip-inclusive 0 or L (#63)', () => {
  for (const L of [24, 36, 48, 60, 72]) {
    const stations = overlayWidthStations(L);
    assert.ok(!stations.includes(0), `L=${L} must not include tip 0`);
    assert.ok(!stations.includes(L), `L=${L} must not include tip L`);
    for (const s of stations) {
      assert.ok(s >= 6 && s <= L - 6, `station ${s} within [6, L−6] for L=${L}`);
      assert.equal((s - 6) % 12, 0, `station ${s} is 6+12k`);
    }
  }
});

// --- EXIF-oriented bottom along approved axis (#63) ---

test('pickBottomTowardTop: larger y is bottom (EXIF-oriented photo, y↓) (#63)', () => {
  // Axis along +y (down the photo): start at top, end at bottom of span
  const start: [number, number] = [100, 50]; // top of photo
  const end: [number, number] = [100, 450]; // bottom of photo
  const { bottom, top, ux, uy } = pickBottomTowardTop(start, end);
  assert.deepEqual(bottom, end, 'end nearer photo bottom is bottom');
  assert.deepEqual(top, start);
  // Unit from bottom → top points up (−y)
  assert.ok(Math.abs(ux) < 1e-9);
  assert.ok(uy < 0, `uy=${uy} must point toward photo top`);
});

test('pickBottomTowardTop: flipped axis endpoints still pick EXIF bottom (#63)', () => {
  const a: [number, number] = [50, 400]; // bottom-ish
  const b: [number, number] = [50, 40]; // top-ish
  const r1 = pickBottomTowardTop(a, b);
  const r2 = pickBottomTowardTop(b, a);
  assert.deepEqual(r1.bottom, a);
  assert.deepEqual(r2.bottom, a);
  assert.deepEqual(r1.top, b);
  assert.deepEqual(r2.top, b);
});

test('pickBottomTowardTop: length-axis direction stays on approved span (not photo upright) (#63)', () => {
  // Diagonal approved axis — bottom is still the larger-y end, unit follows the diagonal
  const start: [number, number] = [10, 10];
  const end: [number, number] = [210, 410];
  const { bottom, top, ux, uy } = pickBottomTowardTop(start, end);
  assert.deepEqual(bottom, end);
  assert.deepEqual(top, start);
  const len = Math.hypot(top[0] - bottom[0], top[1] - bottom[1]);
  assert.ok(Math.abs(Math.hypot(ux, uy) - 1) < 1e-9);
  assert.ok(Math.abs(ux - (top[0] - bottom[0]) / len) < 1e-9);
  assert.ok(Math.abs(uy - (top[1] - bottom[1]) / len) < 1e-9);
});

test('axisRightUnit: right of bottom→top travel in canvas (y↓) (#63)', () => {
  // Travel up (−y): facing up, right is +x
  const [rx, ry] = axisRightUnit(0, -1);
  assert.ok(rx > 0.99 && Math.abs(ry) < 1e-9, `right of up should be +x, got (${rx},${ry})`);
  // Travel +x (right): facing right, right is +y (down)
  const [rx2, ry2] = axisRightUnit(1, 0);
  assert.ok(Math.abs(rx2) < 1e-9 && ry2 > 0.99, `right of +x should be +y, got (${rx2},${ry2})`);
});

// --- Overlay plan geometry (#63) ---

test('buildOverlayPlan: length line on axis-right outside slab; widths at 12in stations (#63)', () => {
  // Uniform 480×100 slab @ 10 px/in → L=48in, axis +x. Photo taller so bottom is clear.
  // Place slab in a tall canvas so EXIF bottom (large y) picks the +x? Wait axis is +x (horizontal).
  // For horizontal axis both ends have same y — tie-break must be stable.
  const W = 480, H = 200;
  const bitset = new Uint8Array(W * H);
  // Slab occupies y=50..149, x=0..479 (full width strip)
  for (let y = 50; y < 150; y++) for (let x = 0; x < W; x++) bitset[y * W + x] = 1;
  const box = orientedRect(minAreaRect(bitset, W, H)!, 0); // long side +x
  const scale = 10; // px/in
  const lengthIn = 48;
  const plan = buildOverlayPlan({
    bitset,
    widthPx: W,
    heightPx: H,
    bbox: box,
    scale,
    lengthIn,
    lengthLabel: '48"',
    // Identity inventory map (source == inventory) for unit geometry
    mapToInventory: (x, y) => [x, y],
  });

  assert.ok(plan.length, 'must include length dimension');
  assert.equal(plan.widths.length, 4, 'stations 6,18,30,42');
  assert.deepEqual(
    plan.widths.map((w) => w.stationIn),
    [6, 18, 30, 42],
  );

  // Length graphic must sit to the axis-right of the wood (outside edge)
  const mid = plan.length;
  // For axis +x, bottom tie-break: if y equal, pickBottomTowardTop uses a documented rule.
  // Right of bottom→top should be outside the slab along the short axis.
  assert.ok(
    mid.outside,
    'length dimension must be flagged outside the slab on axis-right',
  );

  // Width arrows: tips at left/right slab edges (perp extent), text on line
  for (const w of plan.widths) {
    assert.ok(w.left && w.right, 'width has left/right tips');
    assert.ok(typeof w.label === 'string' && w.label.length > 0, 'width has measurement text');
    // Across wood: left and right differ primarily along short axis (±y for +x length)
    const dx = w.right[0] - w.left[0];
    const dy = w.right[1] - w.left[1];
    assert.ok(Math.abs(dy) > Math.abs(dx), 'width span is across (perp to +x length)');
  }

  // Color contract for draw consumers
  assert.equal(plan.stroke, '#000000');
  assert.ok(plan.fontPx >= 18, `fontPx ${plan.fontPx} large enough to read`);
});

test('buildOverlayPlan: stations measured from EXIF bottom, not tip-inclusive M1 every-6 (#63)', () => {
  // Vertical slab: length along +y (photo upright matches axis). Bottom = larger y.
  const W = 100, H = 480;
  const bitset = new Uint8Array(W * H).fill(1);
  const box = orientedRect(minAreaRect(bitset, W, H)!, 90); // long side +y
  const plan = buildOverlayPlan({
    bitset,
    widthPx: W,
    heightPx: H,
    bbox: box,
    scale: 10,
    lengthIn: 48,
    lengthLabel: '48"',
    mapToInventory: (x, y) => [x, y],
  });
  assert.deepEqual(
    plan.widths.map((w) => w.stationIn),
    [6, 18, 30, 42],
    'must be 12in overlay stations, not M1 every-6 tip-trimmed list',
  );
  // First station is 6in up from photo-bottom end of span
  const first = plan.widths[0];
  // Bottom of photo is y=H-ish; 6in @ 10px/in = 60px toward top → y ≈ H-1 - 60
  assert.ok(first.center[1] > H / 2, 'first station nearer the photo bottom half');
});

test('buildOverlayPlan: dishonest upright-photo axes rejected — uses approved bbox axis (#63)', () => {
  // Slab long along +x but we approve axis at 0; plan length direction must follow bbox, not image H.
  const W = 400, H = 120;
  const bitset = new Uint8Array(W * H).fill(1);
  const box = orientedRect(minAreaRect(bitset, W, H)!, 0);
  const plan: OverlayPlan = buildOverlayPlan({
    bitset,
    widthPx: W,
    heightPx: H,
    bbox: box,
    scale: 10,
    lengthIn: 40,
    lengthLabel: '40"',
    mapToInventory: (x, y) => [x, y],
  });
  // Length line endpoints should differ mainly in x (along approved axis), not y
  const lx = Math.abs(plan.length.a[0] - plan.length.b[0]);
  const ly = Math.abs(plan.length.a[1] - plan.length.b[1]);
  assert.ok(lx > ly * 2, `length graphic follows approved +x axis (dx=${lx}, dy=${ly})`);
});

// --- Ty UAT nits (#67) ---

test('buildOverlayPlan: length endpoints snap to mask tips, not oversized bbox corners (#67)', () => {
  // Wood occupies x=100..299 only; synthetic bbox long side extends past tips (x=50..350).
  const W = 400, H = 160;
  const bitset = new Uint8Array(W * H);
  for (let y = 40; y < 100; y++) for (let x = 100; x < 300; x++) bitset[y * W + x] = 1;
  const bbox = {
    corners: [
      [350, 100],
      [350, 40],
      [50, 40],
      [50, 100],
    ] as [number, number][],
    longSidePx: 300,
    angleDeg: 0,
  };
  const plan = buildOverlayPlan({
    bitset,
    widthPx: W,
    heightPx: H,
    bbox,
    scale: 10,
    lengthIn: 20,
    lengthLabel: '20"',
    mapToInventory: (x, y) => [x, y],
  });

  // Length line sits on axis-right; project a/b onto the length axis through the
  // wood centroid — endpoints must match mask span ends, not bbox corners.
  const oriented = pickBottomTowardTop([100, 70], [299, 70]);
  const strip = (p: [number, number]): [number, number] => {
    const cx = 199.5, cy = 70;
    const along = (p[0] - cx) * oriented.ux + (p[1] - cy) * oriented.uy;
    return [cx + oriented.ux * along, cy + oriented.uy * along];
  };
  const xs = [strip(plan.length.a)[0], strip(plan.length.b)[0]].sort((a, b) => a - b);
  // Mask tips ≈ 100 and 299 (inclusive pixels); bbox corners at 50 and 350
  assert.ok(Math.abs(xs[0] - 100) <= 2, `mask min tip ${xs[0]} ≈ 100, not bbox 50`);
  assert.ok(Math.abs(xs[1] - 299) <= 2, `mask max tip ${xs[1]} ≈ 299, not bbox 350`);
  assert.ok(Math.abs(xs[0] - 50) > 20, 'must not use bbox corner at 50');
  assert.ok(Math.abs(xs[1] - 350) > 20, 'must not use bbox corner at 350');
});

test('buildOverlayPlan: width labels sit axis-left outside the slab (#67)', () => {
  // Uniform strip: length +x, width along y. Axis-right of bottom→top is −y (up).
  const W = 480, H = 200;
  const bitset = new Uint8Array(W * H);
  for (let y = 50; y < 150; y++) for (let x = 0; x < W; x++) bitset[y * W + x] = 1;
  const box = orientedRect(minAreaRect(bitset, W, H)!, 0);
  const plan = buildOverlayPlan({
    bitset,
    widthPx: W,
    heightPx: H,
    bbox: box,
    scale: 10,
    lengthIn: 48,
    lengthLabel: '48"',
    mapToInventory: (x, y) => [x, y],
  });
  assert.ok(plan.widths.length > 0);
  for (const w of plan.widths) {
    assert.ok(w.labelAt, 'width mark must expose labelAt');
    // left/right tips still on wood edges
    assert.ok(Math.abs(w.left[1] - 149) <= 2 || Math.abs(w.left[1] - 50) <= 2);
    assert.ok(Math.abs(w.right[1] - 149) <= 2 || Math.abs(w.right[1] - 50) <= 2);
    // labelAt on axis-left = opposite of axis-right from center
    // For this geometry, axis-right is toward smaller y; axis-left toward larger y
    // (outside past the bottom edge y≈149).
    const cy = w.center[1];
    assert.ok(
      w.labelAt[1] > Math.max(w.left[1], w.right[1]) + 4,
      `width labelAt y=${w.labelAt[1]} must sit past slab edge (left of travel), not on wood center y=${cy}`,
    );
    assert.ok(
      Math.abs(w.labelAt[0] - w.center[0]) < 3,
      'width label stays on the station cross-section (same x as center)',
    );
  }
  // Length stays axis-right (outside opposite side)
  const lenY = (plan.length.a[1] + plan.length.b[1]) / 2;
  assert.ok(lenY < 50 - 4, `length dim stays axis-right outside top edge, got y=${lenY}`);
});

test('buildOverlayPlan: font one step smaller than prior 28 / scale*1.2 (#67)', () => {
  const W = 480, H = 200;
  const bitset = new Uint8Array(W * H);
  for (let y = 50; y < 150; y++) for (let x = 0; x < W; x++) bitset[y * W + x] = 1;
  const box = orientedRect(minAreaRect(bitset, W, H)!, 0);
  const scale = 10;
  const plan = buildOverlayPlan({
    bitset,
    widthPx: W,
    heightPx: H,
    bbox: box,
    scale,
    lengthIn: 48,
    lengthLabel: '48"',
    mapToInventory: (x, y) => [x, y],
  });
  const oldFont = Math.max(28, Math.round(scale * 1.2));
  assert.ok(plan.fontPx < oldFont, `fontPx ${plan.fontPx} must be < prior ${oldFont}`);
  assert.ok(plan.fontPx >= 18, `fontPx ${plan.fontPx} still legible`);
  // Concrete contract: max(22, round(scale*1.0))
  assert.equal(plan.fontPx, Math.max(22, Math.round(scale * 1.0)));
});


// --- Length dim must not overshoot wood footprint (#69) ---

/** Tilted-axis slab: irregular mask + approved bbox long side ~10° from vertical. */
function tiltedSlabFixture() {
  const W = 300, H = 600;
  const bitset = new Uint8Array(W * H);
  for (let y = 50; y <= 550; y++) {
    const t = (y - 50) / 500;
    const x0 = Math.round(80 + t * 20);
    const x1 = Math.round(180 + t * 40);
    for (let x = x0; x <= x1; x++) bitset[y * W + x] = 1;
  }
  const ang = (10 * Math.PI) / 180;
  const ux0 = Math.sin(ang);
  const uy0 = Math.cos(ang);
  const rx0 = -uy0;
  const ry0 = ux0;
  const cx = 140, cy = 300, halfL = 280, halfW = 90;
  const corners: [number, number][] = [
    [cx + ux0 * halfL + rx0 * halfW, cy + uy0 * halfL + ry0 * halfW],
    [cx + ux0 * halfL - rx0 * halfW, cy + uy0 * halfL - ry0 * halfW],
    [cx - ux0 * halfL - rx0 * halfW, cy - uy0 * halfL - ry0 * halfW],
    [cx - ux0 * halfL + rx0 * halfW, cy - uy0 * halfL + ry0 * halfW],
  ];
  const bbox = { corners, longSidePx: halfL * 2, angleDeg: 80 };
  return { W, H, bitset, bbox };
}

function maskWoodAabb(bitset: Uint8Array, W: number, H: number) {
  let minX = W, maxX = 0, minY = H, maxY = 0;
  for (let y = 0; y < H; y++) {
    for (let x = 0; x < W; x++) {
      if (!bitset[y * W + x]) continue;
      if (x < minX) minX = x;
      if (x > maxX) maxX = x;
      if (y < minY) minY = y;
      if (y > maxY) maxY = y;
    }
  }
  return { minX, maxX, minY, maxY };
}

test('buildOverlayPlan: length axial span = robust tip stations; no AABB overshoot along axis (#69)', () => {
  const { W, H, bitset, bbox } = tiltedSlabFixture();
  const scale = 10;
  const wood = maskWoodAabb(bitset, W, H);
  const slabBounds = {
    x: wood.minX - 8,
    y: wood.minY - 8,
    w: wood.maxX - wood.minX + 16,
    h: wood.maxY - wood.minY + 16,
  };
  const inv = inventorySourceMap(slabBounds, { widthPx: W, heightPx: H }, 900, 1200);
  const plan = buildOverlayPlan({
    bitset,
    widthPx: W,
    heightPx: H,
    bbox,
    scale,
    lengthIn: 50,
    lengthLabel: '50"',
    mapToInventory: inv.mapToInventory,
  });

  // Wood AABB in inventory space (for axis-right clearance only)
  let mMinX = Infinity, mMaxX = -Infinity;
  for (let y = 0; y < H; y++) {
    for (let x = 0; x < W; x++) {
      if (!bitset[y * W + x]) continue;
      const [mx] = inv.mapToInventory(x, y);
      if (mx < mMinX) mMinX = mx;
      if (mx > mMaxX) mMaxX = mx;
    }
  }

  // Robust tip stations along approved bbox axis (0.2% / 99.8%)
  const { start: aa, end: bb } = axisEndpoints(bbox);
  const ex = bb[0] - aa[0], ey = bb[1] - aa[1], elen = Math.hypot(ex, ey) || 1;
  const ux = ex / elen, uy = ey / elen;
  const cx = bbox.corners.reduce((s, c) => s + c[0], 0) / 4;
  const cy = bbox.corners.reduce((s, c) => s + c[1], 0) / 4;
  const cProj = cx * ux + cy * uy;
  const projs: number[] = [];
  for (let y = 0; y < H; y++) {
    for (let x = 0; x < W; x++) {
      if (!bitset[y * W + x]) continue;
      projs.push(x * ux + y * uy);
    }
  }
  projs.sort((p, q) => p - q);
  const lo = Math.min(Math.floor(projs.length * 0.002), projs.length - 1);
  const hi = Math.max(Math.floor(projs.length * 0.998), lo);
  const tipMin = projs[lo];
  const tipMax = projs[hi];
  // Centerline tip positions (same as maskAxisSegment start/end)
  const tipStart: [number, number] = [cx + ux * (tipMin - cProj), cy + uy * (tipMin - cProj)];
  const tipEnd: [number, number] = [cx + ux * (tipMax - cProj), cy + uy * (tipMax - cProj)];
  const oriented = pickBottomTowardTop(tipStart, tipEnd);

  // Inventory map is isotropic scale+translate → directions preserved; axial span scales.
  const mapBot = inv.mapToInventory(oriented.bottom[0], oriented.bottom[1]);
  const mapTop = inv.mapToInventory(oriented.top[0], oriented.top[1]);
  const tipAxial = Math.hypot(mapTop[0] - mapBot[0], mapTop[1] - mapBot[1]);
  const lenAxial = Math.hypot(plan.length.b[0] - plan.length.a[0], plan.length.b[1] - plan.length.a[1]);
  assert.ok(
    Math.abs(lenAxial - tipAxial) <= 2,
    `length span ${lenAxial.toFixed(1)} must equal centerline tip span ${tipAxial.toFixed(1)} (no speck overshoot)`,
  );

  // Axial stations of length ends = robust tip stations (pure axis-right offset does not change along-u).
  // Inventory map is isotropic scale+translate, so axis direction is preserved.
  const mapOrigin = inv.mapToInventory(0, 0);
  const mapU = inv.mapToInventory(oriented.ux, oriented.uy);
  const iux = mapU[0] - mapOrigin[0];
  const iuy = mapU[1] - mapOrigin[1];
  const ilen = Math.hypot(iux, iuy) || 1;
  const nux = iux / ilen, nuy = iuy / ilen;
  const lenProjs = [plan.length.a[0] * nux + plan.length.a[1] * nuy, plan.length.b[0] * nux + plan.length.b[1] * nuy].sort(
    (a, b) => a - b,
  );
  const tipProjs = [mapBot[0] * nux + mapBot[1] * nuy, mapTop[0] * nux + mapTop[1] * nuy].sort((a, b) => a - b);
  assert.ok(Math.abs(lenProjs[0] - tipProjs[0]) <= 2, `length min station ${lenProjs[0]} ≈ tip ${tipProjs[0]}`);
  assert.ok(Math.abs(lenProjs[1] - tipProjs[1]) <= 2, `length max station ${lenProjs[1]} ≈ tip ${tipProjs[1]}`);

  // Length stays axis-right of wood (clearance to the right in inventory x for this fixture)
  const lenMidX = (plan.length.a[0] + plan.length.b[0]) / 2;
  assert.ok(lenMidX > mMaxX + 4, `length dim must sit outside wood on axis-right (x=${lenMidX} vs maxX=${mMaxX})`);
});

test('buildOverlayPlan: width labels fully left of wood AABB after inventory map (#69)', () => {
  const { W, H, bitset, bbox } = tiltedSlabFixture();
  const scale = 10;
  const wood = maskWoodAabb(bitset, W, H);
  const slabBounds = {
    x: wood.minX - 8,
    y: wood.minY - 8,
    w: wood.maxX - wood.minX + 16,
    h: wood.maxY - wood.minY + 16,
  };
  const inv = inventorySourceMap(slabBounds, { widthPx: W, heightPx: H }, 900, 1200);
  const plan = buildOverlayPlan({
    bitset,
    widthPx: W,
    heightPx: H,
    bbox,
    scale,
    lengthIn: 50,
    lengthLabel: '50"',
    mapToInventory: inv.mapToInventory,
  });
  assert.ok(plan.widths.length > 0, 'expected width stations');

  let mMinX = Infinity, mMaxX = -Infinity, mMinY = Infinity, mMaxY = -Infinity;
  for (let y = 0; y < H; y++) {
    for (let x = 0; x < W; x++) {
      if (!bitset[y * W + x]) continue;
      const [mx, my] = inv.mapToInventory(x, y);
      if (mx < mMinX) mMinX = mx;
      if (mx > mMaxX) mMaxX = mx;
      if (my < mMinY) mMinY = my;
      if (my > mMaxY) mMaxY = my;
    }
  }

  for (const w of plan.widths) {
    // Label anchor fully off the wood footprint (axis-left), with margin for glyph half-width
    const margin = plan.fontPx * 0.55; // textAlign will grow away from wood; still keep anchor clear
    const onWood =
      w.labelAt[0] >= mMinX - 1 &&
      w.labelAt[0] <= mMaxX + 1 &&
      w.labelAt[1] >= mMinY - 1 &&
      w.labelAt[1] <= mMaxY + 1;
    assert.ok(
      !onWood,
      `width labelAt (${w.labelAt[0].toFixed(0)},${w.labelAt[1].toFixed(0)}) must be outside wood AABB`,
    );
    // Axis-left = past the left tip (smaller across); for this nearly-vertical slab, left of wood in x
    assert.ok(
      w.labelAt[0] < mMinX - 2,
      `width label ${w.label} x=${w.labelAt[0].toFixed(0)} must be left of wood minX=${mMinX.toFixed(0)} (margin~${margin.toFixed(0)})`,
    );
    // Width arrows still touch wood edges (left/right tips inside/on AABB)
    assert.ok(w.left[0] >= mMinX - 3 && w.left[0] <= mMaxX + 3);
    assert.ok(w.right[0] >= mMinX - 3 && w.right[0] <= mMaxX + 3);
  }
});

// --- Length/width dims must follow approved axis, not screen tip hack (#70) ---

// --- Length/width dims must follow approved axis, not screen tip hack (#70) ---

/**
 * ~25° approved axis. Irregular tips sit far off the centerline on opposite
 * sides so tip-to-tip ≠ (ux,uy). #69 screen-hack follows tip pixels and fails
 * the parallel-axis / pure axis-right offset asserts; classic offset passes.
 */
function tiltedAxis25Fixture() {
  const W = 420, H = 520;
  const ang = (25 * Math.PI) / 180;
  const ux0 = Math.sin(ang);
  const uy0 = Math.cos(ang);
  const rx0 = -uy0;
  const ry0 = ux0;
  const cx = 210, cy = 260, halfL = 160, halfW = 50;
  const bitset = new Uint8Array(W * H);
  for (let y = 0; y < H; y++) {
    for (let x = 0; x < W; x++) {
      const along = (x - cx) * ux0 + (y - cy) * uy0;
      const across = (x - cx) * rx0 + (y - cy) * ry0;
      const t = (along + halfL) / (2 * halfL);
      // Strong opposite bias at the tips (±0.85*halfW) so tip pixels diverge from axis
      const centerAcross = (t - 0.5) * 2 * halfW * 0.85;
      const halfAt = halfW * 0.35;
      if (Math.abs(along) <= halfL && Math.abs(across - centerAcross) <= halfAt) {
        bitset[y * W + x] = 1;
      }
    }
  }
  const corners: [number, number][] = [
    [cx + ux0 * halfL + rx0 * halfW, cy + uy0 * halfL + ry0 * halfW],
    [cx + ux0 * halfL - rx0 * halfW, cy + uy0 * halfL - ry0 * halfW],
    [cx - ux0 * halfL - rx0 * halfW, cy - uy0 * halfL - ry0 * halfW],
    [cx - ux0 * halfL + rx0 * halfW, cy - uy0 * halfL + ry0 * halfW],
  ];
  const bbox = { corners, longSidePx: halfL * 2, angleDeg: 90 - 25 };
  return { W, H, bitset, bbox, ux0, uy0, rx0, ry0, halfL, cx, cy };
}

test('buildOverlayPlan: length a→b || approved (ux,uy); width left→right || (rx,ry) (#70)', () => {
  const { W, H, bitset, bbox, cx, cy } = tiltedAxis25Fixture();
  const scale = 10;
  const plan = buildOverlayPlan({
    bitset,
    widthPx: W,
    heightPx: H,
    bbox,
    scale,
    lengthIn: 32,
    lengthLabel: '32"',
    mapToInventory: (x, y) => [x, y],
  });

  const { start: aa, end: bb } = axisEndpoints(bbox);
  const ex = bb[0] - aa[0], ey = bb[1] - aa[1], elen = Math.hypot(ex, ey) || 1;
  const uxB = ex / elen, uyB = ey / elen;
  const cProj = cx * uxB + cy * uyB;
  const projs: number[] = [];
  for (let y = 0; y < H; y++) {
    for (let x = 0; x < W; x++) {
      if (!bitset[y * W + x]) continue;
      projs.push(x * uxB + y * uyB);
    }
  }
  projs.sort((p, q) => p - q);
  const lo = Math.min(Math.floor(projs.length * 0.002), projs.length - 1);
  const hi = Math.max(Math.floor(projs.length * 0.998), lo);
  const tipStart: [number, number] = [cx + uxB * (projs[lo] - cProj), cy + uyB * (projs[lo] - cProj)];
  const tipEnd: [number, number] = [cx + uxB * (projs[hi] - cProj), cy + uyB * (projs[hi] - cProj)];
  const oriented = pickBottomTowardTop(tipStart, tipEnd);
  const { ux, uy, bottom, top } = oriented;
  const [rx, ry] = axisRightUnit(ux, uy);

  const ldx = plan.length.b[0] - plan.length.a[0];
  const ldy = plan.length.b[1] - plan.length.a[1];
  const llen = Math.hypot(ldx, ldy) || 1;
  const lux = ldx / llen, luy = ldy / llen;
  const lengthDot = lux * ux + luy * uy;
  assert.ok(
    lengthDot > 0.9995,
    `length a→b must be || approved axis (dot=${lengthDot.toFixed(6)}; got (${lux.toFixed(4)},${luy.toFixed(4)}) vs (${ux.toFixed(4)},${uy.toFixed(4)}))`,
  );

  // Endpoints = centerline tip stations + pure axis-right (no screen-only tip translation)
  for (const [endPt, tip] of [
    [plan.length.a, bottom],
    [plan.length.b, top],
  ] as const) {
    const ox = endPt[0] - tip[0];
    const oy = endPt[1] - tip[1];
    const along = ox * ux + oy * uy;
    const across = ox * rx + oy * ry;
    assert.ok(
      Math.abs(along) <= 1.5,
      `length end offset must be pure axis-right (along=${along.toFixed(2)} must be ~0; tip=(${tip[0].toFixed(1)},${tip[1].toFixed(1)}))`,
    );
    assert.ok(across > 8, `length end must sit axis-right of centerline tip (across=${across.toFixed(1)})`);
  }

  assert.ok(plan.widths.length > 0, 'expected width marks');
  for (const w of plan.widths) {
    const wdx = w.right[0] - w.left[0];
    const wdy = w.right[1] - w.left[1];
    const wlen = Math.hypot(wdx, wdy) || 1;
    const wrx = wdx / wlen, wry = wdy / wlen;
    const widthDot = wrx * rx + wry * ry;
    assert.ok(
      widthDot > 0.999,
      `width left→right must be || axis-right (dot=${widthDot.toFixed(6)} at station ${w.stationIn})`,
    );
    const perp = wrx * ux + wry * uy;
    assert.ok(Math.abs(perp) < 0.02, `width must be ⊥ length axis (dot=${perp.toFixed(4)})`);
  }
});