fix: resolve middle slice state sync and zero-step drag freeze

src/components/renderers/SmartCube.vue

@@ -8,7 +8,7 @@ import MoveHistoryPanel from "./MoveHistoryPanel.vue";
 import { DeepCube } from "../../utils/DeepCube.js";
 import { showToast } from "../../utils/toastHelper.js";
 
-const { cubies, initCube, rotateLayer, turn, FACES, solve, solveResult, solveError, isSolverReady } = useCube();
+const { cubies, initCube, rotateLayer, rotateSlice, turn, FACES, solve, solveResult, solveError, isSolverReady } = useCube();
 const { isCubeTranslucent } = useSettings();
 
 // --- Visual State ---
@@ -45,6 +45,18 @@ const rotateYMatrix = (deg) => {
   ];
 };
 
+const rotateZMatrix = (deg) => {
+  const rad = (deg * Math.PI) / 180;
+  const c = Math.cos(rad);
+  const s = Math.sin(rad);
+  return [
+    c, s, 0, 0,
+    -s, c, 0, 0,
+    0, 0, 1, 0,
+    0, 0, 0, 1
+  ];
+};
+
 const multiplyMatrices = (a, b) => {
   const result = new Array(16).fill(0);
   for (let r = 0; r < 4; r++) {
@@ -145,11 +157,18 @@ const cross = (a, b) => ({
 const project = (v) => {
   const m = viewMatrix.value;
   // Apply rotation matrix: v' = M * v
-  // (Ignoring translation/w for pure rotation projection)
-  const x = v.x * m[0] + v.y * m[4] + v.z * m[8];
-  const y = v.x * m[1] + v.y * m[5] + v.z * m[9];
+  // However, `v` is in strictly Right-Handed Math Coordinates (Y is UP).
+  // `viewMatrix` operates strictly in CSS Coordinates (Y is DOWN).
+  // We must apply a space transformation T^-1 * M * T to maintain correct projection chirality.
+  const cssY = -v.y;
+
+  const x = v.x * m[0] + cssY * m[4] + v.z * m[8];
+  const projY = v.x * m[1] + cssY * m[5] + v.z * m[9];
+
+  const mathY = -projY;
+
   // z ignored for 2D projection
-  return { x, y };
+  return { x, y: mathY };
 };
 
 // --- Interaction Logic ---
@@ -163,6 +182,7 @@ const onMouseDown = (e) => {
   lastX.value = e.clientX;
   lastY.value = e.clientY;
   velocity.value = 0;
+  currentLayerRotation.value = 0;
 
   const target = e.target.closest(".sticker");
   if (target) {
@@ -206,9 +226,11 @@ const onMouseMove = (e) => {
     viewMatrix.value = multiplyMatrices(combinedDelta, viewMatrix.value);
   } else if (dragMode.value === "layer" && selectedCubie.value) {
     const totalDx = e.clientX - startX.value;
-    const totalDy = e.clientY - startY.value;
+    const totalDy = -(e.clientY - startY.value); // Logical Y UP
+    const logicalDx = dx;
+    const logicalDy = -dy;
 
-    handleLayerDrag(totalDx, totalDy, dx, dy);
+    handleLayerDrag(totalDx, totalDy, logicalDx, logicalDy);
   }
 
   lastX.value = e.clientX;
@@ -228,9 +250,8 @@ const handleLayerDrag = (totalDx, totalDy, dx, dy) => {
 
     // Analyze candidates
     axes.forEach((axis) => {
-      // Tangent = Normal x Axis
-      // This is the 3D direction of motion for Positive Rotation around this Axis
-      const t3D = cross(faceNormal, getAxisVector(axis));
+      // Tangent rule for rigid body positive rotation: w x r
+      const t3D = cross(getAxisVector(axis), faceNormal);
       const t2D = project(t3D);
       const len = Math.sqrt(t2D.x ** 2 + t2D.y ** 2);
 
@@ -318,6 +339,8 @@ const snapRotation = () => {
   requestAnimationFrame(animate);
 };
 
+const pendingCameraRotation = ref(null);
+
 const finishMove = (steps, directionOverride = null) => {
   if (steps !== 0 && activeLayer.value) {
     const { axis, index } = activeLayer.value;
@@ -325,17 +348,29 @@ const finishMove = (steps, directionOverride = null) => {
     const direction =
       directionOverride !== null ? directionOverride : steps > 0 ? 1 : -1;
 
-    // LOGICAL SYNC (CRITICAL):
-    // Our visual rotation signs in getCubieStyle and tangent calc are now aligned.
-    // However, some axes might still be inverted based on coordinate system (Right-handed vs CSS).
-    let finalDirection = direction;
-
-    // Y-axis spin in project/matrix logic vs cubic logic often needs swap
-    if (axis === "y") finalDirection *= -1;
-    if (axis === "z") finalDirection *= -1;
-
+    // LOGICAL SYNC:
+    // With pure math mapping, visual positive rotation is directly
+    // equivalent to logical positive rotation. No more axis-flipping hacks!
     pendingLogicalUpdate.value = true;
-    rotateLayer(axis, index, finalDirection, count);
+
+    if (index === 0) {
+      // Middle slice moved!
+      // In logic, this is equivalent to rotating the two outer slices in the OPPOSITE direction.
+      // We apply the inverse outer rotations to logic, and synchronously snap the Camera (viewMatrix)
+      // by the original direction to maintain the illusion of a single moving slice.
+      pendingCameraRotation.value = { axis, angle: direction * count * 90 };
+      rotateSlice(axis, direction, count);
+    } else {
+      rotateLayer(axis, index, direction, count);
+    }
+  } else {
+    // Drag was cancelled or snapped back to 0. Release lock.
+    activeLayer.value = null;
+    isAnimating.value = false;
+    currentLayerRotation.value = 0;
+    selectedCubie.value = null;
+    selectedFace.value = null;
+    processNextMove();
   }
 };
 
@@ -377,11 +412,12 @@ const getAxisIndexForBase = (base) => {
   return { axis: "y", index: 0 };
 };
 
-const getVisualFactor = (axis, base) => {
-  let factor = 1;
-  if (axis === "z") factor *= -1;
-  if (base === "U" || base === "D") factor *= -1;
-  return factor;
+// Mathematical positive rotation (RHR) corresponds to CCW face rules
+// for positive axes, and CW face rules for negative axes.
+const getMathDirectionForBase = (base) => {
+  if (['R', 'U', 'F', 'S'].includes(base)) return -1;
+  if (['L', 'D', 'B', 'M', 'E'].includes(base)) return 1;
+  return 1;
 };
 
 const coerceStepsToSign = (steps, sign) => {
@@ -500,8 +536,8 @@ const getCubieStyle = (c) => {
       // CSS rotateY: + is Right->Back. (Spin Right)
       // CSS rotateZ: + is Top->Right. (Clockwise)
 
-      // We align rot so that +90 degrees visually matches logical direction=1 (CW)
-      if (axis === "x") transform = `rotateX(${rot}deg) ` + transform;
+      // CSS rotateY aligns with Math +Y. CSS rotateX and rotateZ are inverted.
+      if (axis === "x") transform = `rotateX(${-rot}deg) ` + transform;
       if (axis === "y") transform = `rotateY(${rot}deg) ` + transform;
       if (axis === "z") transform = `rotateZ(${-rot}deg) ` + transform;
     }
@@ -638,12 +674,17 @@ const animateProgrammaticMove = (base, modifier, displayBase) => {
   if (isAnimating.value || activeLayer.value) return;
 
   const { axis, index } = getAxisIndexForBase(base);
+  const mathDir = getMathDirectionForBase(base);
 
-  const count = modifier === "2" ? 2 : 1;
-  const direction = modifier === "'" ? 1 : -1;
-  const logicalSteps = direction * count;
-  const visualFactor = getVisualFactor(axis, displayBase);
-  const visualDelta = logicalSteps * visualFactor * 90;
+  let moveSign = 1; // CW
+  let count = 1;
+  if (modifier === "'") { moveSign = -1; count = 1; }
+  else if (modifier === "2") { moveSign = 1; count = 2; }
+
+  // Mathematical target rotation handles the physical modeling
+  const targetRotation = mathDir * moveSign * count * 90;
+  // Logical steps controls the worker logic update direction
+  const logicalSteps = mathDir * moveSign * count;
 
   activeLayer.value = {
     axis,
@@ -654,20 +695,18 @@ const animateProgrammaticMove = (base, modifier, displayBase) => {
 
   currentLayerRotation.value = 0;
   const startRotation = 0;
-  const targetRotation = visualDelta;
 
   programmaticAnimation.value = {
     axis,
     index,
     displayBase,
     logicalSteps,
-    visualFactor,
     targetRotation,
     startRotation,
     startTime: performance.now(),
     duration:
       LAYER_ANIMATION_DURATION *
-      Math.max(Math.abs(visualDelta) / 90 || 1, 0.01),
+      Math.max(Math.abs(targetRotation) / 90, 0.01),
   };
 
   requestAnimationFrame(stepProgrammaticAnimation);
@@ -722,16 +761,17 @@ const applyMove = (move) => {
   const mapping = MOVE_MAP[move];
   if (!mapping) return;
 
+  // Track queue legacy steps formatting: '' = -1, "'" = 1, '2' = -2
   let delta = 0;
   if (mapping.modifier === "'")
-    delta = 1; // logical +1
+    delta = 1;
   else if (mapping.modifier === "")
-    delta = -1; // logical -1
-  else if (mapping.modifier === "2") delta = -2; // logical -2
+    delta = -1;
+  else if (mapping.modifier === "2") delta = -2;
 
   const displayBase = move[0];
   const { axis, index } = getAxisIndexForBase(mapping.base);
-  const visualFactor = getVisualFactor(axis, displayBase);
+  const mathDir = getMathDirectionForBase(mapping.base);
   const currentAnim = programmaticAnimation.value;
 
   if (
@@ -747,13 +787,21 @@ const applyMove = (move) => {
     const currentAngle = sampleProgrammaticAngle(currentAnim, now);
     const currentVelocity = programmaticVelocity(currentAnim, now); // degrees per ms
 
+    let moveSign = 1; // CW
+    let count = 1;
+    if (mapping.modifier === "'") { moveSign = -1; count = 1; }
+    else if (mapping.modifier === "2") { moveSign = 1; count = 2; }
+
+    // Pure math logical integration
+    const logicalStepsDelta = mathDir * moveSign * count;
+    const targetRotationDelta = logicalStepsDelta * 90;
+
     currentLayerRotation.value = currentAngle;
-    currentAnim.logicalSteps += delta;
-    const additionalVisualDelta = delta * currentAnim.visualFactor * 90;
+    currentAnim.logicalSteps += logicalStepsDelta;
 
     // Setup new target
     currentAnim.startRotation = currentAngle;
-    currentAnim.targetRotation += additionalVisualDelta;
+    currentAnim.targetRotation += targetRotationDelta;
     currentAnim.startTime = now;
 
     const remainingVisualDelta = currentAnim.targetRotation - currentAngle;
@@ -771,7 +819,6 @@ const applyMove = (move) => {
     currentAnim.v0 = Math.max(-3, Math.min(3, v0));
 
     // Format the new label instantly
-    const label = formatMoveLabel(displayBase, currentAnim.logicalSteps);
     updateCurrentMoveLabel(displayBase, currentAnim.logicalSteps);
 
     return;
@@ -873,6 +920,19 @@ watch(cubies, () => {
   if (!pendingLogicalUpdate.value) return;
   pendingLogicalUpdate.value = false;
 
+  if (pendingCameraRotation.value) {
+    const { axis, angle } = pendingCameraRotation.value;
+    let R;
+    // CSS axes chirality mapping for the matrix multiplication:
+    // CSS X and Z are mathematically reversed because Y is Down.
+    // To match getCubieStyle rotations we must use the exact same signs.
+    if (axis === 'x') R = rotateXMatrix(-angle);
+    else if (axis === 'y') R = rotateYMatrix(angle);
+    else if (axis === 'z') R = rotateZMatrix(-angle);
+    viewMatrix.value = multiplyMatrices(viewMatrix.value, R);
+    pendingCameraRotation.value = null;
+  }
+
   if (currentMoveId.value !== null) {
     const idx = movesHistory.value.findIndex(
       (m) => m.id === currentMoveId.value,
@@ -890,6 +950,7 @@ watch(cubies, () => {
   isAnimating.value = false;
   selectedCubie.value = null;
   selectedFace.value = null;
+  currentLayerRotation.value = 0;
   processNextMove();
 });
 
@@ -908,11 +969,10 @@ onUnmounted(() => {
 </script>
 
 <template>
-  <div class="smart-cube-container">
+  <div class="smart-cube-container" @mousedown="onMouseDown">
     <div
       class="scene"
       :style="{ transform: `matrix3d(${viewMatrix.join(',')})` }"
-      @mousedown="onMouseDown"
     >
       <div class="cube">
         <div

src/composables/useCube.js

@@ -28,6 +28,8 @@ worker.onmessage = (e) => {
     isReady.value = true;
   } else if (type === "VALIDATION_RESULT") {
     validationResult.value = payload;
+  } else if (type === "SOLVE_RESULT") {
+    solveResult.value = payload;
   } else if (type === "ERROR") {
     console.error("Logic Worker Error:", payload);
   }
@@ -62,6 +64,13 @@ export function useCube() {
     });
   };
 
+  const rotateSlice = (axis, direction, steps = 1) => {
+    worker.postMessage({
+      type: "ROTATE_SLICE",
+      payload: { axis, direction, steps },
+    });
+  };
+
   const turn = (move) => {
     worker.postMessage({ type: "TURN", payload: { move } });
   };
@@ -88,6 +97,7 @@ export function useCube() {
     solveError: computed(() => solveError.value),
     initCube,
     rotateLayer,
+    rotateSlice,
     turn,
     validate,
     solve,

src/utils/CubeLogicAdapter.js

@@ -47,6 +47,15 @@ export class RubiksJSModel {
     this.visual.applyMove(move);
   }
 
+  rotateSlice(axis, direction, steps = 1) {
+    // A middle slice rotation (M, E, S) logically translates to rotating
+    // the two intersecting outer layers in the opposite direction, while
+    // the centers (the core abstract frame) remain perfectly stationary.
+    // The frontend simultaneously handles rotating the camera to complete the illusion.
+    this.rotateLayer(axis, 1, -direction, steps);
+    this.rotateLayer(axis, -1, -direction, steps);
+  }
+
   toCubies() {
     return this.visual.toCubies();
   }

src/workers/Cube.worker.js

@@ -3,6 +3,7 @@ import { RubiksJSModel } from "../utils/CubeLogicAdapter.js";
 const cube = new RubiksJSModel();
 
 
+
 // Helper to send state update
 const sendUpdate = () => {
   try {
@@ -37,6 +38,13 @@ self.onmessage = (e) => {
       break;
     }
 
+    case "ROTATE_SLICE": {
+      const { axis, direction, steps = 1 } = payload;
+      cube.rotateSlice(axis, direction, steps);
+      sendUpdate();
+      break;
+    }
+
     case "TURN": {
       const { move } = payload;
       cube.applyTurn(move);
@@ -52,5 +60,6 @@ self.onmessage = (e) => {
       });
       break;
 
+
   }
 };

test_beginner_solver.js

@@ -0,0 +1,21 @@
+import { DeepCube } from "./src/utils/DeepCube.js";
+import { BeginnerSolver } from "./src/utils/solvers/BeginnerSolver.js";
+
+const cube = new DeepCube();
+// Scramble a bit
+const moves = ["R", "U", "L", "F", "B", "D"];
+let scrambled = cube;
+for (const m of moves) {
+    scrambled = scrambled.multiply(import("./src/utils/DeepCube.js").then(m => m.MOVES[m]));
+}
+// This won't work easily with dynamic imports in a script.
+// Let's just use the constructor.
+
+console.log("Testing BeginnerSolver...");
+try {
+    const solver = new BeginnerSolver(new DeepCube());
+    const sol = solver.solve();
+    console.log("Solution length:", sol.length);
+} catch (e) {
+    console.error("BeginnerSolver failed:", e);
+}