feat: scaffold mvp shell and content runtime

js/gameplay/difficulty/anchors.js

@@ -0,0 +1,55 @@
+const BOUNDS = {
+  left: 32,
+  right: 358,
+  top: 130,
+  bottom: 560,
+}
+
+export function createAnchorGrid(columns = 6, rows = 8) {
+  const anchors = []
+  const width = BOUNDS.right - BOUNDS.left
+  const height = BOUNDS.bottom - BOUNDS.top
+  const stepX = width / (columns - 1)
+  const stepY = height / (rows - 1)
+
+  for (let row = 0; row < rows; row += 1) {
+    for (let column = 0; column < columns; column += 1) {
+      anchors.push({
+        id: `anchor_${row}_${column}`,
+        x: BOUNDS.left + column * stepX,
+        y: BOUNDS.top + row * stepY,
+      })
+    }
+  }
+
+  return anchors
+}
+
+export function getLayerDistribution(density, layers) {
+  const presets = {
+    low: [0.4, 0.35, 0.25],
+    medium: [0.3, 0.3, 0.25, 0.15],
+    medium_high: [0.28, 0.27, 0.25, 0.2],
+    high: [0.25, 0.25, 0.25, 0.25],
+  }
+  const base = presets[density] ?? presets.medium
+  const sliced = base.slice(0, layers)
+  const total = sliced.reduce((sum, value) => sum + value, 0)
+
+  return sliced.map((value) => value / total)
+}
+
+export function allocateLayerCounts(totalPieces, density, layers) {
+  const distribution = getLayerDistribution(density, layers)
+  const counts = distribution.map((value) => Math.floor(totalPieces * value))
+  let assigned = counts.reduce((sum, value) => sum + value, 0)
+
+  while (assigned < totalPieces) {
+    for (let index = 0; index < counts.length && assigned < totalPieces; index += 1) {
+      counts[index] += 1
+      assigned += 1
+    }
+  }
+
+  return counts
+}

js/gameplay/difficulty/classify-deadlock.js

@@ -0,0 +1,47 @@
+import { getClickablePieces } from './overlap-graph.js'
+
+function getPotentialMatches(slot, clickablePieces) {
+  return clickablePieces.filter((piece) => {
+    const sameCount = slot.filter((slottedPiece) => slottedPiece.elementId === piece.elementId).length
+    return sameCount >= 2
+  })
+}
+
+export function classifyDeadlock(runtimeState, boardState) {
+  const slot = runtimeState.slot ?? []
+  const bypass = runtimeState.bypass ?? []
+  const clickablePieces = getClickablePieces(boardState)
+
+  if (slot.length < 7) {
+    return {
+      type: 'none',
+      clickablePieces,
+    }
+  }
+
+  const matchablePieces = getPotentialMatches(slot, clickablePieces)
+
+  if (matchablePieces.length > 0) {
+    return {
+      type: 'none',
+      clickablePieces,
+      matchablePieces,
+    }
+  }
+
+  if (bypass.length > 0) {
+    return {
+      type: 'soft',
+      clickablePieces,
+      matchablePieces: [],
+    }
+  }
+
+  return {
+    type: 'hard',
+    clickablePieces,
+    matchablePieces: [],
+  }
+}
+
+export default classifyDeadlock

js/gameplay/difficulty/evaluate-board.js

@@ -0,0 +1,29 @@
+import { getClickablePieces } from './overlap-graph.js'
+
+function clamp(value, min, max) {
+  return Math.min(max, Math.max(min, value))
+}
+
+export function evaluateBoard(boardState, levelPreset) {
+  const pieces = (boardState.pieces ?? []).filter((piece) => !piece.removed)
+  const clickablePieces = getClickablePieces(boardState)
+  const totalPieces = pieces.length
+  const initialClickableRatio = totalPieces === 0 ? 0 : clickablePieces.length / totalPieces
+  const targetPassRate = levelPreset?.targetPassRate ?? 0.75
+  const visibilityBonus = (initialClickableRatio - 0.3) * 0.35
+  const densityPenalty = levelPreset?.density === 'high' ? 0.05 : levelPreset?.density === 'medium_high' ? 0.03 : 0
+  const toolFreePassRate = clamp(targetPassRate + visibilityBonus - densityPenalty, 0.45, 0.99)
+  const toolAssistPassRate = clamp(toolFreePassRate + 0.12, toolFreePassRate, 1)
+  const avgTurnsToFinish = totalPieces / 1.2
+
+  return {
+    totalPieces,
+    initialClickableRatio,
+    simulatedPassRate: toolFreePassRate,
+    avgTurnsToFinish,
+    toolFreePassRate,
+    toolAssistPassRate,
+  }
+}
+
+export default evaluateBoard

js/gameplay/difficulty/generate-board.js

@@ -0,0 +1,138 @@
+import { createAnchorGrid, allocateLayerCounts } from './anchors.js'
+import { evaluateBoard } from './evaluate-board.js'
+import { buildOverlapGraph } from './overlap-graph.js'
+import { createRng, shuffleWithRng } from './random.js'
+
+function normalizePiecesPerElement(piecesPerElement, elementCount) {
+  if (Array.isArray(piecesPerElement)) {
+    return piecesPerElement.slice(0, elementCount)
+  }
+
+  return Array.from({ length: elementCount }, () => piecesPerElement)
+}
+
+function pickElements(city, levelPreset, rng) {
+  const shuffled = shuffleWithRng(city.elements, rng)
+  const categorySeen = new Set()
+  const selected = []
+
+  for (const element of shuffled) {
+    if (!categorySeen.has(element.category)) {
+      selected.push(element)
+      categorySeen.add(element.category)
+    }
+    if (selected.length === levelPreset.elementCount) {
+      return selected
+    }
+  }
+
+  for (const element of shuffled) {
+    if (!selected.includes(element)) {
+      selected.push(element)
+    }
+    if (selected.length === levelPreset.elementCount) {
+      break
+    }
+  }
+
+  return selected
+}
+
+function createPiecePool(selectedElements, counts) {
+  const pieces = []
+  let sequence = 1
+
+  selectedElements.forEach((element, elementIndex) => {
+    const count = counts[elementIndex]
+    for (let offset = 0; offset < count; offset += 1) {
+      pieces.push({
+        id: `piece_${String(sequence).padStart(4, '0')}`,
+        elementId: element.id,
+      })
+      sequence += 1
+    }
+  })
+
+  return pieces
+}
+
+function createLayerAnchors(anchorGrid, rng) {
+  return shuffleWithRng(anchorGrid, rng)
+}
+
+function placePieces(piecePool, levelPreset, rng) {
+  const anchors = createAnchorGrid()
+  const layerCounts = allocateLayerCounts(piecePool.length, levelPreset.density, levelPreset.layers)
+  const placedPieces = []
+  let poolIndex = 0
+
+  for (let layer = 0; layer < layerCounts.length; layer += 1) {
+    const layerAnchors = createLayerAnchors(anchors, rng)
+    const previousLayerPieces = placedPieces.filter((piece) => piece.layer === layer - 1)
+
+    for (let index = 0; index < layerCounts[layer]; index += 1) {
+      const source = piecePool[poolIndex]
+      const overlapChance = levelPreset.density === 'high'
+        ? 0.85
+        : levelPreset.density === 'medium_high'
+          ? 0.7
+          : levelPreset.density === 'medium'
+            ? 0.55
+            : 0.35
+
+      let anchor = layerAnchors[index % layerAnchors.length]
+
+      if (layer > 0 && previousLayerPieces.length > 0 && rng() < overlapChance) {
+        const target = previousLayerPieces[Math.floor(rng() * previousLayerPieces.length)]
+        anchor = { x: target.x + 6, y: target.y + 6 }
+      }
+
+      placedPieces.push({
+        ...source,
+        layer,
+        x: Math.round(anchor.x + (rng() - 0.5) * 12),
+        y: Math.round(anchor.y + (rng() - 0.5) * 12),
+        width: 64,
+        height: 64,
+        rotation: Math.round((rng() - 0.5) * 12),
+        removed: false,
+      })
+
+      poolIndex += 1
+    }
+  }
+
+  return placedPieces
+}
+
+export function generateBoard({ cityId, levelId, seed, contentSystem }) {
+  const city = contentSystem.getCity(cityId)
+  const levelPreset = contentSystem.getLevelPreset(cityId, levelId)
+
+  if (!city || !levelPreset) {
+    throw new Error(`Unknown board target: ${cityId}#${levelId}`)
+  }
+
+  const effectiveSeed = seed ?? levelPreset.seedBase
+  const rng = createRng(effectiveSeed)
+  const selectedElements = pickElements(city, levelPreset, rng)
+  const counts = normalizePiecesPerElement(levelPreset.piecesPerElement, levelPreset.elementCount)
+  const piecePool = createPiecePool(selectedElements, counts)
+  const pieces = placePieces(shuffleWithRng(piecePool, rng), levelPreset, rng)
+  const overlapGraph = buildOverlapGraph(pieces)
+  const boardState = {
+    boardId: `${cityId}-${levelId}-${effectiveSeed}`,
+    cityId,
+    levelId,
+    seed: effectiveSeed,
+    pieces,
+    overlapGraph,
+    metrics: {},
+  }
+
+  boardState.metrics = evaluateBoard(boardState, levelPreset)
+
+  return boardState
+}
+
+export default generateBoard

js/gameplay/difficulty/index.js

@@ -0,0 +1,9 @@
+export { classifyDeadlock } from './classify-deadlock.js'
+export { evaluateBoard } from './evaluate-board.js'
+export { generateBoard } from './generate-board.js'
+export {
+  buildOverlapGraph,
+  getClickablePieces,
+  rebuildGraphAfterShuffle,
+  rebuildGraphAfterUndo,
+} from './overlap-graph.js'

js/gameplay/difficulty/overlap-graph.js

@@ -0,0 +1,74 @@
+function getPieceArea(piece) {
+  return piece.width * piece.height
+}
+
+function overlapArea(left, right) {
+  const overlapWidth = Math.max(0, Math.min(left.x + left.width, right.x + right.width) - Math.max(left.x, right.x))
+  const overlapHeight = Math.max(0, Math.min(left.y + left.height, right.y + right.height) - Math.max(left.y, right.y))
+
+  return overlapWidth * overlapHeight
+}
+
+function overlapsCenterZone(lower, upper) {
+  const centerWidth = lower.width * 0.5
+  const centerHeight = lower.height * 0.5
+  const centerBox = {
+    x: lower.x + lower.width * 0.25,
+    y: lower.y + lower.height * 0.25,
+    width: centerWidth,
+    height: centerHeight,
+  }
+
+  return overlapArea(centerBox, upper) > 0
+}
+
+export function buildOverlapGraph(pieces) {
+  const graph = Object.fromEntries(pieces.map((piece) => [piece.id, []]))
+
+  for (let leftIndex = 0; leftIndex < pieces.length; leftIndex += 1) {
+    for (let rightIndex = 0; rightIndex < pieces.length; rightIndex += 1) {
+      if (leftIndex === rightIndex) {
+        continue
+      }
+
+      const blocker = pieces[leftIndex]
+      const blocked = pieces[rightIndex]
+
+      if (blocker.layer <= blocked.layer) {
+        continue
+      }
+
+      const ratio = overlapArea(blocker, blocked) / getPieceArea(blocked)
+
+      if (ratio >= 0.2 && overlapsCenterZone(blocked, blocker)) {
+        graph[blocker.id].push(blocked.id)
+      }
+    }
+  }
+
+  return graph
+}
+
+export function getClickablePieces(boardState) {
+  const pieces = (boardState.pieces ?? []).filter((piece) => !piece.removed)
+  const indegree = Object.fromEntries(pieces.map((piece) => [piece.id, 0]))
+  const graph = boardState.overlapGraph ?? {}
+
+  for (const blockedIds of Object.values(graph)) {
+    for (const blockedId of blockedIds) {
+      if (blockedId in indegree) {
+        indegree[blockedId] += 1
+      }
+    }
+  }
+
+  return pieces.filter((piece) => indegree[piece.id] === 0)
+}
+
+export function rebuildGraphAfterShuffle(boardState) {
+  return buildOverlapGraph(boardState.pieces ?? [])
+}
+
+export function rebuildGraphAfterUndo(boardState) {
+  return buildOverlapGraph(boardState.pieces ?? [])
+}

js/gameplay/difficulty/random.js

@@ -0,0 +1,36 @@
+export function hashSeed(input) {
+  const value = String(input)
+  let hash = 2166136261
+
+  for (let index = 0; index < value.length; index += 1) {
+    hash ^= value.charCodeAt(index)
+    hash = Math.imul(hash, 16777619)
+  }
+
+  return hash >>> 0
+}
+
+export function createRng(seed) {
+  let state = typeof seed === 'number' ? seed >>> 0 : hashSeed(seed)
+
+  return function next() {
+    state += 0x6D2B79F5
+    let value = state
+    value = Math.imul(value ^ (value >>> 15), value | 1)
+    value ^= value + Math.imul(value ^ (value >>> 7), value | 61)
+    return ((value ^ (value >>> 14)) >>> 0) / 4294967296
+  }
+}
+
+export function shuffleWithRng(items, rng) {
+  const result = [...items]
+
+  for (let index = result.length - 1; index > 0; index -= 1) {
+    const swapIndex = Math.floor(rng() * (index + 1))
+    const temp = result[index]
+    result[index] = result[swapIndex]
+    result[swapIndex] = temp
+  }
+
+  return result
+}