// Tool helpers: reach, brushes, and plain digging.
// ---------- Tools ----------
function inReach(x, y) { const dx = x - (bot.x + bot.w / 2), dy = y - (bot.y + bot.h / 2); return dx * dx + dy * dy <= REACH * REACH; }
function forBrush(cx, cy, r, fn) {
  const r2 = (r + 0.5) * (r + 0.5);
  for (let dy = -r; dy <= r; dy++) for (let dx = -r; dx <= r; dx++) {
    if (dx * dx + dy * dy > r2) continue;
    const x = cx + dx, y = cy + dy;
    if (x < 0 || y < 0 || x >= W || y >= H) continue;
    if (!inReach(x, y)) continue;
    if (fn(x, y, y * W + x) === false) return;
  }
}
// Drill: breaks solids loose. Nothing goes into the bag.
// how far the drill reaches: set by the bit, and stretched or shortened by the pulse width
function drillReach(w = drillWidth) { return Math.round(BIT_TIERS[player.bitTier].reach * (PULSE_W[w] || PULSE_W[1]).reach); }
function inDrillReach(x, y, w) { const dx = x - (bot.x + bot.w / 2), dy = y - (bot.y + bot.h / 2), R2 = drillReach(w); return dx * dx + dy * dy <= R2 * R2; }
// Plain digging in a circle. The game itself uses the resonance drill (drill.js); the tests use
// this to clear rock quickly.
function toolDig(cx, cy, r) {
  const tier = BIT_TIERS[player.bitTier];
  let dug = 0, tooHard = 0, far = 0;
  forBrush(cx, cy, r, (x, y, i) => {
    if (!inDrillReach(x, y)) { far++; return; }
    const m = mat[i];
    if (bgm[i] && (m === EMPTY || PH[m] === PH_GAS || PH[m] === PH_LIQUID)) { if (cutTree(i, x, y, tier)) dug++; return; }
    if (PH[m] !== PH_SOLID) return;
    if (PARTMAT[m] || part[i] || mach[i]) return;
    const h = HARD[m];
    if (h > tier.hard) { tooHard = m; return; }
    const p = digp[i] + tier.speed * 60 / (1 + h * h * 0.6);
    if (p >= 255) {
      const to = YLD[m];
      const b = blockP[((y / BS) | 0) * BW + ((x / BS) | 0)];
      setCell(i, to, temp[i], 0);
      discover(to, x, y, m, 'dig');
      if (b === BP_WALL && !blockIntegrity(((y / BS) | 0) * BW + ((x / BS) | 0))) blockP[((y / BS) | 0) * BW + ((x / BS) | 0)] = 0;
      dug++;
      if ((dug & 3) === 0) emit({ t: 'debris', x, y, m });
    } else digp[i] = p;
  });
  stats.dug += dug;
  let status = '';
  void 0;
  if (far && !dug && !tooHard) status = `Out of reach; your bit reaches ${drillReach()} grains.`;
  if (tooHard && !dug) {
    const need = BIT_TIERS.find(b => b.hard >= HARD[tooHard]);
    const nb = need ? need.name.toLowerCase() : 'better bit';
    status = HARD[tooHard] > 6 ? `${MD[tooHard].name} cannot be drilled.` : `${MD[tooHard].name} is too hard; needs ${/^[aeiou]/.test(nb) ? 'an' : 'a'} ${nb}.`;
  }
  return { dug, status, tooHard };
}