// 通用工具
export const TILE = 32;
export const ROOM_W = 800;
export const ROOM_H = 608;
export const GRID_W = ROOM_W / TILE;   // 25
export const GRID_H = ROOM_H / TILE;   // 19

export const clamp = (v, a, b) => (v < a ? a : v > b ? b : v);
export const lerp = (a, b, t) => a + (b - a) * t;
export const sgn = v => (v < 0 ? -1 : v > 0 ? 1 : 0);
export const rand = (a, b) => a + Math.random() * (b - a);
export const randInt = (a, b) => Math.floor(a + Math.random() * (b - a + 1));
export const pick = arr => arr[Math.floor(Math.random() * arr.length)];

export function overlap(a, b) {
  return a.x < b.x + b.w && a.x + a.w > b.x && a.y < b.y + b.h && a.y + a.h > b.y;
}
export function pointIn(px, py, r) {
  return px >= r.x && px <= r.x + r.w && py >= r.y && py <= r.y + r.h;
}

/** 浅色/深色化 hex 颜色，n>0 变亮 n<0 变暗 */
export function shade(hex, n) {
  const h = hex.replace('#', '');
  const v = parseInt(h.length === 3 ? h.split('').map(c => c + c).join('') : h, 16);
  let r = (v >> 16) & 255, g = (v >> 8) & 255, b = v & 255;
  r = clamp(r + n, 0, 255); g = clamp(g + n, 0, 255); b = clamp(b + n, 0, 255);
  return `rgb(${r},${g},${b})`;
}

/** 时间毫秒 -> m:ss.cc */
export function fmtTime(ms) {
  const t = Math.max(0, ms);
  const m = Math.floor(t / 60000);
  const s = Math.floor((t % 60000) / 1000);
  const c = Math.floor((t % 1000) / 10);
  return `${m}:${String(s).padStart(2, '0')}.${String(c).padStart(2, '0')}`;
}

/** 平滑的确定性伪随机（用于装饰，不影响帧同步） */
export function hashNoise(x, y) {
  let h = x * 374761393 + y * 668265263;
  h = (h ^ (h >> 13)) * 1274126177;
  return ((h ^ (h >> 16)) >>> 0) / 4294967295;
}