import {
  DEFAULT_TOTAL_WIDTH,
  MAJOR_TICK_GAP,
  MID_TICK_GAP,
  MINOR_TICK_GAP,
  type Tick,
} from "../models/ruler";
import { normalizeTotalWidth } from "./segmentService";

const tickCache = new Map<number, Tick[]>();

/**
 * 生成标尺刻度数据，并按 totalWidth 做缓存复用。
 */
export function buildTicks(totalWidth: number = DEFAULT_TOTAL_WIDTH): Tick[] {
  const safeTotalWidth = normalizeTotalWidth(totalWidth);
  const cachedTicks = tickCache.get(safeTotalWidth);
  if (cachedTicks) {
    return cachedTicks;
  }

  const ticks: Tick[] = [];
  for (let x = 0; x <= safeTotalWidth; x += MINOR_TICK_GAP) {
    if (x % MAJOR_TICK_GAP === 0) {
      ticks.push({ x, type: "major", label: String(x) });
    } else if (x % MAJOR_TICK_GAP === MID_TICK_GAP) {
      ticks.push({ x, type: "mid" });
    } else {
      ticks.push({ x, type: "minor" });
    }
  }

  tickCache.set(safeTotalWidth, ticks);
  return ticks;
}