// 大纲编辑器纯逻辑：按卷分组、伏笔窗口徽标文案、接近回收窗口提示（UX §6.7）。
// OutlineChapterView/ForeshadowWindowView 已由 OpenAPI 强类型，无需手动收窄。

import type { ForeshadowWindowView, OutlineChapterView } from "@/lib/api/types";

export interface VolumeGroup {
  volume: number;
  chapters: OutlineChapterView[];
}

// 按 volume 分组（保持章号升序）；卷号升序。
export function groupByVolume(
  chapters: readonly OutlineChapterView[] | undefined,
): VolumeGroup[] {
  const byVolume = new Map<number, OutlineChapterView[]>();
  for (const ch of chapters ?? []) {
    const list = byVolume.get(ch.volume) ?? [];
    byVolume.set(ch.volume, [...list, ch]);
  }
  return [...byVolume.entries()]
    .sort(([a], [b]) => a - b)
    .map(([volume, list]) => ({
      volume,
      chapters: [...list].sort((a, b) => a.no - b.no),
    }));
}

// 伏笔窗口徽标文案：`⚑ F-012 (40-60)` / `⚑ F-012 (≤60)` / `⚑ F-012`。
export function windowBadgeLabel(window: ForeshadowWindowView): string {
  const from = window.expected_close_from;
  const to = window.expected_close_to;
  if (typeof from === "number" && typeof to === "number") {
    return `⚑ ${window.code} (${from}-${to})`;
  }
  if (typeof to === "number") return `⚑ ${window.code} (≤${to})`;
  if (typeof from === "number") return `⚑ ${window.code} (≥${from})`;
  return `⚑ ${window.code}`;
}

// 接近回收：本章号落在窗口 [from,to] 内（提示「本章可回收」，UX §6.7 ⚑ 可回收）。
export function isCloseWindow(
  chapter: OutlineChapterView,
  window: ForeshadowWindowView,
): boolean {
  const to = window.expected_close_to;
  if (typeof to !== "number") return false;
  const from = window.expected_close_from ?? to;
  return chapter.no >= from && chapter.no <= to;
}