onenote-manager

/**
 * Helpers that return large results in small, model-driven pages, plus a small
 * LRU cache so paging a document does not re-hit OneNote on every page turn.
 */

export interface TextPage {
  text: string;
  offset: number;
  chars_returned: number;
  total_chars: number;
  next_offset: number | null;
  has_more: boolean;
}

export function sliceText(fullText: string, offset: number, maxChars: number): TextPage {
  const total = fullText.length;
  const start = Math.min(Math.max(offset | 0, 0), total);
  const size = Math.max(maxChars | 0, 1);
  const end = Math.min(total, start + size);
  return {
    text: fullText.slice(start, end),
    offset: start,
    chars_returned: end - start,
    total_chars: total,
    next_offset: end < total ? end : null,
    has_more: end < total,
  };
}

export interface ItemPage<T> {
  items: T[];
  offset: number;
  count_returned: number;
  total_count: number;
  next_offset: number | null;
  has_more: boolean;
}

export function sliceItems<T>(items: T[], offset: number, limit: number): ItemPage<T> {
  const total = items.length;
  const start = Math.min(Math.max(offset | 0, 0), total);
  const size = Math.max(limit | 0, 1);
  const end = Math.min(total, start + size);
  return {
    items: items.slice(start, end),
    offset: start,
    count_returned: end - start,
    total_count: total,
    next_offset: end < total ? end : null,
    has_more: end < total,
  };
}

export class DocCache<V> {
  private readonly max: number;
  private readonly map = new Map<string, V>();

  constructor(max = 16) {
    this.max = max;
  }

  get(key: string): V | undefined {
    const value = this.map.get(key);
    if (value !== undefined) {
      this.map.delete(key);
      this.map.set(key, value);
    }
    return value;
  }

  set(key: string, value: V): void {
    if (this.map.has(key)) this.map.delete(key);
    this.map.set(key, value);
    while (this.map.size > this.max) {
      const oldest = this.map.keys().next().value;
      if (oldest === undefined) break;
      this.map.delete(oldest);
    }
  }
}