import { Injectable } from '@nestjs/common';
import { generateShortId } from '../../common/utils/id.util';
import { KnowledgeBaseStatus } from './types/knowledge-base.types';

export interface KnowledgeBase {
  id: string;
  userId: string;
  title: string;
  description: string;
  status: KnowledgeBaseStatus;
  itemCount: number;
  lastStudiedAt: Date | null;
  createdAt: Date;
  updatedAt: Date;
}

@Injectable()
export class KnowledgeBaseRepository {
  private items: Map<string, KnowledgeBase> = new Map();

  async create(userId: string, dto: any): Promise<KnowledgeBase> {
    const kb: KnowledgeBase = {
      id: generateShortId(),
      userId,
      title: dto.title,
      description: dto.description || '',
      status: 'active',
      itemCount: 0,
      lastStudiedAt: null,
      createdAt: new Date(),
      updatedAt: new Date(),
    };
    this.items.set(kb.id, kb);
    return kb;
  }

  async findById(id: string): Promise<KnowledgeBase | undefined> {
    return this.items.get(id);
  }

  async findAllByUserId(userId: string): Promise<KnowledgeBase[]> {
    return Array.from(this.items.values()).filter(
      (kb) => kb.userId === userId && kb.status !== 'deleted',
    );
  }

  async countByUserId(userId: string): Promise<number> {
    return Array.from(this.items.values()).filter(
      (kb) => kb.userId === userId && kb.status !== 'deleted',
    ).length;
  }

  async update(id: string, dto: any): Promise<KnowledgeBase | undefined> {
    const kb = this.items.get(id);
    if (!kb) return undefined;
    Object.assign(kb, { ...dto, updatedAt: new Date() });
    this.items.set(id, kb);
    return kb;
  }

  async softDelete(id: string): Promise<boolean> {
    const kb = this.items.get(id);
    if (!kb) return false;
    kb.status = 'deleted';
    kb.updatedAt = new Date();
    return true;
  }
}