import { Injectable } from '@nestjs/common';
import { WritableDbService } from '../db/writable-db.service';
import { levelFor } from './levels';

@Injectable()
export class CommunityService {
  constructor(private readonly wdb: WritableDbService) {}

  /** 贡献榜（公开）：按积分降序。*/
  leaderboard(limit = 20) {
    const rows = this.wdb.db
      .prepare(
        `SELECT id, display_name, role, contribution_points
         FROM users WHERE contribution_points > 0
         ORDER BY contribution_points DESC, id ASC LIMIT ?`,
      )
      .all(limit) as any[];
    return rows.map((r, i) => ({
      rank: i + 1,
      id: r.id,
      displayName: r.display_name,
      role: r.role,
      points: r.contribution_points,
      title: levelFor(r.contribution_points).title,
    }));
  }

  /** 某车型的维护者署名列表。*/
  maintainers(modelId: number) {
    return this.wdb.db
      .prepare(
        `SELECT u.id, u.display_name AS displayName, u.role, m.created_at AS since
         FROM model_maintainers m JOIN users u ON u.id = m.user_id
         WHERE m.model_id = ? ORDER BY m.created_at ASC`,
      )
      .all(modelId);
  }

  claim(modelId: number, userId: number) {
    this.wdb.db
      .prepare(
        `INSERT INTO model_maintainers (model_id, user_id) VALUES (?, ?)
         ON CONFLICT(model_id, user_id) DO NOTHING`,
      )
      .run(modelId, userId);
    return this.maintainers(modelId);
  }

  unclaim(modelId: number, userId: number) {
    this.wdb.db
      .prepare('DELETE FROM model_maintainers WHERE model_id = ? AND user_id = ?')
      .run(modelId, userId);
    return this.maintainers(modelId);
  }
}