backend/models/ChatSession.js

const { db } = require('../db');

class ChatSession {
  static find(query) {
    const chain = {
      _sort: null,
      sort: function(sortQuery) {
        this._sort = sortQuery;
        return this;
      },
      then: function(resolve, reject) {
        return new Promise((res, rej) => {
          let q = db.sessions.find(query);
          if (this._sort) q = q.sort(this._sort);
          q.exec((err, docs) => {
            if (err) rej(err);
            else res(docs);
          });
        }).then(resolve, reject);
      },
      catch: function(reject) {
        return this.then(null, reject);
      }
    };
    return chain;
  }

  static async findById(id) {
    return new Promise((resolve, reject) => {
      db.sessions.findOne({ _id: id }, (err, doc) => {
        if (err) reject(err);
        else resolve(doc);
      });
    });
  }

  static async create(sessionData) {
    return new Promise((resolve, reject) => {
      sessionData.createdAt = sessionData.createdAt || new Date();
      sessionData.updatedAt = sessionData.updatedAt || new Date();
      db.sessions.insert(sessionData, (err, newDoc) => {
        if (err) reject(err);
        else resolve(newDoc);
      });
    });
  }

  static async deleteMany(query) {
    return new Promise((resolve, reject) => {
      db.sessions.remove(query, { multi: true }, (err, numRemoved) => {
        if (err) reject(err);
        else resolve(numRemoved);
      });
    });
  }
}

module.exports = ChatSession;