// eslint-disable-next-line import/no-import-module-exports
import { DataTypes } from 'sequelize';

module.exports = sequelize => {
  const { User, Group, FriendRequest, Friendship } = sequelize.models;

  // User <-> Group: Many-to-Many
  // Il modello dichiara esplicitamente la colonna id per evitare che sync() la cerchi
  // sulla tabella UserGroups senza trovarla (causando errori su RETURNING "id").
  const UserGroup = sequelize.define(
    'UserGroup',
    {
      id: { type: DataTypes.INTEGER, primaryKey: true, autoIncrement: true },
      userId: { type: DataTypes.INTEGER, allowNull: false },
      groupId: { type: DataTypes.INTEGER, allowNull: false },
    },
    { timestamps: false }
  );
  User.belongsToMany(Group, { through: UserGroup, foreignKey: 'userId', otherKey: 'groupId' });
  Group.belongsToMany(User, {
    through: UserGroup,
    as: 'members',
    foreignKey: 'groupId',
    otherKey: 'userId',
  });

  // Friendship is a direct link between two users.
  // user1Id will always be less than user2Id to ensure uniqueness.
  Friendship.belongsTo(User, { as: 'user1', foreignKey: 'user1Id' });
  Friendship.belongsTo(User, { as: 'user2', foreignKey: 'user2Id' });

  // User <-> FriendRequest: One-to-Many
  // A User can send many friend requests and receive many friend requests.
  User.hasMany(FriendRequest, {
    as: 'sentRequests',
    foreignKey: 'fromUserId',
    onDelete: 'CASCADE',
  });
  User.hasMany(FriendRequest, {
    as: 'receivedRequests',
    foreignKey: 'toUserId',
    onDelete: 'CASCADE',
  });
  FriendRequest.belongsTo(User, { as: 'fromUser', foreignKey: 'fromUserId' });
  FriendRequest.belongsTo(User, { as: 'toUser', foreignKey: 'toUserId' });
};