const { Op } = require('sequelize');
const { NotFoundError, DatabaseError } = require('../../shared/errors');

class GroupsRepository {
  constructor({ sequelize }) {
    this.sequelize = sequelize;
    this.Group = sequelize.models.Group;
    this.User = sequelize.models.User;
  }

  async findAll(options = {}) {
    try {
      return await this.Group.findAll(options);
    } catch (error) {
      throw new DatabaseError('Failed to fetch groups', error);
    }
  }

  async findByUserId(userId) {
    try {
      return await this.Group.findAll({
        include: [
          {
            model: this.User,
            as: 'members',
            through: { attributes: [] },
          },
        ],
        where: {
          id: {
            [Op.in]: this.sequelize.literal(
              `(SELECT "groupId" FROM "UserGroups" WHERE "userId" = ${parseInt(userId, 10)})`
            ),
          },
        },
      });
    } catch (error) {
      throw new DatabaseError('Failed to fetch groups for user', error);
    }
  }

  async findById(id, includeMembers = false) {
    try {
      const options = {};
      if (includeMembers) {
        options.include = [
          {
            model: this.User,
            as: 'members',
            through: { attributes: [] },
          },
        ];
      }
      const group = await this.Group.findByPk(id, options);
      if (!group) {
        throw new NotFoundError('Group not found');
      }
      return group;
    } catch (error) {
      if (error instanceof NotFoundError) throw error;
      throw new DatabaseError(`Failed to fetch group with id ${id}`, error);
    }
  }

  async create(groupData) {
    try {
      return await this.Group.create(groupData);
    } catch (error) {
      throw new DatabaseError('Failed to create group', error);
    }
  }

  async addMembers(groupId, userIds) {
    try {
      const group = await this.findById(groupId);
      await group.addMembers(userIds);
      return this.findById(groupId, true);
    } catch (error) {
      if (error instanceof NotFoundError) throw error;
      throw new DatabaseError('Failed to add members to group', error);
    }
  }

  async removeMember(groupId, userId) {
    try {
      const group = await this.findById(groupId);
      await group.removeMember(userId);
      return this.findById(groupId, true);
    } catch (error) {
      if (error instanceof NotFoundError) throw error;
      throw new DatabaseError('Failed to remove member from group', error);
    }
  }

  async update(id, updateData) {
    try {
      const group = await this.findById(id);
      return await group.update(updateData);
    } catch (error) {
      if (error instanceof NotFoundError) throw error;
      throw new DatabaseError(`Failed to update group with id ${id}`, error);
    }
  }

  async delete(id) {
    try {
      const group = await this.findById(id);
      await group.destroy();
      return true;
    } catch (error) {
      if (error instanceof NotFoundError) throw error;
      throw new DatabaseError(`Failed to delete group with id ${id}`, error);
    }
  }
}

module.exports = GroupsRepository;