seepur/app/Utils/UserChildUtils.js

const Link = use('App/Models/Link');
const Child = use('App/Models/Child');
class UserChildUtils {
    static async isUserConnectedToChild(user_id, child_id) {
        const links = await Link.query().where({ user_id, child_id }).fetch();
        return !!links.rows.length;
    }

    static async isParentOf(user_id, child_id) {
        const links =
            await Link.query().where({ user_id, child_id, is_parent: true }).fetch();
        return !!links.rows.length;
    }

    static async getChildParents(child_id) {
        const links = await Link.query().where({ child_id, is_parent: true }).fetch();
        const parents = await Promise.all(links.rows.map(async l => {
            return l.user().fetch();
        }));
        return parents;
    }

    static async getUserConnections(user_id) {
        const links = await Link.query().where({ user_id }).fetch();
        const connections = await links.rows.reduce(async(_prev, link) => {
            const prev = await _prev;
            const is_parent = link.is_parent;
            const child = await link.child().fetch();
            if (is_parent) {
                const parents = await UserChildUtils.getChildParents(child.id);
                const nonSameUserParents = parents.filter(p => p.id != user_id);
                prev.children.push({
                    ...child.toJSON(),
                    connections: [
                        ...await UserChildUtils.getChildConnections(child.id),
                        ...nonSameUserParents
                    ]
                })
            } else {
                prev.connections.push({
                    ...child.toJSON(),
                    connections: [...await UserChildUtils.getChildParents(child.id)]
                })
            }
            return prev;
        }, Promise.resolve({ children: [], connections: [] }));
        return connections;
    }

    static async getChildConnections(child_id) {
        const links =
            await Link.query().where({ child_id, is_parent: false }).fetch();
        const connections = await Promise.all(links.rows.map(async l => {
            return l.user().fetch();
        }));
        return connections;
    }
    static async addConnection(child_id, user_id, is_parent = false) {
        const link = await Link.create({ child_id, user_id, is_parent });
        const user = await link.user().fetch();
        const child = await link.child().fetch();
        return {
            user,
            child,
            is_parent
        }
    }

    static async deleteChild(child_id) {
        const child = await Child.find(child_id)
        const childLinks = await child.links().fetch();

        const promises = [...childLinks.rows.map(l => (l.delete())), child.delete()];
        return await Promise.all(promises);
    }
}

module.exports = UserChildUtils;