const UserError = require('vn-loopback/util/user-error');

module.exports = Self => {
    Self.remoteMethod('moveChild', {
        description: 'Changes the parent of a child department',
        accessType: 'WRITE',
        accepts: [{
            arg: 'id',
            type: 'Number',
            description: 'The department id',
            http: {source: 'path'}
        }, {
            arg: 'parentId',
            type: 'Number',
            description: 'New parent id',
        }],
        returns: {
            type: 'Object',
            root: true
        },
        http: {
            path: `/:id/moveChild`,
            verb: 'POST'
        }
    });

    Self.moveChild = async(id, parentId = null) => {
        const models = Self.app.models;
        const child = await models.Department.findById(id);

        if (id == parentId) return;

        if (parentId) {
            const parent = await models.Department.findById(parentId);

            if (child.lft < parent.lft && child.rgt > parent.rgt)
                throw new UserError('You cannot move a parent to its own sons');
        }

        return child.updateAttribute('parentFk', parentId);
    };
};