const models = require('../models');
import * as api from '../../client/src/api';
import { EndpointError, EndpointHandler, catchUnhandledErrors } from './types';
import tag from '../models/tag';

export const ModifyTagEndpointHandler: EndpointHandler = async (req: any, res: any) => {
    if (!api.checkModifySongRequest(req)) {
        const e: EndpointError = {
            internalMessage: 'Invalid ModifyTag request: ' + JSON.stringify(req.body),
            httpStatus: 400
        };
        throw e;
    }
    const reqObject: api.ModifyTagRequest = req.body;

    const getTag = async (id:Number) => {
        const tag = await models.Tag.findAll({
            where: {
                id: id
            }
        });
        if(tag.length != 1) {
            const e: EndpointError = {
                internalMessage: 'There is no tag with id ' + id + '.',
                httpStatus: 400
            };
            throw e;
        }
        return tag[0];
    }

    // If applicable, start retrieving the new parent tag.
    const maybeNewParentPromise:Promise<any>|Promise<undefined> = 
        (reqObject.parentId) ? getTag(reqObject.parentId) : (async () => { return undefined })();

    // Start retrieving the tag to modify.
    var tagInstancePromise: Promise<any> = getTag(req.params.id);

    // Upon finish retrieving artists and albums, modify the song.
    await Promise.all([maybeNewParentPromise, tagInstancePromise])
        .then(async (values: any) => {
            var [maybeParent, tag] = values;
            if(reqObject.name) { tag.setName(reqObject.name) };
            if(reqObject.parentId) { tag.setParent(maybeParent) };
            await tag.save();
        })
        .then(() => {
            res.status(200).send({});
        })
        .catch(catchUnhandledErrors);
}