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

const getSequelizeWhere = (queryElem: api.SongQueryElem) => {
    var and = [];

    var sequelizeOps:any = {};
    sequelizeOps[api.SongQueryFilterOp.Eq] = Op.eq;
    sequelizeOps[api.SongQueryFilterOp.Ne] = Op.ne;
    sequelizeOps[api.SongQueryFilterOp.In] = Op.in;
    sequelizeOps[api.SongQueryFilterOp.NotIn] = Op.notIn;
    sequelizeOps[api.SongQueryElemOp.And] = Op.and;
    sequelizeOps[api.SongQueryElemOp.Or] = Op.or;

    var sequelizeProps:any = {};
    sequelizeProps[api.SongQueryElemProperty.id] = "id";
    sequelizeProps[api.SongQueryElemProperty.artistIds] = "artistIds";
    sequelizeProps[api.SongQueryElemProperty.albumIds] = "albumIds";

    if (queryElem.prop && queryElem.propOperator && queryElem.propOperand) {
        const prop = sequelizeProps[queryElem.prop];
        const op = sequelizeOps[queryElem.propOperator];
        var filter:any = {};
        filter[op] = queryElem.propOperand;
        var where:any = {};
        where[prop] = filter;
        and.push(where);
    }
    if (queryElem.childrenOperator && queryElem.children) {
        const children = queryElem.children.map((child: api.SongQueryElem) => getSequelizeWhere(child));
        const op = sequelizeOps[queryElem.childrenOperator];
        var where:any = {};
        where[op] = children;
        and.push(where)
    }

    return {
        [Op.and]: and
    };
}

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

    await models.Song.findAll({
        where: getSequelizeWhere(reqObject.query)
    })
        .then((songs: any[]) => {
            const response: api.QuerySongsResponse = {
                ids: songs.map((song: any) => {
                    return song.id;
                })
            };
            res.send(response);
        })
        .catch(catchUnhandledErrors);
}