import * as api from '../../client/src/api';
import { EndpointError, EndpointHandler, catchUnhandledErrors } from './types';
import Knex from 'knex';

export const ModifyArtistEndpointHandler: EndpointHandler = async (req: any, res: any, knex: Knex) => {
    if (!api.checkModifyArtistRequest(req)) {
        const e: EndpointError = {
            internalMessage: 'Invalid ModifyArtist request: ' + JSON.stringify(req.body),
            httpStatus: 400
        };
        throw e;
    }
    const reqObject: api.ModifyArtistRequest = req.body;
    const { id: userId } = req.user;

    console.log("User ", userId, ": Modify Artist ", reqObject);

    await knex.transaction(async (trx) => {
        try {
            const artistId = parseInt(req.params.id);

            // Start retrieving the artist itself.
            const artistPromise = trx.select('id')
                .from('artists')
                .where({ 'user': userId })
                .where({ id: artistId })
                .then((r: any) => (r && r[0]) ? r[0]['id'] : undefined)

            // Start retrieving tags.
            const tagIdsPromise = reqObject.tagIds ?
                trx.select('id')
                    .from('artists_tags')
                    .whereIn('id', reqObject.tagIds)
                    .then((ts: any) => ts.map((t: any) => t['tagId'])) :
                (async () => { return undefined })();

            // Wait for the requests to finish.
            var [artist, tags] = await Promise.all([artistPromise, tagIdsPromise]);;

            // Check that we found all objects we need.
            if ((reqObject.tagIds && tags.length !== reqObject.tagIds.length) ||
                !artist) {
                const e: EndpointError = {
                    internalMessage: 'Not all artists and/or tags exist for ModifyArtist request: ' + JSON.stringify(req.body),
                    httpStatus: 400
                };
                throw e;
            }

            // Modify the artist.
            var update: any = {};
            if ("name" in reqObject) { update["name"] = reqObject.name; }
            if ("storeLinks" in reqObject) { update["storeLinks"] = JSON.stringify(reqObject.storeLinks || []); }
            const modifyArtistPromise = trx('artists')
                .where({ 'user': userId })
                .where({ 'id': artistId })
                .update(update)

            // Remove unlinked tags.
            // TODO: test this!
            const removeUnlinkedTags = tags ?
                trx('artists_tags')
                    .where({ 'artistId': artistId })
                    .whereNotIn('tagId', reqObject.tagIds || [])
                    .delete() :
                undefined;

            // Link new tags.
            // TODO: test this!
            const addTags = tags ? trx('artists_tags')
                .where({ 'artistId': artistId })
                .then((ts: any) => ts.map((t: any) => t['tagId']))
                .then((doneTagIds: number[]) => {
                    // Get the set of tags that are not yet linked
                    const toLink = tags.filter((id: number) => {
                        return !doneTagIds.includes(id);
                    });
                    const insertObjects = toLink.map((tagId: number) => {
                        return {
                            tagId: tagId,
                            artistId: artistId,
                        }
                    })

                    // Link them
                    return Promise.all(
                        insertObjects.map((obj: any) =>
                            trx('artists_tags').insert(obj)
                        )
                    );
                }) : undefined;

            // Wait for all operations to finish.
            await Promise.all([
                modifyArtistPromise,
                removeUnlinkedTags,
                addTags
            ]);

            // Respond to the request.
            res.status(200).send();

        } catch (e) {
            catchUnhandledErrors(e);
            trx.rollback();
        }
    })
}