MuDBase/server/db/Album.ts

import Knex from "knex";
import { AlbumBaseWithRefs, AlbumWithDetails, AlbumWithRefs } from "../../client/src/api/api";
import * as api from '../../client/src/api/api';
import asJson from "../lib/asJson";
import { DBError, DBErrorKind } from "../endpoints/types";

// Returns an album with details, or null if not found.
export async function getAlbum(id: number, userId: number, knex: Knex):
    Promise<AlbumWithDetails> {
    // Start transfers for tracks, tags and artists.
    // Also request the album itself.
    const tagsPromise: Promise<api.TagWithId[]> =
        knex.select('tagId')
            .from('albums_tags')
            .where({ 'albumId': id })
            .then((tags: any) => tags.map((tag: any) => tag['tagId']))
            .then((ids: number[]) =>
                knex.select(['id', 'name', 'parentId'])
                    .from('tags')
                    .whereIn('id', ids)
            );

    const tracksPromise: Promise<api.TrackWithId[]> =
        knex.select('trackId')
            .from('tracks_albums')
            .where({ 'albumId': id })
            .then((tracks: any) => tracks.map((track: any) => track['trackId']))
            .then((ids: number[]) =>
                knex.select(['id', 'name', 'storeLinks'])
                    .from('tracks')
                    .whereIn('id', ids)
            );

    const artistsPromise: Promise<api.ArtistWithId[]> =
        knex.select('artistId')
            .from('artists_albums')
            .where({ 'albumId': id })
            .then((artists: any) => artists.map((artist: any) => artist['artistId']))
            .then((ids: number[]) =>
                knex.select(['id', 'name', 'storeLinks'])
                    .from('artists')
                    .whereIn('id', ids)
            );

    const albumPromise: Promise<api.Album | undefined> =
        knex.select('name', 'storeLinks')
            .from('albums')
            .where({ 'user': userId })
            .where({ id: id })
            .then((albums: any) => albums[0]);

    // Wait for the requests to finish.
    const [album, tags, tracks, artists] =
        await Promise.all([albumPromise, tagsPromise, tracksPromise, artistsPromise]);

    if (album) {
        return {
            mbApi_typename: 'album',
            name: album['name'],
            artists: artists as api.ArtistWithId[],
            tags: tags as api.TagWithId[],
            tracks: tracks as api.TrackWithId[],
            storeLinks: asJson(album['storeLinks'] || []),
        };
    }

    const e: DBError = {
        name: "DBError",
        kind: DBErrorKind.ResourceNotFound,
        message: 'Not all resources were found.',
    };
    throw e;
}

// Returns the id of the created album.
export async function createAlbum(userId: number, album: AlbumWithRefs, knex: Knex): Promise<number> {
    return await knex.transaction(async (trx) => {
        try {
            // Start retrieving artists.
            const artistIdsPromise: Promise<number[]> =
                trx.select('id')
                    .from('artists')
                    .where({ 'user': userId })
                    .whereIn('id', album.artistIds)
                    .then((as: any) => as.map((a: any) => a['id']));

            // Start retrieving tags.
            const tagIdsPromise: Promise<number[]> =
                trx.select('id')
                    .from('tags')
                    .where({ 'user': userId })
                    .whereIn('id', album.tagIds)
                    .then((as: any) => as.map((a: any) => a['id']));

            // Start retrieving tracks.
            const trackIdsPromise: Promise<number[]> =
                trx.select('id')
                    .from('tracks')
                    .where({ 'user': userId })
                    .whereIn('id', album.trackIds)
                    .then((as: any) => as.map((a: any) => a['id']));

            // Wait for the requests to finish.
            var [artists, tags, tracks] = await Promise.all([artistIdsPromise, tagIdsPromise, trackIdsPromise]);;

            // Check that we found all artists and tags we need.
            if ((new Set(artists.map((a: any) => a['id'])) !== new Set(album.artistIds)) ||
                (new Set(tags.map((a: any) => a['id'])) !== new Set(album.tagIds)) ||
                (new Set(tracks.map((a: any) => a['id'])) !== new Set(album.trackIds))) {
                const e: DBError = {
                    name: "DBError",
                    kind: DBErrorKind.ResourceNotFound,
                    message: 'Not all to-be-linked resources were found.',
                };
                throw e;
            }

            // Create the album.
            const albumId = (await trx('albums')
                .insert({
                    name: album.name,
                    storeLinks: JSON.stringify(album.storeLinks || []),
                    user: userId,
                })
                .returning('id') // Needed for Postgres
            )[0];

            // Link the artists via the linking table.
            if (artists && artists.length) {
                await trx('artists_albums').insert(
                    artists.map((artistId: number) => {
                        return {
                            artistId: artistId,
                            albumId: albumId,
                        }
                    })
                )
            }

            // Link the tags via the linking table.
            if (tags && tags.length) {
                await trx('albums_tags').insert(
                    tags.map((tagId: number) => {
                        return {
                            albumId: albumId,
                            tagId: tagId,
                        }
                    })
                )
            }

            // Link the tracks via the linking table.
            if (tracks && tracks.length) {
                await trx('tracks_albums').insert(
                    tracks.map((trackId: number) => {
                        return {
                            albumId: albumId,
                            trackId: trackId,
                        }
                    })
                )
            }

            return albumId;

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

export async function modifyAlbum(userId: number, albumId: number, album: AlbumBaseWithRefs, knex: Knex): Promise<void> {
    await knex.transaction(async (trx) => {
        try {
            // Start retrieving the album itself.
            const albumIdPromise: Promise<number | undefined> =
                trx.select('id')
                    .from('albums')
                    .where({ 'user': userId })
                    .where({ id: albumId })
                    .then((r: any) => (r && r[0]) ? r[0]['id'] : undefined);

            // Start retrieving artists if we are modifying those.
            const artistIdsPromise: Promise<number[] | undefined> =
                album.artistIds ?
                    trx.select('artistId')
                        .from('artists_albums')
                        .whereIn('artistId', album.artistIds)
                        .then((as: any) => as.map((a: any) => a['artistId']))
                    : (async () => undefined)();

            // Start retrieving tracks if we are modifying those.
            const trackIdsPromise: Promise<number[] | undefined> =
                album.trackIds ?
                    trx.select('artistId')
                        .from('tracks_albums')
                        .whereIn('albumId', album.trackIds)
                        .then((as: any) => as.map((a: any) => a['trackId']))
                    : (async () => undefined)();

            // Start retrieving tags if we are modifying those.
            const tagIdsPromise =
                album.tagIds ?
                    trx.select('id')
                        .from('albums_tags')
                        .whereIn('tagId', album.tagIds)
                        .then((ts: any) => ts.map((t: any) => t['tagId'])) :
                    (async () => undefined)();

            // Wait for the requests to finish.
            var [oldAlbum, artists, tags, tracks] = await Promise.all([albumIdPromise, artistIdsPromise, tagIdsPromise, trackIdsPromise]);;

            // Check that we found all objects we need.
            if ((!artists || new Set(artists.map((a: any) => a['id'])) !== new Set(album.artistIds)) ||
                (!tags || new Set(tags.map((a: any) => a['id'])) !== new Set(album.tagIds)) ||
                (!tracks || new Set(tracks.map((a: any) => a['id'])) !== new Set(album.trackIds)) ||
                !oldAlbum) {
                const e: DBError = {
                    name: "DBError",
                    kind: DBErrorKind.ResourceNotFound,
                    message: 'Not all to-be-linked resources were found.',
                };
                throw e;
            }

            // Modify the album.
            var update: any = {};
            if ("name" in album) { update["name"] = album.name; }
            if ("storeLinks" in album) { update["storeLinks"] = JSON.stringify(album.storeLinks || []); }

            const modifyAlbumPromise = trx('albums')
                .where({ 'user': userId })
                .where({ 'id': albumId })
                .update(update)

            // Remove unlinked artists.
            const removeUnlinkedArtists = artists ? trx('artists_albums')
                .where({ 'albumId': albumId })
                .whereNotIn('artistId', album.artistIds || [])
                .delete() : undefined;

            // Remove unlinked tags.
            const removeUnlinkedTags = tags ? trx('albums_tags')
                .where({ 'albumId': albumId })
                .whereNotIn('tagId', album.tagIds || [])
                .delete() : undefined;

            // Remove unlinked tracks.
            const removeUnlinkedTracks = tracks ? trx('tracks_albums')
                .where({ 'albumId': albumId })
                .whereNotIn('trackId', album.trackIds || [])
                .delete() : undefined;

            // Link new artists.
            const addArtists = artists ? trx('artists_albums')
                .where({ 'albumId': albumId })
                .then((as: any) => as.map((a: any) => a['artistId']))
                .then((doneArtistIds: number[]) => {
                    // Get the set of artists that are not yet linked
                    const toLink = (artists || []).filter((id: number) => {
                        return !doneArtistIds.includes(id);
                    });
                    const insertObjects = toLink.map((artistId: number) => {
                        return {
                            artistId: artistId,
                            albumId: albumId,
                        }
                    })

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

            // Link new tracks.
            const addTracks = tracks ? trx('tracks_albums')
                .where({ 'albumId': albumId })
                .then((as: any) => as.map((a: any) => a['trackId']))
                .then((doneTrackIds: number[]) => {
                    // Get the set of artists that are not yet linked
                    const toLink = (tracks || []).filter((id: number) => {
                        return !doneTrackIds.includes(id);
                    });
                    const insertObjects = toLink.map((trackId: number) => {
                        return {
                            trackId: trackId,
                            albumId: albumId,
                        }
                    })

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

            // Link new tags.
            const addTags = tags ? trx('albums_tags')
                .where({ 'albumId': albumId })
                .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,
                            albumId: albumId,
                        }
                    })

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

            // Wait for all operations to finish.
            await Promise.all([
                modifyAlbumPromise,
                removeUnlinkedArtists,
                removeUnlinkedTags,
                removeUnlinkedTracks,
                addArtists,
                addTags,
                addTracks,
            ]);

            return;

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

    const e: DBError = {
        kind: DBErrorKind.Unknown,
        message: "Reached the unreachable.",
        name: "DBError"
    }
    throw e;
}

export async function deleteAlbum(userId: number, albumId: number, knex: Knex): Promise<void> {
    await knex.transaction(async (trx) => {
        try {
            // Start by retrieving the album itself for sanity.
            const confirmAlbumId: number | undefined =
                await trx.select('id')
                    .from('albums')
                    .where({ 'user': userId })
                    .where({ id: albumId })
                    .then((r: any) => (r && r[0]) ? r[0]['id'] : undefined);

            if (!confirmAlbumId) {
                const e: DBError = {
                    name: "DBError",
                    kind: DBErrorKind.ResourceNotFound,
                    message: 'Not all resources were found.',
                };
                throw e;
            }

            // Start deleting artist associations with the album.
            const deleteArtistsPromise: Promise<any> =
                trx.delete()
                    .from('artists_albums')
                    .where({ 'albumId': albumId });

            // Start deleting tag associations with the album.
            const deleteTagsPromise: Promise<any> =
                trx.delete()
                    .from('albums_tags')
                    .where({ 'albumId': albumId });

            // Start deleting track associations with the album.
            const deleteTracksPromise: Promise<any> =
                trx.delete()
                    .from('tracks_albums')
                    .where({ 'albumId': albumId });

            // Start deleting the album.
            const deleteAlbumPromise: Promise<any> =
                trx.delete()
                    .from('albums')
                    .where({ id: albumId });

            // Wait for the requests to finish.
            await Promise.all([deleteArtistsPromise, deleteTagsPromise, deleteTracksPromise, deleteAlbumPromise]);
        } catch (e) {
            trx.rollback();
            throw e;
        }
    })
}