import Knex from "knex";
import { ArtistBaseWithRefs, ArtistWithDetails, ArtistWithRefs } from "../../client/src/api/api";
import * as api from '../../client/src/api/api';
import asJson from "../lib/asJson";
import { DBError, DBErrorKind } from "../endpoints/types";
import { makeNotFoundError } from "./common";
var _ = require('lodash')

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

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

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

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

    // Wait for the requests to finish.
    const [artist, tags, albums, tracks] =
        await Promise.all([artistPromise, tagsPromise, albumsPromise, tracksPromise]);

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

    throw makeNotFoundError();
}

// Returns the id of the created artist.
export async function createArtist(userId: number, artist: ArtistWithRefs, knex: Knex): Promise<number> {
    return await knex.transaction(async (trx) => {
        // Start retrieving albums.
        const albumIdsPromise: Promise<number[]> =
            trx.select('id')
                .from('albums')
                .where({ 'user': userId })
                .whereIn('id', artist.albumIds || [])
                .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', artist.trackIds || [])
                .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', artist.tagIds || [])
                .then((as: any) => as.map((a: any) => a['id']));

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

        // Check that we found all artists and tags we need.
        if (!_.isEqual(albums.sort(), (artist.albumIds || []).sort()) ||
            !_.isEqual(tags.sort(), (artist.tagIds || []).sort()) ||
            !_.isEqual(tracks.sort(), (artist.trackIds || []).sort())) {
            throw makeNotFoundError();
        }

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

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

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

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

        console.log('created artist', artist, ', ID ', artistId);
        return artistId;
    })
}

export async function modifyArtist(userId: number, artistId: number, artist: ArtistBaseWithRefs, knex: Knex): Promise<void> {
    await knex.transaction(async (trx) => {
        // Start retrieving the artist itself.
        const artistIdPromise: Promise<number | undefined | null> =
            trx.select('id')
                .from('artists')
                .where({ 'user': userId })
                .where({ id: artistId })
                .then((r: any) => (r && r[0]) ? r[0]['id'] : null);

        // Start retrieving albums if we are modifying those.
        const albumIdsPromise: Promise<number[] | undefined | null> =
            artist.albumIds ?
                trx.select('id')
                    .from('albums')
                    .whereIn('id', artist.albumIds)
                    .then((as: any) => as.map((a: any) => a['id']))
                : (async () => null)();

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

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

        // Wait for the requests to finish.
        var [oldArtist, albums, tags, tracks] = await Promise.all([artistIdPromise, albumIdsPromise, tagIdsPromise, trackIdsPromise]);;

        // Check that we found all objects we need.
        if ((albums === undefined || !_.isEqual((albums || []).sort(), (artist.albumIds || []).sort())) ||
            (tags === undefined || !_.isEqual((tags || []).sort(), (artist.tagIds || []).sort())) ||
            (tracks === undefined || !_.isEqual((tracks || []).sort(), (artist.trackIds || []).sort())) ||
            !oldArtist) {
            throw makeNotFoundError();
        }

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

        const modifyArtistPromise = trx('artists')
            .where({ 'user': userId })
            .where({ 'id': artistId })
            .update(update)

        // Remove unlinked albums.
        const removeUnlinkedAlbums = albums ? trx('artists_albums')
            .where({ 'artistId': artistId })
            .whereNotIn('albumId', artist.albumIds || [])
            .delete() : undefined;

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

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

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

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

        // Link new tags.
        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,
            removeUnlinkedAlbums,
            removeUnlinkedTags,
            removeUnlinkedTracks,
            addAlbums,
            addTags,
            addTracks,
        ]);

        return;
    })
}

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

        if (!confirmArtistId) {
            throw makeNotFoundError();
        }

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

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

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

        // Start deleting the artist.
        const deleteArtistPromise: Promise<any> =
            trx.delete()
                .from('artists')
                .where({ id: artistId });

        // Wait for the requests to finish.
        await Promise.all([deleteAlbumsPromise, deleteTagsPromise, deleteTracksPromise, deleteArtistPromise]);
    })
}