import Knex from "knex";
import { TrackBaseWithRefs, TrackWithDetails, TrackWithRefs } 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 track with details, or null if not found.
export async function getTrack(id: number, userId: number, knex: Knex):
    Promise<TrackWithDetails> {
    // Start transfers for tracks, tags and artists.
    // Also request the track itself.
    const tagsPromise: Promise<api.TagWithId[]> =
        knex.select('tagId')
            .from('tracks_tags')
            .where({ 'trackId': id })
            .then((tags: any) => tags.map((tag: any) => tag['tagId']))
            .then((ids: number[]) =>
                knex.select(['id', 'name', 'parentId'])
                    .from('tags')
                    .whereIn('id', ids)
            );

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

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


    const albumPromise: Promise<api.AlbumWithId | null> =
        trackPromise
            .then((t: api.Track | undefined) =>
                t ? knex.select('id', 'name', 'storeLinks')
                    .from('albums')
                    .where({ 'user': userId })
                    .where({ id: t.albumId })
                    .then((albums: any) => albums.length > 0 ? albums[0] : null)
                    : (() => null)()
            )

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

    if (track) {
        return {
            mbApi_typename: 'track',
            name: track['name'],
            artists: artists as api.ArtistWithId[],
            tags: tags as api.TagWithId[],
            album: album as api.AlbumWithId | null,
            storeLinks: asJson(track['storeLinks'] || []),
        };
    } else {
        throw makeNotFoundError();
    }
}

// Returns the id of the created track.
export async function createTrack(userId: number, track: TrackWithRefs, knex: Knex): Promise<number> {
    return await knex.transaction(async (trx) => {

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

        // Start retrieving album.
        const albumIdPromise: Promise<number | null> =
            track.albumId ?
                trx.select('id')
                    .from('albums')
                    .where({ 'user': userId, 'id': track.albumId })
                    .then((albums: any) => albums.map((album: any) => album['id']))
                    .then((ids: number[]) =>
                        ids.length > 0 ? ids[0] : (() => null)()
                    ) :
                (async () => null)();

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

        // Check that we found all artists and tags we need.
        if (!_.isEqual((artists as number[]).sort(), track.artistIds.sort()) ||
            (!_.isEqual((tags as number[]).sort(), track.tagIds.sort())) ||
            (track.albumId && (album === null))) {
            throw makeNotFoundError();
        }

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

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

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

        console.log('created track', track, ', ID ', trackId);
        return trackId;
    })
}

export async function modifyTrack(userId: number, trackId: number, track: TrackBaseWithRefs, knex: Knex): Promise<void> {
    await knex.transaction(async (trx) => {
        // Start retrieving the track itself.
        const trackIdPromise: Promise<number | undefined> =
            trx.select('id')
                .from('tracks')
                .where({ 'user': userId })
                .where({ id: trackId })
                .then((r: any) => (r && r[0]) ? r[0]['id'] : undefined);

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

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

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

        // Check that we found all objects we need.
        if ((!artists || !_.isEqual(artists.sort(), (track.artistIds || []).sort())) ||
            (!tags || !_.isEqual(tags.sort(), (track.tagIds || []).sort())) ||
            !oldTrack) {
            throw makeNotFoundError();
        }

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

        const modifyTrackPromise = trx('tracks')
            .where({ 'user': userId })
            .where({ 'id': trackId })
            .update(update)

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

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

        // Link new artists.
        const addArtists = artists ? trx('artists_tracks')
            .where({ 'trackId': trackId })
            .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,
                        trackId: trackId,
                    }
                })

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

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

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

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

        return;
    })
}

export async function deleteTrack(userId: number, trackId: number, knex: Knex): Promise<void> {
    await knex.transaction(async (trx) => {
        // FIXME remove

        let tracks = await trx.select('id', 'name')
        .from('tracks');
        console.log("All tracks:", tracks);

        // Start by retrieving the track itself for sanity.
        const confirmTrackId: number | undefined =
            await trx.select('id')
                .from('tracks')
                .where({ 'user': userId })
                .where({ id: trackId })
                .then((r: any) => (r && r[0]) ? r[0]['id'] : undefined);

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

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

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

        // Start deleting the track.
        const deleteTrackPromise: Promise<any> =
            trx.delete()
                .from('tracks')
                .where({ id: trackId });

        // Wait for the requests to finish.
        await Promise.all([deleteArtistsPromise, deleteTagsPromise, deleteTrackPromise]);
    })
}