listy/lists/monthly.go

package lists

import (
	"context"
	"fmt"
	"time"

	"gitea.ravianand.me/Dan6erbond/listy/core"
	"gitea.ravianand.me/Dan6erbond/listy/internal"
	"gitea.ravianand.me/Dan6erbond/listy/models"
	"gitea.ravianand.me/Dan6erbond/listy/users"
	"github.com/zmb3/spotify/v2"
)

func SyncMonthlyList(ctx context.Context, app *core.App, user *models.User) (int, error) {
	client, err := users.GetSpotifyClient(ctx, app, user)

	if err != nil {
		return 0, err
	}

	beginningOfMonth := internal.BeginningOfMonth()

	playlistName := fmt.Sprintf("%d %d", beginningOfMonth.Year(), beginningOfMonth.Month())

	var playlist *spotify.SimplePlaylist

	playlists, err := client.CurrentUsersPlaylists(ctx)

	if err != nil {
		return 0, err
	}

PLAYLISTS:
	for page := 1; ; page++ {
		for _, pl := range playlists.Playlists {
			if pl.Name == playlistName {
				playlist = &pl
				break PLAYLISTS
			}
		}

		err := client.NextPage(ctx, playlists)

		if err == spotify.ErrNoMorePages {
			break
		}

		if err != nil {
			return 0, err
		}
	}

	if playlist == nil {
		fullPlaylist, err := client.CreatePlaylistForUser(ctx, user.SpotifyID, playlistName, "", false, false)

		if err != nil {
			return 0, err
		}

		playlist = &fullPlaylist.SimplePlaylist
	}

	var playlistTracks []spotify.PlaylistItemTrack
	items, err := client.GetPlaylistItems(ctx, playlist.ID)

	if err != nil {
		return 0, err
	}

	for page := 1; ; page++ {
		for _, item := range items.Items {
			playlistTracks = append(playlistTracks, item.Track)
		}

		err := client.NextPage(ctx, items)

		if err == spotify.ErrNoMorePages {
			break
		}

		if err != nil {
			return 0, err
		}
	}

	tracks, err := client.CurrentUsersTracks(ctx)

	if err != nil {
		return 0, err
	}

	var trackIDs []spotify.ID

TRACKS:
	for page := 1; ; page++ {
	TRACK:
		for _, track := range tracks.Tracks {
			for _, t := range playlistTracks {
				if t.Track.ID == track.ID {
					continue TRACK
				}
			}

			addedAt, err := time.Parse(time.RFC3339, track.AddedAt)

			if err != nil {
				return 0, err
			}

			if addedAt.Before(beginningOfMonth) {
				break TRACKS
			}

			fmt.Println("Adding", track.Name, "(added at", track.AddedAt+")")

			trackIDs = append(trackIDs, track.ID)
		}

		err := client.NextPage(ctx, tracks)

		if err == spotify.ErrNoMorePages {
			break
		}

		if err != nil {
			return 0, err
		}
	}

	if len(trackIDs) > 0 {
		_, err = client.AddTracksToPlaylist(ctx, playlist.ID, trackIDs...)

		if err != nil {
			return 0, err
		}

		return len(trackIDs), nil
	}

	return 0, nil
}