streamrip-go/internal/config/config.go

package config

import (
	"errors"
	"fmt"
	"os"
	"path/filepath"
	"strings"
	"sync"
	"time"

	"github.com/pelletier/go-toml/v2"
)

const CurrentConfigVersion = "2.2.0"

var ErrOutdatedConfig = errors.New("config version mismatch")

// Config holds the on-disk config (File) and the runtime view with CLI
// overrides applied (Session).
//
// mu guards File, Session and the write to Path. Provider clients refresh OAuth
// tokens from inside concurrent download workers, so both the struct fields and
// the config-file write have to be serialized; without this, two workers
// refreshing at once raced each other and issued two concurrent os.WriteFile
// calls against the same path.
type Config struct {
	Path    string
	mu      sync.Mutex
	File    ConfigData
	Session ConfigData
}

type ConfigData struct {
	Downloads    DownloadsConfig              `toml:"downloads"`
	Qobuz        QobuzConfig                  `toml:"qobuz"`
	Tidal        TidalConfig                  `toml:"tidal"`
	Deezer       DeezerConfig                 `toml:"deezer"`
	Yandex       YandexConfig                 `toml:"yandex"`
	Beatport     BeatportConfig               `toml:"beatport"`
	Soundcloud   SoundcloudConfig             `toml:"soundcloud"`
	Database     DatabaseConfig               `toml:"database"`
	Conversion   ConversionConfig             `toml:"conversion"`
	QobuzFilters QobuzDiscographyFilterConfig `toml:"qobuz_filters"`
	Artwork      ArtworkConfig                `toml:"artwork"`
	Metadata     MetadataConfig               `toml:"metadata"`
	Filepaths    FilepathsConfig              `toml:"filepaths"`
	LastFM       LastFMConfig                 `toml:"lastfm"`
	CLI          CLIConfig                    `toml:"cli"`
	Misc         MiscConfig                   `toml:"misc"`
}

type DownloadsConfig struct {
	Folder               string `toml:"folder"`
	SourceSubdirectories bool   `toml:"source_subdirectories"`
	DiscSubdirectories   bool   `toml:"disc_subdirectories"`
	Concurrency          bool   `toml:"concurrency"`
	MaxConnections       int    `toml:"max_connections"`
	RequestsPerMinute    int    `toml:"requests_per_minute"`
	VerifySSL            bool   `toml:"verify_ssl"`
}

type QobuzConfig struct {
	Quality         int      `toml:"quality"`
	UseAuthToken    bool     `toml:"use_auth_token"`
	EmailOrUserID   string   `toml:"email_or_userid"`
	PasswordOrToken string   `toml:"password_or_token"`
	AppID           string   `toml:"app_id"`
	Secrets         []string `toml:"secrets"`

	// Vendor app credentials for the mobile API fallback. Defaulted in code;
	// override here when Qobuz rotates them, instead of waiting for a release.
	MobileAppID     string `toml:"mobile_app_id"`
	MobileAppSecret string `toml:"mobile_app_secret"`
}

type TidalConfig struct {
	Quality        int    `toml:"quality"`
	DownloadVideos bool   `toml:"download_videos"`
	PreferAtmos    bool   `toml:"prefer_atmos"`
	UserID         string `toml:"user_id"`
	CountryCode    string `toml:"country_code"`
	AccessToken    string `toml:"access_token"`
	RefreshToken   string `toml:"refresh_token"`
	TokenExpiry    int64  `toml:"token_expiry"`

	// Vendor OAuth app credentials. Defaulted in code; override on rotation.
	AppClientID     string `toml:"app_client_id"`
	AppClientSecret string `toml:"app_client_secret"`
}

type DeezerConfig struct {
	Quality                    int    `toml:"quality"`
	LowerQualityIfNotAvailable bool   `toml:"lower_quality_if_not_available"`
	ARL                        string `toml:"arl"`
	Email                      string `toml:"email"`
	Password                   string `toml:"password"`
	RefreshToken               string `toml:"refresh_token"`

	// Vendor protocol keys. Defaulted in code; override on rotation.
	APIKey         string `toml:"api_key"`
	GatewayKey     string `toml:"gateway_key"`
	BlowfishSecret string `toml:"blowfish_secret"`
}

type YandexConfig struct {
	Quality     int    `toml:"quality"`
	AccessToken string `toml:"access_token"`
	UserID      string `toml:"user_id"`

	// Vendor request-signing keys. Defaulted in code; override on rotation.
	SignKey           string `toml:"sign_key"`
	LegacyMP3SignSalt string `toml:"legacy_mp3_sign_salt"`
}

type BeatportConfig struct {
	Quality                 int    `toml:"quality"`
	VariousArtistsThreshold int    `toml:"various_artists_threshold"`
	Username                string `toml:"username"`
	Password                string `toml:"password"`
	AccessToken             string `toml:"access_token"`
	RefreshToken            string `toml:"refresh_token"`
	TokenExpiry             int64  `toml:"token_expiry"`

	// Vendor OAuth app credential. Defaulted in code; override on rotation.
	AppClientID string `toml:"app_client_id"`
}

// SoundcloudConfig has no client_id/app_version: soundcloud is handled via
// yt-dlp, which supplies its own, so those keys were read by no code.
type SoundcloudConfig struct {
	Quality int `toml:"quality"`
}

type DatabaseConfig struct {
	DownloadsEnabled       bool   `toml:"downloads_enabled"`
	DownloadsPath          string `toml:"downloads_path"`
	FailedDownloadsEnabled bool   `toml:"failed_downloads_enabled"`
	FailedDownloadsPath    string `toml:"failed_downloads_path"`
}

type ConversionConfig struct {
	Enabled      bool   `toml:"enabled"`
	Codec        string `toml:"codec"`
	SamplingRate int    `toml:"sampling_rate"`
	BitDepth     int    `toml:"bit_depth"`
	LossyBitrate int    `toml:"lossy_bitrate"`
}

type QobuzDiscographyFilterConfig struct {
	Extras          bool `toml:"extras"`
	Repeats         bool `toml:"repeats"`
	NonAlbums       bool `toml:"non_albums"`
	Features        bool `toml:"features"`
	NonStudioAlbums bool `toml:"non_studio_albums"`
	NonRemaster     bool `toml:"non_remaster"`
}

type ArtworkConfig struct {
	Embed         bool   `toml:"embed"`
	EmbedSize     string `toml:"embed_size"`
	EmbedMaxWidth int    `toml:"embed_max_width"`
	SaveArtwork   bool   `toml:"save_artwork"`
	SavedMaxWidth int    `toml:"saved_max_width"`
}

type MetadataConfig struct {
	SetPlaylistToAlbum     bool     `toml:"set_playlist_to_album"`
	RenumberPlaylistTracks bool     `toml:"renumber_playlist_tracks"`
	ArtistSeparator        string   `toml:"artist_separator"`
	Exclude                []string `toml:"exclude"`
}

type FilepathsConfig struct {
	AddSinglesToFolder bool   `toml:"add_singles_to_folder"`
	FolderFormat       string `toml:"folder_format"`
	TrackFormat        string `toml:"track_format"`
	RestrictCharacters bool   `toml:"restrict_characters"`
	TruncateTo         int    `toml:"truncate_to"`
}

type LastFMConfig struct {
	Source         string `toml:"source"`
	FallbackSource string `toml:"fallback_source"`
}

type CLIConfig struct {
	TextOutput       bool `toml:"text_output"`
	ProgressBars     bool `toml:"progress_bars"`
	MaxSearchResults int  `toml:"max_search_results"`
}

type MiscConfig struct {
	Version string `toml:"version"`
}

func Load(path string) (*Config, error) {
	resolvedPath, err := resolvePath(path)
	if err != nil {
		return nil, err
	}

	if _, err = os.Stat(resolvedPath); errors.Is(err, os.ErrNotExist) {
		cfg := DefaultConfigData()
		if err = saveConfigData(resolvedPath, cfg); err != nil {
			return nil, err
		}
		return &Config{Path: resolvedPath, File: cfg, Session: cloneConfigData(cfg)}, nil
	}
	if err != nil {
		return nil, err
	}

	raw, err := os.ReadFile(resolvedPath)
	if err != nil {
		return nil, err
	}

	data := DefaultConfigData()
	if err = toml.Unmarshal(raw, &data); err != nil {
		return nil, err
	}
	applyRuntimeDefaults(&data)

	if data.Misc.Version != CurrentConfigVersion {
		return nil, fmt.Errorf("%w: need to update from %q to %q", ErrOutdatedConfig, data.Misc.Version, CurrentConfigVersion)
	}

	if err = Validate(&data); err != nil {
		return nil, err
	}

	return &Config{Path: resolvedPath, File: data, Session: cloneConfigData(data)}, nil
}

// Vendor app credentials and protocol keys.
//
// These are the provider apps' own identifiers and signing keys, not user
// secrets, and they are baked in so the tool works out of the box. They are
// mirrored into the config so that when a provider rotates one, a user can fix
// their install with a config edit instead of waiting for a new release.
const (
	DefaultQobuzMobileAppID     = "312369995"
	DefaultQobuzMobileAppSecret = "e79f8b9be485692b0e5f9dd895826368"
	DefaultTidalAppClientID     = "fX2JxdmntZWK0ixT"
	DefaultTidalAppClientSecret = "1Nm5AfDAjxrgJFJbKNWLeAyKGVGmINuXPPLHVXAvxAg="
	DefaultDeezerAPIKey         = "4VCYIJUCDLOUELGD1V8WBVYBNVDYOXEWSLLZDONGBBDFVXTZJRXPR29JRLQFO6ZE"
	DefaultDeezerGatewayKey     = "VBK1FSUEXHTSDBJJ"
	DefaultDeezerBlowfishSecret = "g4el58wc0zvf9na1"
	DefaultYandexSignKey        = "kzqU4XhfCaY6B6JTHODeq5"
	DefaultYandexLegacyMP3Salt  = "XGRlBW9FXlekgbPrRHuSiA"
	DefaultBeatportAppClientID  = "ryZ8LuyQVPqbK2mBX2Hwt4qSMtnWuTYSqBPO92yQ"
)

// applyVendorDefaults fills in any vendor credential the user has not set, so
// the provider clients never have to nil-check them.
func applyVendorDefaults(data *ConfigData) {
	if data.Qobuz.MobileAppID == "" {
		data.Qobuz.MobileAppID = DefaultQobuzMobileAppID
	}
	if data.Qobuz.MobileAppSecret == "" {
		data.Qobuz.MobileAppSecret = DefaultQobuzMobileAppSecret
	}
	if data.Tidal.AppClientID == "" {
		data.Tidal.AppClientID = DefaultTidalAppClientID
	}
	if data.Tidal.AppClientSecret == "" {
		data.Tidal.AppClientSecret = DefaultTidalAppClientSecret
	}
	if data.Deezer.APIKey == "" {
		data.Deezer.APIKey = DefaultDeezerAPIKey
	}
	if data.Deezer.GatewayKey == "" {
		data.Deezer.GatewayKey = DefaultDeezerGatewayKey
	}
	if data.Deezer.BlowfishSecret == "" {
		data.Deezer.BlowfishSecret = DefaultDeezerBlowfishSecret
	}
	if data.Yandex.SignKey == "" {
		data.Yandex.SignKey = DefaultYandexSignKey
	}
	if data.Yandex.LegacyMP3SignSalt == "" {
		data.Yandex.LegacyMP3SignSalt = DefaultYandexLegacyMP3Salt
	}
	if data.Beatport.AppClientID == "" {
		data.Beatport.AppClientID = DefaultBeatportAppClientID
	}
}

// qualityRange is the accepted quality id range per source on the global 0-4
// scale.
//
// The ceiling is 4 everywhere because each provider maps the scale onto its own
// ladder and saturates at the top: deezer's buildFormatPriority treats anything
// >= 2 as FLAC, and soundcloud ignores the value entirely. Only the floor
// differs: Qobuz and Beatport have no equivalent of tier 0.
var qualityRange = map[string][2]int{
	"qobuz":      {1, 4},
	"tidal":      {0, 4},
	"deezer":     {0, 4},
	"soundcloud": {0, 4},
	"yandex":     {0, 4},
	"beatport":   {1, 4},
}

// Validate rejects config values that would otherwise fail much later, deep in
// a rip, or be silently patched over at individual call sites. Load previously
// checked nothing but misc.version, so a negative max_connections or a bogus
// conversion codec was accepted and only noticed mid-download.
//
// It normalizes what can be normalized (the conversion codec, which until now
// was only canonicalized when it arrived via --codec) and errors on the rest.
func Validate(data *ConfigData) error {
	for source, bounds := range qualityRange {
		var q int
		switch source {
		case "qobuz":
			q = data.Qobuz.Quality
		case "tidal":
			q = data.Tidal.Quality
		case "deezer":
			q = data.Deezer.Quality
		case "soundcloud":
			q = data.Soundcloud.Quality
		case "yandex":
			q = data.Yandex.Quality
		case "beatport":
			q = data.Beatport.Quality
		}
		if q < bounds[0] || q > bounds[1] {
			return fmt.Errorf("config: %s.quality is %d, must be %d-%d", source, q, bounds[0], bounds[1])
		}
	}

	if data.Downloads.MaxConnections < 1 {
		return fmt.Errorf("config: downloads.max_connections is %d, must be >= 1", data.Downloads.MaxConnections)
	}
	if data.Downloads.RequestsPerMinute == 0 {
		return errors.New("config: downloads.requests_per_minute is 0; use a positive value, or a negative value to disable throttling")
	}
	if data.Filepaths.TruncateTo < 1 {
		return fmt.Errorf("config: filepaths.truncate_to is %d, must be >= 1", data.Filepaths.TruncateTo)
	}

	if data.Conversion.Enabled {
		codec, err := NormalizeCodec(data.Conversion.Codec)
		if err != nil {
			return fmt.Errorf("config: conversion.codec: %w", err)
		}
		data.Conversion.Codec = codec
	}

	// artwork.*_max_width uses -1 (and any non-positive value) to mean "do not
	// downscale", so there is no lower bound to enforce here.

	return nil
}

// NormalizeCodec canonicalizes a conversion codec name. It lives here, rather
// than only in the CLI flag parser, so a codec set in the config file goes
// through the same check.
func NormalizeCodec(raw string) (string, error) {
	codec := strings.ToUpper(strings.TrimSpace(raw))
	switch codec {
	case "ALAC", "FLAC", "MP3", "AAC", "VORBIS":
		return codec, nil
	case "OGG":
		return "VORBIS", nil
	default:
		return "", fmt.Errorf("unsupported codec %q (expected ALAC, FLAC, OGG, MP3, AAC)", raw)
	}
}

// UpgradeOutdated rewrites an outdated config at the current version. It runs
// automatically, without prompting, so it copies the original aside first: the
// rewrite re-serializes the whole file from the parsed struct, which drops any
// key this version does not know about. It returns the config path and the
// backup path.
//
// This is a version stamp, not a migration framework. There are no per-version
// transforms, so a future key rename still needs explicit handling here.
func UpgradeOutdated(path string) (resolved string, backup string, err error) {
	resolvedPath, err := resolvePath(path)
	if err != nil {
		return "", "", err
	}
	raw, err := os.ReadFile(resolvedPath)
	if err != nil {
		return "", "", err
	}

	backupPath := fmt.Sprintf("%s.bak-%d", resolvedPath, time.Now().Unix())
	if err = os.WriteFile(backupPath, raw, 0o600); err != nil {
		return "", "", fmt.Errorf("could not back up %s before upgrading: %w", resolvedPath, err)
	}

	data := DefaultConfigData()
	if err = toml.Unmarshal(raw, &data); err != nil {
		return "", "", err
	}
	applyRuntimeDefaults(&data)
	data.Misc.Version = CurrentConfigVersion
	if err = Validate(&data); err != nil {
		return "", "", err
	}
	if err = saveConfigData(resolvedPath, data); err != nil {
		return "", "", err
	}
	return resolvedPath, backupPath, nil
}

func (c *Config) SaveFile() error {
	c.mu.Lock()
	defer c.mu.Unlock()
	return c.saveFileLocked()
}

func (c *Config) saveFileLocked() error {
	return saveConfigData(c.Path, c.File)
}

// UpdateTokens applies fn to both the on-disk and session copies of the config
// under the config lock, then persists the result. Provider token refresh must
// go through this rather than mutating c.File/c.Session directly, because it
// runs concurrently from download workers.
func (c *Config) UpdateTokens(fn func(file, session *ConfigData)) error {
	if fn == nil {
		return nil
	}
	c.mu.Lock()
	defer c.mu.Unlock()
	fn(&c.File, &c.Session)
	// An empty Path means there is no config file backing this Config (tests,
	// and callers that loaded defaults only); the in-memory update still has to
	// happen, but there is nothing to write.
	if strings.TrimSpace(c.Path) == "" {
		return nil
	}
	return c.saveFileLocked()
}

func DefaultConfigData() ConfigData {
	home, _ := os.UserHomeDir()
	appDir := defaultAppDir()
	downloadsFolder := filepath.Join(home, "StreamripDownloads")

	data := ConfigData{
		Downloads: DownloadsConfig{
			Folder:               downloadsFolder,
			SourceSubdirectories: false,
			DiscSubdirectories:   true,
			Concurrency:          true,
			MaxConnections:       6,
			RequestsPerMinute:    60,
			VerifySSL:            true,
		},
		Qobuz: QobuzConfig{
			Quality:      3,
			UseAuthToken: false,
		},
		Tidal: TidalConfig{
			Quality:        3,
			DownloadVideos: true,
			PreferAtmos:    false,
		},
		Deezer: DeezerConfig{
			Quality:                    2,
			LowerQualityIfNotAvailable: true,
		},
		Yandex: YandexConfig{
			Quality: 2,
		},
		Beatport: BeatportConfig{
			Quality:                 3,
			VariousArtistsThreshold: 3,
		},
		Soundcloud: SoundcloudConfig{
			Quality: 0,
		},
		Database: DatabaseConfig{
			DownloadsEnabled:       true,
			DownloadsPath:          filepath.Join(appDir, "downloads.db"),
			FailedDownloadsEnabled: true,
			FailedDownloadsPath:    filepath.Join(appDir, "failed_downloads.db"),
		},
		Conversion: ConversionConfig{
			Enabled:      false,
			Codec:        "ALAC",
			SamplingRate: 48000,
			BitDepth:     24,
			LossyBitrate: 320,
		},
		QobuzFilters: QobuzDiscographyFilterConfig{},
		Artwork: ArtworkConfig{
			Embed:         true,
			EmbedSize:     "large",
			EmbedMaxWidth: -1,
			SaveArtwork:   true,
			SavedMaxWidth: -1,
		},
		Metadata: MetadataConfig{
			SetPlaylistToAlbum:     true,
			RenumberPlaylistTracks: true,
			ArtistSeparator:        "; ",
			Exclude:                []string{},
		},
		Filepaths: FilepathsConfig{
			AddSinglesToFolder: false,
			FolderFormat:       "{albumartist} - {title} ({year}) [{container}] [{bit_depth}B-{sampling_rate}kHz]",
			TrackFormat:        "{tracknumber:02}. {artist} - {title}{explicit}",
			RestrictCharacters: false,
			TruncateTo:         120,
		},
		LastFM: LastFMConfig{
			Source: "qobuz",
		},
		CLI: CLIConfig{
			TextOutput:       true,
			ProgressBars:     true,
			MaxSearchResults: 100,
		},
		Misc: MiscConfig{
			Version: CurrentConfigVersion,
		},
	}

	applyVendorDefaults(&data)
	return data
}

func resolvePath(path string) (string, error) {
	// 0o700: this directory holds the credential-bearing config and the
	// download databases.
	if path != "" {
		if err := os.MkdirAll(filepath.Dir(path), 0o700); err != nil {
			return "", err
		}
		return path, nil
	}
	appDir := defaultAppDir()
	if err := os.MkdirAll(appDir, 0o700); err != nil {
		return "", err
	}
	return filepath.Join(appDir, "config.toml"), nil
}

func defaultAppDir() string {
	base, err := os.UserConfigDir()
	if err != nil {
		return "."
	}
	return filepath.Join(base, "streamrip")
}

func saveConfigData(path string, data ConfigData) error {
	// 0o700/0o600: this file holds plaintext provider passwords, Deezer ARL
	// cookies and OAuth access/refresh tokens, so it must not be world-readable.
	if err := os.MkdirAll(filepath.Dir(path), 0o700); err != nil {
		return err
	}
	b, err := toml.Marshal(data)
	if err != nil {
		return err
	}
	if err := os.WriteFile(path, b, 0o600); err != nil {
		return err
	}
	// Tighten an existing file that a previous version created as 0o644.
	return os.Chmod(path, 0o600)
}

func applyRuntimeDefaults(data *ConfigData) {
	applyVendorDefaults(data)
	home, _ := os.UserHomeDir()
	appDir := defaultAppDir()
	if data.Downloads.Folder == "" {
		data.Downloads.Folder = filepath.Join(home, "StreamripDownloads")
	}
	if data.Database.DownloadsPath == "" {
		data.Database.DownloadsPath = filepath.Join(appDir, "downloads.db")
	}
	if data.Database.FailedDownloadsPath == "" {
		data.Database.FailedDownloadsPath = filepath.Join(appDir, "failed_downloads.db")
	}
}

// CloneConfigData returns a deep copy of in. The slice fields must not be
// shared between Config.File and Config.Session, or writing one silently
// mutates the other.
func CloneConfigData(in ConfigData) ConfigData {
	return cloneConfigData(in)
}

func cloneConfigData(in ConfigData) ConfigData {
	out := in
	out.Qobuz.Secrets = append([]string(nil), in.Qobuz.Secrets...)
	out.Metadata.Exclude = append([]string(nil), in.Metadata.Exclude...)
	return out
}