navidrome/model/metadata/metadata.go

package metadata

import (
	"cmp"
	"io/fs"
	"math"
	"path"
	"regexp"
	"strconv"
	"strings"
	"time"
	"unicode/utf8"

	"github.com/google/uuid"
	"github.com/navidrome/navidrome/consts"
	"github.com/navidrome/navidrome/log"
	"github.com/navidrome/navidrome/model"
	"github.com/navidrome/navidrome/utils/slice"
)

type Info struct {
	FileInfo        FileInfo
	Tags            model.RawTags
	AudioProperties AudioProperties
	HasPicture      bool
	PictureHash     string
}

type FileInfo interface {
	fs.FileInfo
	BirthTime() time.Time
}

type AudioProperties struct {
	Duration   time.Duration
	BitRate    int
	BitDepth   int
	SampleRate int
	Channels   int
	Codec      string
}

type Date string

func (d Date) Year() int {
	if d == "" {
		return 0
	}
	y, _ := strconv.Atoi(string(d[:4]))
	return y
}

type Pair string

func (p Pair) Key() string   { return p.parse(0) }
func (p Pair) Value() string { return p.parse(1) }
func (p Pair) parse(i int) string {
	parts := strings.SplitN(string(p), consts.Zwsp, 2)
	if len(parts) > i {
		return parts[i]
	}
	return ""
}
func (p Pair) String() string {
	return string(p)
}
func NewPair(key, value string) string {
	return key + consts.Zwsp + value
}

func New(filePath string, info Info) Metadata {
	return Metadata{
		filePath:    filePath,
		fileInfo:    info.FileInfo,
		tags:        clean(filePath, info.Tags),
		audioProps:  info.AudioProperties,
		hasPicture:  info.HasPicture,
		pictureHash: info.PictureHash,
	}
}

type Metadata struct {
	filePath    string
	fileInfo    FileInfo
	tags        model.Tags
	audioProps  AudioProperties
	hasPicture  bool
	pictureHash string
}

func (md Metadata) FilePath() string     { return md.filePath }
func (md Metadata) ModTime() time.Time   { return md.fileInfo.ModTime() }
func (md Metadata) BirthTime() time.Time { return md.fileInfo.BirthTime() }
func (md Metadata) Size() int64          { return md.fileInfo.Size() }
func (md Metadata) Suffix() string {
	return strings.ToLower(strings.TrimPrefix(path.Ext(md.filePath), "."))
}
func (md Metadata) AudioProperties() AudioProperties         { return md.audioProps }
func (md Metadata) Length() float32                          { return float32(md.audioProps.Duration.Milliseconds()) / 1000 }
func (md Metadata) HasPicture() bool                         { return md.hasPicture }
func (md Metadata) PictureHash() string                      { return md.pictureHash }
func (md Metadata) All() model.Tags                          { return md.tags }
func (md Metadata) Strings(key model.TagName) []string       { return md.tags[key] }
func (md Metadata) String(key model.TagName) string          { return md.first(key) }
func (md Metadata) Int(key model.TagName) int64              { v, _ := strconv.Atoi(md.first(key)); return int64(v) }
func (md Metadata) Bool(key model.TagName) bool              { v, _ := strconv.ParseBool(md.first(key)); return v }
func (md Metadata) Date(key model.TagName) Date              { return md.date(key) }
func (md Metadata) NumAndTotal(key model.TagName) (int, int) { return md.tuple(key) }
func (md Metadata) Float(key model.TagName, def ...float64) float64 {
	return float(md.first(key), def...)
}
func (md Metadata) NullableFloat(key model.TagName) *float64 { return nullableFloat(md.first(key)) }

func (md Metadata) Gain(key model.TagName) *float64 {
	v := strings.TrimSpace(strings.Replace(md.first(key), "dB", "", 1))
	return nullableFloat(v)
}
func (md Metadata) Pairs(key model.TagName) []Pair {
	values := md.tags[key]
	return slice.Map(values, func(v string) Pair { return Pair(v) })
}
func (md Metadata) first(key model.TagName) string {
	if v, ok := md.tags[key]; ok && len(v) > 0 {
		return v[0]
	}
	return ""
}

func float(value string, def ...float64) float64 {
	v := nullableFloat(value)
	if v != nil {
		return *v
	}
	if len(def) > 0 {
		return def[0]
	}
	return 0
}

func nullableFloat(value string) *float64 {
	v, err := strconv.ParseFloat(value, 64)
	if err != nil || v == math.Inf(-1) || math.IsInf(v, 1) || math.IsNaN(v) {
		return nil
	}
	return &v
}

// Used for tracks and discs
func (md Metadata) tuple(key model.TagName) (int, int) {
	tag := md.first(key)
	if tag == "" {
		return 0, 0
	}
	tuple := strings.Split(tag, "/")
	t1, t2 := 0, 0
	t1, _ = strconv.Atoi(tuple[0])
	if len(tuple) > 1 {
		t2, _ = strconv.Atoi(tuple[1])
	} else {
		t2tag := md.first(key + "total")
		t2, _ = strconv.Atoi(t2tag)
	}
	return t1, t2
}

var dateRegex = regexp.MustCompile(`([12]\d\d\d)`)

func (md Metadata) date(tagName model.TagName) Date {
	return Date(md.first(tagName))
}

// date tries to parse a date from a tag, it tries to get at least the year. See the tests for examples.
func parseDate(filePath string, tagName model.TagName, tagValue string) string {
	if len(tagValue) < 4 {
		return ""
	}

	// first get just the year
	match := dateRegex.FindStringSubmatch(tagValue)
	if len(match) == 0 {
		log.Debug("Error parsing date", "file", filePath, "tag", tagName, "date", tagValue)
		return ""
	}

	// if the tag is just the year, return it
	if len(tagValue) < 5 {
		return match[1]
	}

	// if the tag is too long, truncate it
	tagValue = tagValue[:min(10, len(tagValue))]

	// then try to parse the full date
	for _, mask := range []string{"2006-01-02", "2006-01"} {
		_, err := time.Parse(mask, tagValue)
		if err == nil {
			return tagValue
		}
	}
	log.Debug("Error parsing month and day from date", "file", filePath, "tag", tagName, "date", tagValue)
	return match[1]
}

// clean filters out tags that are not in the mappings or are empty,
// combine equivalent tags and remove duplicated values.
// It keeps the order of the tags names as they are defined in the mappings.
func clean(filePath string, tags model.RawTags) model.Tags {
	lowered := lowerTags(tags)
	mappings := model.TagMappings()
	cleaned := make(model.Tags, len(mappings))

	for name, mapping := range mappings {
		mapping = mapping.WithParticipantExceptions(name)
		var values []string
		switch mapping.Type {
		case model.TagTypePair:
			values = processPairMapping(name, mapping, lowered)
		default:
			values = processRegularMapping(mapping, lowered)
		}
		cleaned[name] = values
	}

	cleaned = filterEmptyTags(cleaned)
	return sanitizeAll(filePath, cleaned)
}

func processRegularMapping(mapping model.TagConf, lowered model.Tags) []string {
	var values []string
	for _, alias := range mapping.Aliases {
		if vs, ok := lowered[model.TagName(alias)]; ok {
			splitValues := mapping.SplitTagValue(vs)
			values = append(values, splitValues...)
		}
	}
	return values
}

func lowerTags(tags model.RawTags) model.Tags {
	lowered := make(model.Tags, len(tags))
	for k, v := range tags {
		lowered[model.TagName(strings.ToLower(k))] = v
	}
	return lowered
}

func processPairMapping(name model.TagName, mapping model.TagConf, lowered model.Tags) []string {
	var aliasValues []string
	for _, alias := range mapping.Aliases {
		if vs, ok := lowered[model.TagName(alias)]; ok {
			aliasValues = append(aliasValues, vs...)
		}
	}

	// always parse id3 pairs. For lyrics, Taglib appears to always provide lyrics:xxx
	// Prefer that over format-specific tags
	id3Base := parseID3Pairs(name, lowered)

	if len(aliasValues) > 0 {
		// For lyrics, don't use parseVorbisPairs as parentheses in lyrics content
		// should not be interpreted as language keys (e.g. "(intro)" is not a language)
		if name == model.TagLyrics {
			for _, v := range aliasValues {
				id3Base = append(id3Base, NewPair("xxx", v))
			}
		} else {
			id3Base = append(id3Base, parseVorbisPairs(aliasValues)...)
		}
	}
	return id3Base
}

func parseID3Pairs(name model.TagName, lowered model.Tags) []string {
	var pairs []string
	prefix := string(name) + ":"
	for tagKey, tagValues := range lowered {
		keyStr := string(tagKey)
		if after, ok := strings.CutPrefix(keyStr, prefix); ok {
			keyPart := after
			if keyPart == string(name) {
				keyPart = ""
			}
			for _, v := range tagValues {
				pairs = append(pairs, NewPair(keyPart, v))
			}
		}
	}
	return pairs
}

var vorbisPairRegex = regexp.MustCompile(`\(([^()]+(?:\([^()]*\)[^()]*)*)\)`)

// parseVorbisPairs, from
//
//	"Salaam Remi (drums (drum set) and organ)",
//
// to
//
//	"drums (drum set) and organ" -> "Salaam Remi",
func parseVorbisPairs(values []string) []string {
	pairs := make([]string, 0, len(values))
	for _, value := range values {
		matches := vorbisPairRegex.FindAllStringSubmatch(value, -1)
		if len(matches) == 0 {
			pairs = append(pairs, NewPair("", value))
			continue
		}
		key := strings.TrimSpace(matches[0][1])
		key = strings.ToLower(key)
		valueWithoutKey := strings.TrimSpace(strings.Replace(value, "("+matches[0][1]+")", "", 1))
		pairs = append(pairs, NewPair(key, valueWithoutKey))
	}
	return pairs
}

func filterEmptyTags(tags model.Tags) model.Tags {
	for k, v := range tags {
		clean := filterDuplicatedOrEmptyValues(v)
		if len(clean) == 0 {
			delete(tags, k)
		} else {
			tags[k] = clean
		}
	}
	return tags
}

func filterDuplicatedOrEmptyValues(values []string) []string {
	seen := make(map[string]struct{}, len(values))
	var result []string
	for _, v := range values {
		if v == "" {
			continue
		}
		if _, ok := seen[v]; ok {
			continue
		}
		seen[v] = struct{}{}
		result = append(result, v)
	}
	return result
}

func sanitizeAll(filePath string, tags model.Tags) model.Tags {
	cleaned := model.Tags{}
	for k, v := range tags {
		tag, found := model.TagMappings()[k]
		if !found {
			continue
		}

		var values []string
		for _, value := range v {
			cleanedValue := sanitize(filePath, k, tag, value)
			if cleanedValue != "" {
				values = append(values, cleanedValue)
			}
		}
		if len(values) > 0 {
			cleaned[k] = values
		}
	}
	return cleaned
}

const defaultMaxTagLength = 1024

func sanitize(filePath string, tagName model.TagName, tag model.TagConf, value string) string {
	// First truncate the value to the maximum length
	maxLength := cmp.Or(tag.MaxLength, defaultMaxTagLength)
	if len(value) > maxLength {
		log.Trace("Truncated tag value", "tag", tagName, "value", value, "length", len(value), "maxLength", maxLength)
		value = value[:maxLength]
		// Drop the partial rune the cut may have left: at most 3 trailing bytes,
		// so a pre-existing invalid run elsewhere is never consumed.
		for range 3 {
			if r, size := utf8.DecodeLastRuneInString(value); r != utf8.RuneError || size != 1 {
				break
			}
			value = value[:len(value)-1]
		}
	}

	switch tag.Type {
	case model.TagTypeDate:
		value = parseDate(filePath, tagName, value)
		if value == "" {
			log.Trace("Invalid date tag value", "tag", tagName, "value", value)
		}
	case model.TagTypeInteger:
		_, err := strconv.Atoi(value)
		if err != nil {
			log.Trace("Invalid integer tag value", "tag", tagName, "value", value)
			return ""
		}
	case model.TagTypeFloat:
		_, err := strconv.ParseFloat(value, 64)
		if err != nil {
			log.Trace("Invalid float tag value", "tag", tagName, "value", value)
			return ""
		}
	case model.TagTypeUUID:
		u, err := uuid.Parse(value)
		if err != nil {
			log.Trace("Invalid UUID tag value", "tag", tagName, "value", value)
			return ""
		}
		// Store the canonical form: uuid.Parse accepts braces, urn: prefixes and any
		// two-byte wrapper, and a wrapped value would never match an exact-match query
		value = u.String()
	}
	return value
}