132 lines
3.3 KiB
Go
132 lines
3.3 KiB
Go
package download
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import (
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"context"
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"errors"
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"fmt"
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"net/http"
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"net/url"
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"strings"
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"unicode"
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"unicode/utf8"
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"github.com/PuerkitoBio/goquery"
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)
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var electronicKeywords = toLower([]string{
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"Ambient", "Bass", "Big Room", "Breakbeat", "Dance", "Disco", "Downtempo",
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"Drum And Bass", "Dub", "Dubstep", "EDM", "Electro", "Electronic", "Electronica",
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"Eurodance", "Gabber", "Garage", "Hardcore", "Hardstyle", "House", "Industrial",
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"Jungle", "Moombahton", "Synthpop", "Synthwave", "Techno", "Trance", "Trap",
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"Trip Hop", "Vaporwave",
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})
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var nonElectronicKeywords = toLower([]string{
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"Blues", "Chillout", "Classical", "Country", "Folk", "Funk", "Hip Hop", "Jazz",
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"Latin", "Metal", "Pop", "R&B", "Rap", "Reggae", "Rock", "Soul",
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})
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func toLower(ss []string) []string {
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out := make([]string, len(ss))
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for i, s := range ss {
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out[i] = strings.ToLower(s)
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}
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return out
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}
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func fetchGenre(ctx context.Context, httpClient *http.Client, artist, title string) (string, error) {
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// Escape the path segments: names containing '/', '?', or '#' would
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// otherwise change the URL structure and fetch the wrong page.
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reqURL := fmt.Sprintf("https://www.last.fm/music/%s/%s/+tags", url.PathEscape(artist), url.PathEscape(title))
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doc, err := fetchGenrePage(ctx, httpClient, reqURL)
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if err != nil {
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return "", err
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}
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tags := parseGenreTags(doc)
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if len(tags) > 2 {
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tags = tags[:2]
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}
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filtered := filterTags(tags)
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if len(filtered) == 0 {
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return "", errors.New("no data found")
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}
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return formatTags(filtered), nil
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}
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func fetchGenrePage(ctx context.Context, httpClient *http.Client, pageURL string) (*goquery.Document, error) {
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req, err := http.NewRequestWithContext(ctx, http.MethodGet, pageURL, nil)
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if err != nil {
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return nil, err
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}
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resp, err := httpClient.Do(req)
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if err != nil {
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return nil, err
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}
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defer resp.Body.Close()
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if resp.StatusCode != http.StatusOK {
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return nil, fmt.Errorf("unexpected status code: %d", resp.StatusCode)
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}
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return goquery.NewDocumentFromReader(resp.Body)
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}
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func parseGenreTags(doc *goquery.Document) []string {
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var tags []string
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doc.Find("ol.big-tags .big-tags-item-name a").Each(func(_ int, s *goquery.Selection) {
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if tag := strings.TrimSpace(s.Text()); tag != "" {
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tags = append(tags, tag)
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}
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})
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return tags
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}
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func matchesKeyword(tag string, keywords []string) bool {
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tagLower := strings.ToLower(tag)
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for _, kw := range keywords {
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if strings.Contains(tagLower, kw) {
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return true
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}
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}
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return false
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}
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func filterTags(tags []string) []string {
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var electronic, nonElectronic []string
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for _, tag := range tags {
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if matchesKeyword(tag, electronicKeywords) {
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electronic = append(electronic, tag)
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} else if matchesKeyword(tag, nonElectronicKeywords) {
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nonElectronic = append(nonElectronic, tag)
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}
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}
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if len(electronic) > 0 {
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return append(electronic, nonElectronic...)
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}
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return electronic
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}
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func formatTags(tags []string) string {
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formatted := make([]string, 0, len(tags))
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for _, tag := range tags {
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tag = strings.TrimSpace(tag)
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if tag == "" {
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continue
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}
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words := strings.Fields(tag)
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for i, w := range words {
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r, size := utf8.DecodeRuneInString(w)
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words[i] = string(unicode.ToUpper(r)) + strings.ToLower(w[size:])
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}
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formatted = append(formatted, strings.Join(words, " "))
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}
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return strings.Join(formatted, " / ")
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}
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