added song cache

Author: RonitNath

music.go

@@ -3,6 +3,7 @@ package main
 import (
 	"encoding/json"
 	"os/exec"
+	"sync"
 )
 
 // Song : Song information fetched from youtube-dl. More fields exist in the JSON response, but this is what we need.
@@ -13,7 +14,43 @@ type Song struct {
 	WebpageURL string `json:"webpage_url"`
 }
 
+type SongCache struct {
+	cache map[string]Song
+	mux   sync.RWMutex
+}
+
+var songCache = SongCache{
+	cache: make(map[string]Song),
+}
+
+func (sc *SongCache) Get(url string) (Song, bool) {
+	sc.mux.RLock()
+	defer sc.mux.RUnlock()
+	song, exists := sc.cache[url]
+	return song, exists
+}
+
+func (sc *SongCache) Set(url string, song Song) {
+	sc.mux.Lock()
+	defer sc.mux.Unlock()
+	sc.cache[url] = song
+}
+
 func fetchSong(url string) (Song, error) {
+	// Check cache first
+	if song, exists := songCache.Get(url); exists {
+		return song, nil
+	}
+
+	// If not in cache, fetch and store
+	song, err := fetchSongFromYoutubeDL(url)
+	if err == nil {
+		songCache.Set(url, song)
+	}
+	return song, err
+}
+
+func fetchSongFromYoutubeDL(url string) (Song, error) {
 	// Maybe make this function return a promise or something in the future
 	var songData Song
 	// JSON dump has no extra overhead, and we get more info that we need that might be useful