UI update 02

Assets/songsDatabase/SongDataController/SongButton.cs

@@ -7,6 +7,10 @@ using DG.Tweening;
 public class SongButton : MonoBehaviour
 {
     private static readonly bool VerboseLogs = false;
+    private const string SongSelectedIndexPrefsPrefix = "song_selected_";
+    private const string SongSelectedIdPrefsPrefix = "song_selected_id_";
+    private const string SongSelectedDifficultyPrefsPrefix = "song_selected_difficulty_";
+
     [Header("thisSong_so")]
     public ScriptableObject thisSong_so;
     [Header("Inspector")]
@@ -58,6 +62,23 @@ public class SongButton : MonoBehaviour
         return song_songSerialID;
     }
 
+    public static string BuildSongSelectedIndexPrefsKey(string dlcKey)
+    {
+        string safeDlcKey = string.IsNullOrEmpty(dlcKey) ? "default_0" : dlcKey;
+        return SongSelectedIndexPrefsPrefix + safeDlcKey;
+    }
+
+    public static string BuildSongSelectedIdPrefsKey(string dlcKey)
+    {
+        string safeDlcKey = string.IsNullOrEmpty(dlcKey) ? "default_0" : dlcKey;
+        return SongSelectedIdPrefsPrefix + safeDlcKey;
+    }
+
+    public static string BuildSongSelectedDifficultyPrefsKey(int songId)
+    {
+        return SongSelectedDifficultyPrefsPrefix + Mathf.Max(0, songId);
+    }
+
     public void Start()
     {
         if (selected_boarder != null)
@@ -111,7 +132,7 @@ public class SongButton : MonoBehaviour
             sd = SongDataLibrary.Instance.GetSongDataByID(songID) ?? sd;
         if (sd != null)
         {
-            Sprite resolvedBackground = sd.GetResolvedBackgroundPic();
+            Sprite resolvedIllustration = sd.GetResolvedIllustration();
             Sprite resolvedProfile = sd.GetResolvedCardProfileImage();
 
             if (songNameText != null) songNameText.text = sd.songName;
@@ -176,7 +197,7 @@ public class SongButton : MonoBehaviour
             // Set rank images for the first three difficulties
             SetDifficultyRankImages(sd);
 
-            if (buttonImage != null) buttonImage.sprite = resolvedBackground;
+            if (buttonImage != null) buttonImage.sprite = resolvedIllustration != null ? resolvedIllustration : songSprite;
 
             if (profileImage != null)
             {
@@ -252,10 +273,7 @@ public class SongButton : MonoBehaviour
         {
             selectedSong.EnsurePersistentDataLoaded();
             selectedSong.GetAbsoluteHighestScore(out int bestTotal, out int bestDiff, out string bestDiffName);
-            if (bestDiff >= 0)
-            {
-                selectedSong.thisLevel_selectedDifficultyID = bestDiff;
-            }
+            selectedSong.thisLevel_selectedDifficultyID = ResolvePreferredDifficulty(selectedSong, bestDiff);
             if (currentSelected != null && currentSelected != this)
             {
                 currentSelected.FadeOutSelectedBorder();
@@ -273,9 +291,11 @@ public class SongButton : MonoBehaviour
             // Save per-DLC selected song index to PlayerPrefs
             string dlcKey = SongSelectUI.CurrentDlcKey;
             if (string.IsNullOrEmpty(dlcKey)) dlcKey = "default_0";
-            string prefsKey = "song_selected_" + dlcKey;
+            string prefsKey = BuildSongSelectedIndexPrefsKey(dlcKey);
             int index = GetIndexAmongSongButtons();
             PlayerPrefs.SetInt(prefsKey, index);
+            PlayerPrefs.SetInt(BuildSongSelectedIdPrefsKey(dlcKey), selectedSong.songID);
+            PlayerPrefs.SetInt(BuildSongSelectedDifficultyPrefsKey(selectedSong.songID), selectedSong.thisLevel_selectedDifficultyID);
             PlayerPrefs.Save();
             if (VerboseLogs) Debug.Log($"SongButton: saved selected song index {index} for key {prefsKey}");
         }
@@ -285,6 +305,82 @@ public class SongButton : MonoBehaviour
         }
     }
 
+    private int ResolvePreferredDifficulty(SongData selectedSong, int bestDiff)
+    {
+        if (selectedSong == null)
+        {
+            return 0;
+        }
+
+        int songId = selectedSong.songID;
+        string difficultyKey = BuildSongSelectedDifficultyPrefsKey(songId);
+        if (PlayerPrefs.HasKey(difficultyKey))
+        {
+            int savedDifficulty = PlayerPrefs.GetInt(difficultyKey, selectedSong.thisLevel_selectedDifficultyID);
+            if (IsDifficultyAvailable(selectedSong, savedDifficulty))
+            {
+                return savedDifficulty;
+            }
+        }
+
+        if (IsDifficultyAvailable(selectedSong, selectedSong.thisLevel_selectedDifficultyID))
+        {
+            return selectedSong.thisLevel_selectedDifficultyID;
+        }
+
+        if (bestDiff >= 0 && IsDifficultyAvailable(selectedSong, bestDiff))
+        {
+            return bestDiff;
+        }
+
+        return GetFirstAvailableDifficulty(selectedSong);
+    }
+
+    private bool IsDifficultyAvailable(SongData song, int difficulty)
+    {
+        if (song == null || difficulty < 0)
+        {
+            return false;
+        }
+
+        return song.GetResolvedChartFile(difficulty) != null;
+    }
+
+    private int GetFirstAvailableDifficulty(SongData song)
+    {
+        if (song == null)
+        {
+            return 0;
+        }
+
+        if (song.chartFiles != null)
+        {
+            for (int i = 0; i < song.chartFiles.Count; i++)
+            {
+                ChartFileEntry entry = song.chartFiles[i];
+                if (entry == null)
+                {
+                    continue;
+                }
+
+                if (song.GetResolvedChartFile(entry.difficulty) != null)
+                {
+                    return Mathf.Max(0, entry.difficulty);
+                }
+            }
+        }
+
+        for (int difficulty = 0; difficulty <= 3; difficulty++)
+        {
+            if (song.GetResolvedChartFile(difficulty) != null)
+            {
+                return difficulty;
+            }
+        }
+
+        return 0;
+    }
+
     private int GetIndexAmongSongButtons()
     {
         // Use parent traversal to find only SongButton siblings, to avoid mismatch when other UI children exist.