feat: add sub category

app/Models/MusicSubcategory.php

@@ -0,0 +1,85 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\HasMany;
+class MusicSubcategory extends Model
+{
+        protected $table = 'music_subcategories';
+    
+    protected $fillable = [
+        'category_id', 'name', 'slug', 'description', 'image_id', 'order', 'is_active'
+    ];
+    
+    protected $casts = [
+        'is_active' => 'boolean',
+        'order' => 'integer',
+    ];
+    
+    public function category(): BelongsTo
+    {
+        return $this->belongsTo(MusicCategory::class, 'category_id');
+    }
+    
+    public function playlists(): HasMany
+    {
+        return $this->hasMany(MusicPlaylist::class, 'subcategory_id');
+    }
+    
+    public function image(): BelongsTo
+    {
+        return $this->belongsTo(Image::class);
+    }
+    
+    public function getActivePlaylistsAttribute()
+    {
+        return $this->playlists()->where('is_active', true)->orderBy('order')->get();
+    }
+    
+    // Get total music count across all playlists in this subcategory
+    public function getTotalMusicCountAttribute()
+    {
+        return $this->playlists()
+            ->withCount('musics')
+            ->get()
+            ->sum('musics_count');
+    }
+    
+    // Get total duration across all music in this subcategory
+    public function getTotalDurationAttribute()
+    {
+        $totalSeconds = 0;
+        foreach ($this->playlists as $playlist) {
+            foreach ($playlist->musics as $music) {
+                $totalSeconds += $this->durationToSeconds($music->duration);
+            }
+        }
+        return $this->secondsToDuration($totalSeconds);
+    }
+    
+    private function durationToSeconds($duration)
+    {
+        if (!$duration) return 0;
+        $parts = explode(':', $duration);
+        if (count($parts) === 2) {
+            return (int)$parts[0] * 60 + (int)$parts[1];
+        } elseif (count($parts) === 3) {
+            return (int)$parts[0] * 3600 + (int)$parts[1] * 60 + (int)$parts[2];
+        }
+        return 0;
+    }
+    
+    private function secondsToDuration($seconds)
+    {
+        $hours = floor($seconds / 3600);
+        $minutes = floor(($seconds % 3600) / 60);
+        $secs = $seconds % 60;
+        
+        if ($hours > 0) {
+            return sprintf("%d:%02d:%02d", $hours, $minutes, $secs);
+        }
+        return sprintf("%d:%02d", $minutes, $secs);
+    }
+}