Initial commit - SoundWave v1.0

- Full PWA support with offline capabilities
- Comprehensive search across songs, playlists, and channels
- Offline playlist manager with download tracking
- Pre-built frontend for zero-build deployment
- Docker-based deployment with docker compose
- Material-UI dark theme interface
- YouTube audio download and management
- Multi-user authentication support

backend/channel/serializers.py

@@ -0,0 +1,54 @@
+"""Channel serializers"""
+
+from rest_framework import serializers
+from channel.models import Channel
+import re
+
+
+class ChannelSubscribeSerializer(serializers.Serializer):
+    """Channel subscription from URL"""
+    url = serializers.URLField(required=True, help_text="YouTube channel URL")
+
+    def validate_url(self, value):
+        """Extract channel ID from URL"""
+        # Match various YouTube channel URL patterns
+        patterns = [
+            r'youtube\.com/channel/(UC[\w-]+)',
+            r'youtube\.com/@([\w-]+)',
+            r'youtube\.com/c/([\w-]+)',
+            r'youtube\.com/user/([\w-]+)',
+        ]
+        
+        for pattern in patterns:
+            match = re.search(pattern, value)
+            if match:
+                return match.group(1)
+        
+        # If it's just a channel ID
+        if value.startswith('UC') and len(value) == 24:
+            return value
+            
+        raise serializers.ValidationError("Invalid YouTube channel URL")
+
+
+class ChannelSerializer(serializers.ModelSerializer):
+    """Channel serializer"""
+    status_display = serializers.CharField(source='get_sync_status_display', read_only=True)
+    progress_percent = serializers.SerializerMethodField()
+
+    class Meta:
+        model = Channel
+        fields = '__all__'
+        read_only_fields = ['created_date', 'last_refreshed']
+    
+    def get_progress_percent(self, obj):
+        """Calculate download progress percentage"""
+        if obj.video_count == 0:
+            return 0
+        return int((obj.downloaded_count / obj.video_count) * 100)
+
+
+class ChannelListSerializer(serializers.Serializer):
+    """Channel list response"""
+    data = ChannelSerializer(many=True)
+    paginate = serializers.BooleanField(default=True)