"""
Plugin Distribution System Signals

Handles automatic ZIP creation when plugin versions are released.
"""
import logging
from django.db.models.signals import pre_save, post_save
from django.dispatch import receiver
from django.utils import timezone

from .models import PluginVersion
from .utils import create_plugin_zip

logger = logging.getLogger(__name__)


@receiver(pre_save, sender=PluginVersion)
def auto_build_plugin_on_release(sender, instance, **kwargs):
    """
    Automatically build ZIP package when a version is marked as released.
    
    This ensures:
    1. ZIP file is always up-to-date with source code
    2. File size and checksum are auto-calculated
    3. No manual intervention needed for releases
    
    Triggers on:
    - New version created with status 'released'
    - Existing version status changed to 'released'
    
    Note: Only 'released' status makes the version available for download.
    """
    # Only build ZIP when status is 'released'
    should_build = False
    
    if not instance.pk:
        # New instance - build if status is released
        if instance.status == 'released':
            should_build = True
            logger.info(f"New plugin version {instance.plugin.slug} v{instance.version} created with status 'released' - building ZIP")
    else:
        # Existing instance - check if status changed to released
        try:
            old_instance = PluginVersion.objects.get(pk=instance.pk)
            old_status = old_instance.status
            new_status = instance.status
            
            # Build if moving to released from any other status
            if new_status == 'released' and old_status != 'released':
                should_build = True
                logger.info(f"Building plugin ZIP for {instance.plugin.slug} v{instance.version} (status: {old_status} -> released)")
            elif old_status == 'released' and new_status == 'released':
                # No status change, already released - no rebuild
                return
        except PluginVersion.DoesNotExist:
            return
    
    if not should_build:
        return
    
    # Build the ZIP
    try:
        file_path, checksum, file_size = create_plugin_zip(
            platform=instance.plugin.platform,
            plugin_slug=instance.plugin.slug,
            version=instance.version,
            update_version=True
        )
        
        if not file_path:
            logger.error(f"Failed to build ZIP for {instance.plugin.slug} v{instance.version}")
            return
        
        # Update the instance with new file info
        instance.file_path = file_path
        instance.checksum = checksum
        instance.file_size = file_size
        
        # Set released_at if not already set
        if not instance.released_at:
            instance.released_at = timezone.now()
        
        logger.info(f"Built plugin ZIP: {file_path} ({file_size} bytes, checksum: {checksum[:16]}...)")
        
    except Exception as e:
        logger.error(f"Error building ZIP for {instance.plugin.slug} v{instance.version}: {e}")