"""
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 or update_ready.
    
    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
    """
    # Skip if this is a new instance (no pk yet)
    if not instance.pk:
        return
    
    try:
        # Get the old instance to check for status change
        old_instance = PluginVersion.objects.get(pk=instance.pk)
    except PluginVersion.DoesNotExist:
        return
    
    # Check if status is changing TO 'released' or 'update_ready'
    release_statuses = ['released', 'update_ready']
    old_status = old_instance.status
    new_status = instance.status
    
    # Only trigger build if:
    # 1. Status is changing
    # 2. New status is a release status
    # 3. Old status was not a release status (avoid rebuilding on every save)
    if old_status == new_status:
        return
    
    if new_status not in release_statuses:
        return
    
    # If moving from one release status to another, don't rebuild
    if old_status in release_statuses:
        logger.info(f"Plugin {instance.plugin.slug} v{instance.version}: Status changing from {old_status} to {new_status}, no rebuild needed")
        return
    
    logger.info(f"Building plugin ZIP for {instance.plugin.slug} v{instance.version} (status: {old_status} -> {new_status})")
    
    # Build the ZIP
    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 moving to released status and not already set
    if new_status in release_statuses and not instance.released_at:
        instance.released_at = timezone.now()
    
    logger.info(f"Built plugin ZIP: {file_path} ({file_size} bytes, checksum: {checksum[:16]}...)")