import os
import shutil
from datetime import datetime, timedelta
from src.log_registry import LogRegistry

class LogPruner:
 """
    Handles the automated deletion of old and insignificant session logs.
    Ensures that only whitelisted or significant sessions (based on size/content) 
    are preserved long-term.
    """

 def __init__(self, log_registry: LogRegistry, logs_dir: str) -> None:
  """
        Initializes the LogPruner.

        Args:
            log_registry: An instance of LogRegistry to check session data.
            logs_dir: The path to the directory containing session sub-directories.
        """
  self.log_registry = log_registry
  self.logs_dir = logs_dir

 def prune(self, max_age_days: int = 1, min_size_kb: int = 2) -> None:
  """
        Prunes old and small session directories from the logs directory.

        Deletes session directories that meet the following criteria:
        1. The session start time is older than max_age_days.
        2. The session name is NOT in the whitelist provided by the LogRegistry.
        3. The total size of all files within the session directory is less than min_size_kb.
        """
  now = datetime.now()
  cutoff_time = now - timedelta(days=max_age_days)
  # Ensure the base logs directory exists.
  if not os.path.isdir(self.logs_dir):
   return
   # Get sessions that are old and not whitelisted from the registry
  old_sessions_to_check = self.log_registry.get_old_non_whitelisted_sessions(cutoff_time)
  # Prune sessions if their size is less than threshold
  for session_info in old_sessions_to_check:
   session_id = session_info['session_id']
   session_path = session_info['path']
   if not session_path:
    continue
    
   # Resolve path
   resolved_path = session_path
   if not os.path.isabs(resolved_path):
    if resolved_path.startswith('logs' + os.sep) or resolved_path.startswith('logs/'):
     # Resolve relative to the project root (two levels up from self.logs_dir)
     project_root = os.path.dirname(os.path.dirname(os.path.abspath(self.logs_dir)))
     resolved_path = os.path.join(project_root, resolved_path)
   
   if not os.path.isdir(resolved_path):
    continue
    
   # Calculate total size of files in the directory
   total_size = 0
   try:
    for entry in os.scandir(resolved_path):
     if entry.is_file():
      total_size += entry.stat().st_size
   except OSError:
    continue
    # Prune if the total size is less than threshold
   if total_size < (min_size_kb * 1024):
    try:
     shutil.rmtree(resolved_path)
     # Also remove from registry to keep it in sync
     if session_id in self.log_registry.data:
      del self.log_registry.data[session_id]
    except OSError:
     pass
  self.log_registry.save_registry()