# prediction_state_service.py
import json
import os
from typing import Optional, List
from datetime import datetime
from prediction_state import PredictionState
from calendar_manager import CalendarManager
from typing import TYPE_CHECKING
if TYPE_CHECKING:
    from prediction_controller import PredictionController

class PredictionStateService:
    """Service for saving and loading complete prediction states"""
    
    DEFAULT_STATE_EXTENSION = '.prediction.json'
    
    @staticmethod
    def save_prediction_state(calendar_manager: CalendarManager, 
                            prediction_controller, 
                            filename: str) -> bool:
        """Save complete prediction state to file"""
        try:
            # Ensure proper extension
            if not filename.endswith(PredictionStateService.DEFAULT_STATE_EXTENSION):
                filename += PredictionStateService.DEFAULT_STATE_EXTENSION
            
            # Create prediction state
            state = PredictionState(
                launch_date=prediction_controller.get_launch_date(),
                duration_years=prediction_controller.get_duration().years if prediction_controller.get_duration() else None,
                prediction_date=prediction_controller.get_prediction(),
                entries=calendar_manager.list_entries()
            )
            
            # Ensure directory exists
            os.makedirs(os.path.dirname(filename) if os.path.dirname(filename) else '.', exist_ok=True)
            
            # Save to file with pretty formatting
            with open(filename, 'w', encoding='utf-8') as f:
                json.dump(state.to_dict(), f, indent=4, ensure_ascii=False)
            
            return True
            
        except Exception as e:
            print(f"Error saving prediction state to file {filename}: {e}")
            return False
    
    @staticmethod
    def load_prediction_state(filename: str) -> Optional[PredictionState]:
        """Load prediction state from file"""
        try:
            if not os.path.exists(filename):
                print(f"File {filename} does not exist")
                return None
            
            with open(filename, 'r', encoding='utf-8') as f:
                data = json.load(f)
            
            return PredictionState.from_dict(data)
            
        except (FileNotFoundError, json.JSONDecodeError) as e:
            print(f"Error loading prediction state from file {filename}: {e}")
            return None
        except Exception as e:
            print(f"Unexpected error loading prediction state from file {filename}: {e}")
            return None
    
    @staticmethod
    def restore_from_state(state: PredictionState, 
                          calendar_manager: CalendarManager,
                          prediction_controller) -> bool:
        """Restore calendar manager and prediction controller from state"""
        try:
            # Clear current entries and load from state
            calendar_manager.clear_entries()
            calendar_manager.entries.extend(state.entries)
            
            # Restore prediction controller state if available
            if state.launch_date and state.duration_years:
                success = prediction_controller.set_parameters(
                    state.launch_date.isoformat(), 
                    state.duration_years
                )
                if not success:
                    print("Warning: Could not restore prediction parameters")
            
            return True
            
        except Exception as e:
            print(f"Error restoring from state: {e}")
            return False
    
    @staticmethod
    def get_state_summary(filename: str):
        """Get summary information about a state file without loading entries"""
        try:
            if not os.path.exists(filename):
                return None
            
            with open(filename, 'r', encoding='utf-8') as f:
                data = json.load(f)
            
            return {
                'version': data.get('version', 'Unknown'),
                'created_at': data.get('created_at'),
                'launch_date': data.get('launch_date'),
                'duration_years': data.get('duration_years'),
                'prediction_date': data.get('prediction_date'),
                'entry_count': len(data.get('entries', []))
            }
            
        except Exception as e:
            print(f"Error getting state summary from {filename}: {e}")
            return None
    
    @staticmethod
    def list_state_files(directory: str = '.') -> List[str]:
        """List all prediction state files in a directory"""
        try:
            files = []
            for filename in os.listdir(directory):
                if filename.endswith(PredictionStateService.DEFAULT_STATE_EXTENSION):
                    files.append(os.path.join(directory, filename))
            return sorted(files)
        except Exception as e:
            print(f"Error listing state files in {directory}: {e}")
            return []