"""
Configuration Manager for the application.
Handles loading and saving of application settings to a JSON file.
"""
import json
from pathlib import Path
from typing import Dict, Any, Optional, List

from . import logger
from ..core.export_profiles import ExportProfile, ExportField

log = logger.get_logger(__name__)


class ConfigManager:
    """Manages loading and saving configuration from/to a JSON file."""

    def __init__(self, config_path: Path):
        """
        Initializes the ConfigManager.

        Args:
            config_path: The path to the configuration file.
        """
        self.config_path: Path = config_path
        self.config: Dict[str, Any] = self._get_default_config()
        # In-memory representation as objects
        self.export_profiles: List[ExportProfile] = []

    @staticmethod
    def _get_default_config() -> Dict[str, Any]:
        """Provides the default configuration structure."""
        default_profile = ExportProfile(
            name="Default",
            fields=[
                ExportField(column_name="batch_id", data_path="batch_id"),
                ExportField(column_name="timetag", data_path="header.header_data.signal_descr.ttag"),
            ]
        )
        return {
            "last_opened_file": "",
            "last_output_file": "", # <-- NUOVA CHIAVE
            "active_export_profile_name": "Default",
            "export_profiles": [default_profile.to_dict()]
        }

    def load_config(self) -> None:
        """Loads the configuration from the JSON file."""
        log.info(f"Attempting to load configuration from: {self.config_path}")
        if self.config_path.is_file():
            try:
                with open(self.config_path, 'r', encoding='utf-8') as f:
                    loaded_data = json.load(f)
                
                self.config['last_opened_file'] = loaded_data.get('last_opened_file', '')
                self.config['last_output_file'] = loaded_data.get('last_output_file', '') # <-- NUOVA RIGA
                self.config['active_export_profile_name'] = loaded_data.get('active_export_profile_name', 'Default')
                
                profiles_data = loaded_data.get("export_profiles", [])
                self.export_profiles = [ExportProfile.from_dict(p_data) for p_data in profiles_data]
                
                if not self.export_profiles:
                    log.warning("No export profiles found in config, loading defaults.")
                    self._load_default_profiles()
                
                log.info(f"Configuration loaded successfully. Found {len(self.export_profiles)} export profiles.")

            except (json.JSONDecodeError, IOError, KeyError) as e:
                log.error(f"Failed to load or parse config file: {e}. Using defaults.")
                self._load_defaults()
        else:
            log.warning("Configuration file not found. Using default settings.")
            self._load_defaults()

    def _load_defaults(self):
        """Loads all default settings into the manager."""
        self.config = self._get_default_config()
        self._load_default_profiles()

    def _load_default_profiles(self):
        """Loads just the default profiles from the default config."""
        default_conf = self._get_default_config()
        profiles_data = default_conf.get("export_profiles", [])
        self.export_profiles = [ExportProfile.from_dict(p_data) for p_data in profiles_data]

    def save_config(self) -> None:
        """Saves the current configuration to the JSON file."""
        log.info(f"Saving configuration to: {self.config_path}")
        
        data_to_save = {
            "last_opened_file": self.get("last_opened_file", ""),
            "last_output_file": self.get("last_output_file", ""), # <-- NUOVA RIGA
            "active_export_profile_name": self.get("active_export_profile_name", "Default"),
            "export_profiles": [profile.to_dict() for profile in self.export_profiles]
        }
        
        try:
            self.config_path.parent.mkdir(parents=True, exist_ok=True)
            with open(self.config_path, 'w', encoding='utf-8') as f:
                json.dump(data_to_save, f, indent=4)
            log.info("Configuration saved successfully.")
        except IOError as e:
            log.error(f"Failed to save configuration file: {e}")

    def get(self, key: str, default: Optional[Any] = None) -> Any:
        """Gets a value from the configuration."""
        return self.config.get(key, default)

    def set(self, key: str, value: Any) -> None:
        """Sets a value in the configuration."""
        self.config[key] = value
        
    def get_export_profiles(self) -> List[ExportProfile]:
        """Returns the list of loaded export profiles."""
        return self.export_profiles

    def save_export_profiles(self, profiles: List[ExportProfile]):
        """Updates the list of export profiles and saves the config."""
        self.export_profiles = profiles
        self.save_config()