import os
import json
from config_schema import AppConfig
from constants import CONFIG_FILE, Color
from logger import logger

def load_config() -> AppConfig:
    """
    Loads the user's config file and validates using Pydantic.
    """
    user_cfg = {}
    if os.path.exists(CONFIG_FILE):
        try:
            with open(CONFIG_FILE, 'r', encoding='utf-8') as f:
                user_cfg = json.load(f)
        except Exception as e:
            logger.error(f"Failed to read config file, falling back to defaults: {e}")
            print(f" {Color.YELLOW}⚠ Config file corrupted. Using defaults.{Color.RESET}")
            
    constraints_file = os.path.join(os.path.dirname(__file__), 'constraints.json')
    if os.path.exists(constraints_file):
        try:
            with open(constraints_file, 'r', encoding='utf-8') as f:
                constraints = json.load(f)
                user_cfg.update(constraints)
        except Exception as e:
            logger.error(f"Failed to read constraints.json: {e}")
            
    validation_failed = False
    try:
        app_cfg = AppConfig(**{k:v for k,v in user_cfg.items() if not k.startswith('_')})
    except Exception as e:
        logger.error(f"Config Validation Error: {e}")
        print(f" {Color.YELLOW}⚠ Config validation failed: {e}{Color.RESET}")
        print(f" {Color.YELLOW}⚠ Using safe defaults. The original config was not overwritten.{Color.RESET}")
        app_cfg = AppConfig()
        validation_failed = True
        
    # Restore internal variables (starting with _)
    for key, value in user_cfg.items():
        if key.startswith('_'):
            setattr(app_cfg, key, value)
            
    _sector_map = {}
    for category, tickers in app_cfg.universe_categories.items():
        for t in tickers:
            _sector_map[t] = category.split(' ')[0].replace('&', '').replace('/', '')
    app_cfg.sector_map = _sector_map
    
    if not validation_failed:
        save_config(app_cfg)
    return app_cfg

def save_config(cfg: AppConfig) -> None:
    """Saves the active configuration dictionary to disk."""
    try:
        with open(CONFIG_FILE, 'w', encoding='utf-8') as f:
            cfg_dict = cfg.model_dump()
            for key, val in cfg.__dict__.items():
                if key not in cfg_dict:
                    cfg_dict[key] = val
            json.dump({k: v for k, v in cfg_dict.items() if not k.startswith('_')}, f, indent=4)
    except Exception as e:
        logger.error(f"Could not save config to {CONFIG_FILE}: {e}")