import json
import os
from pathlib import Path
from typing import List, Dict
from datetime import datetime

MEAL_FILE = "meal_tracker.json"

def save_preferences(preferences: Dict) -> str:
    with open('user_preferences.json', 'w') as f:
        json.dump(preferences, f, indent=4)
    return "Preferences saved successfully!"

def load_preferences() -> Dict:
    if os.path.exists('user_preferences.json'):
        with open('user_preferences.json', 'r') as f:
            return json.load(f)
    return {
        "physical_info": {"height": 170, "weight": 70.0, "age": 30},
        "focus_areas": {"custom": "", "selected": []},
        "diet_preferences": {"custom": "", "selected": []}
    }

def load_meals():
    """Load meals from the JSON file."""
    if Path(MEAL_FILE).exists():
        with open(MEAL_FILE, 'r') as f:
            return json.load(f)
    return []

def save_meal_to_database(new_meal):
    """Save a new meal to the JSON file, maintaining chronological order."""
    meals = load_meals()
    meals.append(new_meal)
    
    meals.sort(key=lambda x: datetime.strptime(x['date'], "%Y-%m-%d %H:%M:%S"))
    
    with open(MEAL_FILE, 'w') as f:
        json.dump(meals, f, indent=2)

def get_meals_markdown(meals):
    """Convert meals to a markdown string for display."""
    if not meals:
        return "No meals recorded yet."
    
    markdown = "## Recorded Meals\n\n"
    for meal in meals:
        markdown += f"**Date:** {meal['date']}\n"
        markdown += f"**Type:** {meal['meal_type']}\n"
        markdown += f"**Description:** {meal['description']}\n"
        if meal['tags']:
            markdown += f"**Tags:** {', '.join(meal['tags'])}\n"
        markdown += "\n---\n\n"
    
    return markdown

def save_meals(meals):
    """Save all meals to the JSON file."""
    with open(MEAL_FILE, 'w') as f:
        json.dump(meals, f, indent=2)

def get_macros_for_diet(diet_name: str) -> Dict[str, int]:
    """
    Return macronutrient ratios for a given diet
    """
    # You can expand this function with more diet types and their corresponding macros
    macros = {
        "Balanced Diet": {"carbs": 50, "protein": 20, "fat": 30},
        "Zone Diet": {"carbs": 40, "protein": 30, "fat": 30},
        "Ketogenic Diet (Keto)": {"carbs": 75, "protein": 20, "fat": 5},
        "Vegan Diet": {"carbs": 58, "protein": 15, "fat": 27},
        "Mediterranean Diet": {"carbs": 50, "protein": 17, "fat": 33},
        "Paleo Diet": {"carbs": 30, "protein": 30, "fat": 40},
        "Low-Carb Diet": {"carbs": 20, "protein": 35, "fat": 45},
        "High-Protein Diet": {"carbs": 25, "protein": 35, "fat": 40},
        "Vegetarian Diet": {"carbs": 55, "protein": 20, "fat": 25}
    }
    return macros.get(diet_name, {"carbs": 50, "protein": 20, "fat": 30})  # Default balanced diet