import os
import subprocess
from PIL import Image
import customtkinter as ctk

def parse_float(val_str: str) -> float:
    """Safely parse a string to float, handling both '.' and ',' as decimal separators."""
    if not val_str:
        return None
    clean_val = val_str.replace(',', '.')
    try:
        return float(clean_val)
    except ValueError:
        return None

def format_float(val: float, precision: int = 1) -> str:
    """Format a float for display."""
    if val is None:
        return ""
    return f"{val:.{precision}f}"

def get_bmi_status(bmi):
    if bmi < 16: return "Severely Underweight", "bmi_severely_underweight.svg", "#3498db"
    if bmi < 18.5: return "Underweight", "bmi_underweight.svg", "#3498db"
    if bmi < 25: return "Normal", "bmi_normal.svg", "#2ecc71"
    if bmi < 30: return "Overweight", "bmi_overweight.svg", "#f1c40f"
    return "Obese", "bmi_severely_obese.svg", "#e74c3c"

def get_bmi_icon(bmi: float, size: tuple = (100, 100)) -> ctk.CTkImage:
    """
    Returns a CTkImage for the given BMI.
    Converts SVG to PNG using rsvg-convert if needed.
    """
    if bmi is None: return None
    
    _, filename, _ = get_bmi_status(bmi)
    
    base_dir = os.path.dirname(os.path.abspath(__file__))
    assets_dir = os.path.join(base_dir, "assets", "bmi_icons")
    cache_dir = os.path.join(assets_dir, "png_cache")
    
    svg_path = os.path.join(assets_dir, filename)
    png_filename = filename.replace(".svg", f"_{size[0]}x{size[1]}.png")
    png_path = os.path.join(cache_dir, png_filename)
    
    if not os.path.exists(svg_path):
        print(f"Warning: Icon not found at {svg_path}")
        return None
        
    if not os.path.exists(cache_dir):
        os.makedirs(cache_dir)
        
    # Convert if PNG doesn't exist
    if not os.path.exists(png_path):
        try:
            subprocess.run([
                "rsvg-convert",
                "-w", str(size[0]),
                "-h", str(size[1]),
                "-o", png_path,
                svg_path
            ], check=True)
        except (subprocess.CalledProcessError, FileNotFoundError) as e:
            print(f"Error converting SVG: {e}")
            return None
            
    try:
        img = Image.open(png_path)
        return ctk.CTkImage(light_image=img, dark_image=img, size=size)
    except Exception as e:
        print(f"Error loading image: {e}")
        return None