import csv
import os
import logging
from dataclasses import dataclass, asdict
from typing import List

logger = logging.getLogger(__name__)

@dataclass
class Pen:
    Make: str = "N/A"
    Model: str = "N/A"
    Date_Purchased: str = "N/A"
    Vendor: str = "N/A"
    Nib: str = "N/A"
    Nib_Material: str = "N/A"
    Body: str = "N/A"
    Cap: str = "N/A"
    Post: str = "N/A"
    Current_Ink: str = "N/A"
    Inked_date: str = "N/A"
    Notes: str = "N/A"

class PenTracker:
    def __init__(self, storage_file: str = None):
        if storage_file is None:
            storage_file = os.getenv('PEN_TRACKER_CSV', 'Pens.csv')
        self.storage_file = storage_file
        self.headers = [
            'Make', 'Model', 'Date-Purchased', 'Vendor', 'Nib',
            'Nib-Material', 'Body', 'Cap', 'Post',
            'Current-Ink', 'Inked-date', 'Notes'
        ]
        self.key_map = {
            'Date-Purchased': 'Date_Purchased',
            'Inked-date': 'Inked_date',
            'Nib-Material': 'Nib_Material',
            'Current-Ink': 'Current_Ink'
        }
        self.reverse_key_map = {v: k for k, v in self.key_map.items()}
        self.pens: List[Pen] = self.load_data()

    def _sort_pens(self):
        """Sorts the pens list by Make, then by Model alphabetically."""
        self.pens.sort(key=lambda x: (x.Make.lower(), x.Model.lower()))

    def load_data(self) -> List[Pen]:
        """Loads data from the CSV file."""
        if not os.path.exists(self.storage_file):
            self._create_empty_csv()
            return []
        
        pens = []
        try:
            # Standard, clean way to open the file
            with open(self.storage_file, mode='r', encoding='utf-8-sig') as f:
                reader = csv.DictReader(f)
                for row in reader:
                    # Strip whitespace from keys and values, handle empty values
                    clean_row = {k.strip(): (v.strip() if v else "N/A") for k, v in row.items()}
                    # Map keys to dataclass field names
                    mapped_row = {self.key_map.get(k, k): v for k, v in clean_row.items()}
                    pens.append(Pen(**mapped_row))
            pens.sort(key=lambda x: (x.Make.lower(), x.Model.lower()))
        except Exception as e:
            logger.error(f"Error loading CSV: {e}")
        return pens

    def _create_empty_csv(self):
        """Creates the CSV file with headers if it is missing."""
        with open(self.storage_file, mode='w', newline='', encoding='utf-8') as f:
            writer = csv.DictWriter(f, fieldnames=self.headers)
            writer.writeheader()

    def save_data(self):
        """Sorts the data before writing to ensure persistent alphabetical order."""
        self._sort_pens()
        with open(self.storage_file, mode='w', newline='', encoding='utf-8') as f:
            writer = csv.DictWriter(f, fieldnames=self.headers)
            writer.writeheader()
            for pen in self.pens:
                row = asdict(pen)
                # Map back to CSV keys
                csv_row = {k.replace('_', '-'): v for k, v in row.items()}
                writer.writerow(csv_row)