# calendar_manager.py
import json
import uuid
from datetime import datetime

class CalendarEntry:
    def __init__(self, start_date, end_date, keyword, entry_id=None, corrected_start_date=None, corrected_end_date=None, commentary: str = ""):
        self.id = entry_id if entry_id else str(uuid.uuid4())
        # Convert string dates to datetime if necessary
        self.start_date = (
            datetime.fromisoformat(start_date) 
            if isinstance(start_date, str) 
            else start_date
        )
        self.end_date = (
            datetime.fromisoformat(end_date) 
            if isinstance(end_date, str) 
            else end_date
        )
        self.keyword = keyword
        self.corrected_start_date = corrected_start_date
        self.corrected_end_date = corrected_end_date
        self.commentary = commentary                                                        
    def to_dict(self):
        return {
            'id': self.id,
            'start_date': self.start_date.isoformat(),
            'end_date': self.end_date.isoformat(),
            'keyword': self.keyword,
            'corrected_start_date': self.corrected_start_date.isoformat() if self.corrected_start_date else None,
            'corrected_end_date': self.corrected_end_date.isoformat() if self.corrected_end_date else None,
            'commentary': self.commentary,         
        }
    
    @classmethod
    def from_dict(cls, data):
        return cls(
            start_date=datetime.fromisoformat(data['start_date']),
            end_date=datetime.fromisoformat(data['end_date']),
            keyword=data['keyword'],
            entry_id=data['id'],
            corrected_start_date=datetime.fromisoformat(data['corrected_start_date']) if data.get('corrected_start_date') else None,
            corrected_end_date=datetime.fromisoformat(data['corrected_end_date']) if data.get('corrected_end_date') else None,
            commentary=data.get('commentary', ""),
        )

    def __repr__(self):
        return (f"CalendarEntry(id={self.id}, start_date={self.start_date}, "
                f"end_date={self.end_date}, keyword='{self.keyword}', "
                f"corrected_start_date={self.corrected_start_date}, corrected_end_date={self.corrected_end_date})")

class CalendarManager:
    def __init__(self, filename=None):
        self.filename = filename
        self.entries = []
        if filename:
            self.entries = self.add_entries_from_file(filename)

    def switch_file(self, new_filename):
        """Switch to a new file."""
        self.filename = new_filename
        
    def load_file(self, new_filename):
        """Clears current entries and loads entries from new file."""
        self.clear_entries()
        self.add_entries_from_file(new_filename)
        self.switch_file(new_filename)
        
    def add_entries_from_file(self, file_path):
        """Add events from another JSON file to the current calendar."""
        try:
            with open(file_path, 'r') as f:
                data = json.load(f)
                new_entries = [CalendarEntry.from_dict(entry) for entry in data]
                self.entries.extend(new_entries)
                self.save_entries()
                return new_entries
        except (FileNotFoundError, json.JSONDecodeError) as e:
            print(f"Error reading file {file_path}: {e}")
            return []

    def clear_entries(self):
        self.entries = []

    def save_entries(self):
        """Save the current list of events to the file."""
        if self.filename:
            try:
                with open(self.filename, 'w') as f:
                    json.dump([entry.to_dict() for entry in self.entries], f, indent=4)
            except Exception as e:
                print(f"Error writing to file {self.filename}: {e}")

    def add_entry(self, start_date, end_date, keyword, commentary: str = ""):
        """Add a new event to the calendar."""
        new_entry = CalendarEntry(start_date, end_date, keyword, commentary=commentary)
        self.entries.append(new_entry)
        self.save_entries()
        return new_entry

    def modify_entry(self, entry_id, start_date=None, end_date=None, keyword=None, commentary=None):
        """Modify an existing event by ID."""
        entry = self.get_entry_by_id(entry_id)
        if entry:
            if start_date:
                entry.start_date = start_date
            if end_date:
                entry.end_date = end_date
            if keyword:
                entry.keyword = keyword
            if commentary is not None:
                entry.commentary = commentary
            self.save_entries()
            return entry
        return None

    def delete_entry(self, entry_id):
        """Delete an event by ID."""
        entry = self.get_entry_by_id(entry_id)
        if entry:
            self.entries.remove(entry)
            self.save_entries()
            return entry
        return None

    def get_entry_by_id(self, entry_id):
        """Get an event by its ID."""
        return next((entry for entry in self.entries if entry.id == entry_id), None)

    def list_entries(self):
        """List all calendar entries."""
        return self.entries

    def correct_dates(self, list_of_events):
        for entry in self.entries:
            entry.corrected_start_date = None
            entry.corrected_end_date = None
            
        for start_date, end_date, original_id in list_of_events:
            entry = self.get_entry_by_id(original_id)
            entry.corrected_start_date = start_date
            entry.corrected_end_date = end_date