"""
Calendar operations for Microsoft Graph API.
"""

import os
from datetime import datetime, timedelta

from .client import fetch_with_aiohttp


async def fetch_calendar_events(
    headers, days_back=1, days_forward=6, start_date=None, end_date=None
):
    """
    Fetch calendar events from Microsoft Graph API.

    Args:
        headers (dict): Headers including authentication.
        days_back (int): Number of days to look back.
        days_forward (int): Number of days to look forward.
        start_date (datetime): Optional start date, overrides days_back if provided.
        end_date (datetime): Optional end date, overrides days_forward if provided.

    Returns:
        tuple: (events, total_count) where events is a list of event dictionaries
               and total_count is the total number of events.
    """
    # Calculate date range
    if start_date is None:
        start_date = datetime.now() - timedelta(days=days_back)

    if end_date is None:
        end_date = start_date + timedelta(days=days_forward)

    # Format dates for API
    start_date_str = start_date.strftime("%Y-%m-%dT00:00:00Z")
    end_date_str = end_date.strftime("%Y-%m-%dT23:59:59Z")

    # Prepare the API query
    calendar_url = (
        f"https://graph.microsoft.com/v1.0/me/calendarView?"
        f"startDateTime={start_date_str}&endDateTime={end_date_str}&"
        f"$select=id,subject,organizer,start,end,location,isAllDay,showAs,sensitivity&$count=true"
    )

    events = []

    # Make the API request
    response_data = await fetch_with_aiohttp(calendar_url, headers)
    events.extend(response_data.get("value", []))

    # Check if there are more events (pagination)
    next_link = response_data.get("@odata.nextLink")
    while next_link:
        response_data = await fetch_with_aiohttp(next_link, headers)
        events.extend(response_data.get("value", []))
        next_link = response_data.get("@odata.nextLink")

    # Return events and total count
    total_count = response_data.get("@odata.count", len(events))
    return events, total_count