from flask import Flask, Response
from icalendar import Calendar, Event
from datetime import datetime
import pytz
import uuid


class Webserver:
    def __init__(self, ip, port, db_instance):
        self.ip = ip
        self.port = port
        self.db = db_instance

        self.app = Flask(__name__)
        self.tz = pytz.timezone("Europe/Amsterdam")

        self._register_routes()

    def _register_routes(self):
        self.app.add_url_rule("/", "index", lambda: "Calendar server running ✅")
        self.app.add_url_rule("/calendar.ics", "calendar", self._calendar_endpoint)

    def _fetch_shifts(self):
        con = self.db._get_connection()
        cur = con.cursor()

        cur.execute("""
            SELECT shift_start, shift_end, department, description
            FROM shifts
            ORDER BY shift_start ASC
        """)

        rows = cur.fetchall()
        con.close()

        shifts = []
        for row in rows:
            start_str, end_str, department, description = row

            # Convert string → datetime
            start = self._parse_datetime(start_str)
            end = self._parse_datetime(end_str)

            shifts.append({
                "start": start,
                "end": end,
                "description": f"{description} ",
                "department": f"{department} "
            })

        return shifts

    def _parse_datetime(self, dt_str):
        dt = datetime.fromisoformat(dt_str)
        if dt.tzinfo is None:
            dt = self.tz.localize(dt)
        return dt

    def _calendar_endpoint(self):
        cal = Calendar()
        cal.add('prodid', '-//Shift Calendar//example//')
        cal.add('version', '2.0')

        shifts = self._fetch_shifts()

        for shift in shifts:
            event = Event()
            event.add('uid', str(uuid.uuid4()))
            event.add('dtstart', shift["start"])
            event.add('dtend', shift["end"])
            event.add('summary', shift["department"])
            event.add('description', shift["description"])
            event.add('dtstamp', datetime.now(tz=self.tz))

            cal.add_component(event)

        return Response(cal.to_ical(), mimetype="text/calendar")

    def run(self):
        print(f"🚀 Starting server on {self.ip}:{self.port}")
        self.app.run(host=self.ip, port=self.port)