#!/usr/bin/env python3
import json
import os
import sys
import zoneinfo
from datetime import datetime, timedelta

ZULIP_PATH = os.path.join(os.path.dirname(os.path.abspath(__file__)), "../../")
sys.path.insert(0, ZULIP_PATH)

from zerver.lib.timezone import get_canonical_timezone_map

OUT_PATH = os.path.join(ZULIP_PATH, "web", "generated", "timezones.json")


def get_utc_offset(tz_name: str) -> str:
    """Get UTC offset for a timezone in the format UTC(+HH:MM)."""
    try:
        now = datetime.now(zoneinfo.ZoneInfo(tz_name))
        offset: timedelta | None = now.utcoffset()

        if offset is None:
            return "UTC(+00:00)"

        offset_seconds = offset.total_seconds()
        hours, remainder = divmod(offset_seconds, 3600)
        minutes = remainder // 60
        if minutes == 0:
            return f"UTC{int(hours):+d}"
        return f"UTC{int(hours):+d}:{int(minutes):02d}"

    except Exception as e:
        print(f"Error processing {tz_name}: {e}")
        return "UTC(?)"


timezones = sorted(
    zoneinfo.available_timezones() - {"Factory", "localtime"} - set(get_canonical_timezone_map())
)


timezone_data = [{"name": tz, "utc_offset": get_utc_offset(tz)} for tz in timezones]


with open(OUT_PATH, "w") as f:
    json.dump({"timezones": timezone_data}, f)