#!/usr/bin/env python3
import json
import time
from datetime import date, datetime, timezone
from http.server import ThreadingHTTPServer, SimpleHTTPRequestHandler
from pathlib import Path
from urllib.parse import urlparse

ROOT = Path(__file__).resolve().parent
CLOCK_CGI_PATH = "/zzz__2fbc6c3300df7e4483acd44c5044098a9fcc61d6.cgi"


def us_dst_dates_for_year(year: int) -> tuple[int, int]:
    march1 = date(year, 3, 1)
    first_sunday_march = 1 + ((6 - march1.weekday()) % 7)
    second_sunday_march = first_sunday_march + 7

    nov1 = date(year, 11, 1)
    first_sunday_november = 1 + ((6 - nov1.weekday()) % 7)

    return second_sunday_march, first_sunday_november


class Handler(SimpleHTTPRequestHandler):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, directory=str(ROOT), **kwargs)

    def do_GET(self):
        parsed = urlparse(self.path)

        if parsed.path == "/":
            self.send_response(302)
            self.send_header("Location", "/timegov/")
            self.end_headers()
            return

        if parsed.path in {"/simple", "/simple/"}:
            self.path = "/index.html"
            return super().do_GET()

        if parsed.path == "/api/time":
            self.send_response(200)
            self.send_header("Content-Type", "application/json")
            self.send_header("Cache-Control", "no-store")
            self.end_headers()
            payload = {
                "epoch_ms": time.time_ns() // 1_000_000,
                "iso_utc": datetime.now(timezone.utc).isoformat(),
            }
            self.wfile.write(json.dumps(payload).encode("utf-8"))
            return

        if parsed.path == "/api/timegov/auxdata.xml":
            now = datetime.now(timezone.utc)
            dst_start_day, dst_end_day = us_dst_dates_for_year(now.year)
            xml = (
                "<?xml version=\"1.0\" encoding=\"UTF-8\"?>"
                "<timeData>"
                f"<currYear>{now.year}</currYear>"
                f"<DstDates>3 {dst_start_day} 11 {dst_end_day}</DstDates>"
                "<LeapDate>2099 12 31</LeapDate>"
                "</timeData>"
            )
            self.send_response(200)
            self.send_header("Content-Type", "application/xml")
            self.send_header("Cache-Control", "no-store")
            self.end_headers()
            self.wfile.write(xml.encode("utf-8"))
            return

        if parsed.path == CLOCK_CGI_PATH:
            t2 = time.time_ns() // 1_000
            t3 = time.time_ns() // 1_000
            xml = f"<timestamp time2=\"{t2}\" time3=\"{t3}\"/>"
            self.send_response(200)
            self.send_header("Content-Type", "application/xml")
            self.send_header("Cache-Control", "no-store")
            self.end_headers()
            self.wfile.write(xml.encode("utf-8"))
            return

        return super().do_GET()


if __name__ == "__main__":
    server = ThreadingHTTPServer(("0.0.0.0", 8092), Handler)
    server.serve_forever()