"""Minimaler Testwebserver: zeigt Hostname, Zeit und Client-Adresse und loggt jeden Zugriff.

GET /        HTML-Seite
GET /health  "ok" (fuer Skripte)
TLS=yes      HTTPS mit /certs/server.crt + /certs/server.key
"""

import html
import os
import socket
import ssl
import sys
from datetime import datetime
from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer

TLS = os.environ.get("TLS", "no").lower() in ("yes", "true", "1")
MESSAGE = os.environ.get("MESSAGE", "Testwebserver laeuft")
PUBLIC_PORT = os.environ.get("PUBLIC_PORT", "?")
HOST = socket.gethostname()


class Handler(BaseHTTPRequestHandler):
    server_version = "testwebserver/1.0"

    def _send(self, code, body, ctype):
        data = body.encode()
        self.send_response(code)
        self.send_header("Content-Type", f"{ctype}; charset=utf-8")
        self.send_header("Content-Length", str(len(data)))
        self.end_headers()
        if self.command != "HEAD":
            self.wfile.write(data)

    def do_GET(self):
        if self.path == "/health":
            return self._send(200, "ok\n", "text/plain")
        now = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
        rows = "".join(f"<tr><th>{html.escape(k)}</th><td>{html.escape(v)}</td></tr>"
                       for k, v in self.headers.items())
        page = f"""<!doctype html><html lang="de"><head><meta charset="utf-8">
<title>Testwebserver</title>
<style>body{{font-family:sans-serif;max-width:46rem;margin:2rem auto;padding:0 1rem}}
th{{text-align:left;padding-right:1rem;vertical-align:top}}h1{{color:#2a7d2a}}</style></head>
<body><h1>{html.escape(MESSAGE)}</h1>
<p>Container <b>{html.escape(HOST)}</b> &middot; Port {html.escape(PUBLIC_PORT)}
({'HTTPS' if TLS else 'HTTP'}) &middot; {now}</p>
<p>Deine Adresse (wie der Container sie sieht): <b>{html.escape(self.client_address[0])}</b></p>
<h2>Request-Header</h2><table>{rows}</table></body></html>"""
        self._send(200, page, "text/html")

    do_HEAD = do_GET

    def log_message(self, fmt, *args):
        print(f"{datetime.now():%Y-%m-%d %H:%M:%S} {self.client_address[0]} {fmt % args}", flush=True)


def main():
    srv = ThreadingHTTPServer(("0.0.0.0", 8000), Handler)
    if TLS:
        ctx = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER)
        try:
            ctx.load_cert_chain("/certs/server.crt", "/certs/server.key")
        except OSError as exc:
            sys.exit(f"TLS=yes, aber Zertifikat fehlt ({exc}) - ./start.sh erzeugt es")
        # Handshake erst im Request-Thread: ein haengender Client blockiert sonst alle anderen
        srv.socket = ctx.wrap_socket(srv.socket, server_side=True, do_handshake_on_connect=False)
    print(f"Testwebserver lauscht ({'HTTPS' if TLS else 'HTTP'}), von aussen Port {PUBLIC_PORT}", flush=True)
    srv.serve_forever()


if __name__ == "__main__":
    main()