import json
import os
import socket
from http.server import BaseHTTPRequestHandler, HTTPServer

import pymysql


def get_env(name, default=None):
    value = os.environ.get(name, default)
    return value if value is not None else default


def db_check():
    host = get_env("DB_HOST")
    port = int(get_env("DB_PORT", "3306"))
    user = get_env("DB_USER")
    password = get_env("DB_PASSWORD")
    dbname = get_env("DB_NAME", "postgres")

    if not host or not user or not password:
        return False, "missing DB_HOST/DB_USER/DB_PASSWORD"

    conn = pymysql.connect(
        host=host,
        port=port,
        user=user,
        password=password,
        database=dbname,
        connect_timeout=5,
        read_timeout=5,
        write_timeout=5,
    )
    try:
        with conn.cursor() as cur:
            cur.execute("SELECT 1")
            cur.fetchone()
        return True, "ok"
    finally:
        conn.close()


class Handler(BaseHTTPRequestHandler):
    def do_GET(self):
        ok, msg = False, ""
        status = 500
        try:
            ok, msg = db_check()
            status = 200 if ok else 500
        except Exception as exc:  # pylint: disable=broad-except
            msg = str(exc)

        body = {
            "status": "ok" if ok else "error",
            "message": msg,
            "hostname": socket.gethostname(),
        }
        data = json.dumps(body).encode("utf-8")

        self.send_response(status)
        self.send_header("Content-Type", "application/json")
        self.send_header("Content-Length", str(len(data)))
        self.end_headers()
        self.wfile.write(data)


if __name__ == "__main__":
    port = int(get_env("PORT", "8080"))
    server = HTTPServer(("0.0.0.0", port), Handler)
    print(f"listening on :{port}")
    server.serve_forever()