import tornado
from tornado.httpclient import AsyncHTTPClient
from tornado.httputil import HTTPHeaders

_LEGACY_PARAM_TO_HEADER_MAP = {
    "qrz_username": "X-QRZ-Username",
    "qrz_password": "X-QRZ-Password",
    "qrz_session_key": "X-QRZ-Session-Key",
    "hamqth_username": "X-HamQTH-Username",
    "hamqth_password": "X-HamQTH-Password",
    "hamqth_session_id": "X-HamQTH-Session-ID",
}


class V1RedirectHandler(tornado.web.RequestHandler):
    """Transparently proxies requests from the old API to the new one,
    returning whatever the v2 endpoint returns, for endpoints with no breaking changes."""

    async def _proxy(self, path):
        new_url = f"{self.request.protocol}://{self.request.host}/api/v2/{path}"
        if self.request.query:
            new_url += f"?{self.request.query}"

        # Copy the incoming headers so we can add translated legacy credentials without changing the original
        # request.
        headers = HTTPHeaders(self.request.headers)
        for param, header in _LEGACY_PARAM_TO_HEADER_MAP.items():
            value = self.get_query_argument(param, default=None)
            if value:
                headers[header] = value

        client = AsyncHTTPClient()
        try:
            response = await client.fetch(
                new_url,
                method=self.request.method,
                headers=headers,
                body=None if self.request.method == "GET" else (self.request.body or b""),
                raise_error=False,
                follow_redirects=False,
                request_timeout=10.0,
            )
        except Exception as e:
            raise tornado.web.HTTPError(502, reason=str(e))

        self.set_status(response.code, response.reason)
        if isinstance(response.headers, HTTPHeaders):
            for name, value in response.headers.get_all():
                # Let Tornado recompute these for the outgoing response
                if name.lower() not in (
                    "content-length",
                    "transfer-encoding",
                    "connection",
                ):
                    self.add_header(name, value)
            if response.body:
                self.write(response.body)

    async def get(self, path):
        await self._proxy(path)

    async def post(self, path):
        await self._proxy(path)