import sys
import time
import threading
import RNS
from http.server import HTTPServer, BaseHTTPRequestHandler
from urllib.parse import parse_qs, urlparse

APP_NAME = "tinyweb"
ASPECTS = ["server"]
GATEWAY_PORT = 8080
REQUEST_TIMEOUT = 60


class GatewayState:
    reticulum = None
    destination = None
    link = None
    link_lock = threading.Lock()
    local_dispatch = None  # set when running inside app.py


def resolve_destination(dest_hash_hex):
    dest_hash = bytes.fromhex(dest_hash_hex)

    if not RNS.Transport.has_path(dest_hash):
        RNS.Transport.request_path(dest_hash)
        print(f"Requesting path to {RNS.prettyhexrep(dest_hash)}...")
        elapsed = 0
        while not RNS.Transport.has_path(dest_hash) and elapsed < 15:
            time.sleep(0.5)
            elapsed += 0.5
        if not RNS.Transport.has_path(dest_hash):
            raise ConnectionError(f"Could not find path to {RNS.prettyhexrep(dest_hash)}")

    server_identity = RNS.Identity.recall(dest_hash)
    GatewayState.destination = RNS.Destination(
        server_identity,
        RNS.Destination.OUT,
        RNS.Destination.SINGLE,
        APP_NAME,
        *ASPECTS,
    )
    print(f"Resolved destination: {RNS.prettyhexrep(dest_hash)}")


def ensure_link():
    with GatewayState.link_lock:
        if GatewayState.link and GatewayState.link.status == RNS.Link.ACTIVE:
            return GatewayState.link

        print("Establishing link...")
        link = RNS.Link(GatewayState.destination)
        elapsed = 0
        while link.status == RNS.Link.PENDING and elapsed < 15:
            time.sleep(0.25)
            elapsed += 0.25

        if link.status != RNS.Link.ACTIVE:
            raise ConnectionError("Link establishment failed")

        GatewayState.link = link
        print("Link established")
        return link


class GatewayHandler(BaseHTTPRequestHandler):

    def _forward(self, method):
        parsed = urlparse(self.path)
        query = parse_qs(parsed.query)

        body = {}
        if method == "POST":
            length = int(self.headers.get("Content-Length", 0))
            raw = self.rfile.read(length).decode()
            body = parse_qs(raw)

        # Parse cookies
        cookies = {}
        cookie_header = self.headers.get("Cookie", "")
        if cookie_header:
            for part in cookie_header.split(";"):
                part = part.strip()
                if "=" in part:
                    k, v = part.split("=", 1)
                    cookies[k.strip()] = v.strip()

        request_data = {
            "method": method,
            "path": parsed.path,
            "query": query,
            "body": body,
            "cookies": cookies,
            "gateway_host": self.headers.get("Host", f"localhost:{GATEWAY_PORT}"),
        }

        try:
            if GatewayState.local_dispatch:
                resp = GatewayState.local_dispatch(request_data)
            else:
                link = ensure_link()
                receipt = link.request(
                    "/tinyweb",
                    data=request_data,
                    timeout=REQUEST_TIMEOUT,
                )

                # Wait for the response
                elapsed = 0
                done_statuses = (RNS.RequestReceipt.READY, RNS.RequestReceipt.DELIVERED, RNS.RequestReceipt.FAILED)
                while receipt.get_status() not in done_statuses and elapsed < REQUEST_TIMEOUT:
                    time.sleep(0.1)
                    elapsed += 0.1

                if receipt.get_status() in (RNS.RequestReceipt.READY, RNS.RequestReceipt.DELIVERED):
                    resp = receipt.get_response()
                elif receipt.get_status() == RNS.RequestReceipt.FAILED:
                    self.send_error(504, "Request to TinyWeb server failed")
                    return
                else:
                    self.send_error(504, "Request to TinyWeb server timed out")
                    return

            self.send_response(resp["status"])
            self.send_header("Content-Type", resp.get("content_type", "text/html; charset=utf-8"))
            for k, v in resp.get("headers", {}).items():
                self.send_header(k, v)
            self.end_headers()
            resp_body = resp.get("body", "")
            if resp_body:
                self.wfile.write(resp_body.encode() if isinstance(resp_body, str) else resp_body)

        except ConnectionError as e:
            GatewayState.link = None
            self.send_error(502, f"Gateway error: {e}")
        except Exception as e:
            GatewayState.link = None
            self.send_error(502, f"Gateway error: {e}")

    def do_GET(self):
        self._forward("GET")

    def do_POST(self):
        self._forward("POST")

    def log_message(self, format, *args):
        print(f"[Gateway] {args[0]}")


def main():
    if len(sys.argv) < 2:
        print(f"Usage: python gateway.py <destination_hash>")
        print(f"  The destination hash is printed by app.py on startup.")
        sys.exit(1)

    dest_hash = sys.argv[1].replace("<", "").replace(">", "")

    GatewayState.reticulum = RNS.Reticulum()
    resolve_destination(dest_hash)

    print(f"Gateway listening on http://localhost:{GATEWAY_PORT}")
    print(f"Open http://localhost:{GATEWAY_PORT} in your browser")
    HTTPServer(("127.0.0.1", GATEWAY_PORT), GatewayHandler).serve_forever()


if __name__ == "__main__":
    main()