"""Same-origin static UI/gateway for the isolated room demo; never proxies arbitrary URLs."""
import argparse
import json
import hint_library
import re
from functools import partial
from http.server import SimpleHTTPRequestHandler, ThreadingHTTPServer
from pathlib import Path
from urllib.parse import urlsplit
import urllib.request
import urllib.error

ROOT = Path(__file__).resolve().parent
ROUTES = {"/room/state": (18776, "/room/state"), "/room/trace": (18776, "/room/trace"),
          "/room/command": (18776, "/room/command"), "/speech/health": (18778, "/health")}

class Handler(SimpleHTTPRequestHandler):
    def list_directory(self, path):
        self.send_error(403)
    def relay(self):
        path = urlsplit(self.path).path
        route = ROUTES.get(path)
        if re.fullmatch(r"/speech/audio/[a-f0-9]{64}\.wav", path):
            route = (18778, path.removeprefix("/speech"))
        if not route or (self.command == "POST" and path != "/room/command") or (self.command == "GET" and path == "/room/command"):
            self.send_error(404)
            return
        if self.command == "POST":
            origin = self.headers.get("Origin")
            if origin and origin != "http://" + self.headers.get("Host", ""):
                self.send_error(403, "Use the room demo page to send commands")
                return
        try:
            size = int(self.headers.get("Content-Length", "0"))
            if size < 0 or size > 65536:
                self.send_error(413)
                return
            body = self.rfile.read(size) if self.command == "POST" else None
            request = urllib.request.Request(f"http://127.0.0.1:{route[0]}{route[1]}",
                data=body, method=self.command, headers={"Content-Type":"application/json", **({"Range":self.headers["Range"]} if "Range" in self.headers else {})})
            try:
                with urllib.request.urlopen(request, timeout=8) as response:
                    data, status = response.read(), response.status
                    content_type = response.headers.get("Content-Type","application/json")
                    content_range = response.headers.get("Content-Range")
            except urllib.error.HTTPError as error:
                data, status = error.read(), error.code
                content_type, content_range = "text/plain", None
            self.send_response(status)
            self.send_header("Content-Type",content_type)
            self.send_header("Accept-Ranges","bytes")
            if content_range:
                self.send_header("Content-Range",content_range)
            self.send_header("Content-Length",str(len(data)))
            self.send_header("Cache-Control","no-store")
            self.end_headers()
            self.wfile.write(data)
        except (OSError, ValueError):
            self.send_error(503, "Local lab service unavailable")
    def hints(self):
        try:
            if self.command == "POST":
                origin=self.headers.get("Origin")
                if origin and origin != "http://" + self.headers.get("Host",""):
                    self.send_error(403)
                    return
                size=int(self.headers.get("Content-Length","0"))
                if not 0<size<=16384:
                    self.send_error(413)
                    return
                result=hint_library.save(json.loads(self.rfile.read(size)))
            else:
                result=hint_library.read()
            status=200
        except hint_library.Conflict as error:
            result,status={"error":str(error)},409
        except (ValueError, OSError) as error:
            result,status={"error":str(error)},400
        data=json.dumps(result).encode()
        self.send_response(status)
        self.send_header("Content-Type","application/json")
        self.send_header("Content-Length",str(len(data)))
        self.send_header("Cache-Control","no-store")
        self.end_headers()
        self.wfile.write(data)
    def do_GET(self):
        if urlsplit(self.path).path == "/hints":
            return self.hints()
        if urlsplit(self.path).path.startswith(("/room/", "/speech/")):
            self.relay()
        else:
            super().do_GET()
    def do_POST(self):
        if urlsplit(self.path).path == "/hints":
            return self.hints()
        self.relay()
    def end_headers(self):
        self.send_header("X-Content-Type-Options","nosniff")
        self.send_header("Cache-Control","no-store")
        super().end_headers()
    def log_message(self,*_): pass

if __name__ == "__main__":
    parser=argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--bind",default="127.0.0.1")
    args=parser.parse_args()
    server=ThreadingHTTPServer((args.bind,18777),partial(Handler,directory=str(ROOT/"gm/build/web")))
    print(f"Room demo UI/gateway: http://{args.bind}:18777/?room=1",flush=True)
    try: server.serve_forever()
    finally: server.server_close()