from __future__ import annotations

import argparse
import json
import random
import time
from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer
from typing import Dict, List


def _parse_frequency_list(raw_value: str) -> List[float]:
    values: List[float] = []
    for item in str(raw_value).split(","):
        text = item.strip()
        if not text:
            continue
        try:
            value = float(text)
        except ValueError as exc:
            raise ValueError(f"invalid frequency value '{text}'") from exc
        if value <= 0.0:
            raise ValueError(f"frequency must be > 0, got {value}")
        values.append(round(value, 6))
    if not values:
        raise ValueError("at least one frequency is required")
    deduplicated: List[float] = []
    seen = set()
    for value in values:
        key = round(value, 6)
        if key in seen:
            continue
        seen.add(key)
        deduplicated.append(value)
    return deduplicated


def _build_payload(
    receiver_id: str,
    base_rssi: float,
    frequencies_mhz: List[float],
) -> Dict[str, object]:
    rows: List[Dict[str, float]] = []
    for index, frequency_mhz in enumerate(frequencies_mhz):
        noise = random.uniform(-1.2, 1.2)
        offset = -2.2 * index
        rows.append({"f_mhz": round(float(frequency_mhz), 6), "rssi": base_rssi + offset + noise})
    return {
        "receiver_id": receiver_id,
        "timestamp_unix": time.time(),
        "samples": rows,
    }


def main() -> int:
    parser = argparse.ArgumentParser()
    parser.add_argument("--receiver-id", required=True)
    parser.add_argument("--port", type=int, default=9000)
    parser.add_argument("--base-rssi", type=float, default=-62.0)
    parser.add_argument("--frequencies-mhz", type=str, default="433.92,868.1")
    args = parser.parse_args()
    state = {
        "enabled": True,
        "frequencies_mhz": _parse_frequency_list(args.frequencies_mhz),
    }

    class Handler(BaseHTTPRequestHandler):
        def log_message(self, format: str, *args2) -> None:
            return

        def do_GET(self) -> None:
            if self.path == "/status":
                payload = {
                    "receiver_id": args.receiver_id,
                    "enabled": bool(state["enabled"]),
                    "frequencies_mhz": list(state["frequencies_mhz"]),
                    "status": "ok",
                }
                raw = json.dumps(payload).encode("utf-8")
                self.send_response(200)
                self.send_header("Content-Type", "application/json")
                self.send_header("Content-Length", str(len(raw)))
                self.end_headers()
                self.wfile.write(raw)
                return

            if self.path != "/measurements":
                self.send_response(404)
                self.end_headers()
                return

            if not bool(state["enabled"]):
                raw = json.dumps(
                    {
                        "status": "error",
                        "error": "receiver transmission is paused",
                        "receiver_id": args.receiver_id,
                    }
                ).encode("utf-8")
                self.send_response(503)
                self.send_header("Content-Type", "application/json")
                self.send_header("Content-Length", str(len(raw)))
                self.end_headers()
                self.wfile.write(raw)
                return

            payload = _build_payload(
                receiver_id=args.receiver_id,
                base_rssi=args.base_rssi,
                frequencies_mhz=list(state["frequencies_mhz"]),
            )
            raw = json.dumps(payload).encode("utf-8")
            self.send_response(200)
            self.send_header("Content-Type", "application/json")
            self.send_header("Content-Length", str(len(raw)))
            self.end_headers()
            self.wfile.write(raw)

        def do_POST(self) -> None:
            if self.path != "/control":
                self.send_response(404)
                self.end_headers()
                return
            content_length = int(self.headers.get("Content-Length", "0"))
            body = self.rfile.read(content_length) if content_length > 0 else b"{}"
            try:
                payload = json.loads(body.decode("utf-8"))
            except json.JSONDecodeError:
                payload = {}

            enabled = payload.get("enabled")
            frequencies_raw = payload.get("frequencies_mhz")
            has_enabled = isinstance(enabled, bool)
            has_frequencies = frequencies_raw is not None
            if not has_enabled and not has_frequencies:
                raw = json.dumps(
                    {
                        "status": "error",
                        "error": "at least one of fields 'enabled' or 'frequencies_mhz' must be provided",
                    }
                ).encode("utf-8")
                self.send_response(400)
                self.send_header("Content-Type", "application/json")
                self.send_header("Content-Length", str(len(raw)))
                self.end_headers()
                self.wfile.write(raw)
                return

            if has_enabled:
                state["enabled"] = bool(enabled)

            if has_frequencies:
                if not isinstance(frequencies_raw, list):
                    raw = json.dumps(
                        {"status": "error", "error": "field 'frequencies_mhz' must be an array"}
                    ).encode("utf-8")
                    self.send_response(400)
                    self.send_header("Content-Type", "application/json")
                    self.send_header("Content-Length", str(len(raw)))
                    self.end_headers()
                    self.wfile.write(raw)
                    return
                try:
                    parsed_frequencies = _parse_frequency_list(",".join(str(x) for x in frequencies_raw))
                except ValueError as exc:
                    raw = json.dumps({"status": "error", "error": str(exc)}).encode("utf-8")
                    self.send_response(400)
                    self.send_header("Content-Type", "application/json")
                    self.send_header("Content-Length", str(len(raw)))
                    self.end_headers()
                    self.wfile.write(raw)
                    return
                state["frequencies_mhz"] = parsed_frequencies

            raw = json.dumps(
                {
                    "status": "ok",
                    "receiver_id": args.receiver_id,
                    "enabled": bool(state["enabled"]),
                    "frequencies_mhz": list(state["frequencies_mhz"]),
                }
            ).encode("utf-8")
            self.send_response(200)
            self.send_header("Content-Type", "application/json")
            self.send_header("Content-Length", str(len(raw)))
            self.end_headers()
            self.wfile.write(raw)

    server = ThreadingHTTPServer(("0.0.0.0", args.port), Handler)
    print(f"mock_receiver({args.receiver_id}) listening on :{args.port}")
    server.serve_forever()
    return 0


if __name__ == "__main__":
    raise SystemExit(main())