"""TX campaign executor — synthesises and transmits signals via a local SDR.

The TxExecutor receives a transmitter config dict (matching the
``sdr_agent`` control method's schema) and a step schedule, then for each
step builds a signal chain with the block generator and transmits it via
the local SDR device.

Supported modulations (``modulation`` field in config):
    BPSK, QPSK, 8PSK, 16QAM, 64QAM, 256QAM, FSK, OOK, GMSK, OQPSK

Example config dict (matches CampaignConfig transmitter with
``control_method: sdr_agent``)::

    {
        "id": "synthetic-tx",
        "type": "sdr",
        "control_method": "sdr_agent",
        "sdr_agent": {
            "modulation": "QPSK",
            "order": 4,
            "symbol_rate": 1000000,
            "center_frequency": 0.0,
            "filter": "rrc",
            "rolloff": 0.35
        },
        "schedule": [
            {"label": "step1", "duration": 10, "power_dbm": -10}
        ]
    }
"""

from __future__ import annotations

import logging
import threading
from typing import Any

logger = logging.getLogger(__name__)


def _parse_hz(val: object) -> float:
    """Parse a frequency value that may be a float (Hz) or a string like '2.45GHz'."""
    if isinstance(val, (int, float)):
        return float(val)
    s = str(val).strip()
    for suffix, mult in (("GHz", 1e9), ("MHz", 1e6), ("kHz", 1e3), ("Hz", 1.0)):
        if s.endswith(suffix):
            return float(s[: -len(suffix)]) * mult
    return float(s)


def _parse_seconds(val: object) -> float:
    """Parse a duration value that may be a float (seconds) or a string like '5s'."""
    if isinstance(val, (int, float)):
        return float(val)
    s = str(val).strip()
    return float(s[:-1]) if s.endswith("s") else float(s)


# Mapping from modulation name → (PSK/QAM order, generator_type)
# 'psk' uses PSKGenerator, 'qam' uses QAMGenerator
_MOD_TABLE: dict[str, tuple[int, str]] = {
    "BPSK": (1, "psk"),
    "QPSK": (2, "psk"),
    "8PSK": (3, "psk"),
    "16QAM": (4, "qam"),
    "64QAM": (6, "qam"),
    "256QAM": (8, "qam"),
}

_SPECIAL_MODS = {"FSK", "OOK", "GMSK", "OQPSK"}

# usrp-uhd-client's tx_recording() streams 2 000-sample chunks and loops the
# source buffer for the full tx_time, so only this many samples ever need to
# be in RAM regardless of step duration or sample rate.
# 50 000 complex64 samples ≈ 400 kB — enough spectral diversity for looping.
_SYNTH_BLOCK_SAMPLES = 50_000


class TxExecutor:
    """Synthesise and transmit a signal campaign via a local SDR.

    Args:
        config: Transmitter config dict (must have ``sdr_agent`` sub-dict with
            modulation params, and ``schedule`` list of step dicts).
        sdr_device: SDR device name to open in TX mode (e.g. "pluto", "usrp").
        stop_event: External event that aborts the TX loop mid-step.
    """

    def __init__(
        self,
        config: dict,
        sdr_device: str = "unknown",
        stop_event: threading.Event | None = None,
    ) -> None:
        self.config = config
        self.sdr_device = sdr_device
        self.stop_event = stop_event or threading.Event()
        self._sdr: Any = None

    def run(self) -> None:
        """Execute all steps in the schedule, transmitting for each step duration."""
        agent_cfg: dict = self.config.get("sdr_agent") or {}
        schedule: list[dict] = self.config.get("schedule") or []

        if not schedule:
            logger.warning("TxExecutor: no schedule steps — nothing to transmit")
            return

        modulation: str = agent_cfg.get("modulation", "QPSK").upper()
        symbol_rate: float = float(agent_cfg.get("symbol_rate", 1e6))
        center_freq: float = _parse_hz(agent_cfg.get("center_frequency", 0.0))
        filter_type: str = agent_cfg.get("filter", "rrc").lower()
        rolloff: float = float(agent_cfg.get("rolloff", 0.35))

        # Upsampling factor: samples_per_symbol, fixed at 8 for SDR compatibility.
        sps = 8
        sample_rate = symbol_rate * sps

        self._init_sdr(sample_rate, center_freq)
        try:
            for step in schedule:
                if self.stop_event.is_set():
                    break
                self._execute_step(step, modulation, sps, symbol_rate, filter_type, rolloff)
        finally:
            self._close_sdr()

    def _execute_step(
        self,
        step: dict,
        modulation: str,
        sps: int,
        symbol_rate: float,
        filter_type: str,
        rolloff: float,
    ) -> None:
        duration: float = _parse_seconds(step.get("duration", 10.0))
        label: str = step.get("label", "step")
        gain: float = float(step.get("power_dbm") or 0.0)
        sample_rate = symbol_rate * sps

        logger.info(
            "TX step '%s': %.0f s, %s @ %.3f MHz (sps=%d, filter=%s)",
            label,
            duration,
            modulation,
            symbol_rate / 1e6,
            sps,
            filter_type,
        )

        num_samples = int(duration * sample_rate)

        # Synthesise a short representative block. tx_recording() loops this
        # buffer for the full tx_time using a 2 000-sample streaming callback,
        # so peak memory is O(_SYNTH_BLOCK_SAMPLES) regardless of duration.
        block_size = min(num_samples, _SYNTH_BLOCK_SAMPLES)
        signal = self._synthesise(modulation, sps, block_size, filter_type, rolloff)

        if self._sdr is not None:
            try:
                # Apply gain update if SDR supports it
                if hasattr(self._sdr, "set_tx_gain"):
                    self._sdr.set_tx_gain(gain)
                self._sdr.tx_recording(signal, tx_time=duration)
            except Exception as exc:
                logger.error("TX step '%s' SDR error: %s", label, exc)
        else:
            # No SDR available — simulate by sleeping for the step duration.
            logger.warning("TX step '%s': no SDR — simulating %.0f s delay", label, duration)
            self.stop_event.wait(timeout=duration)

    def _synthesise(
        self,
        modulation: str,
        sps: int,
        num_samples: int,
        filter_type: str,
        rolloff: float,
    ):
        """Build a block-generator chain and return IQ samples as a numpy array."""
        try:
            import numpy as np

            from ria_toolkit_oss.signal.block_generator import (
                BinarySource,
                GMSKModulator,
                Mapper,
                OOKModulator,
                OQPSKModulator,
                RaisedCosineFilter,
                RootRaisedCosineFilter,
                Upsampling,
            )
            from ria_toolkit_oss.signal.block_generator.continuous_modulation.fsk_modulator import (
                FSKModulator,
            )
        except ImportError as exc:
            raise RuntimeError(f"ria_toolkit_oss block generator not available: {exc}") from exc

        # ── Special modulations with their own source-connected modulator ──
        if modulation in ("OOK", "GMSK", "OQPSK"):
            src = BinarySource()
            if modulation == "OOK":
                mod = OOKModulator(src, samples_per_symbol=sps)
            elif modulation == "GMSK":
                mod = GMSKModulator(src, samples_per_symbol=sps)
            else:
                mod = OQPSKModulator(src, samples_per_symbol=sps)
            recording = mod.record(num_samples)
            flat = np.asarray(recording.data).flatten().astype(np.complex64)
            if len(flat) < num_samples:
                flat = np.tile(flat, num_samples // len(flat) + 1)
            return flat[:num_samples]

        if modulation == "FSK":
            symbol_rate = num_samples / sps
            bits_per_sym = 1  # 2-FSK
            num_bits = max(num_samples // sps, 128) * bits_per_sym
            bits = BinarySource()((1, num_bits))
            mod = FSKModulator(
                num_bits_per_symbol=bits_per_sym,
                frequency_spacing=symbol_rate * 0.5,
                symbol_duration=1.0 / max(symbol_rate, 1.0),
                sampling_frequency=symbol_rate * sps,
            )
            flat = np.asarray(mod(bits)).flatten().astype(np.complex64)
            if len(flat) < num_samples:
                flat = np.tile(flat, num_samples // len(flat) + 1)
            return flat[:num_samples]

        # ── PSK / QAM via Mapper → Upsampling → pulse filter ──────────────
        if modulation not in _MOD_TABLE:
            logger.warning("Unknown modulation %r — defaulting to QPSK", modulation)
            modulation = "QPSK"

        bits_per_sym, gen_type = _MOD_TABLE[modulation]
        mod_family = "QAM" if gen_type == "qam" else "PSK"

        source = BinarySource()
        mapper = Mapper(constellation_type=mod_family, num_bits_per_symbol=bits_per_sym)
        upsampler = Upsampling(factor=sps)

        mapper.connect_input([source])
        upsampler.connect_input([mapper])

        if filter_type in ("rrc",):
            pulse_filter = RootRaisedCosineFilter(span_in_symbols=6, upsampling_factor=sps, beta=rolloff)
            pulse_filter.connect_input([upsampler])
            recording = pulse_filter.record(num_samples)
        elif filter_type in ("rc",):
            pulse_filter = RaisedCosineFilter(span_in_symbols=6, upsampling_factor=sps, beta=rolloff)
            pulse_filter.connect_input([upsampler])
            recording = pulse_filter.record(num_samples)
        else:
            # "none", "rect", "gaussian" — use upsampler output directly
            recording = upsampler.record(num_samples)

        flat = np.asarray(recording.data).flatten().astype(np.complex64)
        if len(flat) < num_samples:
            flat = np.tile(flat, num_samples // len(flat) + 1)
        return flat[:num_samples]

    def _init_sdr(self, sample_rate: float, center_freq: float) -> None:
        try:
            from ria_toolkit_oss.sdr import get_sdr_device

            self._sdr = get_sdr_device(self.sdr_device)
            self._sdr.init_tx(
                sample_rate=sample_rate,
                center_frequency=center_freq,
                gain=0,
                channel=0,
                gain_mode="manual",
            )
            logger.info(
                "TX SDR initialised: %s @ %.3f MHz, %.1f Msps", self.sdr_device, center_freq / 1e6, sample_rate / 1e6
            )
        except Exception as exc:
            logger.warning("TX SDR init failed (%s) — will simulate: %s", self.sdr_device, exc)
            self._sdr = None

    def _close_sdr(self) -> None:
        if self._sdr is not None:
            try:
                self._sdr.close()
            except Exception as exc:
                logger.debug("TX SDR close error: %s", exc)
            self._sdr = None