"""Underrun policies: pause, zero, repeat."""

from __future__ import annotations

import asyncio
import time

import numpy as np

from ria_toolkit_oss.agent.config import AgentConfig
from ria_toolkit_oss.agent.streamer import Streamer
from ria_toolkit_oss.sdr.mock import MockSDR


class RecordingMockSDR(MockSDR):
    def __init__(self, buffer_size: int):
        super().__init__(buffer_size=buffer_size)
        self.tx_produced: list[np.ndarray] = []

    def _stream_tx(self, callback):
        self._enable_tx = True
        self._tx_initialized = True
        while self._enable_tx:
            result = callback(self.rx_buffer_size)
            self.tx_produced.append(np.asarray(result).copy())
            time.sleep(0.005)


class FakeWs:
    def __init__(self):
        self.json_sent = []
        self.bytes_sent = []

    async def send_json(self, p):
        self.json_sent.append(p)

    async def send_bytes(self, b):
        self.bytes_sent.append(b)


def _iq_frame(samples: np.ndarray) -> bytes:
    interleaved = np.empty(samples.size * 2, dtype=np.float32)
    interleaved[0::2] = samples.real
    interleaved[1::2] = samples.imag
    return interleaved.tobytes()


def _start_cfg(policy: str, buf: int = 8) -> dict:
    return {
        "type": "tx_start",
        "app_id": "a",
        "radio_config": {
            "device": "mock",
            "buffer_size": buf,
            "tx_sample_rate": 1_000_000,
            "tx_gain": -20,
            "tx_center_frequency": 2.45e9,
            "underrun_policy": policy,
        },
    }


def test_underrun_pause_stops_session_and_emits_status():
    sdr = RecordingMockSDR(buffer_size=8)

    async def scenario():
        ws = FakeWs()
        s = Streamer(ws=ws, sdr_factory=lambda d, i: sdr, cfg=AgentConfig(tx_enabled=True))
        await s.on_message(_start_cfg("pause"))
        # Do not push any buffers. The callback underruns on first tick and
        # the watchdog should emit "underrun" and tear down.
        for _ in range(100):
            if any(m.get("type") == "tx_status" and m.get("state") == "underrun" for m in ws.json_sent):
                break
            await asyncio.sleep(0.01)
        for _ in range(50):
            if s._tx is None:
                break
            await asyncio.sleep(0.01)
        return ws, s

    ws, s = asyncio.run(scenario())
    states = [m["state"] for m in ws.json_sent if m.get("type") == "tx_status"]
    assert "underrun" in states
    assert s._tx is None


def test_underrun_zero_keeps_session_alive():
    sdr = RecordingMockSDR(buffer_size=8)

    async def scenario():
        ws = FakeWs()
        s = Streamer(ws=ws, sdr_factory=lambda d, i: sdr, cfg=AgentConfig(tx_enabled=True))
        await s.on_message(_start_cfg("zero"))
        # Let it produce several underrun-filled buffers.
        await asyncio.sleep(0.08)
        still_alive = s._tx is not None
        await s.on_message({"type": "tx_stop", "app_id": "a"})
        return ws, still_alive

    ws, still_alive = asyncio.run(scenario())
    # No underrun status emitted (policy absorbs it silently).
    assert not any(m.get("type") == "tx_status" and m.get("state") == "underrun" for m in ws.json_sent)
    assert still_alive
    # All produced buffers are zero (no real data was pushed).
    assert sdr.tx_produced, "expected at least one TX callback invocation"
    assert all(not np.any(b != 0) for b in sdr.tx_produced)


def test_underrun_repeat_replays_last_buffer():
    BUF = 8
    sdr = RecordingMockSDR(buffer_size=BUF)
    marker = np.arange(BUF, dtype=np.complex64) + 1  # distinct non-zero buffer

    async def scenario():
        ws = FakeWs()
        s = Streamer(ws=ws, sdr_factory=lambda d, i: sdr, cfg=AgentConfig(tx_enabled=True))
        await s.on_message(_start_cfg("repeat", buf=BUF))
        await s.on_binary(_iq_frame(marker))
        # Give the executor time to consume the real frame + several repeats.
        await asyncio.sleep(0.08)
        await s.on_message({"type": "tx_stop", "app_id": "a"})
        return ws, sdr

    ws, sdr = asyncio.run(scenario())
    # No underrun status emitted.
    assert not any(m.get("type") == "tx_status" and m.get("state") == "underrun" for m in ws.json_sent)
    # At least two buffers equal to the marker — the real one and ≥1 repeat.
    matching = [b for b in sdr.tx_produced if np.array_equal(b, marker)]
    assert len(matching) >= 2, f"expected ≥2 buffers matching marker, got {len(matching)}"