"""Tests for RemoteTransmitterController — mocks paramiko and ZMQ entirely.

paramiko and zmq are optional runtime deps; these tests inject fakes into
sys.modules so they run regardless of whether the packages are installed.
"""

from __future__ import annotations

import json
import sys
import threading
import time
from types import ModuleType
from unittest.mock import MagicMock, patch

import pytest

# ---------------------------------------------------------------------------
# Fake modules injected into sys.modules before any import of the controller
# ---------------------------------------------------------------------------


def _make_fake_paramiko(mock_ssh_instance):
    """Return a fake paramiko module whose SSHClient() returns mock_ssh_instance."""
    mod = MagicMock(spec=ModuleType)
    mod.SSHClient = MagicMock(return_value=mock_ssh_instance)
    mod.AutoAddPolicy = MagicMock()
    return mod


def _make_fake_zmq(mock_socket_instance):
    """Return a fake zmq module whose Context().socket() returns mock_socket_instance."""
    mock_context = MagicMock()
    mock_context.socket.return_value = mock_socket_instance
    mod = MagicMock(spec=ModuleType)
    mod.Context = MagicMock(return_value=mock_context)
    mod.REQ = "REQ"
    return mod, mock_context


# ---------------------------------------------------------------------------
# Fixtures
# ---------------------------------------------------------------------------


def _ok_response(fn="set_radio") -> bytes:
    return json.dumps({"status": True, "message": "", "error_message": ""}).encode()


def _err_response(fn="set_radio", msg="boom") -> bytes:
    return json.dumps({"status": False, "message": "", "error_message": msg}).encode()


def _make_mock_socket(recv_side_effect=None):
    sock = MagicMock()
    if recv_side_effect is not None:
        sock.recv.side_effect = recv_side_effect
    else:
        sock.recv.return_value = _ok_response()
    return sock


def _make_controller(mock_socket=None, *, startup_wait=0):
    """Build a controller with all external I/O mocked via sys.modules injection."""
    mock_sock = mock_socket or _make_mock_socket()
    mock_ssh = MagicMock()
    mock_stdout = MagicMock()
    mock_stdout.channel = MagicMock()
    mock_ssh.exec_command.return_value = (MagicMock(), mock_stdout, MagicMock())

    fake_paramiko = _make_fake_paramiko(mock_ssh)
    fake_zmq, mock_context = _make_fake_zmq(mock_sock)

    with (
        patch.dict("sys.modules", {"paramiko": fake_paramiko, "zmq": fake_zmq}),
        patch(
            "ria_toolkit_oss.remote_control.remote_transmitter_controller._STARTUP_WAIT_S",
            startup_wait,
        ),
    ):
        from ria_toolkit_oss.remote_control.remote_transmitter_controller import (
            RemoteTransmitterController,
        )

        ctrl = RemoteTransmitterController(
            host="192.168.1.10",
            ssh_user="ubuntu",
            ssh_key_path="/home/user/.ssh/id_rsa",
            zmq_port=5556,
        )

    ctrl._mock_ssh = mock_ssh
    ctrl._mock_socket = mock_sock
    ctrl._mock_context = mock_context
    ctrl._fake_paramiko = fake_paramiko
    return ctrl


# ---------------------------------------------------------------------------
# Connection setup
# ---------------------------------------------------------------------------


class TestConnectionSetup:
    def test_ssh_connects_with_correct_args(self):
        ctrl = _make_controller()
        ctrl._mock_ssh.connect.assert_called_once_with(
            hostname="192.168.1.10",
            username="ubuntu",
            key_filename="/home/user/.ssh/id_rsa",
        )

    def test_ssh_starts_remote_server(self):
        ctrl = _make_controller()
        cmd = ctrl._mock_ssh.exec_command.call_args[0][0]
        assert "remote_transmitter" in cmd
        assert "--port" in cmd
        assert "5556" in cmd

    def test_zmq_connects_to_host_port(self):
        ctrl = _make_controller()
        ctrl._mock_socket.connect.assert_called_once_with("tcp://192.168.1.10:5556")

    def test_host_key_policy_set_to_auto_add(self):
        """AutoAddPolicy is applied so we don't prompt in headless execution."""
        ctrl = _make_controller()
        ctrl._mock_ssh.set_missing_host_key_policy.assert_called_once()


# ---------------------------------------------------------------------------
# ZMQ message format
# ---------------------------------------------------------------------------


class TestSendFormat:
    def test_set_radio_sends_correct_dict(self):
        ctrl = _make_controller()
        ctrl.set_radio("pluto", "ip:192.168.2.1")
        sent = json.loads(ctrl._mock_socket.send.call_args[0][0].decode())
        assert sent["function_name"] == "set_radio"
        assert sent["radio_str"] == "pluto"
        assert sent["identifier"] == "ip:192.168.2.1"

    def test_set_radio_default_identifier(self):
        ctrl = _make_controller()
        ctrl.set_radio("hackrf")
        sent = json.loads(ctrl._mock_socket.send.call_args[0][0].decode())
        assert sent["identifier"] == ""

    def test_init_tx_sends_correct_dict(self):
        ctrl = _make_controller()
        ctrl.init_tx(center_frequency=2.4e9, sample_rate=20e6, gain=30, channel=1)
        sent = json.loads(ctrl._mock_socket.send.call_args[0][0].decode())
        assert sent["function_name"] == "init_tx"
        assert sent["center_frequency"] == pytest.approx(2.4e9)
        assert sent["sample_rate"] == pytest.approx(20e6)
        assert sent["gain"] == pytest.approx(30)
        assert sent["channel"] == 1
        assert sent["gain_mode"] == "absolute"

    def test_init_tx_default_channel_zero(self):
        ctrl = _make_controller()
        ctrl.init_tx(center_frequency=2.4e9, sample_rate=20e6, gain=0)
        sent = json.loads(ctrl._mock_socket.send.call_args[0][0].decode())
        assert sent["channel"] == 0

    def test_stop_sends_correct_dict(self):
        ctrl = _make_controller()
        ctrl.stop()
        sent = json.loads(ctrl._mock_socket.send.call_args[0][0].decode())
        assert sent["function_name"] == "stop"


# ---------------------------------------------------------------------------
# Error handling
# ---------------------------------------------------------------------------


class TestErrorHandling:
    def test_error_response_raises_runtime_error(self):
        sock = _make_mock_socket()
        sock.recv.return_value = _err_response(msg="radio not found")
        ctrl = _make_controller(mock_socket=sock)
        with pytest.raises(RuntimeError, match="radio not found"):
            ctrl.set_radio("pluto")

    def test_error_message_included_in_exception(self):
        sock = _make_mock_socket()
        sock.recv.return_value = _err_response(msg="gain out of range")
        ctrl = _make_controller(mock_socket=sock)
        with pytest.raises(RuntimeError, match="gain out of range"):
            ctrl.init_tx(center_frequency=2.4e9, sample_rate=20e6, gain=999)

    def test_send_on_closed_controller_raises(self):
        ctrl = _make_controller()
        ctrl.close()
        with pytest.raises(RuntimeError, match="closed"):
            ctrl._send({"function_name": "set_radio", "radio_str": "pluto", "identifier": ""})

    def test_missing_paramiko_raises_runtime_error(self):
        """If paramiko is absent, connecting gives a clear RuntimeError."""
        import importlib

        import ria_toolkit_oss.remote_control.remote_transmitter_controller as mod

        with patch.dict("sys.modules", {"paramiko": None}):
            with pytest.raises((RuntimeError, ImportError)):
                mod.RemoteTransmitterController(
                    host="h", ssh_user="u", ssh_key_path="/k"
                )


# ---------------------------------------------------------------------------
# transmit_async / wait_transmit
# ---------------------------------------------------------------------------


class TestTransmitAsync:
    def test_transmit_async_returns_immediately(self):
        """transmit_async must not block — the ZMQ recv may take duration_s seconds."""

        def slow_recv():
            time.sleep(0.1)
            return _ok_response("transmit")

        sock = _make_mock_socket()
        sock.recv.side_effect = slow_recv
        ctrl = _make_controller(mock_socket=sock)

        t0 = time.monotonic()
        ctrl.transmit_async(duration_s=5.0)
        elapsed = time.monotonic() - t0

        assert elapsed < 0.05, "transmit_async must not block"
        ctrl.wait_transmit(timeout=2.0)

    def test_transmit_async_sends_correct_duration(self):
        ctrl = _make_controller()
        ctrl.transmit_async(duration_s=12.5)
        ctrl.wait_transmit(timeout=1.0)
        sent = json.loads(ctrl._mock_socket.send.call_args[0][0].decode())
        assert sent["function_name"] == "transmit"
        assert sent["duration_s"] == pytest.approx(12.5)

    def test_wait_transmit_joins_thread(self):
        ctrl = _make_controller()
        ctrl.transmit_async(duration_s=0.01)
        ctrl.wait_transmit(timeout=2.0)
        assert ctrl._tx_thread is None

    def test_wait_transmit_noop_if_no_thread(self):
        ctrl = _make_controller()
        ctrl.wait_transmit()  # should not raise

    def test_transmit_async_error_is_logged_not_raised(self):
        """Background thread errors must not propagate to caller."""
        sock = _make_mock_socket()
        sock.recv.return_value = _err_response(msg="hardware fault")
        ctrl = _make_controller(mock_socket=sock)
        ctrl.transmit_async(duration_s=0.01)
        ctrl.wait_transmit(timeout=2.0)  # should not raise


# ---------------------------------------------------------------------------
# close / teardown
# ---------------------------------------------------------------------------


class TestClose:
    def test_close_terminates_zmq_context(self):
        ctrl = _make_controller()
        ctrl.close()
        ctrl._mock_context.term.assert_called_once()

    def test_close_closes_zmq_socket(self):
        ctrl = _make_controller()
        ctrl.close()
        ctrl._mock_socket.close.assert_called_once()

    def test_close_closes_ssh(self):
        ctrl = _make_controller()
        ctrl.close()
        ctrl._mock_ssh.close.assert_called_once()

    def test_close_is_idempotent(self):
        ctrl = _make_controller()
        ctrl.close()
        ctrl.close()  # second call must not raise

    def test_stop_calls_close(self):
        ctrl = _make_controller()
        ctrl.stop()
        assert ctrl._socket is None
        assert ctrl._ssh is None