"""
Unit tests for rnode_interface.py

Tests KISS protocol escaping/unescaping, configuration validation,
and firmware version validation.
"""

import pytest
import sys
from unittest.mock import MagicMock, patch

# Mock RNS before importing rnode_interface
sys.modules['RNS'] = MagicMock()

from rnode_interface import KISS, ColumbaRNodeInterface


class TestKISSEscape:
    """Tests for KISS.escape() byte escaping."""

    def test_escape_fend(self):
        """FEND (0xC0) should be escaped to 0xDB 0xDC."""
        data = bytes([0xC0])
        escaped = KISS.escape(data)
        assert escaped == bytes([0xDB, 0xDC])

    def test_escape_fesc(self):
        """FESC (0xDB) should be escaped to 0xDB 0xDD."""
        data = bytes([0xDB])
        escaped = KISS.escape(data)
        assert escaped == bytes([0xDB, 0xDD])

    def test_escape_mixed_special_bytes(self):
        """Multiple special bytes should all be escaped."""
        data = bytes([0xC0, 0xDB, 0xC0])
        escaped = KISS.escape(data)
        # 0xDB must be escaped first, then 0xC0
        assert escaped == bytes([0xDB, 0xDC, 0xDB, 0xDD, 0xDB, 0xDC])

    def test_escape_no_special_bytes(self):
        """Data without special bytes should pass through unchanged."""
        data = bytes([0x00, 0x01, 0x02, 0xFF])
        escaped = KISS.escape(data)
        assert escaped == data

    def test_escape_empty_data(self):
        """Empty data should return empty."""
        data = bytes()
        escaped = KISS.escape(data)
        assert escaped == bytes()

    def test_escape_all_fend(self):
        """All FEND bytes should be escaped."""
        data = bytes([0xC0, 0xC0, 0xC0])
        escaped = KISS.escape(data)
        assert escaped == bytes([0xDB, 0xDC, 0xDB, 0xDC, 0xDB, 0xDC])


class TestKISSUnescape:
    """Tests for KISS.unescape() byte unescaping."""

    def test_unescape_fend(self):
        """0xDB 0xDC should be unescaped to FEND (0xC0)."""
        data = bytes([0xDB, 0xDC])
        unescaped = KISS.unescape(data)
        assert unescaped == bytes([0xC0])

    def test_unescape_fesc(self):
        """0xDB 0xDD should be unescaped to FESC (0xDB)."""
        data = bytes([0xDB, 0xDD])
        unescaped = KISS.unescape(data)
        assert unescaped == bytes([0xDB])

    def test_unescape_mixed(self):
        """Multiple escape sequences should all be unescaped."""
        data = bytes([0xDB, 0xDC, 0xDB, 0xDD, 0xDB, 0xDC])
        unescaped = KISS.unescape(data)
        assert unescaped == bytes([0xC0, 0xDB, 0xC0])

    def test_unescape_no_escape_sequences(self):
        """Data without escape sequences should pass through unchanged."""
        data = bytes([0x00, 0x01, 0x02, 0xFF])
        unescaped = KISS.unescape(data)
        assert unescaped == data

    def test_unescape_empty_data(self):
        """Empty data should return empty."""
        data = bytes()
        unescaped = KISS.unescape(data)
        assert unescaped == bytes()


class TestKISSRoundTrip:
    """Tests for escape/unescape round-trip consistency."""

    def test_roundtrip_special_bytes(self):
        """escape(unescape(x)) should equal x for escaped data."""
        original_unescaped = bytes([0xC0, 0xDB, 0x00, 0xFF])
        escaped = KISS.escape(original_unescaped)
        roundtrip = KISS.unescape(escaped)
        assert roundtrip == original_unescaped

    def test_roundtrip_random_data(self):
        """Round-trip should work for arbitrary byte sequences."""
        original = bytes(range(256))
        escaped = KISS.escape(original)
        roundtrip = KISS.unescape(escaped)
        assert roundtrip == original


class TestKISSErrorMessages:
    """Tests for KISS.get_error_message()."""

    def test_error_initradio(self):
        """Error 0x01 should return radio initialization message."""
        msg = KISS.get_error_message(0x01)
        assert "Radio initialization failed" in msg

    def test_error_txfailed(self):
        """Error 0x02 should return transmission failed message."""
        msg = KISS.get_error_message(0x02)
        assert "Transmission failed" in msg

    def test_error_queue_full(self):
        """Error 0x04 should return queue overflow message."""
        msg = KISS.get_error_message(0x04)
        assert "queue" in msg.lower()

    def test_error_invalid_config(self):
        """Error 0x40 should return config error with TX power hint."""
        msg = KISS.get_error_message(0x40)
        assert "Invalid configuration" in msg
        assert "TX power" in msg

    def test_error_unknown(self):
        """Unknown error codes should return hex representation."""
        msg = KISS.get_error_message(0xFF)
        assert "0xFF" in msg or "Unknown" in msg


class TestValidateConfig:
    """Tests for ColumbaRNodeInterface._validate_config()."""

    def create_interface(self, **overrides):
        """Create a test interface with mocked dependencies."""
        config = {
            'target_device_name': 'RNode Test',
            'connection_mode': 'ble',
            'frequency': 915000000,
            'bandwidth': 250000,
            'txpower': 17,
            'sf': 11,
            'cr': 5,
            'st_alock': None,
            'lt_alock': None,
            'mode': 'full',
            'enable_framebuffer': True,
        }
        config.update(overrides)

        with patch.object(ColumbaRNodeInterface, '__init__', lambda x, *args: None):
            iface = ColumbaRNodeInterface.__new__(ColumbaRNodeInterface)
            iface.FREQ_MIN = 137000000
            iface.FREQ_MAX = 3000000000
            iface.frequency = config['frequency']
            iface.txpower = config['txpower']
            iface.bandwidth = config['bandwidth']
            iface.sf = config['sf']
            iface.cr = config['cr']
            iface.st_alock = config['st_alock']
            iface.lt_alock = config['lt_alock']
            return iface

    def test_valid_config(self):
        """Valid configuration should not raise."""
        iface = self.create_interface()
        iface._validate_config()  # Should not raise

    def test_frequency_below_min(self):
        """Frequency below 137 MHz should raise ValueError."""
        iface = self.create_interface(frequency=100000000)
        with pytest.raises(ValueError, match="frequency"):
            iface._validate_config()

    def test_frequency_above_max(self):
        """Frequency above 3000 MHz should raise ValueError."""
        iface = self.create_interface(frequency=4000000000)
        with pytest.raises(ValueError, match="frequency"):
            iface._validate_config()

    def test_frequency_at_min_boundary(self):
        """Frequency at 137 MHz (min) should be valid."""
        iface = self.create_interface(frequency=137000000)
        iface._validate_config()  # Should not raise

    def test_frequency_at_max_boundary(self):
        """Frequency at 3000 MHz (max) should be valid."""
        iface = self.create_interface(frequency=3000000000)
        iface._validate_config()  # Should not raise

    def test_txpower_negative(self):
        """Negative TX power should raise ValueError."""
        iface = self.create_interface(txpower=-1)
        with pytest.raises(ValueError, match="TX power"):
            iface._validate_config()

    def test_txpower_above_max(self):
        """TX power above 22 dBm should raise ValueError."""
        iface = self.create_interface(txpower=25)
        with pytest.raises(ValueError, match="TX power"):
            iface._validate_config()

    def test_txpower_at_max(self):
        """TX power at 22 dBm should be valid."""
        iface = self.create_interface(txpower=22)
        iface._validate_config()  # Should not raise

    def test_bandwidth_below_min(self):
        """Bandwidth below 7800 Hz should raise ValueError."""
        iface = self.create_interface(bandwidth=5000)
        with pytest.raises(ValueError, match="bandwidth"):
            iface._validate_config()

    def test_bandwidth_above_max(self):
        """Bandwidth above 1625000 Hz should raise ValueError."""
        iface = self.create_interface(bandwidth=2000000)
        with pytest.raises(ValueError, match="bandwidth"):
            iface._validate_config()

    def test_sf_below_min(self):
        """Spreading factor below 5 should raise ValueError."""
        iface = self.create_interface(sf=4)
        with pytest.raises(ValueError, match="spreading factor"):
            iface._validate_config()

    def test_sf_above_max(self):
        """Spreading factor above 12 should raise ValueError."""
        iface = self.create_interface(sf=13)
        with pytest.raises(ValueError, match="spreading factor"):
            iface._validate_config()

    def test_cr_below_min(self):
        """Coding rate below 5 should raise ValueError."""
        iface = self.create_interface(cr=4)
        with pytest.raises(ValueError, match="coding rate"):
            iface._validate_config()

    def test_cr_above_max(self):
        """Coding rate above 8 should raise ValueError."""
        iface = self.create_interface(cr=9)
        with pytest.raises(ValueError, match="coding rate"):
            iface._validate_config()

    def test_st_alock_negative(self):
        """Negative short-term airtime limit should raise ValueError."""
        iface = self.create_interface(st_alock=-1.0)
        with pytest.raises(ValueError, match="short-term airtime"):
            iface._validate_config()

    def test_st_alock_above_100(self):
        """Short-term airtime limit above 100% should raise ValueError."""
        iface = self.create_interface(st_alock=101.0)
        with pytest.raises(ValueError, match="short-term airtime"):
            iface._validate_config()

    def test_st_alock_valid(self):
        """Valid short-term airtime limit should not raise."""
        iface = self.create_interface(st_alock=10.0)
        iface._validate_config()  # Should not raise

    def test_lt_alock_negative(self):
        """Negative long-term airtime limit should raise ValueError."""
        iface = self.create_interface(lt_alock=-0.1)
        with pytest.raises(ValueError, match="long-term airtime"):
            iface._validate_config()

    def test_lt_alock_above_100(self):
        """Long-term airtime limit above 100% should raise ValueError."""
        iface = self.create_interface(lt_alock=100.1)
        with pytest.raises(ValueError, match="long-term airtime"):
            iface._validate_config()

    def test_alock_none_is_valid(self):
        """None airtime limits should be valid (disabled)."""
        iface = self.create_interface(st_alock=None, lt_alock=None)
        iface._validate_config()  # Should not raise


class TestValidateFirmware:
    """Tests for ColumbaRNodeInterface._validate_firmware()."""

    def create_interface_for_firmware(self, maj_version, min_version):
        """Create a test interface for firmware validation."""
        with patch.object(ColumbaRNodeInterface, '__init__', lambda x, *args: None):
            iface = ColumbaRNodeInterface.__new__(ColumbaRNodeInterface)
            iface.REQUIRED_FW_VER_MAJ = 1
            iface.REQUIRED_FW_VER_MIN = 52
            iface.maj_version = maj_version
            iface.min_version = min_version
            iface.firmware_ok = False
            return iface

    def test_firmware_valid_exact_minimum(self):
        """Firmware 1.52 (exact minimum) should be valid."""
        iface = self.create_interface_for_firmware(1, 52)
        iface._validate_firmware()
        assert iface.firmware_ok is True

    def test_firmware_valid_higher_minor(self):
        """Firmware 1.100 should be valid."""
        iface = self.create_interface_for_firmware(1, 100)
        iface._validate_firmware()
        assert iface.firmware_ok is True

    def test_firmware_valid_higher_major(self):
        """Firmware 2.0 should be valid (major > required)."""
        iface = self.create_interface_for_firmware(2, 0)
        iface._validate_firmware()
        assert iface.firmware_ok is True

    def test_firmware_valid_much_higher_major(self):
        """Firmware 5.10 should be valid."""
        iface = self.create_interface_for_firmware(5, 10)
        iface._validate_firmware()
        assert iface.firmware_ok is True

    def test_firmware_invalid_low_minor(self):
        """Firmware 1.51 should be invalid (below 1.52)."""
        iface = self.create_interface_for_firmware(1, 51)
        iface._validate_firmware()
        assert iface.firmware_ok is False

    def test_firmware_invalid_low_major(self):
        """Firmware 0.99 should be invalid."""
        iface = self.create_interface_for_firmware(0, 99)
        iface._validate_firmware()
        assert iface.firmware_ok is False

    def test_firmware_invalid_zero(self):
        """Firmware 0.0 should be invalid."""
        iface = self.create_interface_for_firmware(0, 0)
        iface._validate_firmware()
        assert iface.firmware_ok is False

    def test_firmware_invalid_1_0(self):
        """Firmware 1.0 should be invalid."""
        iface = self.create_interface_for_firmware(1, 0)
        iface._validate_firmware()
        assert iface.firmware_ok is False


class TestKISSConstants:
    """Tests for KISS protocol constants."""

    def test_fend_value(self):
        """FEND should be 0xC0."""
        assert KISS.FEND == 0xC0

    def test_fesc_value(self):
        """FESC should be 0xDB."""
        assert KISS.FESC == 0xDB

    def test_tfend_value(self):
        """TFEND (escaped FEND) should be 0xDC."""
        assert KISS.TFEND == 0xDC

    def test_tfesc_value(self):
        """TFESC (escaped FESC) should be 0xDD."""
        assert KISS.TFESC == 0xDD

    def test_cmd_data_is_zero(self):
        """CMD_DATA should be 0x00."""
        assert KISS.CMD_DATA == 0x00

    def test_radio_states(self):
        """Radio states should have expected values."""
        assert KISS.RADIO_STATE_OFF == 0x00
        assert KISS.RADIO_STATE_ON == 0x01
        assert KISS.RADIO_STATE_ASK == 0xFF