"""Unit tests for SunSpec register decode_response exception handling.

These tests verify the logic without importing modbus module directly.
"""

import pytest

from solaredge2mqtt.core.exceptions import InvalidRegisterDataException


class TestInvalidRegisterDataExceptionUsage:
    """Tests for InvalidRegisterDataException usage in error handling."""

    def test_exception_raised_from_unicode_error(self):
        """Test raising InvalidRegisterDataException from UnicodeDecodeError."""
        unicode_err = UnicodeDecodeError(
            "utf-8", b"\xc2", 5, 6, "invalid continuation byte"
        )
        invalid_registers = [0x5465, 0x7374, 0xC200]

        with pytest.raises(InvalidRegisterDataException) as exc_info:
            try:
                raise unicode_err
            except UnicodeDecodeError as e:
                raise InvalidRegisterDataException(
                    register_id="c_manufacturer",
                    address=40123,
                    raw_values=invalid_registers,
                    original_error=e,
                ) from e

        # Verify exception attributes
        exc = exc_info.value
        assert exc.register_id == "c_manufacturer"
        assert exc.address == 40123
        assert exc.raw_values == invalid_registers
        assert isinstance(exc.original_error, UnicodeDecodeError)
        assert exc.__cause__ == unicode_err

    def test_exception_message_format(self):
        """Test that exception message is properly formatted."""
        original_err = UnicodeDecodeError(
            "utf-8", b"\xc2", 0, 1, "invalid start byte"
        )

        exc = InvalidRegisterDataException(
            register_id="c_model",
            address=40139,
            raw_values=[0xFFFF, 0x0000],
            original_error=original_err,
        )

        msg = str(exc)
        assert "Invalid data in register 'c_model'" in msg
        assert "at address 40139" in msg
        assert "invalid start byte" in msg

    def test_exception_with_different_error_types(self):
        """Test InvalidRegisterDataException with various error types."""
        # Test with ValueError
        value_err = ValueError("Invalid register length")
        exc1 = InvalidRegisterDataException(
            register_id="test1",
            address=1,
            raw_values=[],
            original_error=value_err,
        )
        assert "ValueError" in str(exc1) or "Invalid register length" in str(exc1)

        # Test with generic Exception
        generic_err = Exception("Generic error")
        exc2 = InvalidRegisterDataException(
            register_id="test2",
            address=2,
            raw_values=[0x1234],
            original_error=generic_err,
        )
        assert "Generic error" in str(exc2)


class TestMeterDetectionLogic:
    """Tests for meter detection conditional logic."""

    def test_should_detect_meter_all_conditions_met(self):
        """Test meter detection when all conditions are satisfied."""

        def should_detect_meter(enabled, in_inverter_raw, value):
            """Simulates _should_detect_meter logic."""
            return enabled and in_inverter_raw and value > 0

        # All conditions true
        assert should_detect_meter(True, True, 174) is True

        # Not enabled
        assert should_detect_meter(False, True, 174) is False

        # Not in inverter_raw
        assert should_detect_meter(True, False, 174) is False

        # Value is 0 (not installed)
        assert should_detect_meter(True, True, 0) is False

        # Value is negative
        assert should_detect_meter(True, True, -1) is False

    def test_safe_dictionary_access_pattern(self):
        """Test safe dictionary access with .get() method."""
        inverter_raw = {
            "meter0": 0,
            "meter1": 174,
            "meter2": 348,
            "c_manufacturer": "SolarEdge",
        }

        # Test .get() returns value when present
        assert inverter_raw.get("meter1") == 174

        # Test .get() returns None when absent
        assert inverter_raw.get("meter3") is None

        # Test .get() with default value
        assert inverter_raw.get("meter3", "unknown") == "unknown"

        # Test in operator
        assert "meter1" in inverter_raw
        assert "meter3" not in inverter_raw


class TestErrorLoggingPatterns:
    """Tests for error logging patterns used in the code."""

    def test_error_message_construction(self):
        """Test error message construction patterns."""
        meter_id = "meter2"
        address = 40123
        register_id = "c_manufacturer"

        # Test meter skip message
        skip_msg = (
            f"Skipping {meter_id} due to invalid register data in device info"
        )
        assert "Skipping meter2" in skip_msg
        assert "invalid register data" in skip_msg

        # Test register decode failure message
        decode_msg = (
            f"Failed to decode register '{register_id}' at address {address}"
        )
        assert "Failed to decode register 'c_manufacturer'" in decode_msg
        assert "40123" in decode_msg

        # Test meter address logging
        meter_address = 174
        address_msg = f"Meter address from inverter: {meter_id}={meter_address}"
        assert "meter2=174" in address_msg

    def test_debug_message_with_raw_values(self):
        """Test debug message format with raw register values."""
        register_id = "c_model"
        address = 40139
        value_type_name = "STRING"
        raw_values = [0x5465, 0x7374, 0xC200, 0x0000]

        debug_msg = (
            f"Raw register values for '{register_id}' "
            f"(address {address}, type {value_type_name}): {raw_values}"
        )

        assert "c_model" in debug_msg
        assert "40139" in debug_msg
        assert "STRING" in debug_msg
        assert str(raw_values) in debug_msg


class TestRefactoredMethodStructure:
    """Tests for the refactored method structure."""

    def test_detect_meters_separates_concerns(self):
        """Test that meter detection logic is properly separated."""
        # This test verifies the conceptual separation

        def detect_meters_high_level():
            """High-level meter detection flow."""
            meters = ["meter0", "meter1", "meter2"]
            detected = []

            for meter in meters:
                if should_detect(meter):
                    try:
                        read_device_info(meter)
                        detected.append(meter)
                    except Exception:
                        log_error(meter)
                        continue

            return detected

        def should_detect(meter):
            """Conditional logic extracted."""
            return meter in ["meter1", "meter2"]

        def read_device_info(meter):
            """Device info reading extracted."""
            if meter == "meter1":
                raise Exception("Invalid data")

        def log_error(meter):
            """Error logging extracted."""
            pass  # Logging logic

        # Test the flow
        result = detect_meters_high_level()
        assert "meter0" not in result  # Not detected
        assert "meter1" not in result  # Failed with exception
        assert "meter2" in result  # Successfully detected

