"""degradation.py DTO 单元测试。

覆盖 ``DegradationLevel`` 枚举与 ``RecoveryStatus`` 的字段赋值、默认值、
不可变语义与 ``__post_init__`` 校验逻辑。
"""

from __future__ import annotations

import dataclasses
from datetime import datetime

import pytest
from yuxi.channels.contract.dtos.degradation import (
    DegradationLevel,
    RecoveryStatus,
)
from yuxi.channels.contract.errors import ValidationError

pytestmark = pytest.mark.unit


@pytest.mark.unit
class TestDegradationLevel:
    """降级等级枚举测试。"""

    def test_enum_values_are_correct(self):
        # Arrange
        # Act
        # Assert
        assert DegradationLevel.HEALTHY == "healthy"
        assert DegradationLevel.DEGRADED == "degraded"
        assert DegradationLevel.UNHEALTHY == "unhealthy"

    def test_enum_inherits_from_str(self):
        # Arrange
        # Act
        # Assert
        assert issubclass(DegradationLevel, str)
        assert isinstance(DegradationLevel.HEALTHY, str)

    def test_enum_has_three_members(self):
        # Arrange
        # Act
        members = list(DegradationLevel)
        # Assert
        assert len(members) == 3


@pytest.mark.unit
class TestRecoveryStatus:
    """恢复状态 DTO 测试。"""

    def test_required_fields_are_assigned(self):
        # Arrange
        # Act
        status = RecoveryStatus(plugin_id="plugin-1")
        # Assert
        assert status.plugin_id == "plugin-1"

    def test_defaults_are_correct(self):
        # Arrange
        # Act
        status = RecoveryStatus(plugin_id="plugin-1")
        # Assert
        assert status.retry_count == 0
        assert status.last_retry_at is None
        assert status.next_retry_at is None
        assert status.recovered is False
        assert status.failure_reason is None

    def test_custom_values_are_assigned(self):
        # Arrange
        now = datetime(2026, 1, 1, 12, 0, 0)
        later = datetime(2026, 1, 1, 12, 5, 0)
        # Act
        status = RecoveryStatus(
            plugin_id="plugin-1",
            retry_count=2,
            last_retry_at=now,
            next_retry_at=later,
            recovered=False,
            failure_reason="connection refused",
        )
        # Assert
        assert status.retry_count == 2
        assert status.last_retry_at is now
        assert status.next_retry_at is later
        assert status.recovered is False
        assert status.failure_reason == "connection refused"

    def test_max_retry_count_is_valid(self):
        # Arrange
        # Act
        status = RecoveryStatus(plugin_id="plugin-1", retry_count=3)
        # Assert - retry_count 上限 3
        assert status.retry_count == 3

    def test_is_frozen(self):
        # Arrange
        status = RecoveryStatus(plugin_id="plugin-1")
        # Act / Assert
        with pytest.raises(dataclasses.FrozenInstanceError):
            status.plugin_id = "other"  # type: ignore[misc]

    def test_empty_plugin_id_raises_validation_error(self):
        # Arrange
        # Act / Assert
        with pytest.raises(ValidationError) as exc_info:
            RecoveryStatus(plugin_id="")
        assert exc_info.value.field == "plugin_id"

    def test_negative_retry_count_raises_validation_error(self):
        # Arrange
        # Act / Assert
        with pytest.raises(ValidationError) as exc_info:
            RecoveryStatus(plugin_id="plugin-1", retry_count=-1)
        assert exc_info.value.field == "retry_count"

    def test_exceeding_retry_count_raises_validation_error(self):
        # Arrange
        # Act / Assert - retry_count 超过 3 应抛出
        with pytest.raises(ValidationError) as exc_info:
            RecoveryStatus(plugin_id="plugin-1", retry_count=4)
        assert exc_info.value.field == "retry_count"