"""标题库 UseCase 单元测试."""

from __future__ import annotations

from unittest.mock import MagicMock, patch

import pytest

from packages.application.title_library.commands import (
    CreateTitleLibraryCommand,
    IncrementTitleUsageCommand,
    PickTitleCommand,
    UpdateTitleLibraryCommand,
)
from packages.application.title_library.use_cases import (
    CreateTitleLibraryUseCase,
    DeleteTitleLibraryUseCase,
    GetTitleLibraryUseCase,
    IncrementTitleUsageUseCase,
    ListTitleLibraryUseCase,
    PickTitleUseCase,
    UpdateTitleLibraryUseCase,
)
from packages.domain.exceptions import NotFoundError, QuotaExceededError
from packages.domain.title_library import TitleLibraryItem


def _make_item(id: str, name: str, text: str, usage_count: int = 0, category: str = "default") -> TitleLibraryItem:
    return TitleLibraryItem(
        id=id,
        user_id="user_1",
        name=name,
        text=text,
        category=category,
        description="",
        tags=[],
        usage_count=usage_count,
        is_active=True,
        metadata_={},
    )


@pytest.fixture
def mock_repo():
    return MagicMock()


@pytest.fixture
def sample_item():
    return _make_item("title_1", "爆款标题", "这是一个爆款标题文案", usage_count=5)


class TestListTitleLibraryUseCase:
    """ListTitleLibraryUseCase 测试"""

    def test_list_returns_results(self, mock_repo, sample_item):
        """正常返回标题列表"""
        mock_repo.list_by_user.return_value = [sample_item]
        use_case = ListTitleLibraryUseCase(mock_repo)

        result = use_case.execute("user_1")

        assert len(result) == 1
        assert result[0].id == "title_1"
        mock_repo.list_by_user.assert_called_once_with("user_1", category=None, skip=0, limit=50)

    def test_list_with_category(self, mock_repo, sample_item):
        """按分类过滤"""
        mock_repo.list_by_user.return_value = [sample_item]
        use_case = ListTitleLibraryUseCase(mock_repo)

        use_case.execute("user_1", category="电商")

        mock_repo.list_by_user.assert_called_once_with("user_1", category="电商", skip=0, limit=50)

    def test_list_with_pagination(self, mock_repo, sample_item):
        """带分页参数"""
        mock_repo.list_by_user.return_value = [sample_item]
        use_case = ListTitleLibraryUseCase(mock_repo)

        use_case.execute("user_1", skip=10, limit=20)

        mock_repo.list_by_user.assert_called_once_with("user_1", category=None, skip=10, limit=20)

    def test_empty_list(self, mock_repo):
        """空列表"""
        mock_repo.list_by_user.return_value = []
        use_case = ListTitleLibraryUseCase(mock_repo)

        result = use_case.execute("user_1")

        assert result == []


class TestGetTitleLibraryUseCase:
    """GetTitleLibraryUseCase 测试"""

    def test_get_existing(self, mock_repo, sample_item):
        """获取存在的标题"""
        mock_repo.get.return_value = sample_item
        use_case = GetTitleLibraryUseCase(mock_repo)

        result = use_case.execute("title_1", "user_1")

        assert result is not None
        assert result.id == "title_1"
        mock_repo.get.assert_called_once_with("title_1", "user_1")

    def test_get_nonexistent_returns_none(self, mock_repo):
        """获取不存在的标题返回 None"""
        mock_repo.get.return_value = None
        use_case = GetTitleLibraryUseCase(mock_repo)

        result = use_case.execute("nonexistent", "user_1")

        assert result is None


class TestCreateTitleLibraryUseCase:
    """CreateTitleLibraryUseCase 测试"""

    def test_create_success(self, mock_repo, sample_item):
        """创建成功"""
        mock_repo.count_by_user.return_value = 0
        mock_repo.create.return_value = sample_item
        use_case = CreateTitleLibraryUseCase(mock_repo)

        command = CreateTitleLibraryCommand(
            user_id="user_1",
            name="新标题",
            text="新标题文案",
            category="default",
            description="",
            tags=[],
            metadata_={},
        )
        result = use_case.execute(command, plan_name="free")

        assert result.id == "title_1"
        mock_repo.count_by_user.assert_called_once_with("user_1")
        mock_repo.create.assert_called_once()

    def test_create_quota_exceeded(self, mock_repo):
        """超过配额时抛出 QuotaExceededError"""
        mock_repo.count_by_user.return_value = 9999
        use_case = CreateTitleLibraryUseCase(mock_repo)

        command = CreateTitleLibraryCommand(
            user_id="user_1",
            name="新标题",
            text="文案",
            category="default",
            description="",
            tags=[],
            metadata_={},
        )
        with pytest.raises(QuotaExceededError):
            use_case.execute(command, plan_name="free")

        mock_repo.create.assert_not_called()

    def test_create_with_tags_and_metadata(self, mock_repo, sample_item):
        """创建时带 tags 和 metadata_"""
        mock_repo.count_by_user.return_value = 0
        mock_repo.create.return_value = sample_item
        use_case = CreateTitleLibraryUseCase(mock_repo)

        command = CreateTitleLibraryCommand(
            user_id="user_1",
            name="带标签标题",
            text="文案",
            category="电商",
            description="测试描述",
            tags=["爆款", "促销"],
            metadata_={"source": "manual"},
        )
        use_case.execute(command, plan_name="premium")

        created = mock_repo.create.call_args[0][0]
        assert isinstance(created, TitleLibraryItem)
        assert created.name == "带标签标题"
        assert created.category == "电商"
        assert created.tags == ["爆款", "促销"]
        assert created.metadata_ == {"source": "manual"}


class TestUpdateTitleLibraryUseCase:
    """UpdateTitleLibraryUseCase 测试"""

    def test_update_name(self, mock_repo, sample_item):
        """更新标题名称"""
        mock_repo.get.return_value = sample_item
        mock_repo.update.side_effect = lambda x: x
        use_case = UpdateTitleLibraryUseCase(mock_repo)

        command = UpdateTitleLibraryCommand(title_id="title_1", user_id="user_1", name="新名称")
        result = use_case.execute(command)

        assert result.name == "新名称"
        # 其他字段不变
        assert result.text == "这是一个爆款标题文案"
        mock_repo.get.assert_called_once_with("title_1", "user_1")
        mock_repo.update.assert_called_once()

    def test_update_multiple_fields(self, mock_repo, sample_item):
        """同时更新多个字段"""
        mock_repo.get.return_value = sample_item
        mock_repo.update.side_effect = lambda x: x
        use_case = UpdateTitleLibraryUseCase(mock_repo)

        command = UpdateTitleLibraryCommand(
            title_id="title_1",
            user_id="user_1",
            text="新文案内容",
            category="美食",
            is_active=False,
        )
        result = use_case.execute(command)

        assert result.text == "新文案内容"
        assert result.category == "美食"
        assert result.is_active is False

    def test_update_nonexistent_raises(self, mock_repo):
        """更新不存在的标题抛出 NotFoundError"""
        mock_repo.get.return_value = None
        use_case = UpdateTitleLibraryUseCase(mock_repo)

        command = UpdateTitleLibraryCommand(title_id="noexist", user_id="user_1", name="新名称")
        with pytest.raises(NotFoundError, match="not found"):
            use_case.execute(command)

        mock_repo.update.assert_not_called()


class TestDeleteTitleLibraryUseCase:
    """DeleteTitleLibraryUseCase 测试"""

    def test_delete_success(self, mock_repo):
        """删除成功"""
        mock_repo.delete.return_value = True
        use_case = DeleteTitleLibraryUseCase(mock_repo)

        result = use_case.execute("title_1", "user_1")

        assert result is True
        mock_repo.delete.assert_called_once_with("title_1", "user_1")

    def test_delete_nonexistent_returns_false(self, mock_repo):
        """删除不存在的返回 False"""
        mock_repo.delete.return_value = False
        use_case = DeleteTitleLibraryUseCase(mock_repo)

        result = use_case.execute("noexist", "user_1")

        assert result is False


class TestIncrementTitleUsageUseCase:
    """IncrementTitleUsageUseCase 测试"""

    def test_increment_positive(self, mock_repo):
        """正增量时调用 repository"""
        mock_repo.increment_usage_count.return_value = True
        use_case = IncrementTitleUsageUseCase(mock_repo)

        command = IncrementTitleUsageCommand(title_id="title_1", user_id="user_1", increment=1)
        result = use_case.execute(command)

        assert result is True
        mock_repo.increment_usage_count.assert_called_once_with("title_1", "user_1", increment=1)

    def test_increment_zero_returns_false(self, mock_repo):
        """增量为0返回False，不调用repository"""
        use_case = IncrementTitleUsageUseCase(mock_repo)

        command = IncrementTitleUsageCommand(title_id="title_1", user_id="user_1", increment=0)
        result = use_case.execute(command)

        assert result is False
        mock_repo.increment_usage_count.assert_not_called()

    def test_increment_negative_returns_false(self, mock_repo):
        """负增量返回False"""
        use_case = IncrementTitleUsageUseCase(mock_repo)

        command = IncrementTitleUsageCommand(title_id="title_1", user_id="user_1", increment=-1)
        result = use_case.execute(command)

        assert result is False
        mock_repo.increment_usage_count.assert_not_called()

    def test_increment_large_number(self, mock_repo):
        """大增量值"""
        mock_repo.increment_usage_count.return_value = True
        use_case = IncrementTitleUsageUseCase(mock_repo)

        command = IncrementTitleUsageCommand(title_id="title_1", user_id="user_1", increment=10)
        use_case.execute(command)

        mock_repo.increment_usage_count.assert_called_once_with("title_1", "user_1", increment=10)


class TestPickTitleUseCase:
    """PickTitleUseCase 智能选标题测试"""

    def test_pick_from_multiple(self, mock_repo):
        """从多个标题中选一个（最少使用的前5个中随机）"""
        items = [_make_item(f"t{i}", f"标题{i}", f"文案{i}", usage_count=i) for i in range(10)]
        mock_repo.list_by_user.return_value = items
        use_case = PickTitleUseCase(mock_repo)

        command = PickTitleCommand(user_id="user_1")
        result = use_case.execute(command)

        assert result is not None
        assert isinstance(result, TitleLibraryItem)
        # 选出的应该是使用次数最少的前5个之一（0-4）
        assert result.usage_count <= 4
        mock_repo.list_by_user.assert_called_once()

    def test_pick_empty_returns_none(self, mock_repo):
        """空标题库返回 None"""
        mock_repo.list_by_user.return_value = []
        use_case = PickTitleUseCase(mock_repo)

        command = PickTitleCommand(user_id="user_1")
        result = use_case.execute(command)

        assert result is None

    def test_pick_with_category(self, mock_repo):
        """按分类选标题"""
        items = [_make_item("t1", "标题1", "文案1", category="美食")]
        mock_repo.list_by_user.return_value = items
        use_case = PickTitleUseCase(mock_repo)

        command = PickTitleCommand(user_id="user_1", category="美食")
        result = use_case.execute(command)

        assert result is not None
        call_kwargs = mock_repo.list_by_user.call_args[1]
        assert call_kwargs["category"] == "美食"
        assert call_kwargs["is_active"] is True

    def test_pick_exclude_ids(self, mock_repo):
        """排除指定ID"""
        items = [
            _make_item("t1", "标题1", "文案1", usage_count=1),
            _make_item("t2", "标题2", "文案2", usage_count=2),
            _make_item("t3", "标题3", "文案3", usage_count=3),
        ]
        mock_repo.list_by_user.return_value = items
        use_case = PickTitleUseCase(mock_repo)

        command = PickTitleCommand(user_id="user_1", exclude_ids=["t1", "t2"])
        result = use_case.execute(command)

        # 排除两个后只剩t3
        assert result.id == "t3"

    def test_pick_exclude_all_falls_back(self, mock_repo):
        """排除全部时从所有标题中选"""
        items = [
            _make_item("t1", "标题1", "文案1", usage_count=1),
            _make_item("t2", "标题2", "文案2", usage_count=2),
        ]
        mock_repo.list_by_user.return_value = items
        use_case = PickTitleUseCase(mock_repo)

        command = PickTitleCommand(user_id="user_1", exclude_ids=["t1", "t2"])
        result = use_case.execute(command)

        # 排除全部后fallback到全部，所以还是能选出一个
        assert result is not None
        assert result.id in ("t1", "t2")

    def test_pick_single_item(self, mock_repo):
        """只有一个标题时选它"""
        item = _make_item("only", "唯一标题", "唯一文案", usage_count=10)
        mock_repo.list_by_user.return_value = [item]
        use_case = PickTitleUseCase(mock_repo)

        command = PickTitleCommand(user_id="user_1")
        result = use_case.execute(command)

        assert result.id == "only"

    def test_pick_prefers_less_used(self, mock_repo):
        """倾向于选择使用次数少的"""
        items = [
            _make_item("t_used", "常用", "常用", usage_count=100),
            _make_item("t_fresh", "新的", "新的", usage_count=0),
        ]
        mock_repo.list_by_user.return_value = items
        use_case = PickTitleUseCase(mock_repo)

        # 跑多次，验证使用少的出现在候选池里
        results = set()
        for _ in range(20):
            command = PickTitleCommand(user_id="user_1")
            r = use_case.execute(command)
            if r:
                results.add(r.id)

        # 两个都在候选池（少于5个），所以都可能被选中
        assert "t_used" in results or "t_fresh" in results