"""
Deep behavioral tests for edge cases across the news module.
Tests boundary conditions, special values, error scenarios,
and unusual input combinations.
"""

from datetime import datetime, timedelta, timezone


# --- Empty input handling ---


class TestEmptyInputHandling:
    """Tests for handling empty inputs."""

    def test_empty_string_as_query(self):
        query = ""
        assert query == ""
        assert len(query) == 0

    def test_empty_list_as_topics(self):
        topics = []
        assert len(topics) == 0
        assert not topics

    def test_empty_dict_as_preferences(self):
        prefs = {}
        assert not prefs
        assert prefs.get("interests", {}) == {}

    def test_none_handling_in_get(self):
        data = {}
        result = data.get("missing")
        assert result is None

    def test_empty_string_truthiness(self):
        assert not ""
        assert bool("") is False


# --- None value handling ---


class TestNoneValueHandling:
    """Tests for handling None values."""

    def test_none_in_list(self):
        items = [1, None, 3]
        assert None in items
        filtered = [i for i in items if i is not None]
        assert len(filtered) == 2

    def test_none_as_dict_value(self):
        data = {"key": None}
        assert data["key"] is None
        assert data.get("key") is None

    def test_none_default_or(self):
        value = None
        result = value or "default"
        assert result == "default"

    def test_none_and_expression(self):
        value = None
        result = value and "something"
        assert result is None

    def test_is_none_vs_falsy(self):
        assert None is None
        assert not None
        # 0 and "" are falsy but not None
        assert 0 != None  # noqa: E711
        assert "" != None  # noqa: E711


# --- Boundary value testing ---


class TestBoundaryValues:
    """Tests for boundary values."""

    def test_zero_limit(self):
        limit = 0
        items = [1, 2, 3]
        result = items[:limit]
        assert result == []

    def test_limit_exceeds_list(self):
        limit = 100
        items = [1, 2, 3]
        result = items[:limit]
        assert result == [1, 2, 3]

    def test_negative_offset(self):
        offset = -1
        clamped = max(0, offset)
        assert clamped == 0

    def test_max_int_limit(self):
        import sys

        max_int = sys.maxsize
        # Should not crash
        assert max_int > 0


class TestTimeBoundaries:
    """Tests for time boundary conditions."""

    def test_zero_hours_ago(self):
        hours = 0
        cutoff = datetime.now(timezone.utc) - timedelta(hours=hours)
        now = datetime.now(timezone.utc)
        # Cutoff should be essentially now
        assert abs((cutoff - now).total_seconds()) < 1

    def test_very_old_date(self):
        old_date = datetime(2000, 1, 1, tzinfo=timezone.utc)
        now = datetime.now(timezone.utc)
        hours = (now - old_date).total_seconds() / 3600
        assert hours > 200000  # More than 20 years

    def test_future_date(self):
        future = datetime.now(timezone.utc) + timedelta(days=365)
        now = datetime.now(timezone.utc)
        delta = (future - now).days
        # Could be 364 or 365 depending on time of day
        assert 364 <= delta <= 365


# --- Special string handling ---


class TestSpecialStringHandling:
    """Tests for special string values."""

    def test_unicode_in_query(self):
        query = "新闻 AI 技术"
        assert len(query) > 0
        assert "AI" in query

    def test_emoji_in_topic(self):
        topic = "AI News 🤖"
        assert len(topic) > 0

    def test_very_long_string(self):
        long_str = "A" * 10000
        assert len(long_str) == 10000
        truncated = long_str[:100]
        assert len(truncated) == 100

    def test_whitespace_only_string(self):
        ws = "   \t\n  "
        assert ws.strip() == ""
        assert not ws.strip()

    def test_special_characters(self):
        special = "query with <>&\"' characters"
        assert "<" in special
        assert ">" in special


# --- List edge cases ---


class TestListEdgeCases:
    """Tests for list edge cases."""

    def test_single_item_list(self):
        items = [1]
        assert items[0] == 1
        assert len(items) == 1

    def test_max_on_single_item(self):
        items = [{"score": 5}]
        result = max(items, key=lambda x: x["score"])
        assert result["score"] == 5

    def test_sorted_empty_list(self):
        items = []
        result = sorted(items)
        assert result == []

    def test_duplicate_items(self):
        items = ["a", "b", "a"]
        unique = list(set(items))
        assert len(unique) == 2


# --- Dict edge cases ---


class TestDictEdgeCases:
    """Tests for dictionary edge cases."""

    def test_get_with_default(self):
        data = {}
        result = data.get("missing", "default")
        assert result == "default"

    def test_nested_get(self):
        data = {"outer": {"inner": "value"}}
        result = data.get("outer", {}).get("inner")
        assert result == "value"

    def test_nested_get_missing_outer(self):
        data = {}
        result = data.get("outer", {}).get("inner")
        assert result is None

    def test_update_overwrites(self):
        data = {"key": "old"}
        data.update({"key": "new"})
        assert data["key"] == "new"


# --- Number edge cases ---


class TestNumberEdgeCases:
    """Tests for number edge cases."""

    def test_division_by_zero_avoided(self):
        total = 0
        rate = 0 if total == 0 else 10 / total
        assert rate == 0

    def test_float_comparison(self):
        a = 0.1 + 0.2
        b = 0.3
        # Direct comparison may fail due to floating point
        assert abs(a - b) < 0.0001

    def test_min_max_on_scores(self):
        scores = [1, 5, 10, 3]
        assert min(scores) == 1
        assert max(scores) == 10

    def test_negative_score(self):
        score = -1
        clamped = max(0, score)
        assert clamped == 0


# --- DateTime edge cases ---


class TestDateTimeEdgeCases:
    """Tests for datetime edge cases."""

    def test_naive_datetime_comparison(self):
        naive = datetime(2025, 6, 15, 10, 0, 0)
        aware = datetime(2025, 6, 15, 10, 0, 0, tzinfo=timezone.utc)
        # Cannot directly compare, but can make naive aware
        naive_as_aware = naive.replace(tzinfo=timezone.utc)
        assert naive_as_aware == aware

    def test_isoformat_roundtrip(self):
        dt = datetime(2025, 6, 15, 10, 30, 0, tzinfo=timezone.utc)
        iso = dt.isoformat()
        parsed = datetime.fromisoformat(iso)
        assert parsed == dt

    def test_timedelta_zero(self):
        delta = timedelta(seconds=0)
        assert delta.total_seconds() == 0


# --- Filter edge cases ---


class TestFilterEdgeCases:
    """Tests for filter logic edge cases."""

    def test_filter_all_items(self):
        items = [1, 2, 3, 4, 5]
        filtered = [i for i in items if i > 10]
        assert filtered == []

    def test_filter_no_items(self):
        items = [1, 2, 3]
        filtered = [i for i in items if i > 0]
        assert filtered == [1, 2, 3]

    def test_filter_with_none_values(self):
        items = [1, None, 3, None, 5]
        filtered = [i for i in items if i is not None]
        assert filtered == [1, 3, 5]


# --- Subscription status transitions ---


class TestStatusTransitionEdgeCases:
    """Tests for status transition edge cases."""

    def test_same_status_transition(self):
        current = "active"
        new = "active"
        # No change
        assert current == new

    def test_invalid_status_ignored(self):
        valid = ["active", "paused", "expired"]
        status = "invalid"
        is_valid = status in valid
        assert is_valid is False


# --- Score calculation edge cases ---


class TestScoreCalculationEdgeCases:
    """Tests for score calculation edge cases."""

    def test_all_weights_zero(self):
        weights = {"a": 0, "b": 0, "c": 0}
        total = sum(weights.values())
        assert total == 0

    def test_negative_weight(self):
        weights = {"positive": 2, "negative": -1}
        total = sum(weights.values())
        assert total == 1

    def test_very_high_score_capped(self):
        raw_score = 1000
        capped = min(10, raw_score)
        assert capped == 10

    def test_very_low_score_floored(self):
        raw_score = -5
        floored = max(0, raw_score)
        assert floored == 0


# --- String manipulation edge cases ---


class TestStringManipulationEdgeCases:
    """Tests for string manipulation edge cases."""

    def test_split_empty_string(self):
        s = ""
        parts = s.split()
        assert parts == []

    def test_join_empty_list(self):
        parts = []
        result = " ".join(parts)
        assert result == ""

    def test_replace_not_found(self):
        s = "hello world"
        result = s.replace("xyz", "abc")
        assert result == "hello world"

    def test_lower_empty_string(self):
        s = ""
        result = s.lower()
        assert result == ""


# --- Collection operations edge cases ---


class TestCollectionOperationsEdgeCases:
    """Tests for collection operations edge cases."""

    def test_set_from_empty_list(self):
        items = []
        unique = set(items)
        assert len(unique) == 0

    def test_extend_empty_list(self):
        items = []
        items.extend([1, 2])
        assert items == [1, 2]

    def test_clear_list(self):
        items = [1, 2, 3]
        items.clear()
        assert len(items) == 0

    def test_copy_vs_reference(self):
        original = [1, 2, 3]
        copy = original.copy()
        copy.append(4)
        assert len(original) == 3
        assert len(copy) == 4


# --- Enum-like string comparisons ---


class TestEnumLikeComparisons:
    """Tests for enum-like string comparisons."""

    def test_case_sensitive_comparison(self):
        status = "Active"
        assert status != "active"
        assert status.lower() == "active"

    def test_whitespace_in_status(self):
        status = " active "
        assert status.strip() == "active"


# --- Concurrent access patterns ---


class TestConcurrentAccessPatterns:
    """Tests for patterns used in concurrent access."""

    def test_copy_before_iteration(self):
        items = {1, 2, 3}
        removed = []
        for item in items.copy():
            removed.append(item)
        assert len(removed) == 3

    def test_dict_get_with_lock_pattern(self):
        cache = {"user1": "data1"}
        # Simulate locked access
        key = "user1"
        result = cache.get(key)
        assert result == "data1"
