"""Regression tests for topic/channel skill auto-injection after /new or /reset.

Covers the fix for issue #6508.

Before the fix:
    1. User sends ``/new`` — ``reset_session`` creates a fresh SessionEntry
       with ``created_at == updated_at``.
    2. User sends the next message.
    3. ``get_or_create_session`` finds the entry and bumps
       ``entry.updated_at = now`` (microseconds after ``created_at``).
    4. ``_handle_message_with_agent`` checks
       ``_is_new_session = (created_at == updated_at) or was_auto_reset``.
       Both are False → ``_is_new_session = False`` → topic/channel skills
       are silently skipped for the first message of a manually reset session.

After the fix:
    ``reset_session`` stamps the new entry with ``is_fresh_reset=True``.
    ``_handle_message_with_agent`` ORs this into ``_is_new_session`` and
    consumes the flag immediately after the check, so subsequent messages
    are treated as continuing the session and the flag does not leak.

We use ``was_auto_reset`` for surprise resets (idle/daily/suspended) and
``is_fresh_reset`` for user-initiated resets because the former also drives
a "Session automatically reset due to inactivity" user-facing notice and
a context-note prepend into the agent's prompt — both wrong for an explicit
/new or /reset.
"""

from gateway.config import GatewayConfig, Platform
from gateway.session import SessionEntry, SessionSource, SessionStore


def _make_store(tmp_path):
    return SessionStore(sessions_dir=tmp_path, config=GatewayConfig())


def _make_source(chat_id="123", user_id="u1"):
    return SessionSource(
        platform=Platform.TELEGRAM,
        chat_id=chat_id,
        user_id=user_id,
    )


def _is_new_session(entry) -> bool:
    """Mirror of the predicate in ``_handle_message_with_agent``.

    Kept in-sync with the production check so this test fails loudly if the
    upstream logic regresses.
    """
    return (
        entry.created_at == entry.updated_at
        or getattr(entry, "was_auto_reset", False)
        or getattr(entry, "is_fresh_reset", False)
    )


# ---------------------------------------------------------------------------
# reset_session stamps is_fresh_reset=True
# ---------------------------------------------------------------------------

class TestResetSessionStampsFreshReset:
    def test_reset_session_sets_is_fresh_reset_true(self, tmp_path):
        store = _make_store(tmp_path)
        source = _make_source()
        store.get_or_create_session(source)
        session_key = store._generate_session_key(source)

        new_entry = store.reset_session(session_key)

        assert new_entry is not None
        assert new_entry.is_fresh_reset is True

    def test_reset_session_unknown_key_returns_none(self, tmp_path):
        store = _make_store(tmp_path)
        assert store.reset_session("unknown:key") is None

    def test_fresh_session_does_not_have_is_fresh_reset(self, tmp_path):
        """A vanilla first-time session should not carry the flag."""
        store = _make_store(tmp_path)
        entry = store.get_or_create_session(_make_source())
        assert entry.is_fresh_reset is False


# ---------------------------------------------------------------------------
# Core regression: _is_new_session stays True after updated_at bump
# ---------------------------------------------------------------------------

class TestIsNewSessionSurvivesUpdatedAtBump:
    def test_is_new_session_true_after_reset_then_next_message(self, tmp_path):
        """The actual bug: _is_new_session was False on message after /reset."""
        store = _make_store(tmp_path)
        source = _make_source()
        store.get_or_create_session(source)
        session_key = store._generate_session_key(source)

        # User sends /reset
        store.reset_session(session_key)

        # Next inbound message — get_or_create_session bumps updated_at
        entry = store.get_or_create_session(source)

        # Before the fix: created_at != updated_at, was_auto_reset=False → False
        # After the fix: is_fresh_reset=True carries the signal through the bump
        assert _is_new_session(entry) is True

    def test_flag_consumed_after_first_read(self, tmp_path):
        """After the message handler consumes is_fresh_reset, the NEXT
        message should not be treated as a new session (skill re-injection
        must not fire a second time).
        """
        store = _make_store(tmp_path)
        source = _make_source()
        store.get_or_create_session(source)
        session_key = store._generate_session_key(source)
        store.reset_session(session_key)

        # First message — handler consumes the flag
        entry = store.get_or_create_session(source)
        assert _is_new_session(entry) is True
        entry.is_fresh_reset = False  # what _handle_message_with_agent does

        # Second message — must not be treated as new
        entry = store.get_or_create_session(source)
        assert _is_new_session(entry) is False


# ---------------------------------------------------------------------------
# Vanilla-session behavior is unchanged
# ---------------------------------------------------------------------------

class TestVanillaBehaviorUnaffected:
    def test_ongoing_session_not_flagged_as_new(self, tmp_path):
        store = _make_store(tmp_path)
        source = _make_source()
        store.get_or_create_session(source)

        # Second message on the same session — updated_at bumps,
        # is_fresh_reset was never set
        entry = store.get_or_create_session(source)
        assert entry.is_fresh_reset is False
        assert _is_new_session(entry) is False

    def test_idle_auto_reset_does_not_set_is_fresh_reset(self, tmp_path):
        """Idle/daily auto-resets use was_auto_reset — confirm they do NOT
        also set is_fresh_reset (which would double-fire the skill path and
        not leak through the auto-reset guard).
        """
        store = _make_store(tmp_path)
        source = _make_source()
        entry = store.get_or_create_session(source)

        # Simulate the auto-reset code path: get_or_create_session's internal
        # branch that sets was_auto_reset does NOT touch is_fresh_reset.
        # Construct a fresh entry the same way that branch does.
        store._entries.pop(store._generate_session_key(source))
        fresh = SessionEntry(
            session_key=entry.session_key,
            session_id="new_id",
            created_at=entry.created_at,
            updated_at=entry.created_at,
            origin=source,
            was_auto_reset=True,
            auto_reset_reason="idle",
        )
        assert fresh.is_fresh_reset is False
        assert fresh.was_auto_reset is True


# ---------------------------------------------------------------------------
# Persistence through sessions.json round-trip
# ---------------------------------------------------------------------------

class TestPersistence:
    def test_is_fresh_reset_survives_to_dict_from_dict(self, tmp_path):
        """Protect against the gateway restarting between /reset and the
        next message — the flag must be persisted in sessions.json.
        """
        store = _make_store(tmp_path)
        source = _make_source()
        store.get_or_create_session(source)
        session_key = store._generate_session_key(source)
        new_entry = store.reset_session(session_key)

        assert new_entry.is_fresh_reset is True
        restored = SessionEntry.from_dict(new_entry.to_dict())
        assert restored.is_fresh_reset is True

    def test_default_false_when_missing_from_dict(self, tmp_path):
        """Older sessions.json files written before this field existed must
        load cleanly with is_fresh_reset defaulting to False.
        """
        data = {
            "session_key": "telegram:1:123",
            "session_id": "sess1",
            "created_at": "2026-01-01T00:00:00",
            "updated_at": "2026-01-01T00:00:00",
        }
        entry = SessionEntry.from_dict(data)
        assert entry.is_fresh_reset is False
