"""Domain tests for the schedule bounded context.

Deliberately synchronous and dependency-free: no pytest-asyncio, no fakes, no
IO. Everything under `deerflow.domain.schedule.model` is pure, and this file is
the proof — if a rule here ever needs a stub, the rule has leaked out of the
inner ring.

The three `status_after_*` truth tables (TestStatusAfter*) are the reason this
commit exists: those rules used to be static methods on
`app/scheduler/service.py` with no direct coverage at all, reachable only
through the service's integration tests.
"""

from __future__ import annotations

from datetime import UTC, datetime, timedelta

import pytest

from deerflow.domain.schedule.model import (
    ACTIVE_RUN_STATUSES,
    ContextMode,
    InvalidContextModeError,
    InvalidScheduleError,
    RunStatus,
    ScheduledRun,
    ScheduledTask,
    SchedulePolicy,
    ScheduleSpec,
    ScheduleType,
    TaskNotMutableError,
    TaskStatus,
    TriggerKind,
)

NOW = datetime(2026, 7, 27, 12, 0, tzinfo=UTC)
NO_DELAY = SchedulePolicy(min_once_delay_seconds=0)
MIN_60 = SchedulePolicy(min_once_delay_seconds=60)


def cron_spec(expr: str = "0 9 * * *", timezone: str = "UTC") -> ScheduleSpec:
    return ScheduleSpec.cron_schedule(expr, timezone)


def once_spec(*, after_seconds: int = 3600, timezone: str = "UTC") -> ScheduleSpec:
    return ScheduleSpec.once_at(NOW + timedelta(seconds=after_seconds), timezone)


def make_task(
    *,
    schedule: ScheduleSpec | None = None,
    status: TaskStatus = TaskStatus.ENABLED,
    context_mode: ContextMode = ContextMode.FRESH_THREAD_PER_RUN,
    thread_id: str | None = None,
) -> ScheduledTask:
    return ScheduledTask(
        task_id="task-1",
        user_id="user-1",
        title="Daily summary",
        prompt="Summarize",
        schedule=schedule if schedule is not None else cron_spec(),
        status=status,
        context_mode=context_mode,
        thread_id=thread_id,
    )


# ---------------------------------------------------------------- A. ScheduleSpec invariants


class TestScheduleSpecInvariants:
    def test_unknown_timezone_is_rejected(self):
        with pytest.raises(InvalidScheduleError, match="Unknown timezone"):
            ScheduleSpec.cron_schedule("0 9 * * *", "Mars/Olympus_Mons")

    def test_cron_without_expression_is_rejected(self):
        with pytest.raises(InvalidScheduleError, match="requires schedule_spec"):
            ScheduleSpec(ScheduleType.CRON, "UTC")

    @pytest.mark.parametrize("expr", ["0 9 * *", "0 9 * * * *", "0"])
    def test_cron_must_have_exactly_five_fields(self, expr):
        with pytest.raises(InvalidScheduleError, match="exactly 5 fields"):
            ScheduleSpec.cron_schedule(expr, "UTC")

    def test_once_without_run_at_is_rejected(self):
        with pytest.raises(InvalidScheduleError, match="requires run_at"):
            ScheduleSpec(ScheduleType.ONCE, "UTC")

    def test_direct_construction_cannot_bypass_validation(self):
        """A frozen dataclass is still constructible field-by-field, so the
        rules have to live in __post_init__ rather than in the factories."""
        with pytest.raises(InvalidScheduleError, match="exactly 5 fields"):
            ScheduleSpec(ScheduleType.CRON, "UTC", cron="not-a-cron")

    def test_cron_whitespace_is_normalized_on_construction(self):
        assert ScheduleSpec(ScheduleType.CRON, "UTC", cron="  0   9  *  *  * ").cron == "0 9 * * *"

    def test_naive_run_at_is_localized_to_the_schedule_timezone(self):
        spec = ScheduleSpec.once_at(datetime(2026, 8, 1, 9, 0), "Asia/Shanghai")  # noqa: DTZ001 -- naive input is the subject
        assert spec.run_at.utcoffset() == timedelta(hours=8)
        assert spec.run_at.astimezone(UTC) == datetime(2026, 8, 1, 1, 0, tzinfo=UTC)

    def test_aware_run_at_is_left_alone(self):
        run_at = datetime(2026, 8, 1, 9, 0, tzinfo=UTC)
        assert ScheduleSpec.once_at(run_at, "Asia/Shanghai").run_at == run_at

    def test_zulu_iso_input_is_accepted_as_the_same_instant(self):
        """The shape the frontend actually submits: `zonedLocalToUtcIso` output,
        which carries a trailing Z. It is already aware, so localization must
        leave it alone rather than reinterpreting it in the task's timezone."""
        spec = ScheduleSpec.once_at(datetime.fromisoformat("2026-08-01T01:00:00Z"), "Asia/Shanghai")
        assert spec.run_at == datetime(2026, 8, 1, 1, 0, tzinfo=UTC)


# ---------------------------------------------------------------- A2. from_primitives


class TestFromPrimitives:
    """The one construction path that starts from untrusted strings.

    Both boundaries -- the HTTP body and the stored JSON column -- arrive as a
    schedule type plus a loose mapping, so the rule for turning that into a
    value object lives here rather than being written out once per adapter.
    Each adapter is left with the part that is genuinely its own: which keys
    its format uses.

    Values are type-checked rather than assumed. The signature says `str |
    None` because that is the contract, but both callers read from data a
    client can influence, so a non-string has to be rejected here rather than
    reaching `datetime.fromisoformat` or the cron parser.
    """

    def test_builds_a_cron_schedule(self):
        spec = ScheduleSpec.from_primitives("cron", cron="0 9 * * *", run_at=None, timezone="Asia/Shanghai")
        assert spec.schedule_type is ScheduleType.CRON
        assert spec.cron == "0 9 * * *"
        assert spec.timezone == "Asia/Shanghai"

    def test_builds_a_once_schedule_from_an_iso_string(self):
        spec = ScheduleSpec.from_primitives("once", cron=None, run_at="2026-08-01T09:00:00", timezone="Asia/Shanghai")
        assert spec.schedule_type is ScheduleType.ONCE
        assert spec.run_at == datetime(2026, 8, 1, 1, 0, tzinfo=UTC)

    def test_a_trailing_z_run_at_is_the_same_instant(self):
        """The shape the frontend submits (`zonedLocalToUtcIso`)."""
        spec = ScheduleSpec.from_primitives("once", cron=None, run_at="2026-08-01T01:00:00Z", timezone="Asia/Shanghai")
        assert spec.run_at == datetime(2026, 8, 1, 1, 0, tzinfo=UTC)

    def test_unknown_schedule_type_is_rejected(self):
        with pytest.raises(InvalidScheduleError, match="Unsupported schedule_type"):
            ScheduleSpec.from_primitives("teleport", cron="0 9 * * *", run_at=None, timezone="UTC")

    @pytest.mark.parametrize("cron", [None, 5, ""])
    def test_cron_without_a_usable_expression_is_rejected(self, cron):
        with pytest.raises(InvalidScheduleError, match="requires schedule_spec"):
            ScheduleSpec.from_primitives("cron", cron=cron, run_at=None, timezone="UTC")

    @pytest.mark.parametrize("run_at", [None, 5])
    def test_once_without_a_string_run_at_is_rejected(self, run_at):
        with pytest.raises(InvalidScheduleError, match="requires run_at"):
            ScheduleSpec.from_primitives("once", cron=None, run_at=run_at, timezone="UTC")

    def test_an_unparseable_run_at_is_rejected(self):
        with pytest.raises(InvalidScheduleError, match="unparseable run_at"):
            ScheduleSpec.from_primitives("once", cron=None, run_at="next tuesday", timezone="UTC")

    def test_the_irrelevant_field_is_ignored(self):
        """A boundary that carries both keys must not be rejected for it."""
        spec = ScheduleSpec.from_primitives("cron", cron="0 9 * * *", run_at="2026-08-01T09:00:00", timezone="UTC")
        assert spec.run_at is None

    def test_value_rules_still_come_from_post_init(self):
        """Not re-implemented here -- this is why each adapter stays thin."""
        with pytest.raises(InvalidScheduleError, match="exactly 5 fields"):
            ScheduleSpec.from_primitives("cron", cron="0 9 * *", run_at=None, timezone="UTC")
        with pytest.raises(InvalidScheduleError, match="Unknown timezone"):
            ScheduleSpec.from_primitives("cron", cron="0 9 * * *", run_at=None, timezone="Mars/Olympus_Mons")

    def test_whitespace_in_a_cron_expression_is_normalized(self):
        spec = ScheduleSpec.from_primitives("cron", cron="  0  9 * * * ", run_at=None, timezone="UTC")
        assert spec.cron == "0 9 * * *"


# ---------------------------------------------------------------- B. next_after


class TestNextAfter:
    def test_once_in_the_future_returns_run_at(self):
        spec = once_spec(after_seconds=3600)
        assert spec.next_after(NOW) == NOW + timedelta(seconds=3600)

    def test_once_in_the_past_returns_none(self):
        spec = ScheduleSpec.once_at(NOW - timedelta(seconds=1), "UTC")
        assert spec.next_after(NOW) is None

    def test_once_exactly_now_returns_none(self):
        """`run_at > now`, not `>=` (schedules.py:44)."""
        assert ScheduleSpec.once_at(NOW, "UTC").next_after(NOW) is None

    def test_cron_returns_the_next_occurrence_in_utc(self):
        # 09:00 UTC daily; NOW is 12:00 UTC, so the next one is tomorrow.
        assert cron_spec("0 9 * * *", "UTC").next_after(NOW) == datetime(2026, 7, 28, 9, 0, tzinfo=UTC)

    def test_cron_is_evaluated_in_the_schedule_timezone(self):
        # 09:00 Shanghai == 01:00 UTC. NOW (12:00 UTC) is past today's, so the
        # answer is tomorrow 01:00 UTC -- not 09:00 UTC.
        assert cron_spec("0 9 * * *", "Asia/Shanghai").next_after(NOW) == datetime(2026, 7, 28, 1, 0, tzinfo=UTC)

    def test_cron_absorbs_a_dst_transition(self):
        """US DST starts 2026-03-08, so the same wall-clock cron maps to a
        different UTC instant on either side of it. This is what evaluating in
        the schedule's timezone buys."""
        spec = cron_spec("0 9 * * *", "America/New_York")
        before = spec.next_after(datetime(2026, 3, 7, 0, 0, tzinfo=UTC))
        after = spec.next_after(datetime(2026, 3, 9, 0, 0, tzinfo=UTC))
        assert before == datetime(2026, 3, 7, 14, 0, tzinfo=UTC)  # EST, UTC-5
        assert after == datetime(2026, 3, 9, 13, 0, tzinfo=UTC)  # EDT, UTC-4

    def test_naive_now_is_read_as_utc(self):
        spec = cron_spec("0 9 * * *", "UTC")
        assert spec.next_after(NOW.replace(tzinfo=None)) == spec.next_after(NOW)


# ---------------------------------------------------------------- C. ensure_launchable


class TestEnsureLaunchable:
    def test_once_in_the_past_is_rejected(self):
        spec = ScheduleSpec.once_at(NOW - timedelta(hours=1), "UTC")
        with pytest.raises(InvalidScheduleError, match="must be in the future"):
            spec.ensure_launchable(NOW, NO_DELAY)

    def test_once_closer_than_the_minimum_delay_is_rejected(self):
        with pytest.raises(InvalidScheduleError, match="at least 60 seconds"):
            once_spec(after_seconds=59).ensure_launchable(NOW, MIN_60)

    def test_once_exactly_at_the_minimum_delay_is_accepted(self):
        assert once_spec(after_seconds=60).ensure_launchable(NOW, MIN_60) == NOW + timedelta(seconds=60)

    def test_cron_is_never_subject_to_the_delay_floor(self):
        """router:105 / router:196 apply the floor only to `once`; a cron
        schedule whose next fire is seconds away is perfectly legal."""
        spec = cron_spec("* * * * *", "UTC")
        assert spec.ensure_launchable(NOW, MIN_60) is not None

    def test_naive_now_is_read_as_utc(self):
        """Same tolerance as next_after: a caller handing over a naive clock
        reading must not silently shift the delay floor by the local offset."""
        spec = once_spec(after_seconds=3600)
        assert spec.ensure_launchable(NOW.replace(tzinfo=None), MIN_60) == spec.ensure_launchable(NOW, MIN_60)

    def test_matches_next_after_for_a_valid_once_schedule(self):
        spec = once_spec(after_seconds=3600)
        assert spec.ensure_launchable(NOW, MIN_60) == spec.next_after(NOW)


# ---------------------------------------------------------------- D. value semantics


class TestScheduleSpecEquality:
    """A value object is its values -- two specs built from equivalent inputs
    must compare equal, because the repository relies on that to decide whether
    a schedule actually changed.

    Serialization shape (the JSON written to `scheduled_tasks.schedule_spec`)
    is deliberately NOT tested here: that mapping lives in the adapter layer,
    and so do its tests.
    """

    def test_equivalent_cron_inputs_converge(self):
        assert ScheduleSpec.cron_schedule("  0  9 * * * ", "UTC") == ScheduleSpec.cron_schedule("0 9 * * *", "UTC")

    def test_equivalent_once_inputs_converge(self):
        naive = ScheduleSpec.once_at(datetime(2026, 8, 1, 9, 0), "Asia/Shanghai")  # noqa: DTZ001 -- naive input is the subject
        aware = ScheduleSpec.once_at(datetime.fromisoformat("2026-08-01T01:00:00Z"), "Asia/Shanghai")
        assert naive == aware

    def test_timezone_is_part_of_identity(self):
        at = datetime(2026, 8, 1, 9, 0, tzinfo=UTC)
        assert ScheduleSpec.once_at(at, "UTC") != ScheduleSpec.once_at(at, "Asia/Shanghai")


# ---------------------------------------------------------------- E. ScheduledTask invariants


class TestScheduledTaskInvariants:
    def test_reuse_thread_requires_a_thread(self):
        with pytest.raises(InvalidContextModeError, match="reuse_thread requires thread_id"):
            make_task(context_mode=ContextMode.REUSE_THREAD, thread_id=None)

    def test_unknown_context_mode_is_a_domain_error(self):
        """Not a bare ValueError -- the router maps the ScheduleError family
        uniformly (router:76-77 was a 422)."""
        with pytest.raises(InvalidContextModeError, match="Unsupported context_mode"):
            ScheduledTask.create(
                user_id="user-1",
                title="t",
                prompt="p",
                schedule=cron_spec(),
                context_mode="teleport",
                thread_id=None,
                now=NOW,
                policy=NO_DELAY,
            )

    def test_create_drops_thread_id_for_fresh_thread_mode(self):
        task = ScheduledTask.create(
            user_id="user-1",
            title="t",
            prompt="p",
            schedule=cron_spec(),
            context_mode=ContextMode.FRESH_THREAD_PER_RUN,
            thread_id="thread-9",
            now=NOW,
            policy=NO_DELAY,
        )
        assert task.thread_id is None

    def test_create_computes_next_run_at_and_defaults(self):
        task = ScheduledTask.create(
            user_id="user-1",
            title="t",
            prompt="p",
            schedule=cron_spec("0 9 * * *", "UTC"),
            context_mode=ContextMode.FRESH_THREAD_PER_RUN,
            thread_id=None,
            now=NOW,
            policy=NO_DELAY,
        )
        assert task.task_id.startswith("task-")
        assert task.status is TaskStatus.ENABLED
        assert task.run_count == 0
        assert task.assistant_id == "lead_agent"
        assert task.next_run_at == datetime(2026, 7, 28, 9, 0, tzinfo=UTC)

    def test_create_rejects_a_once_schedule_inside_the_delay_floor(self):
        with pytest.raises(InvalidScheduleError, match="at least 60 seconds"):
            ScheduledTask.create(
                user_id="user-1",
                title="t",
                prompt="p",
                schedule=once_spec(after_seconds=10),
                context_mode=ContextMode.FRESH_THREAD_PER_RUN,
                thread_id=None,
                now=NOW,
                policy=MIN_60,
            )

    def test_skips_on_overlap_reflects_the_policy(self):
        assert make_task().skips_on_overlap is True


# ---------------------------------------------------------------- F. the three truth tables


class TestStatusAfterLaunch:
    @pytest.mark.parametrize(
        ("schedule", "trigger", "status", "expected"),
        [
            (once_spec(), TriggerKind.SCHEDULED, TaskStatus.RUNNING, TaskStatus.RUNNING),
            (once_spec(), TriggerKind.MANUAL, TaskStatus.ENABLED, TaskStatus.RUNNING),
            (cron_spec(), TriggerKind.MANUAL, TaskStatus.PAUSED, TaskStatus.PAUSED),
            (cron_spec(), TriggerKind.MANUAL, TaskStatus.ENABLED, TaskStatus.ENABLED),
            (cron_spec(), TriggerKind.SCHEDULED, TaskStatus.RUNNING, TaskStatus.ENABLED),
        ],
    )
    def test_truth_table(self, schedule, trigger, status, expected):
        assert make_task(schedule=schedule, status=status).status_after_launch(trigger=trigger) is expected

    def test_manual_trigger_of_paused_once_task_yields_running(self):
        """Decision-order trap: ONCE is tested before the MANUAL+PAUSED rule,
        so the paused branch never sees a once task."""
        task = make_task(schedule=once_spec(), status=TaskStatus.PAUSED)
        assert task.status_after_launch(trigger=TriggerKind.MANUAL) is TaskStatus.RUNNING


class TestStatusAfterFailure:
    @pytest.mark.parametrize(
        ("schedule", "trigger", "status", "expected"),
        [
            (once_spec(), TriggerKind.SCHEDULED, TaskStatus.RUNNING, TaskStatus.FAILED),
            (cron_spec(), TriggerKind.SCHEDULED, TaskStatus.RUNNING, TaskStatus.ENABLED),
            (cron_spec(), TriggerKind.MANUAL, TaskStatus.ENABLED, TaskStatus.ENABLED),
            (cron_spec(), TriggerKind.MANUAL, TaskStatus.PAUSED, TaskStatus.PAUSED),
        ],
    )
    def test_truth_table(self, schedule, trigger, status, expected):
        assert make_task(schedule=schedule, status=status).status_after_failure(trigger=trigger) is expected

    @pytest.mark.parametrize("status", [TaskStatus.ENABLED, TaskStatus.PAUSED])
    def test_failed_manual_trigger_of_once_task_keeps_status(self, status):
        """Decision-order trap: MANUAL is tested before ONCE, so a failed
        manual trigger cannot burn the task's single scheduled occurrence."""
        task = make_task(schedule=once_spec(), status=status)
        assert task.status_after_failure(trigger=TriggerKind.MANUAL) is status


class TestStatusAfterSkip:
    def test_once_is_failed_not_completed(self):
        assert make_task(schedule=once_spec()).status_after_skip() is TaskStatus.FAILED

    def test_cron_stays_enabled(self):
        assert make_task(schedule=cron_spec()).status_after_skip() is TaskStatus.ENABLED


class TestStatusAfterCompletion:
    @pytest.mark.parametrize("outcome", list(RunStatus))
    def test_cron_never_changes_status(self, outcome):
        assert make_task(schedule=cron_spec()).status_after_completion(outcome) is None

    @pytest.mark.parametrize(
        ("outcome", "expected"),
        [
            (RunStatus.SUCCESS, TaskStatus.COMPLETED),
            (RunStatus.INTERRUPTED, TaskStatus.CANCELLED),
            (RunStatus.FAILED, TaskStatus.FAILED),
        ],
    )
    def test_once_maps_each_terminal_outcome(self, outcome, expected):
        assert make_task(schedule=once_spec()).status_after_completion(outcome) is expected

    def test_interrupted_is_cancelled_not_failed(self):
        """A user cancel or same-thread takeover carries no execution failure."""
        task = make_task(schedule=once_spec())
        assert task.status_after_completion(RunStatus.INTERRUPTED) is TaskStatus.CANCELLED


# ---------------------------------------------------------------- G. mutability gate


class TestMutabilityGate:
    def test_ensure_mutable_rejects_a_running_task(self):
        with pytest.raises(TaskNotMutableError, match="currently running"):
            make_task(status=TaskStatus.RUNNING).ensure_mutable()

    @pytest.mark.parametrize("status", [s for s in TaskStatus if s is not TaskStatus.RUNNING])
    def test_ensure_mutable_allows_every_other_status(self, status):
        make_task(status=status).ensure_mutable()

    def test_pause_and_resume_are_gated(self):
        running = make_task(status=TaskStatus.RUNNING)
        with pytest.raises(TaskNotMutableError):
            running.paused()
        with pytest.raises(TaskNotMutableError):
            running.resumed()

    def test_pause_then_resume_round_trips(self):
        task = make_task(status=TaskStatus.ENABLED)
        assert task.paused().status is TaskStatus.PAUSED
        assert task.paused().resumed().status is TaskStatus.ENABLED

    def test_transitions_do_not_mutate_the_original(self):
        task = make_task(status=TaskStatus.ENABLED)
        task.paused()
        assert task.status is TaskStatus.ENABLED


# ---------------------------------------------------------------- H. with_schedule


class TestWithSchedule:
    @pytest.mark.parametrize("status", [TaskStatus.COMPLETED, TaskStatus.FAILED, TaskStatus.CANCELLED])
    def test_terminal_task_is_rearmed_by_a_future_schedule(self, status):
        """claim_due only admits ENABLED rows, so leaving the terminal status
        would return a next_run_at that silently never fires (router:203-208)."""
        task = make_task(schedule=once_spec(), status=status)
        updated = task.with_schedule(once_spec(after_seconds=7200), now=NOW, policy=NO_DELAY)
        assert updated.status is TaskStatus.ENABLED
        assert updated.next_run_at == NOW + timedelta(seconds=7200)

    @pytest.mark.parametrize("status", [TaskStatus.ENABLED, TaskStatus.PAUSED])
    def test_non_terminal_status_is_preserved(self, status):
        updated = make_task(status=status).with_schedule(cron_spec("0 10 * * *"), now=NOW, policy=NO_DELAY)
        assert updated.status is status

    def test_running_task_cannot_be_rescheduled(self):
        task = make_task(status=TaskStatus.RUNNING)
        with pytest.raises(TaskNotMutableError):
            task.with_schedule(cron_spec("0 10 * * *"), now=NOW, policy=NO_DELAY)

    def test_invalid_once_schedule_propagates(self):
        task = make_task(schedule=once_spec(), status=TaskStatus.COMPLETED)
        with pytest.raises(InvalidScheduleError, match="must be in the future"):
            task.with_schedule(ScheduleSpec.once_at(NOW - timedelta(hours=1), "UTC"), now=NOW, policy=NO_DELAY)


# ---------------------------------------------------------------- I. with_context


class TestWithContext:
    def test_switching_to_fresh_thread_clears_the_thread(self):
        task = make_task(context_mode=ContextMode.REUSE_THREAD, thread_id="thread-1")
        updated = task.with_context(ContextMode.FRESH_THREAD_PER_RUN, "thread-1")
        assert updated.context_mode is ContextMode.FRESH_THREAD_PER_RUN
        assert updated.thread_id is None

    def test_switching_to_reuse_thread_without_a_thread_is_rejected(self):
        with pytest.raises(InvalidContextModeError, match="reuse_thread requires thread_id"):
            make_task().with_context(ContextMode.REUSE_THREAD, None)

    def test_switching_to_reuse_thread_keeps_the_thread(self):
        updated = make_task().with_context("reuse_thread", "thread-7")
        assert updated.context_mode is ContextMode.REUSE_THREAD
        assert updated.thread_id == "thread-7"

    def test_running_task_cannot_change_context(self):
        with pytest.raises(TaskNotMutableError):
            make_task(status=TaskStatus.RUNNING).with_context(ContextMode.FRESH_THREAD_PER_RUN, None)


# ---------------------------------------------------------------- J. execution thread


class TestResolveExecutionThread:
    def test_fresh_thread_mode_mints_a_new_thread_every_call(self):
        """Non-idempotent by design -- a dispatch must call this once and reuse
        the value for the run row, the launch, and the result."""
        task = make_task(context_mode=ContextMode.FRESH_THREAD_PER_RUN)
        assert task.resolve_execution_thread() != task.resolve_execution_thread()

    def test_reuse_thread_mode_returns_the_bound_thread(self):
        task = make_task(context_mode=ContextMode.REUSE_THREAD, thread_id="thread-1")
        assert task.resolve_execution_thread() == "thread-1"
        assert task.resolve_execution_thread() == "thread-1"

    def test_reuse_thread_with_an_empty_thread_falls_back_to_a_fresh_one(self):
        """Unreachable for new aggregates (__post_init__ forbids it) but rows
        predating that invariant can still carry this shape."""
        task = make_task()
        legacy = ScheduledTask.__new__(ScheduledTask)
        object.__setattr__(legacy, "context_mode", ContextMode.REUSE_THREAD)
        object.__setattr__(legacy, "thread_id", None)
        assert ScheduledTask.resolve_execution_thread(legacy) != task.thread_id


# ---------------------------------------------------------------- K. ScheduledRun


class TestScheduledRun:
    def test_queued_run_occupies_the_active_slot(self):
        run = ScheduledRun.queued(task_id="task-1", thread_id="thread-1", scheduled_for=NOW, trigger=TriggerKind.SCHEDULED)
        assert run.status is RunStatus.QUEUED
        assert run.is_active is True
        assert run.record_id.startswith("task-run-")

    def test_skipped_tombstone_is_terminal_and_never_queued(self):
        """QUEUED falls inside uq_scheduled_task_run_active's predicate and
        would collide with the pre-existing run still holding the slot."""
        run = ScheduledRun.skipped_tombstone(task_id="task-1", thread_id="thread-1", scheduled_for=NOW, trigger=TriggerKind.SCHEDULED)
        assert run.status is RunStatus.SKIPPED
        assert run.is_active is False

    def test_each_run_gets_a_distinct_identity(self):
        first = ScheduledRun.queued(task_id="task-1", thread_id="t", scheduled_for=NOW, trigger=TriggerKind.MANUAL)
        second = ScheduledRun.queued(task_id="task-1", thread_id="t", scheduled_for=NOW, trigger=TriggerKind.MANUAL)
        assert first.record_id != second.record_id

    def test_active_statuses_are_exactly_queued_and_running(self):
        assert ACTIVE_RUN_STATUSES == (RunStatus.QUEUED, RunStatus.RUNNING)