"""P1 exit-criteria simulation tests (design §7.1 P1, demonstrating §3.3.1).

Phase P1 may begin only once the durable human-in-the-loop suspend/resume
mechanic is *demonstrated*. §7.1 P1 lists four exit criteria; this module is
the executable demonstration of each, driving the committed foundation
(:mod:`agent_team.db.schema` compare-and-set helpers + the atomic,
integrity-checked :mod:`agent_team.state_store`) through the
:mod:`harness.SimPipeline`:

* (a) kill the box mid-wait and have the task resume after restart;
* (b) submit a duplicate answer and confirm it no-ops;
* (c) submit an answer after the deadline expired and confirm it is rejected
  and the task parked;
* (d) two tasks suspended concurrently resume independently to the correct
  thread.

Each criterion has its own test (and a couple of supporting tests for the
delivery/recovery edges §3.3.1 calls out). The tests assert on the *durable*
state — the ledger row status and the integrity-checked task record — so they
verify the real mechanic, not a harness convenience.
"""

from __future__ import annotations

import json
import threading

import pytest

from harness import (
    PostFailingTransport,
    RecordingTransport,
    SimClock,
    SimPipeline,
)

from agent_team.state_store import IntegrityError
from agent_team.task_model import Phase, TaskStatus


# ---------------------------------------------------------------------------
# Baseline: a single happy-path suspend/resume cycle.
# ---------------------------------------------------------------------------


def test_submit_suspends_task_with_open_ledger_row(
    pipeline: SimPipeline, transport: RecordingTransport
) -> None:
    suspended = pipeline.submit(questions=["which repo?"], deadline_in=100)

    record = pipeline.load_record(suspended.thread_id)
    assert record.status is TaskStatus.WAITING_HUMAN
    assert record.current_phase is Phase.CLARIFY

    row = pipeline.ledger_row(suspended.question_id)
    assert row is not None
    assert row["status"] == "open"
    assert row["thread_id"] == suspended.thread_id
    # Delivery happened: a channel_ref was stored and it embeds the question id.
    assert row["channel_ref"] == f"sim:{suspended.question_id}"
    assert (
        transport.posts and transport.posts[0]["question_id"] == suspended.question_id
    )


def test_first_answer_wins_and_resumes_to_plan(pipeline: SimPipeline) -> None:
    suspended = pipeline.submit(questions=["which repo?"], deadline_in=100)

    won = pipeline.submit_answer(
        {"question_id": suspended.question_id, "answer": "core-api", "via": "slack:U1"}
    )
    assert won is True

    outcome = pipeline.resume(suspended.thread_id, suspended.question_id)
    assert outcome.resumed is True
    assert outcome.new_phase is Phase.PLAN

    record = pipeline.load_record(suspended.thread_id)
    assert record.status is TaskStatus.ACTIVE
    assert record.current_phase is Phase.PLAN
    # The won answer was durably folded into the Q&A history.
    assert record.qa_history == [
        {"question_id": suspended.question_id, "turn": 0, "answer": "core-api"}
    ]
    assert pipeline.ledger_row(suspended.question_id)["status"] == "answered"


# ---------------------------------------------------------------------------
# (a) kill the box mid-wait and have the task resume after restart.
# ---------------------------------------------------------------------------


def test_a_restart_mid_wait_then_answer_and_resume(
    pipeline: SimPipeline, transport: RecordingTransport
) -> None:
    suspended = pipeline.submit(questions=["which repo?"], deadline_in=100)

    # "Kill the box": drop the in-memory pipeline; rebuild purely from disk.
    reopened = pipeline.reopen()

    # Durable state survived: ledger row still open, record still WAITING_HUMAN.
    row = reopened.ledger_row(suspended.question_id)
    assert row is not None and row["status"] == "open"
    record = reopened.load_record(suspended.thread_id)
    assert record.status is TaskStatus.WAITING_HUMAN

    # The human answers after the restart; the task converges via the sweep.
    assert reopened.submit_answer(
        {"question_id": suspended.question_id, "answer": "core-api", "via": "slack:U1"}
    )
    summary = reopened.startup_sweep(
        questions_by_qid={suspended.question_id: ["which repo?"]}
    )
    assert summary["resumed"] == [suspended.thread_id]

    resumed_record = reopened.load_record(suspended.thread_id)
    assert resumed_record.status is TaskStatus.ACTIVE
    assert resumed_record.current_phase is Phase.PLAN


def test_a_restart_after_answer_recovers_via_startup_sweep(
    pipeline: SimPipeline,
) -> None:
    """An answer that won *before* the crash must still resume on restart."""
    suspended = pipeline.submit(questions=["which repo?"], deadline_in=100)
    assert pipeline.submit_answer(
        {"question_id": suspended.question_id, "answer": "core-api", "via": "slack:U1"}
    )

    # Crash before the resume worker ran; recover from disk only.
    reopened = pipeline.reopen()
    # Pre-sweep the record is still suspended (resume never ran).
    assert reopened.load_record(suspended.thread_id).status is TaskStatus.WAITING_HUMAN

    summary = reopened.startup_sweep(
        questions_by_qid={suspended.question_id: ["which repo?"]}
    )
    assert summary["resumed"] == [suspended.thread_id]
    assert reopened.load_record(suspended.thread_id).current_phase is Phase.PLAN


# ---------------------------------------------------------------------------
# (b) submit a duplicate answer and confirm it no-ops.
# ---------------------------------------------------------------------------


def test_b_duplicate_answer_no_ops(pipeline: SimPipeline) -> None:
    suspended = pipeline.submit(questions=["which repo?"], deadline_in=100)
    raw = {
        "question_id": suspended.question_id,
        "answer": "core-api",
        "via": "slack:U1",
    }

    first = pipeline.submit_answer(raw)
    second = pipeline.submit_answer(raw)  # exact redelivery / double click
    third = pipeline.submit_answer(
        {
            "question_id": suspended.question_id,
            "answer": "other-repo",
            "via": "github:U2",
        }
    )  # a different answer via a second channel

    assert first is True
    assert second is False
    assert third is False

    # The ledger preserved the *first* answer; later ones never overwrote it.
    row = pipeline.ledger_row(suspended.question_id)
    assert row["status"] == "answered"
    assert json.loads(row["answer_json"]) == "core-api"
    assert row["answered_via"] == "slack:U1"


def test_b_resume_is_single_apply_under_redelivered_resume(
    pipeline: SimPipeline,
) -> None:
    """Even if the resume worker is invoked twice, it applies exactly once."""
    suspended = pipeline.submit(questions=["which repo?"], deadline_in=100)
    assert pipeline.submit_answer(
        {"question_id": suspended.question_id, "answer": "core-api", "via": "slack:U1"}
    )

    first = pipeline.resume(suspended.thread_id, suspended.question_id)
    second = pipeline.resume(suspended.thread_id, suspended.question_id)

    assert first.resumed is True
    assert second.resumed is False
    assert second.superseded is True  # turn guard caught the stale resume

    # The phase advanced exactly one step; the Q&A history has one entry.
    record = pipeline.load_record(suspended.thread_id)
    assert record.current_phase is Phase.PLAN
    assert len(record.qa_history) == 1
    assert pipeline.ledger_row(suspended.question_id)["status"] == "superseded"


# ---------------------------------------------------------------------------
# (c) answer after the deadline -> rejected, task parked.
# ---------------------------------------------------------------------------


def test_c_late_answer_rejected_and_task_parked(
    pipeline: SimPipeline, clock: SimClock
) -> None:
    suspended = pipeline.submit(questions=["which repo?"], deadline_in=50)

    # Time passes beyond the deadline; the timer loop expires + parks.
    clock.advance(51)
    expired = pipeline.run_deadline_sweep()
    assert expired == [suspended.question_id]

    parked = pipeline.load_record(suspended.thread_id)
    assert parked.status is TaskStatus.PARKED
    assert parked.current_phase is Phase.PARKED

    # A late answer loses the compare-and-set against the now-expired row.
    won = pipeline.submit_answer(
        {"question_id": suspended.question_id, "answer": "core-api", "via": "slack:U1"}
    )
    assert won is False
    row = pipeline.ledger_row(suspended.question_id)
    assert row["status"] == "expired"
    assert row["answer_json"] is None

    # A resume attempt on the expired question does nothing.
    outcome = pipeline.resume(suspended.thread_id, suspended.question_id)
    assert outcome.resumed is False


def test_c_deadline_vs_answer_race_answer_first_wins(
    pipeline: SimPipeline, clock: SimClock
) -> None:
    """If the answer lands before the sweep, the sweep must not expire it."""
    suspended = pipeline.submit(questions=["which repo?"], deadline_in=50)
    assert pipeline.submit_answer(
        {"question_id": suspended.question_id, "answer": "core-api", "via": "slack:U1"}
    )

    clock.advance(99)  # well past the deadline
    expired = pipeline.run_deadline_sweep()
    # The question is already 'answered', so the sweep finds nothing to expire.
    assert expired == []
    assert pipeline.ledger_row(suspended.question_id)["status"] == "answered"

    outcome = pipeline.resume(suspended.thread_id, suspended.question_id)
    assert outcome.resumed is True


# ---------------------------------------------------------------------------
# (d) two tasks suspended concurrently resume independently to the correct thread.
# ---------------------------------------------------------------------------


def test_d_two_concurrent_tasks_resume_to_correct_thread(
    pipeline: SimPipeline,
) -> None:
    first = pipeline.submit(questions=["repo for A?"], deadline_in=100)
    second = pipeline.submit(questions=["repo for B?"], deadline_in=100)

    assert first.thread_id != second.thread_id
    assert first.question_id != second.question_id

    # Answer the second task first, with a distinct answer.
    assert pipeline.submit_answer(
        {"question_id": second.question_id, "answer": "repo-B", "via": "slack:U2"}
    )
    assert pipeline.submit_answer(
        {"question_id": first.question_id, "answer": "repo-A", "via": "slack:U1"}
    )

    out_a = pipeline.resume(first.thread_id, first.question_id)
    out_b = pipeline.resume(second.thread_id, second.question_id)
    assert out_a.resumed and out_b.resumed

    rec_a = pipeline.load_record(first.thread_id)
    rec_b = pipeline.load_record(second.thread_id)

    # Each thread carries *its own* answer — no cross-contamination.
    assert rec_a.qa_history[0]["answer"] == "repo-A"
    assert rec_b.qa_history[0]["answer"] == "repo-B"
    assert rec_a.current_phase is Phase.PLAN
    assert rec_b.current_phase is Phase.PLAN


def test_d_concurrent_responders_only_one_wins_per_question(
    pipeline: SimPipeline,
) -> None:
    """Two threads racing the same question: exactly one compare-and-set wins.

    Exercises the §3.3.1 ``BEGIN IMMEDIATE`` serialization in the committed
    ``answer_question`` helper under real OS threads against one SQLite file.
    """
    suspended = pipeline.submit(questions=["which repo?"], deadline_in=100)

    barrier = threading.Barrier(2)
    results: list[bool] = []
    errors: list[BaseException] = []
    lock = threading.Lock()

    def race(via: str) -> None:
        barrier.wait()
        try:
            won = pipeline.submit_answer(
                {"question_id": suspended.question_id, "answer": via, "via": via}
            )
        except BaseException as exc:  # noqa: BLE001 - record, must be empty
            with lock:
                errors.append(exc)
            return
        with lock:
            results.append(won)

    threads = [threading.Thread(target=race, args=(f"slack:U{i}",)) for i in range(2)]
    for thread in threads:
        thread.start()
    for thread in threads:
        thread.join()

    # No lock error is tolerated: the committed BEGIN IMMEDIATE + busy_timeout
    # must *serialize* the responders, so the single winner is the compare-and
    # -set, not a swallowed OperationalError loser (the bug the prior version
    # masked).
    assert errors == [], f"compare-and-set raised under contention: {errors!r}"
    assert sum(1 for r in results if r) == 1  # exactly one winner
    assert results.count(False) == 1  # the other genuinely lost the CAS (rowcount 0)
    assert pipeline.ledger_row(suspended.question_id)["status"] == "answered"


def test_d_concurrent_tasks_survive_restart_independently(
    pipeline: SimPipeline,
) -> None:
    """Two suspended tasks + a crash: each converges to its own thread."""
    first = pipeline.submit(questions=["repo for A?"], deadline_in=100)
    second = pipeline.submit(questions=["repo for B?"], deadline_in=100)
    assert pipeline.submit_answer(
        {"question_id": first.question_id, "answer": "repo-A", "via": "slack:U1"}
    )

    reopened = pipeline.reopen()
    summary = reopened.startup_sweep(
        questions_by_qid={
            first.question_id: ["repo for A?"],
            second.question_id: ["repo for B?"],
        }
    )
    # Only the answered task resumes; the still-open one stays suspended.
    assert summary["resumed"] == [first.thread_id]
    assert reopened.load_record(first.thread_id).current_phase is Phase.PLAN
    assert reopened.load_record(second.thread_id).status is TaskStatus.WAITING_HUMAN


# ---------------------------------------------------------------------------
# Supporting §3.3.1 edges: lost-post delivery + durable integrity.
# ---------------------------------------------------------------------------


def test_lost_post_leaves_open_row_then_reconcile_redelivers(
    tmp_path_factory: pytest.TempPathFactory,
    clock: SimClock,
    post_failing_transport: PostFailingTransport,
) -> None:
    pipeline = SimPipeline(
        tmp_path_factory.mktemp("lostpost") / "state",
        clock=clock,
        transport=post_failing_transport,
    )
    suspended = pipeline.submit(questions=["which repo?"], deadline_in=100)

    # The post failed: the row is open with no channel_ref (no in-flight loss).
    row = pipeline.ledger_row(suspended.question_id)
    assert row["status"] == "open"
    assert row["channel_ref"] is None
    assert post_failing_transport.posts == []

    # Reconcile retries idempotently; the second attempt succeeds.
    redelivered = pipeline.reconcile(
        questions_by_qid={suspended.question_id: ["which repo?"]}
    )
    assert redelivered == 1
    row = pipeline.ledger_row(suspended.question_id)
    assert row["channel_ref"] == f"sim:{suspended.question_id}"


def test_durable_checkpoint_is_integrity_checked(
    pipeline: SimPipeline,
) -> None:
    """Corrupting the durable checkpoint must fail closed, not return junk."""
    suspended = pipeline.submit(questions=["which repo?"], deadline_in=100)
    checkpoint = pipeline._checkpoint_path(suspended.thread_id)  # noqa: SLF001

    # Tamper with the payload after the integrity sidecar was written.
    checkpoint.write_bytes(checkpoint.read_bytes() + b"tampered")

    with pytest.raises(IntegrityError):
        pipeline.load_record(suspended.thread_id)