interactive-story/backend/tests/test_attempt_siblings.py

"""Phase 14 SP4: a retry writes a sibling node instead of rewriting a row.

`test_retry_variants.py` is the behavioral contract from before the tree
existed, and it still passes unchanged: the same URLs, the same payload
shape, the same outcomes. This file asserts the things that are true only of
the new storage. A turn can be several rows, exactly one of them is the
story, and the arrangement costs neither an extra prompt nor an extra turn.

    python -m pytest tests/test_attempt_siblings.py -v
"""
import pytest
from fastapi import Depends
from fastapi.testclient import TestClient
from sqlalchemy.orm import undefer

from app import attempts, auth, limits, models, tree
from app.context import cursors, history
from app.database import Base, SessionLocal, engine, get_db
from app.main import app
from app.routers import adventures

from fakes import ScriptedProvider

SCHEMA = {"player": {"hp": {"min": 0, "max": 100, "initial": 100}}}

GOLD_SCRIPT = """
const modifier = (text) => {
  state.gold = (state.gold || 0) + 10;
  return { text };
};
modifier(text);
"""


@pytest.fixture()
def client(monkeypatch):
    Base.metadata.create_all(bind=engine)
    setup = SessionLocal()
    user = models.User(is_guest=False, email="siblings@example.com")
    setup.add(user)
    setup.flush()
    setup.add(models.Settings(user_id=user.id, api_key="enc:dummy", model="test-model"))
    scenario = models.Scenario(user_id=user.id, title="S", stat_schema=SCHEMA)
    setup.add(scenario)
    setup.flush()
    adv = models.Adventure(
        user_id=user.id, title="Cave", scenario_id=scenario.id,
        script_state={}, world_state={"player": {"hp": 100}},
    )
    setup.add(adv)
    setup.flush()
    setup.add(models.Action(adventure_id=adv.id, index=0, type="start", text="You enter a cave."))
    setup.add(models.AdventureScript(
        adventure_id=adv.id, position=0, enabled=True, name="Gold", output_js=GOLD_SCRIPT,
    ))
    setup.commit()
    adv_id, user_id = adv.id, user.id
    setup.close()

    ScriptedProvider.replies = ["Attempt one."]
    ScriptedProvider.calls = 0
    ScriptedProvider.prompts = []
    monkeypatch.setattr(adventures.turns, "OpenAICompatibleProvider", ScriptedProvider)
    monkeypatch.setattr(auth, "resolve_provider_config", lambda s: auth.ProviderConfig(
        "http://fake", "k", "test-model", False))
    monkeypatch.setattr(limits, "rate_limit", lambda *a, **k: None)
    monkeypatch.setattr(limits, "check_row_cap", lambda *a, **k: None)

    def _current_user(db=Depends(get_db)):
        return db.get(models.User, user_id)

    app.dependency_overrides[auth.get_current_user] = _current_user
    c = TestClient(app)
    c.adv_id = adv_id
    try:
        yield c
    finally:
        app.dependency_overrides.clear()
        adventures.turns._active_turns.clear()
        Base.metadata.drop_all(bind=engine)


def _play(client, text="look around", type="do"):
    r = client.post(f"/api/adventures/{client.adv_id}/actions",
                    json={"type": type, "text": text})
    assert r.status_code == 200, r.text


def _retry(client):
    r = client.post(f"/api/adventures/{client.adv_id}/retry")
    assert r.status_code == 200, r.text


def _page(client) -> dict:
    return client.get(f"/api/adventures/{client.adv_id}").json()


def _rows(adv_id) -> list[models.Action]:
    """Every action row of the adventure, story or not, live or not.

    The query undefers these columns because the session closes before the
    caller reads the result. This file specifically tests the columns that a
    page load never loads.
    """
    db = SessionLocal()
    try:
        return (
            db.query(models.Action)
            .filter(models.Action.adventure_id == adv_id)
            .options(
                undefer(models.Action.state_after),
                undefer(models.Action.world_state_after),
                undefer(models.Action.context_snapshot),
            )
            .order_by(models.Action.depth, models.Action.variant_index)
            .all()
        )
    finally:
        db.close()


# ------------------------------------------------------------- the sibling

def test_a_retry_writes_a_second_row_at_the_same_coordinate(client):
    ScriptedProvider.replies = ["Attempt one.", "Attempt two."]
    _play(client)
    _retry(client)

    rows = _rows(client.adv_id)
    ai = [a for a in rows if a.type == "ai"]
    assert len(ai) == 2, "a retry is a node, not a rewrite"
    assert {(a.branch_id, a.depth) for a in ai} == {(ai[0].branch_id, ai[0].depth)}
    assert [a.text for a in ai] == ["Attempt one.", "Attempt two."]
    # Exactly one of them is the story, and it is the newer take.
    assert [a.live for a in ai] == [False, True]
    # The discarded attempt is untouched, not a copy of anything.
    assert ai[0].state_after is not None


def test_the_story_shows_and_counts_the_turn_once(client):
    ScriptedProvider.replies = ["Attempt one.", "Attempt two."]
    _play(client)
    before = _page(client)["action_count"]
    _retry(client)
    after = _page(client)

    assert after["action_count"] == before, "a discarded attempt is not a turn"
    assert [a["type"] for a in after["actions"]] == ["start", "do", "ai"]
    assert after["actions"][-1]["text"] == "Attempt two."


def test_a_discarded_attempt_never_reaches_the_prompt(client):
    """This is the failure case the branch clause exists to prevent, at
    sibling scale. The losing attempt sits at the same branch and depth as
    the live one, so anything reading the story by coordinate alone would
    replay both."""
    ScriptedProvider.replies = ["Attempt one.", "Attempt two.", "Next turn."]
    _play(client)
    _retry(client)
    _play(client, "go deeper")

    story = ScriptedProvider.prompts[-1][1]
    assert "Attempt two." in story
    assert "Attempt one." not in story


def test_switching_moves_the_story_onto_the_other_row(client):
    ScriptedProvider.replies = [
        "A scratch.\n```state\n{\"player.hp\": -5}\n```",
        "A beating.\n```state\n{\"player.hp\": -40}\n```",
    ]
    _play(client)
    _retry(client)
    newest_id = _page(client)["actions"][-1]["id"]

    r = client.post(
        f"/api/adventures/{client.adv_id}/actions/{newest_id}/variant", json={"index": 0})
    assert r.status_code == 200, r.text
    # A different row answers the request. That is the only change.
    assert r.json()["id"] != newest_id
    assert r.json()["text"].startswith("A scratch")

    rows = _rows(client.adv_id)
    ai = [a for a in rows if a.type == "ai"]
    assert [a.live for a in ai] == [True, False]
    # Both takes remain unchanged in the database.
    assert [a.text.split(".")[0] for a in ai] == ["A scratch", "A beating"]


def test_the_assembled_prompt_is_stored_once_per_turn(client):
    """A snapshot holds about 160 kB of prompt that every attempt at a turn
    shares. Giving each sibling its own copy would make retry multiply the
    size of the largest column in the database. Instead, the prompt moves
    with the live flag."""
    ScriptedProvider.replies = ["Attempt one.", "Attempt two."]
    _play(client)
    _retry(client)

    def holders():
        return [
            a.id for a in _rows(client.adv_id)
            if a.type == "ai" and "sections" in (a.context_snapshot or {})
        ]

    live_holder = holders()
    assert len(live_holder) == 1
    newest = _page(client)["actions"][-1]
    assert live_holder == [newest["id"]]

    client.post(f"/api/adventures/{client.adv_id}/actions/{newest['id']}/variant",
                json={"index": 0})
    moved = holders()
    assert len(moved) == 1 and moved != live_holder, "the prompt follows the story"


# ------------------------------------------------------- removing the turn

def test_undo_takes_every_attempt_with_it(client):
    ScriptedProvider.replies = ["One.", "Two.", "Three."]
    _play(client)
    _retry(client)
    _retry(client)
    assert len([a for a in _rows(client.adv_id) if a.type == "ai"]) == 3

    r = client.post(f"/api/adventures/{client.adv_id}/undo")
    assert r.status_code == 200, r.text
    assert [a.type for a in _rows(client.adv_id)] == ["start"]


def test_deleting_a_retried_turn_deletes_its_attempts(client):
    ScriptedProvider.replies = ["One.", "Two."]
    _play(client)
    _retry(client)
    newest = _page(client)["actions"][-1]

    r = client.delete(f"/api/adventures/{client.adv_id}/actions/{newest['id']}")
    assert r.status_code == 204, r.text
    assert [a.type for a in _rows(client.adv_id)] == ["start", "do"]


def test_deleting_a_turn_through_a_discarded_attempt_still_takes_the_turn(client):
    """The pager hands out whichever id it last saw, and a switch changes which
    row that is. Deleting through the losing sibling must not leave the story
    holding a turn with no attempts."""
    ScriptedProvider.replies = ["One.", "Two."]
    _play(client)
    _retry(client)
    discarded = [a for a in _rows(client.adv_id) if a.type == "ai" and not a.live][0]

    r = client.delete(f"/api/adventures/{client.adv_id}/actions/{discarded.id}")
    assert r.status_code == 204, r.text
    assert [a.type for a in _rows(client.adv_id)] == ["start", "do"]


# ------------------------------------------- what the holdback used to cover

def test_retrying_withdraws_the_memory_the_turn_produced(client):
    """Why summarization no longer holds the newest action back.

    A memory covering the newest turn used to be unreachable by
    construction. The summarizer stopped one action short, because a retry
    rewrote the row under a mark that had already moved past it. Now the
    mark and the memory both name the node, so replacing what a node says
    withdraws them. Undo and delete already had this repair; the holdback
    was the only gap a retry still needed to close.
    """
    ScriptedProvider.replies = ["One.", "Two."]
    _play(client)

    db = SessionLocal()
    try:
        adventure = db.get(models.Adventure, client.adv_id)
        newest = history.newest(adventure)
        memory = models.Memory(
            adventure_id=adventure.id, text="You looked around.",
            source_start=1, source_end=newest.depth,
        )
        tree.attach_memory(memory, newest)
        db.add(memory)
        cursors.MEMORY.anchor_at(adventure, newest)
        cursors.SUMMARY.anchor_at(adventure, newest)
        db.commit()
        covered_depth = newest.depth
    finally:
        db.close()

    _retry(client)

    db = SessionLocal()
    try:
        adventure = db.get(models.Adventure, client.adv_id)
        assert db.query(models.Memory).count() == 0, "the withdrawn memory is gone"
        # The depth range it covered is released, so the block is
        # summarized again from where it began instead of being skipped.
        assert cursors.MEMORY.depth(db, adventure) == 0
        assert cursors.SUMMARY.depth(db, adventure) == 0
        assert covered_depth > 0
    finally:
        db.close()


def test_a_memory_on_an_earlier_turn_survives_a_retry(client):
    """Only the coordinate whose text changed is withdrawn."""
    ScriptedProvider.replies = ["One.", "Two.", "Three."]
    _play(client)
    _play(client, "go deeper")

    db = SessionLocal()
    try:
        adventure = db.get(models.Adventure, client.adv_id)
        earlier = history.tail(adventure, 3)[0]
        memory = models.Memory(
            adventure_id=adventure.id, text="An earlier block.",
            source_start=0, source_end=earlier.depth,
        )
        tree.attach_memory(memory, earlier)
        db.add(memory)
        db.commit()
    finally:
        db.close()

    _retry(client)

    db = SessionLocal()
    try:
        assert [m.text for m in db.query(models.Memory).all()] == ["An earlier block."]
    finally:
        db.close()


# -------------------------------------------------------------- the group

def test_the_group_cache_is_renumbered_as_attempts_arrive(client):
    ScriptedProvider.replies = ["One.", "Two.", "Three."]
    _play(client)
    assert _page(client)["actions"][-1]["variant_count"] == 0  # never retried
    _retry(client)
    _retry(client)

    ai = [a for a in _rows(client.adv_id) if a.type == "ai"]
    assert [a.variant_index for a in ai] == [0, 1, 2]
    assert {a.variant_count for a in ai} == {3}


def test_attempts_module_agrees_with_the_endpoint(client):
    ScriptedProvider.replies = ["One.", "Two."]
    _play(client)
    _retry(client)
    newest = _page(client)["actions"][-1]

    listed = client.get(
        f"/api/adventures/{client.adv_id}/actions/{newest['id']}/variants").json()
    db = SessionLocal()
    try:
        node = db.get(models.Action, newest["id"])
        group = attempts.group(db, node)
        assert [a.text for a in group] == [v["text"] for v in listed]
        assert attempts.live_in(group).id == newest["id"]
    finally:
        db.close()


def test_export_carries_every_attempt_as_its_own_node(client):
    """SP6 changed the answer here, for the same reasons as the rest of that
    subphase.

    A v1 bundle had one entry per turn and folded the group back into a
    `variants` array, because the format had nowhere else to put a second
    take. A v2 bundle has coordinates, so an attempt is a node in the file
    exactly as it is a node in the database, and `live` says which one is
    the story.
    """
    ScriptedProvider.replies = ["One.", "Two."]
    _play(client)
    _retry(client)

    bundle = client.get(f"/api/adventures/{client.adv_id}/export").json()
    ai = [a for a in bundle["actions"] if a["type"] == "ai"]
    assert [(a["text"], a["live"]) for a in ai] == [("One.", False), ("Two.", True)]
    assert len({(a["branch"], a["depth"]) for a in ai}) == 1, "one turn, two takes"
    assert "variants" not in ai[0], "nothing writes the repeating group any more"

    # Importing the bundle puts the group back exactly as it stood.
    imported = client.post("/api/adventures/import", json=bundle).json()["id"]
    rows = _rows(imported)
    ai_rows = [a for a in rows if a.type == "ai"]
    assert [(a.text, a.live) for a in ai_rows] == [("One.", False), ("Two.", True)]
    assert len({(a.branch_id, a.depth) for a in ai_rows}) == 1


def test_a_retry_after_switching_back_files_the_new_attempt_last(client):
    """The group stays in the order the attempts were made.

    `add_attempt` used to number a new take one past the take it replaced.
    That numbering is correct only when the story is standing on the newest
    take. Switch a three-take turn back to the first and retry, and the new
    attempt collides with take 2. `renumber` broke the tie by id and placed
    the new attempt between takes 2 and 3, so the pager listed them in an
    order the player never produced.
    """
    ScriptedProvider.replies = ["One.", "Two.", "Three.", "Four."]
    _play(client)
    _retry(client)
    _retry(client)
    assert [a.text for a in _rows(client.adv_id) if a.type == "ai"] == [
        "One.", "Two.", "Three."]

    live = _page(client)["actions"][-1]
    r = client.post(
        f"/api/adventures/{client.adv_id}/actions/{live['id']}/variant",
        json={"index": 0})
    assert r.status_code == 200, r.text

    _retry(client)
    ai = [a for a in _rows(client.adv_id) if a.type == "ai"]
    assert [a.text for a in ai] == ["One.", "Two.", "Three.", "Four."]
    assert [a.variant_index for a in ai] == [0, 1, 2, 3]
    assert attempts.live_in(ai).text == "Four."


def test_the_adventure_list_quotes_the_take_the_story_tells(client):
    """The index screen and the story have to agree.

    Siblings share a depth, and the newest of them has the highest id. A
    snippet ordered by `(depth, id)` alone quotes whichever attempt was
    written last. After switching back, that attempt is the one the player
    discarded.
    """
    ScriptedProvider.replies = ["One.", "Two."]
    _play(client)
    _retry(client)
    live = _page(client)["actions"][-1]
    assert live["text"] == "Two."
    client.post(f"/api/adventures/{client.adv_id}/actions/{live['id']}/variant",
                json={"index": 0})

    listed = client.get("/api/adventures").json()
    row = [a for a in listed if a["id"] == client.adv_id][0]
    assert "One." in row["snippet"]
    assert "Two." not in row["snippet"]