"""#4402 / #4401: a teaser's card shows what it points at — by reference.

Operator, 2026-09-24: *"the teaser from the patreon post doesn't show the items
that it's supposed to reference"*, and on how: *"discord 'posts' land as normal
and only hidden from the post view they're posted the same day. the nested
items on the unified post are a duplicate or reference of existing content."*

Two properties carry the whole design, and most of what follows pins them:

* NOTHING MOVES. A referenced Discord post keeps its row, its date and its
  place in the feed; only a drop sitting beside its own teaser is left out.
* A family is the creator's LEADING working name, one hop from the seed, inside
  a window. The refusals are the measured false positives, not invented ones.
"""
from collections import Counter
from datetime import UTC, datetime, timedelta

import pytest
from sqlalchemy import select

from backend.app.models import (
    Artist,
    ImageRecord,
    ImportSettings,
    Post,
    PostAssociation,
    Source,
)
from backend.app.services.discord_grouping import DROP_GROUPER
from backend.app.services.post_association_service import PostAssociationService
from backend.app.services.post_feed_service import PostFeedService
from backend.app.services.post_unification import (
    FAMILY_MAX_POSTS,
    Candidate,
    family,
)

T0 = datetime(2026, 9, 1, 12, 0, tzinfo=UTC)
WINDOW = timedelta(days=60)


def _c(image_id, name, *, days=0, post_id=None, phash=None):
    """One image, Discord-shaped, `days` from T0."""
    return Candidate(
        image_id=image_id,
        post_id=post_id if post_id is not None else image_id,
        path=f"20260901_12345678901234{image_id:04d}_01_{name}.png",
        phash=phash,
        at=T0 + timedelta(days=days),
    )


def _family(seed, pool, *, names=None, hashes=None):
    return family(
        seed, pool, Counter(names or {}), Counter(hashes or {}),
        anchor=T0, window=WINDOW,
    )


# --- the family rule, pure ---------------------------------------------------


def test_the_older_wips_of_the_same_piece_are_its_family():
    """The operator's ask exactly: *"yellowroom trickles out variants and I want
    them to show in the grouped post even if they're older"*. Measured shape:
    `Year_20k_wip1 -> wip3 -> Base -> Cndm` over 44 days."""
    seed = [_c(1, "Year_20k_Cndm")]
    pool = [_c(2, "Year_20k_wip1", days=-44), _c(3, "Year_20K_wip3", days=-44),
            _c(4, "Year_20k_Base", days=-20)]

    assert [c.image_id for c in _family(seed, pool)] == [2, 3, 4]


def test_a_family_reads_oldest_first():
    """So the card shows the trickle in the order it happened."""
    seed = [_c(1, "svtt_drench_b")]
    pool = [_c(2, "svtt_wip5", days=-1), _c(3, "svtt_wip1", days=-3)]

    assert [c.image_id for c in _family(seed, pool)] == [3, 2]


def test_a_namesake_outside_the_window_is_not_family():
    """Time does most of the work. Measured on artist 8: every collision found
    spreads over 500 days — `ashley` 1258, `anya` 1217, `image0` 1974."""
    seed = [_c(1, "Ashley_TAIGA")]
    pool = [_c(2, "Ashley_Re4_A", days=-1258)]

    assert _family(seed, pool) == []


def test_a_shared_trailing_word_is_not_family():
    """The one plain collision inside 60 days on artist 8: `bottom`, three
    posts, 56 days apart. No frequency cap can refuse a word that rare — the
    leading-name rule does."""
    seed = [_c(1, "Undyne_insert_bottom_only-C")]
    pool = [_c(2, "Lichgalclc_Lingerie_Bottom_21", days=-56)]

    assert _family(seed, pool) == []


def test_a_leading_name_the_creator_uses_everywhere_is_not_a_family():
    """A character is a habit, not a piece. At the cap the name is gated even
    inside the window."""
    seed = [_c(1, "Bea_Machamp_Shiny")]
    pool = [_c(2, "Bea_Machoke_Shiny", days=-5)]

    assert _family(seed, pool, names={"bea": FAMILY_MAX_POSTS}) == []


def test_the_family_cap_admits_the_measured_long_families():
    """`tentacooler` spans 6 posts over 7 days and `0-k1` 6 over 10 — real
    families, both lost at the pairing cap of 6. That is why the family cap is
    its own number."""
    seed = [_c(1, "Tentacooler")]
    pool = [_c(2, "Tentacooler_c_ins", days=-7)]

    assert [c.image_id for c in _family(seed, pool, names={"tentacooler": 6})] == [2]


def test_a_near_duplicate_joins_the_family_without_a_name():
    """Half of this creator's teasers are screenshots, which carry no name. The
    same file re-posted is still the same file."""
    seed = [_c(1, "image0", phash=0b1011)]
    pool = [_c(2, "image0", days=-10, phash=0b1010)]

    assert [c.image_id for c in _family(seed, pool)] == [2]


def test_a_distant_hash_is_not_a_duplicate():
    """Lesson #4400: same-artist images are similar whether or not they are the
    same piece, so only a NEAR-duplicate counts — the matcher's own line."""
    seed = [_c(1, "image0", phash=0)]
    pool = [_c(2, "image0", days=-10, phash=(1 << 100) - 1)]

    assert _family(seed, pool) == []


def test_a_family_is_one_hop_from_the_seed():
    """Chaining is what lets a family drift: `alpha` reaches an image that also
    carries `beta`, and `beta` must not then reach its own family."""
    seed = [_c(1, "alpha_final")]
    pool = [_c(2, "alpha_beta", days=-3), _c(3, "beta_wip1", days=-4)]

    assert [c.image_id for c in _family(seed, pool)] == [2]


def test_the_seed_never_comes_back_as_its_own_family():
    seed = [_c(1, "Year_20k_Cndm")]

    assert _family(seed, seed + [_c(2, "Year_20k_Base", days=-20)])[0].image_id == 2
    assert len(_family(seed, seed)) == 0


# --- the card, end to end ----------------------------------------------------


async def _channels(db, name):
    artist = Artist(name=name, slug=name)
    db.add(artist)
    await db.flush()
    patreon = Source(artist_id=artist.id, platform="patreon",
                     url=f"https://patreon.com/{name}", enabled=True)
    discord = Source(artist_id=artist.id, platform="discord",
                     url=f"https://discord.com/channels/1/{name}", enabled=True)
    db.add_all([patreon, discord])
    await db.flush()
    return artist, patreon, discord


_seq = iter(range(1, 10_000))


async def _post(db, artist, source, *, at, names, body=None, title=None, synthetic=False):
    post = Post(
        source_id=source.id, artist_id=artist.id,
        external_post_id=f"ext-{next(_seq)}", post_date=at,
        post_title=title, description=body,
        synthesized_by=DROP_GROUPER if synthetic else None,
    )
    db.add(post)
    await db.flush()
    for name in names:
        n = next(_seq)
        db.add(ImageRecord(
            # Discord-shaped whatever the platform: the prefix is stripped, so
            # the NAME below is the leading name.
            path=f"/images/{artist.slug}/20260901_1234567890{n:06d}_01_{name}.png",
            sha256=f"{n:064d}", size_bytes=10, mime="image/png",
            width=10, height=10, origin="downloaded",
            primary_post_id=post.id, artist_id=artist.id,
        ))
    await db.flush()
    return post


async def _link(db, teaser, drop, *, status="linked", linked_by="fc"):
    a = PostAssociation(
        announcement_post_id=teaser.id, payload_post_id=drop.id, score=1.0,
        signals={"identity": 1.0, "identity_token": "year"},
        status=status, linked_by=linked_by if status == "linked" else None,
    )
    db.add(a)
    await db.flush()
    return a


async def _feed(db, artist):
    page = await PostFeedService(db).scroll(artist_id=artist.id, limit=100)
    return {item["id"]: item for item in page["items"]}


@pytest.mark.integration
@pytest.mark.asyncio
async def test_a_teaser_shows_the_drop_it_announced(db):
    """The complaint itself: the card now carries the drop's images and text."""
    artist, patreon, discord = await _channels(db, "unifyartist")
    teaser = await _post(db, artist, patreon, at=T0, names=["Year_20k_teaser"],
                         title="Year 20k", body="Full set in the server")
    drop = await _post(db, artist, discord, at=T0 - timedelta(hours=1),
                       names=["Year_20k_Cndm", "Year_20k_Cndm_alt"],
                       body="@everyone 🍈🍈 the full set", synthetic=True)
    assoc = await _link(db, teaser, drop)
    await db.commit()

    unified = (await _feed(db, artist))[teaser.id]["unified"]

    assert [t["role"] for t in unified["thumbnails"]] == ["drop", "drop"]
    assert {t["post_id"] for t in unified["thumbnails"]} == {drop.id}
    assert unified["links"] == [{
        "association_id": assoc.id, "post_id": drop.id,
        "linked_by": "fc", "token": "year",
    }]
    assert unified["texts"][0]["text"] == "@everyone 🍈🍈 the full set"


@pytest.mark.integration
@pytest.mark.asyncio
async def test_a_drop_beside_its_teaser_leaves_the_feed(db):
    """*"only hidden from the post view they're posted the same day"*."""
    artist, patreon, discord = await _channels(db, "foldartist")
    teaser = await _post(db, artist, patreon, at=T0, names=["Year_20k_teaser"])
    drop = await _post(db, artist, discord, at=T0 - timedelta(hours=2),
                       names=["Year_20k_Cndm"], synthetic=True)
    await _link(db, teaser, drop)
    await db.commit()

    feed = await _feed(db, artist)

    assert teaser.id in feed
    assert drop.id not in feed
    # Left out of the FEED, not out of existence: reachable by id, as every
    # post is, because it is still the images' true origin.
    assert (await PostFeedService(db).get_post(drop.id))["id"] == drop.id


@pytest.mark.integration
@pytest.mark.asyncio
async def test_a_drop_days_from_its_teaser_keeps_its_place(db):
    """A reference does not take anything out of history."""
    artist, patreon, discord = await _channels(db, "keepartist")
    teaser = await _post(db, artist, patreon, at=T0, names=["Year_20k_teaser"])
    drop = await _post(db, artist, discord, at=T0 - timedelta(days=3),
                       names=["Year_20k_Cndm"], synthetic=True)
    await _link(db, teaser, drop)
    await db.commit()

    feed = await _feed(db, artist)

    assert drop.id in feed
    assert feed[teaser.id]["unified"]["thumbnails"][0]["post_id"] == drop.id


@pytest.mark.integration
@pytest.mark.asyncio
async def test_a_proposal_changes_nothing_on_the_card(db):
    """Only a LINKED pair unifies. A pending proposal is a question for the
    review queue, and rendering it would assert a link nobody made."""
    artist, patreon, discord = await _channels(db, "pendingartist")
    teaser = await _post(db, artist, patreon, at=T0, names=["Year_20k_teaser"])
    drop = await _post(db, artist, discord, at=T0 - timedelta(hours=1),
                       names=["Year_20k_Cndm"], synthetic=True)
    await _link(db, teaser, drop, status="pending")
    await db.commit()

    feed = await _feed(db, artist)

    assert feed[teaser.id]["unified"] is None
    assert drop.id in feed


@pytest.mark.integration
@pytest.mark.asyncio
async def test_the_older_variants_come_along_and_nothing_else(db):
    """The family reaches back 44 days for the wips — and not 90 days for a
    namesake, and not at all for a message that only shares a trailing word."""
    artist, patreon, discord = await _channels(db, "familyartist")
    teaser = await _post(db, artist, patreon, at=T0, names=["Year_20k_teaser"])
    drop = await _post(db, artist, discord, at=T0 - timedelta(hours=1),
                       names=["Year_20k_Cndm"], synthetic=True)
    wip = await _post(db, artist, discord, at=T0 - timedelta(days=44),
                      names=["Year_20k_wip1"], body="wip, feedback welcome")
    base = await _post(db, artist, discord, at=T0 - timedelta(days=20),
                       names=["Year_20K_Base"])
    too_old = await _post(db, artist, discord, at=T0 - timedelta(days=90),
                          names=["Year_20k_old"])
    trailing = await _post(db, artist, discord, at=T0 - timedelta(days=5),
                           names=["Other_piece_year"])
    await _link(db, teaser, drop)
    await db.commit()

    feed = await _feed(db, artist)
    unified = feed[teaser.id]["unified"]
    variants = [t["post_id"] for t in unified["thumbnails"] if t["role"] == "variant"]

    assert variants == [wip.id, base.id]
    assert unified["variant_count"] == 2
    assert too_old.id not in variants and trailing.id not in variants
    assert "wip, feedback welcome" in [t["text"] for t in unified["texts"]]
    # Referenced, not moved: every variant is still in the feed on its own.
    assert {wip.id, base.id} <= set(feed)


@pytest.mark.integration
@pytest.mark.asyncio
async def test_the_family_window_is_the_operators_setting(db):
    artist, patreon, discord = await _channels(db, "windowartist")
    teaser = await _post(db, artist, patreon, at=T0, names=["Year_20k_teaser"])
    drop = await _post(db, artist, discord, at=T0 - timedelta(hours=1),
                       names=["Year_20k_Cndm"], synthetic=True)
    await _post(db, artist, discord, at=T0 - timedelta(days=20), names=["Year_20k_wip1"])
    await _link(db, teaser, drop)
    settings = await db.get(ImportSettings, 1)
    settings.discord_family_window_days = 10
    await db.commit()

    unified = (await _feed(db, artist))[teaser.id]["unified"]

    assert unified["variant_count"] == 0


@pytest.mark.integration
@pytest.mark.asyncio
async def test_undo_is_a_dismissal_and_everything_returns(db):
    """The operator chose *"nest automatically, with visible undo"*. The undo
    is the review queue's own dismiss: the drop comes back to the feed, the
    card loses its references, and the dismissed row is what stops the next
    sweep linking the pair straight back."""
    artist, patreon, discord = await _channels(db, "undoartist")
    teaser = await _post(db, artist, patreon, at=T0, names=["Year_20k_teaser"])
    drop = await _post(db, artist, discord, at=T0 - timedelta(hours=1),
                       names=["Year_20k_Cndm"], synthetic=True)
    assoc = await _link(db, teaser, drop)
    await db.commit()

    await PostAssociationService(db).dismiss(assoc.id)
    await db.commit()
    feed = await _feed(db, artist)

    assert feed[teaser.id]["unified"] is None
    assert drop.id in feed
    row = (await db.execute(select(PostAssociation))).scalar_one()
    assert (row.status, row.linked_by) == ("dismissed", None)


@pytest.mark.integration
@pytest.mark.asyncio
async def test_an_operator_accept_is_recorded_as_theirs(db):
    """So the card does not claim FC made a link a person made."""
    artist, patreon, discord = await _channels(db, "acceptartist")
    teaser = await _post(db, artist, patreon, at=T0, names=["Year_20k_teaser"])
    drop = await _post(db, artist, discord, at=T0 - timedelta(hours=1),
                       names=["Year_20k_Cndm"], synthetic=True)
    assoc = await _link(db, teaser, drop, status="pending")
    await db.commit()

    await PostAssociationService(db).accept(assoc.id)
    await db.commit()

    unified = (await _feed(db, artist))[teaser.id]["unified"]
    assert unified["links"][0]["linked_by"] == "operator"


@pytest.mark.integration
@pytest.mark.asyncio
async def test_a_fold_window_of_zero_hides_nothing(db):
    artist, patreon, discord = await _channels(db, "nofoldartist")
    teaser = await _post(db, artist, patreon, at=T0, names=["Year_20k_teaser"])
    drop = await _post(db, artist, discord, at=T0 - timedelta(hours=1),
                       names=["Year_20k_Cndm"], synthetic=True)
    await _link(db, teaser, drop)
    settings = await db.get(ImportSettings, 1)
    settings.discord_link_fold_hours = 0
    await db.commit()

    assert drop.id in await _feed(db, artist)