"""PatreonClient.iter_memberships — parsing only, no network (#387 C2).

The fixture is derived from a REAL capture of the operator's session (Scribe
note #3886) with every piece of account data replaced. It is small on purpose
and each member in it earns its place by covering something the parser has to
survive: a former patron with a null pledge, an active patron with no tier, an
annual cadence, a previous pledge whose included resource has no
`relationships` key at all, and a reward priced in a currency that is not the
patron's.

`_request` is stubbed rather than mocked at the socket: these tests are about
what the client does with a payload, and the HTTP path is already covered by
test_patreon_client.py.
"""

import json
from pathlib import Path

import pytest

from backend.app.services.patreon_client import (
    Membership,
    PatreonClient,
    PatreonDriftError,
)

_FIXTURE = Path(__file__).parent / "fixtures" / "patreon_members_page1.json"


@pytest.fixture
def payload():
    return json.loads(_FIXTURE.read_text())


@pytest.fixture
def client():
    return PatreonClient(cookies_path=None)


def _serve(client, *pages):
    """Stub the shared request path to hand back canned pages in order."""
    calls = []

    def fake(url, params, *, what, scope):
        calls.append((url, dict(params), what))
        return pages[min(len(calls) - 1, len(pages) - 1)]

    client._request = fake
    return calls


# --- the request we send ---------------------------------------------------


def test_we_never_ask_for_the_card_or_address(client, payload):
    """THE privacy guard, and the reason it is first.

    The browser's own include set pulls `latest_pledge.card`, and those card
    resources come back carrying the ACCOUNT HOLDER'S EMAIL in `merchant_name`
    (note #3886). Copying the browser's query string wholesale is the obvious
    move and would have FC fetching payment PII it has no use for. This asserts
    on the params actually sent, so it fails if anyone widens the include set
    back toward the browser's.
    """
    calls = _serve(client, payload)
    list(client.iter_memberships(user_id="1"))
    _url, params, _what = calls[0]
    include = params["include"]
    assert include == "campaign,reward"
    for forbidden in ("card", "address", "payment_method", "latest_pledge"):
        assert forbidden not in include
    assert not any(k.startswith("fields[card") for k in params)


def test_we_do_not_send_the_membership_type_filter(client, payload):
    """The browser filters to the six buckets its settings page shows, which
    excludes lapsed memberships. A DISAPPEARANCE is the signal the roster
    exists to read, so filtering here would manufacture exactly the event C4
    acts on."""
    calls = _serve(client, payload)
    list(client.iter_memberships(user_id="1"))
    assert "filter[membership_type]" not in calls[0][1]


def test_the_user_filter_is_sent_when_given_and_omitted_when_not(client, payload):
    calls = _serve(client, payload)
    list(client.iter_memberships(user_id="248453"))
    assert calls[0][1]["filter[user_id]"] == "248453"

    calls2 = _serve(client, payload)
    list(client.iter_memberships())
    assert "filter[user_id]" not in calls2[0][1]


# --- what we parse out of it ----------------------------------------------


def test_every_member_becomes_a_membership(client, payload):
    client._request = lambda *a, **k: payload
    rows = list(client.iter_memberships(user_id="1"))
    assert len(rows) == len(payload["data"])
    assert all(isinstance(r, Membership) for r in rows)
    # Campaign identity is the join key to Source; it must always be there.
    assert all(r.campaign_id for r in rows)


def test_status_is_the_platforms_own_word_unmapped(client, payload):
    client._request = lambda *a, **k: payload
    rows = list(client.iter_memberships(user_id="1"))
    statuses = {r.status for r in rows}
    assert "active_patron" in statuses
    assert "former_patron" in statuses
    # Nothing normalised, nothing invented.
    assert statuses <= {"active_patron", "former_patron"}


def test_a_former_patron_carries_a_null_amount_and_the_free_flag(client, payload):
    client._request = lambda *a, **k: payload
    former = next(r for r in list(client.iter_memberships(user_id="1"))
                  if r.status == "former_patron")
    assert former.amount_cents is None
    assert former.is_free_member is True


def test_an_active_patron_with_no_tier_is_not_an_error(client, payload):
    """`reward.data` is legitimately null. Absence is a fact about the
    membership, not a parse failure."""
    client._request = lambda *a, **k: payload
    rows = list(client.iter_memberships(user_id="1"))
    untiered = [r for r in rows if not r.tier_names]
    assert untiered, "fixture should contain a member with no reward"
    assert all(r.status for r in untiered)


def test_the_amount_comes_from_the_member_not_the_reward(client, payload):
    """The capture has rewards priced in CAD/DKK/EUR sitting on USD pledges.
    Reading `reward.amount_cents` would report a number the operator has never
    been charged, in a currency they do not pay in."""
    client._request = lambda *a, **k: payload
    rows = list(client.iter_memberships(user_id="1"))
    by_campaign = {r.campaign_id: r for r in rows}

    rewards = {r["id"]: r["attributes"] for r in payload["included"]
               if r["type"] == "reward"}
    for member in payload["data"]:
        rel = (member["relationships"].get("reward") or {}).get("data")
        if not rel:
            continue
        reward = rewards[rel["id"]]
        if reward.get("currency") in (None, "USD"):
            continue
        # Skip the null-amount member: `None != 0` would pass without
        # demonstrating anything. The case worth pinning is a REAL charge
        # sitting beside a reward priced in another currency.
        if member["attributes"]["pledge_amount_cents"] is None:
            continue
        got = by_campaign[member["relationships"]["campaign"]["data"]["id"]]
        assert got.amount_cents == member["attributes"]["pledge_amount_cents"]
        assert got.amount_cents != reward["amount_cents"]
        assert got.currency == member["attributes"]["currency"]
        break
    else:
        pytest.fail("fixture should contain a non-USD reward")


def test_details_carry_the_raw_attributes_but_not_the_whole_page(client, payload):
    """`details` exists so a later question needs no second authenticated
    round-trip — but scoped to the member and its campaign, never the raw page,
    because that is where the card and address resources live."""
    client._request = lambda *a, **k: payload
    row = next(iter(client.iter_memberships(user_id="1")))
    assert set(row.details) == {"member", "campaign"}
    assert "patron_status" in row.details["member"]
    assert json.dumps(row.details).count("@") == 0


# --- pagination ------------------------------------------------------------


def test_pagination_walks_offsets_until_the_total_is_reached(client, payload):
    half = len(payload["data"]) // 2
    page1 = {**payload, "data": payload["data"][:half],
             "meta": {"pagination": {"total": len(payload["data"])}}}
    page2 = {**payload, "data": payload["data"][half:],
             "meta": {"pagination": {"total": len(payload["data"])}}}
    calls = []

    def fake(url, params, *, what, scope):
        calls.append(dict(params))
        return page1 if len(calls) == 1 else page2

    client._request = fake
    rows = list(client.iter_memberships(user_id="1"))
    assert len(rows) == len(payload["data"])
    assert [c["page[offset]"] for c in calls] == ["0", str(half)]


def test_an_empty_page_stops_the_walk_even_if_the_total_disagrees(client):
    """A server that reports more rows than it hands over must not spin us
    forever. The empty page is terminal regardless of the total."""
    page = {"data": [], "included": [], "meta": {"pagination": {"total": 999}}}
    client._request = lambda *a, **k: page
    assert list(client.iter_memberships(user_id="1")) == []


def test_an_empty_roster_is_not_an_error(client):
    page = {"data": [], "included": [], "meta": {"pagination": {"total": 0}}}
    client._request = lambda *a, **k: page
    assert list(client.iter_memberships(user_id="1")) == []


def test_we_never_follow_links_first(client, payload):
    """The response's own `links.first` is built WITHOUT the `/api/` prefix the
    request uses, so following it would hit the web page. Pagination is driven
    by page[offset] instead — asserted here because the bug it prevents looks
    like an auth failure, not a URL mistake."""
    assert "/api/" not in payload["links"]["first"]
    calls = _serve(client, payload)
    list(client.iter_memberships(user_id="1"))
    assert all(url.startswith("https://www.patreon.com/api/") for url, _p, _w in calls)


# --- drift -----------------------------------------------------------------


def test_a_missing_total_is_drift_not_an_empty_roster(client, payload):
    """The distinction that matters most here. An empty roster reads to C4 as
    'you cancelled everything', so a response we cannot verify as COMPLETE must
    raise rather than return a short list."""
    broken = {**payload, "meta": {}}
    client._request = lambda *a, **k: broken
    with pytest.raises(PatreonDriftError, match="pagination"):
        list(client.iter_memberships(user_id="1"))


def test_a_missing_data_list_is_drift(client, payload):
    client._request = lambda *a, **k: {"meta": {"pagination": {"total": 0}}}
    with pytest.raises(PatreonDriftError):
        list(client.iter_memberships(user_id="1"))


def test_a_member_with_no_campaign_is_drift(client, payload):
    mangled = json.loads(json.dumps(payload))
    mangled["data"][0]["relationships"]["campaign"] = {"data": None}
    client._request = lambda *a, **k: mangled
    with pytest.raises(PatreonDriftError, match="campaign"):
        list(client.iter_memberships(user_id="1"))


def test_a_member_with_no_patron_status_is_drift(client, payload):
    mangled = json.loads(json.dumps(payload))
    del mangled["data"][0]["attributes"]["patron_status"]
    client._request = lambda *a, **k: mangled
    with pytest.raises(PatreonDriftError, match="patron_status"):
        list(client.iter_memberships(user_id="1"))


# --- current_user_id -------------------------------------------------------


def test_current_user_id_reads_the_json_api_envelope(client):
    client._request = lambda *a, **k: {"data": {"id": "248453", "type": "user"}}
    assert client.current_user_id() == "248453"


def test_current_user_id_raises_drift_rather_than_guessing(client):
    """This endpoint is INFERRED, not characterized (note #3886). If the
    inference is wrong it must fail loudly — a confidently wrong user id would
    scope the roster to somebody else and return an empty, believable list."""
    client._request = lambda *a, **k: {"data": []}
    with pytest.raises(PatreonDriftError, match="current_user"):
        client.current_user_id()


# --- the seam itself -------------------------------------------------------


def test_the_seam_is_probed_not_required():
    """Milestone 387's whole seam design, and the reason Discord needs no
    'unsupported' branch: a client without the method is simply a client the
    roster never asks. Mirrors ingest_core's `getattr(client, 'post_is_gated')`.
    """
    class ClientWithoutIt:
        pass

    assert getattr(ClientWithoutIt(), "iter_memberships", None) is None
    assert getattr(PatreonClient(cookies_path=None), "iter_memberships", None)