"""Phase 173 (task 04, C3): the one-time startup migration of a
legacy credentials-bearing ``docs_repo``.

Pure/unit level — no live DB: the ``app_settings`` read is a stubbed
overlay engine (the ``test_settings_overlay`` fake-engine idiom), the
write path is monkeypatched (``settings_migrate._write_rows`` — it
captures the rows AND mirrors them into the stubbed read store, so
``resolve_settings()`` resolves the DB rows the migration wrote — the
DB-shadowing pin), the env base comes from ``os.environ`` (``tests/
conftest.py`` pins ``BOR_DOCS_REPO=`` / ``BOR_SETTINGS_DB=0`` — the
fixture flips the switch on per test), and the overlay state is
reset by ``reset_state_for_tests()``.
"""
from __future__ import annotations

import logging
from collections.abc import Iterator

import pytest

from app.core import settings_migrate, settings_overlay
from app.core.settings_overlay import resolve_settings

#: The ONE INFO line the migration logs when it acts (AGENTS rule 10).
_MIGRATED_LINE = (
    "settings: migrated embedded docs-push credentials out of "
    "docs_repo into docs_user/docs_token"
)


class _FakeStore:
    """A controllable ``app_settings`` store: the read (a fake overlay
    engine) and the write (the monkeypatched ``_write_rows``) share
    one dict — a migration write is visible to ``resolve_settings()``
    on the next resolution (the DB-shadowing pin)."""

    def __init__(self, rows: dict[str, str] | None = None) -> None:
        self.rows = dict(rows or {})
        self.writes: list[dict[str, str]] = []

    def install(self, monkeypatch: pytest.MonkeyPatch) -> None:
        store = self

        class _Rows:
            def __iter__(self) -> object:
                return iter(sorted(store.rows.items()))

        class _FakeConn:
            def execute(self, _stmt: object) -> _Rows:
                return _Rows()

            def __enter__(self) -> _FakeConn:
                return self

            def __exit__(self, *exc: object) -> bool:
                return False

        class _FakeEngine:
            def connect(self) -> _FakeConn:  # type: ignore[no-untyped-def]
                return _FakeConn()

        monkeypatch.setattr(
            settings_overlay, "_get_engine", lambda: _FakeEngine()
        )

        def _fake_write(rows: dict[str, str]) -> None:
            store.writes.append(dict(rows))
            store.rows.update(rows)

        monkeypatch.setattr(settings_migrate, "_write_rows", _fake_write)


@pytest.fixture(autouse=True)
def _clean_state(monkeypatch: pytest.MonkeyPatch) -> Iterator[None]:
    settings_overlay.reset_state_for_tests()
    monkeypatch.setenv("BOR_SETTINGS_DB", "1")
    monkeypatch.setenv("BOR_DOCS_REPO", "")
    monkeypatch.setenv("BOR_DOCS_USER", "")
    monkeypatch.setenv("BOR_DOCS_TOKEN", "")
    yield
    settings_overlay.reset_state_for_tests()


def _migrated_lines(caplog: pytest.LogCaptureFixture) -> list[str]:
    """The ``app.settings`` records that carry the migration line."""
    return [
        record.getMessage()
        for record in caplog.records
        if _MIGRATED_LINE in record.getMessage()
    ]


# ---------------------------------------------------------------------------
# (a) the no-op shapes — clean value, malformed segment
# ---------------------------------------------------------------------------


def test_clean_env_url_is_a_noop(monkeypatch: pytest.MonkeyPatch) -> None:
    """(a) a clean env URL with no overrides: ``False``, no rows
    written (the pre-phase behavior stands untouched)."""
    store = _FakeStore()
    store.install(monkeypatch)
    monkeypatch.setenv("BOR_DOCS_REPO", "https://host/r.git")
    assert settings_migrate.migrate_legacy_docs_creds() is False
    assert store.writes == []
    assert store.rows == {}


def test_clean_db_override_is_a_noop(
    monkeypatch: pytest.MonkeyPatch,
) -> None:
    """(a, the DB-source variant) a clean URL arriving as a DB
    override (the effective value, not the env): still a no-op."""
    store = _FakeStore({"docs_repo": "https://host/r.git"})
    store.install(monkeypatch)
    monkeypatch.setenv("BOR_DOCS_REPO", "https://elsewhere/r.git")
    assert settings_migrate.migrate_legacy_docs_creds() is False
    assert store.writes == []
    assert store.rows == {"docs_repo": "https://host/r.git"}


def test_malformed_empty_user_is_a_noop(
    monkeypatch: pytest.MonkeyPatch, caplog: pytest.LogCaptureFixture
) -> None:
    """(d) a malformed ``://:@…`` (empty user) is NOT the legacy
    shape: ``False``, no rows, no log — the value stays as-is
    (nothing breaks, nothing half-migrates)."""
    store = _FakeStore()
    store.install(monkeypatch)
    monkeypatch.setenv("BOR_DOCS_REPO", "https://:@host/r.git")
    with caplog.at_level(logging.INFO, logger="app.settings"):
        assert settings_migrate.migrate_legacy_docs_creds() is False
    assert store.writes == []
    assert store.rows == {}
    assert _migrated_lines(caplog) == []


def test_malformed_empty_pass_is_a_noop(
    monkeypatch: pytest.MonkeyPatch, caplog: pytest.LogCaptureFixture
) -> None:
    """(d, the other malformation) an empty pass (``://u:@…``):
    the same no-op contract — no rows, no log."""
    store = _FakeStore()
    store.install(monkeypatch)
    monkeypatch.setenv("BOR_DOCS_REPO", "https://u:@host/r.git")
    with caplog.at_level(logging.INFO, logger="app.settings"):
        assert settings_migrate.migrate_legacy_docs_creds() is False
    assert store.writes == []
    assert store.rows == {}
    assert _migrated_lines(caplog) == []


def test_subdomain_is_not_a_false_positive(
    monkeypatch: pytest.MonkeyPatch,
) -> None:
    """A ``://user:pass@``-shaped SUBDOMAIN (no trailing ``@`` in
    the URL) must not match — the character classes + the trailing
    ``@`` requirement do that job (the same contract the PUT guard
    pins)."""
    store = _FakeStore()
    store.install(monkeypatch)
    monkeypatch.setenv("BOR_DOCS_REPO", "https://sub.domain.example.com/r.git")
    assert settings_migrate.migrate_legacy_docs_creds() is False
    assert store.writes == []


# ---------------------------------------------------------------------------
# (b) the migration shape — split, DB-shadowing, the one INFO line
# ---------------------------------------------------------------------------


def test_legacy_env_url_is_split_into_three_rows(
    monkeypatch: pytest.MonkeyPatch, caplog: pytest.LogCaptureFixture
) -> None:
    """(b) a legacy env URL with no overrides: ``True``, exactly the
    three rows (clean repo / user / token), and
    ``resolve_settings()`` resolves the clean URL + the credentials
    FROM THE DB rows (they shadow the env — the env value still
    embeds the credentials, the effective value does not)."""
    store = _FakeStore()
    store.install(monkeypatch)
    monkeypatch.setenv("BOR_DOCS_REPO", "https://u:pass@host/r.git")
    with caplog.at_level(logging.INFO, logger="app.settings"):
        assert settings_migrate.migrate_legacy_docs_creds() is True
    assert store.rows == {
        "docs_repo": "https://host/r.git",
        "docs_user": "u",
        "docs_token": "pass",
    }
    assert len(store.writes) == 1  # one write call, one row set
    # DB rows SHADOW the env: the effective value is the clean URL.
    effective = resolve_settings()
    assert effective.docs_repo == "https://host/r.git"
    assert effective.docs_user == "u"
    assert effective.docs_token == "pass"
    # (e) the INFO line is emitted exactly once — and it carries no
    # value (the log discipline, A4).
    assert _migrated_lines(caplog) == [_MIGRATED_LINE]
    for line in _migrated_lines(caplog):
        assert "pass" not in line


def test_second_run_is_a_silent_noop(
    monkeypatch: pytest.MonkeyPatch, caplog: pytest.LogCaptureFixture
) -> None:
    """(b + idempotency) after a migration wrote the three rows, the
    second run finds the ``docs_token`` row → ``False``, no rows
    written, NO second INFO line (the one-line pin, e)."""
    store = _FakeStore()
    store.install(monkeypatch)
    monkeypatch.setenv("BOR_DOCS_REPO", "https://u:pass@host/r.git")
    with caplog.at_level(logging.INFO, logger="app.settings"):
        assert settings_migrate.migrate_legacy_docs_creds() is True
        assert settings_migrate.migrate_legacy_docs_creds() is False
    assert len(store.writes) == 1
    assert _migrated_lines(caplog) == [_MIGRATED_LINE]


def test_legacy_value_from_a_db_override_is_split(
    monkeypatch: pytest.MonkeyPatch,
) -> None:
    """(b, the DB-source variant) the legacy value arriving as a DB
    ``docs_repo`` override (the effective value): the same split —
    the override row is rewritten clean, the credentials join the
    new rows."""
    store = _FakeStore({"docs_repo": "https://u:pass@host/r.git"})
    store.install(monkeypatch)
    monkeypatch.setenv("BOR_DOCS_REPO", "")  # env empty — DB is the source
    assert settings_migrate.migrate_legacy_docs_creds() is True
    assert store.rows == {
        "docs_repo": "https://host/r.git",
        "docs_user": "u",
        "docs_token": "pass",
    }
    effective = resolve_settings()
    assert effective.docs_repo == "https://host/r.git"


# ---------------------------------------------------------------------------
# (c) the clobber guard — an existing docs_token override stands
# ---------------------------------------------------------------------------


def test_existing_token_override_is_never_clobbered(
    monkeypatch: pytest.MonkeyPatch,
) -> None:
    """(c) a legacy env URL while a ``docs_token`` override already
    exists (owner-set, or a previous migration): ``False`` — the
    pre-existing rows are untouched (no clobber)."""
    store = _FakeStore({"docs_token": "owner-token"})
    store.install(monkeypatch)
    monkeypatch.setenv("BOR_DOCS_REPO", "https://u:pass@host/r.git")
    assert settings_migrate.migrate_legacy_docs_creds() is False
    assert store.writes == []
    assert store.rows == {"docs_token": "owner-token"}  # byte-identical
    # the effective value resolves the owner's token, not the URL's.
    assert resolve_settings().docs_token == "owner-token"


def test_existing_token_override_with_clean_repo_is_a_noop(
    monkeypatch: pytest.MonkeyPatch,
) -> None:
    """(c, the clean variant) a token override with a clean repo
    (env or DB): ``False`` — nothing to do, nothing touched."""
    store = _FakeStore({"docs_token": "owner-token"})
    store.install(monkeypatch)
    monkeypatch.setenv("BOR_DOCS_REPO", "https://host/r.git")
    assert settings_migrate.migrate_legacy_docs_creds() is False
    assert store.writes == []
    assert store.rows == {"docs_token": "owner-token"}