"""Where the admin credential lives, and what happens when it does not (phase 11 task 02).

`auth.load_auth_state` is the only code that turns a deployment's environment plus the durable
`meta` rows into the state every request is checked against, and it owns three decisions that
are easy to get subtly wrong and impossible to see in a screenshot:

* the environment **seeds** a password once — after the first boot the stored verifier wins, so
  `/settings` can change it without a redeploy and a restart cannot roll it back;
* a server with neither a stored verifier nor `DASH_ADMIN_PASSWORD` **refuses to start**
  (fail closed) rather than serving the fleet open behind a public domain;
* changing the password rotates the signing secret, which is what signs out every *other*
  browser when there is no session table to walk.

The store here is a dict. That is the point of the `MetaStore` protocol: the security-relevant
branch has no SQLite in it, so these tests assert the decisions rather than the schema — and
one test at the end puts the real `SampleStore` back underneath to prove the durability the
protocol is written against.
"""

from __future__ import annotations

import logging
from dataclasses import FrozenInstanceError
from pathlib import Path
from typing import Any

import pytest

from dashboards import auth
from dashboards.store import SampleStore

#: Nothing in this file is about the cost; `tests/test_auth.py` pins the 600 000 default.
CHEAP = 1_000

PASSWORD = "testpass"


class FakeMeta:
    """The three-method shape `load_auth_state` asks for, with no database in it."""

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

    def get_meta(self, key: str) -> str | None:
        return self.rows.get(key)

    def set_meta(self, key: str, value: str) -> None:
        self.rows[key] = value

    def delete_meta(self, key: str) -> int:
        return 1 if self.rows.pop(key, None) is not None else 0


def load(store: FakeMeta, *, admin_password: str = PASSWORD, **kwargs: Any) -> auth.AuthState:
    return auth.load_auth_state(store, admin_password=admin_password, iterations=CHEAP,
                                **kwargs)


def seed(*, admin_password: str = PASSWORD) -> tuple[FakeMeta, auth.AuthState]:
    """A store that has already booted once, and the state that boot produced."""
    store = FakeMeta()
    return store, load(store, admin_password=admin_password)


# --- first boot: the environment seeds ---------------------------------------------------- #


def test_first_boot_seeds_the_verifier_and_persists_the_secret() -> None:
    store = FakeMeta()
    state = load(store)

    assert state.seeded is True, "this start wrote the verifier row"
    assert state.env_ignored is False, "there was nothing stored to ignore the env with"
    assert auth.verify_password(PASSWORD, store.rows[auth.META_VERIFIER]) is True
    assert store.rows[auth.META_SESSION_SECRET] == state.secret
    assert state.iterations == CHEAP
    assert state.session_hours == auth.SESSION_HOURS


def test_the_seed_is_stored_as_a_verifier_and_never_as_a_password() -> None:
    """`AGENTS.md` invariant 6 on the way *in*: the row is PBKDF2 text, not the secret.

    The completion criterion for the task is that `grep -c testpass` on a real database is 0;
    this is the same claim one layer up, where a regression would show.
    """
    store = FakeMeta()
    state = load(store)
    for value in [*store.rows.values(), state.verifier, state.secret]:
        assert PASSWORD not in value
    assert store.rows[auth.META_VERIFIER].startswith(f"{auth.PBKDF2_ALGO}${CHEAP}$")


def test_the_stored_rows_survive_a_reopen_of_the_real_database(tmp_path: Path) -> None:
    """The whole reason this is in SQLite and not in process memory.

    A restart must not re-seed, must not mint a new signing secret (that would sign every
    browser out on every deploy), and must not need `DASH_ADMIN_PASSWORD` any more.
    """
    path = tmp_path / "dashboards.sqlite3"
    first_store = SampleStore(path)
    try:
        first = auth.load_auth_state(first_store, admin_password=PASSWORD, iterations=CHEAP)
        assert first.seeded is True
    finally:
        first_store.close()

    reopened = SampleStore(path)
    try:
        second = auth.load_auth_state(reopened, admin_password="", iterations=CHEAP)
    finally:
        reopened.close()

    assert second.seeded is False
    assert second.verifier == first.verifier
    assert second.secret == first.secret, "a new secret on every restart would log everyone out"
    assert auth.verify_password(PASSWORD, second.verifier) is True


# --- the stored verifier wins ------------------------------------------------------------- #


def test_a_stored_verifier_beats_a_conflicting_env_password(caplog: pytest.LogCaptureFixture) -> None:
    store, _first = seed()
    original = store.rows[auth.META_VERIFIER]

    with caplog.at_level(logging.WARNING, logger="dashboards.auth"):
        second = load(store, admin_password="some-other-password")

    assert second.env_ignored is True
    assert second.seeded is False
    assert store.rows[auth.META_VERIFIER] == original, "the env must not overwrite the row"
    assert second.verifier == original
    assert auth.verify_password(PASSWORD, second.verifier) is True
    assert auth.verify_password("some-other-password", second.verifier) is False


def test_the_ignored_env_var_is_reported_once_in_fixed_words(caplog: pytest.LogCaptureFixture) -> None:
    """The operator who set `DASH_ADMIN_PASSWORD` and saw nothing happen gets one sentence.

    The sentence must name the variable and the row; it must not name the value, the hash, or
    any prefix of either — that line ends up in a container log, which is exactly where
    invariant 6 says a credential must not go.
    """
    store, _first = seed()
    with caplog.at_level(logging.WARNING, logger="dashboards.auth"):
        state = load(store, admin_password="ignored-now")

    messages = [rec.getMessage() for rec in caplog.records if rec.name == "dashboards.auth"]
    assert messages == [auth.ENV_IGNORED_MESSAGE], "exactly one line, at startup"
    line = messages[0]
    assert "DASH_ADMIN_PASSWORD is ignored" in line
    assert auth.META_VERIFIER in line
    for secret in (PASSWORD, "ignored-now", state.verifier, state.secret):
        assert secret not in line


def test_the_warning_is_not_written_when_the_env_actually_seeded(caplog: pytest.LogCaptureFixture) -> None:
    """`seeded` and `env_ignored` are mutually exclusive, and only the second one speaks."""
    with caplog.at_level(logging.WARNING, logger="dashboards.auth"):
        state = load(FakeMeta())
    assert state.env_ignored is False
    assert [r for r in caplog.records if r.name == "dashboards.auth"] == []


def test_the_environment_variable_can_be_dropped_after_first_boot() -> None:
    """The operator's wording: "configured initially with an env var, not required to change".

    Second boot with no seed at all reuses the row, reports neither `seeded` nor
    `env_ignored`, and stays quiet.
    """
    store, first = seed()
    second = load(store, admin_password="")
    assert second.seeded is False
    assert second.env_ignored is False
    assert second.verifier == first.verifier


def test_a_blank_stored_verifier_counts_as_no_verifier_at_all() -> None:
    """A row of whitespace is not a password — reseeding it is the only way back in."""
    store = FakeMeta({auth.META_VERIFIER: "   \n "})
    state = load(store)
    assert state.seeded is True
    assert auth.verify_password(PASSWORD, store.rows[auth.META_VERIFIER]) is True


# --- fail closed -------------------------------------------------------------------------- #


def test_no_verifier_and_no_seed_refuses_to_start_instead_of_running_open() -> None:
    store = FakeMeta()
    with pytest.raises(RuntimeError) as caught:
        load(store, admin_password="")

    message = str(caught.value)
    assert "DASH_ADMIN_PASSWORD" in message, "names the variable to set"
    assert auth.META_VERIFIER in message, "names the row that would have been used"
    assert auth.META_SESSION_SECRET in message
    assert "DELETE FROM meta WHERE key IN" in message, "gives the reset command"
    assert "sqlite3" in message
    assert store.rows == {}, "refusing means writing nothing, not writing and then complaining"


def test_the_refusal_names_the_database_the_operator_has_to_reset() -> None:
    """`<db>` is a placeholder nobody can run; the real path is what makes the fix copy-paste."""
    with pytest.raises(RuntimeError) as caught:
        auth.load_auth_state(FakeMeta(), admin_password="", db_path="/var/lib/dashboards/d.db")
    assert "/var/lib/dashboards/d.db" in str(caught.value)

    with pytest.raises(RuntimeError) as bare:
        auth.load_auth_state(FakeMeta(), admin_password="")
    assert "<db>" in str(bare.value), "no path known, and no invented one either"


def test_the_refusal_carries_no_password_and_no_verifier() -> None:
    """The message reaches a terminal and a container log; it may carry instructions only."""
    store = FakeMeta()
    with pytest.raises(RuntimeError) as caught:
        load(store, admin_password="")
    assert PASSWORD not in str(caught.value)


# --- the signing secret -------------------------------------------------------------------- #


def test_a_usable_session_secret_is_reused_as_is() -> None:
    """A restart must not rotate the key, or every browser is signed out for nothing."""
    existing = auth.new_secret()
    # a second boot, not a first: the verifier row exists and the secret is what is under test
    store = FakeMeta({auth.META_VERIFIER: auth.hash_password(PASSWORD, iterations=CHEAP),
                      auth.META_SESSION_SECRET: existing})
    state = load(store, admin_password="")
    assert state.secret == existing


@pytest.mark.parametrize("corrupt", [
    "",
    "   ",
    "deadbeef",  # hex, but a 16-bit key is not what we sign a 30-day cookie with
    "z" * 64,  # long enough, and not hex
    "0" * 63,  # one character short of 256 bits
])
def test_a_corrupt_session_secret_is_regenerated_and_persisted(corrupt: str) -> None:
    """The chosen behaviour, stated: replace it and write the replacement.

    The effect on the operator is "every browser is asked to sign in again" — a login prompt,
    not a lockout — which is the safe direction for a damaged row. Refusing to start instead
    would turn a corrupt cell into an outage of a dashboard that still has a working password.
    """
    store, first = seed()
    store.rows[auth.META_SESSION_SECRET] = corrupt

    state = load(store, admin_password="")

    assert state.secret != corrupt
    assert state.secret == store.rows[auth.META_SESSION_SECRET], "the replacement is durable"
    assert len(state.secret) == auth.SECRET_MIN_BYTES * 2
    bytes.fromhex(state.secret)  # raises if the replacement is not the format we mint
    assert state.verifier == first.verifier, "the password is untouched"
    # and the state is usable: a session minted from it reads back
    token = auth.mint_session(state.secret, now=1_700_000_000.0)
    assert auth.read_session(state.secret, token, now=1_700_000_000.0) is not None


# --- changing the password ----------------------------------------------------------------- #


def test_update_verifier_replaces_both_rows_and_returns_the_new_state() -> None:
    store, before = seed()
    old_token = auth.mint_session(before.secret, now=1_700_000_000.0)

    after = auth.update_verifier(store, before, "horse battery staple")

    assert after.secret != before.secret
    assert store.rows[auth.META_SESSION_SECRET] == after.secret
    assert store.rows[auth.META_VERIFIER] == after.verifier
    assert auth.verify_password("horse battery staple", after.verifier) is True
    assert auth.verify_password(PASSWORD, after.verifier) is False
    assert after.session_hours == before.session_hours
    assert after.iterations == before.iterations
    assert after.seeded is False and after.env_ignored is False
    # the browser that was not in front of the form is out: its cookie is signed by the old key
    assert auth.read_session(after.secret, old_token, now=1_700_000_000.0) is None
    # and the new state can still mint one that reads
    fresh = auth.mint_session(after.secret, now=1_700_000_000.0)
    assert auth.read_session(after.secret, fresh, now=1_700_000_000.0) is not None


@pytest.mark.parametrize("blank", ["", "   ", "\t", "\n  \r"])
def test_update_verifier_refuses_to_store_an_empty_password(blank: str) -> None:
    store, before = seed()
    with pytest.raises(ValueError) as caught:
        auth.update_verifier(store, before, blank)

    assert store.rows[auth.META_VERIFIER] == before.verifier
    assert store.rows[auth.META_SESSION_SECRET] == before.secret
    # fixed text: nothing the caller typed is echoed back into a log or a traceback
    assert str(caught.value) == "a new password must not be empty or whitespace"


def test_the_state_is_a_frozen_bundle_of_credentials() -> None:
    """Nothing may mutate a live `AppContext.auth`, and nothing may treat it as display data."""
    _store, state = seed()
    with pytest.raises(FrozenInstanceError):
        state.verifier = "swapped"  # type: ignore[misc]
    assert {"verifier", "secret", "session_hours", "iterations", "seeded", "env_ignored"} == {
        f.name for f in state.__dataclass_fields__.values()}