"""What a classroom is allowed to send.

This is the only place classroom input is read, and everything that
reaches a sanctuary screen comes through it.
"""

import json

import pytest

from parent_call.config import Settings
from parent_call.validation import Invalid, parse

NOW = 1_780_000_000.0


@pytest.fixture
def settings():
    return Settings(max_child_length=40, max_room_length=32, request_ttl=180,
                    max_clock_skew=120)


def body(**fields):
    payload = {"id": "nursery-1", "room": "nursery", "child": "Emma",
               "created_at": NOW}
    payload.update(fields)
    return json.dumps(payload)


def test_a_good_request(settings):
    request = parse(body(), NOW, settings)

    assert (request.id, request.room, request.child) == ("nursery-1", "nursery", "Emma")


def test_only_the_four_fields_survive(settings):
    """A payload cannot smuggle anything through to ProPresenter."""
    request = parse(
        body(message="{Name} OWNS YOU", theme="evil", propresenter="anything"),
        NOW, settings,
    )

    assert set(vars(request)) == {"id", "room", "child", "created_at"}


@pytest.mark.parametrize("payload, reason", [
    (b"\xff\xfe", "payload is not utf-8"),
    ("{{{", "payload is not json"),
    ("[1,2,3]", "payload is not an object"),
    (json.dumps({"room": "nursery", "child": "E", "created_at": NOW}), "id is missing"),
    (json.dumps({"id": 7, "room": "n", "child": "E", "created_at": NOW}), "id is missing"),
])
def test_unusable_payloads(settings, payload, reason):
    with pytest.raises(Invalid) as raised:
        parse(payload, NOW, settings)

    assert raised.value.reason == reason


@pytest.mark.parametrize("field, value", [
    ("id", "has/slash"),
    ("id", "has#hash"),
    ("id", "has+plus"),
    ("id", ""),
    ("id", "x" * 200),
])
def test_ids_that_could_reshape_a_topic(settings, field, value):
    with pytest.raises(Invalid):
        parse(body(**{field: value}), NOW, settings)


def test_the_id_is_reported_back_so_the_classroom_can_be_answered(settings):
    with pytest.raises(Invalid) as raised:
        parse(body(child=""), NOW, settings)

    assert raised.value.request_id == "nursery-1"
    assert raised.value.room == "nursery"


@pytest.mark.parametrize("room", ["a/b", "a+b", "a#b", "", "x" * 99, "  "])
def test_rooms_that_are_not_rooms(settings, room):
    with pytest.raises(Invalid):
        parse(body(room=room), NOW, settings)


def test_room_is_lowercased(settings):
    assert parse(body(room="Nursery"), NOW, settings).room == "nursery"


@pytest.mark.parametrize("child", ["", "   ", "x" * 41])
def test_child_names_that_are_refused(settings, child):
    with pytest.raises(Invalid):
        parse(body(child=child), NOW, settings)


@pytest.mark.parametrize("child, expected", [
    ("Emma\nPASTOR SAYS EVACUATE", "Emma PASTOR SAYS EVACUATE"),
    ("Emma​Rose", "Emma Rose"),
    ("Emma‮", "Emma"),
    ("  Emma   Rose  ", "Emma Rose"),
    ("Zoé", "Zoé"),
])
def test_names_are_made_safe_to_put_on_a_screen(settings, child, expected):
    """Nothing invisible, and nothing that can push text around a screen,
    survives into a sanctuary display."""
    assert parse(body(child=child), NOW, settings).child == expected


def test_an_old_timestamp_is_still_a_valid_shape(settings):
    """How old is too old is policy, and the state machine decides it —
    it has to make the same judgement again when a late approval arrives.
    See test_state.test_a_stale_request_is_never_accepted."""
    assert parse(body(created_at=NOW - 9999), NOW, settings).child == "Emma"


def test_requests_from_the_future(settings):
    with pytest.raises(Invalid) as raised:
        parse(body(created_at=NOW + 3600), NOW, settings)

    assert "future" in raised.value.reason


def test_a_slightly_fast_classroom_clock_is_tolerated(settings):
    assert parse(body(created_at=NOW + 60), NOW, settings).child == "Emma"


@pytest.mark.parametrize("created_at", [None, "soon", True, {}])
def test_timestamps_that_are_not_timestamps(settings, created_at):
    with pytest.raises(Invalid) as raised:
        parse(body(created_at=created_at), NOW, settings)

    assert raised.value.reason == "created_at is missing"