mirror/tests/test_registry.py

"""Unit tests for the roster. No sockets, no async — pure policy."""

from __future__ import annotations

import pytest

from mirror.registry import Registry, RegistryError


def by_target(outbox):
    """Group emitted envelopes by their destination peer id."""
    grouped: dict[str, list[dict]] = {}
    for peer_id, message in outbox:
        grouped.setdefault(peer_id, []).append(message)
    return grouped


def types_for(outbox, peer_id):
    return [m["type"] for m in by_target(outbox).get(peer_id, [])]


def message_for(outbox, peer_id, kind):
    for message in by_target(outbox).get(peer_id, []):
        if message["type"] == kind:
            return message
    raise AssertionError(f"no {kind!r} for {peer_id!r} in {by_target(outbox)}")


@pytest.fixture
def mesh(registry):
    """One sharer, two viewers, and the sharer already mirroring."""
    sharer, _ = registry.join(role="sharer", name="Linux Box")
    v1, _ = registry.join(role="viewer", name="Phone")
    v2, _ = registry.join(role="viewer", name="Tablet")
    registry.publish(sharer, label="Terminal", width=1280, height=720)
    return sharer, v1, v2, registry


class TestJoin:
    def test_viewer_gets_an_empty_roster(self, registry):
        peer_id, outbox = registry.join(role="viewer", name="Phone")
        welcome = message_for(outbox, peer_id, "welcome")
        assert welcome["peerId"] == peer_id
        assert welcome["role"] == "viewer"
        assert welcome["streams"] == []

    def test_ids_are_unique_and_sequential_when_injected(self, registry):
        first, _ = registry.join(role="viewer")
        second, _ = registry.join(role="viewer")
        assert (first, second) == ("p1", "p2")

    def test_generated_ids_do_not_collide(self):
        registry = Registry(id_factory=lambda: "same")
        registry.join(role="viewer")
        with pytest.raises(RegistryError, match="out of peer ids"):
            registry.join(role="viewer")

    def test_default_names_are_useful(self, registry):
        sharer, _ = registry.join(role="sharer")
        viewer, _ = registry.join(role="viewer")
        assert registry.peers[sharer].name == "This device"
        assert registry.peers[viewer].name == "Viewer"

    def test_names_are_sanitised_and_capped(self, registry):
        peer_id, _ = registry.join(role="sharer", name="  a\n\t  b   " + "x" * 80)
        name = registry.peers[peer_id].name
        assert name.startswith("a b ")
        assert len(name) == 48
        assert "\n" not in name and "  " not in name

    def test_unknown_role_is_fatal(self, registry):
        with pytest.raises(RegistryError) as excinfo:
            registry.join(role="spectator")
        assert excinfo.value.code == "bad_role"
        assert excinfo.value.fatal is True

    def test_a_late_viewer_sees_existing_mirrors(self, mesh):
        sharer, _v1, _v2, registry = mesh
        late, outbox = registry.join(role="viewer", name="Late")
        roster = message_for(outbox, late, "welcome")["streams"]
        assert [s["id"] for s in roster] == [sharer]
        assert roster[0]["label"] == "Terminal"
        assert roster[0]["viewers"] == 0


class TestPublish:
    def test_viewers_are_told_and_other_sharers_are_not(self, registry):
        sharer, _ = registry.join(role="sharer", name="A")
        other_sharer, _ = registry.join(role="sharer", name="B")
        viewer, _ = registry.join(role="viewer", name="V")
        outbox = registry.publish(sharer, label="Terminal", width=800, height=600)
        assert types_for(outbox, viewer) == ["stream_added"]
        assert by_target(outbox).get(other_sharer) is None
        added = message_for(outbox, viewer, "stream_added")["stream"]
        assert added == {
            "id": sharer,
            "sharerId": sharer,
            "name": "A",
            "label": "Terminal",
            "displaySurface": "",
            "width": 800,
            "height": 600,
            "audio": False,
            "viewers": 0,
        }

    def test_a_viewer_cannot_publish(self, registry):
        viewer, _ = registry.join(role="viewer")
        with pytest.raises(RegistryError) as excinfo:
            registry.publish(viewer)
        assert excinfo.value.code == "not_sharer"
        assert excinfo.value.fatal is True

    def test_republish_updates_in_place(self, registry):
        sharer, _ = registry.join(role="sharer", name="A")
        registry.join(role="viewer")
        registry.publish(sharer, label="First", width=800, height=600)
        registry.publish(sharer, label="Second", width=1920, height=1080, audio=True)
        assert len(registry.streams) == 1
        assert registry.roster()[0]["label"] == "Second"
        assert registry.roster()[0]["audio"] is True

    def test_unchanged_republish_does_not_re_offer_to_viewers(self, mesh):
        sharer, v1, _v2, registry = mesh
        registry.subscribe(v1, sharer)
        outbox = registry.publish(sharer, label="Terminal", width=1280, height=720)
        # The viewer already has a peer connection; nothing to renegotiate.
        assert types_for(outbox, v1) == ["stream_updated"]
        assert types_for(outbox, sharer) == ["stream_updated"]

    def test_changed_republish_asks_for_a_new_offer_per_viewer(self, mesh):
        sharer, v1, v2, registry = mesh
        registry.subscribe(v1, sharer)
        registry.subscribe(v2, sharer)
        outbox = registry.publish(sharer, label="Terminal", width=1920, height=1080)
        assert types_for(outbox, v1).count("peer_joined") == 1
        assert types_for(outbox, v2).count("peer_joined") == 1
        assert message_for(outbox, v1, "peer_joined")["streamId"] == sharer

    def test_unpublish_clears_the_tile_for_every_viewer(self, mesh):
        """A tile is drawn on `stream_added`, so every viewer must be told it is gone —
        including one that had not subscribed yet."""
        sharer, v1, v2, registry = mesh
        registry.subscribe(v1, sharer)
        outbox = registry.unpublish(sharer)
        assert types_for(outbox, v1) == ["stream_removed"]
        assert types_for(outbox, v2) == ["stream_removed"]
        assert registry.streams == {}
        assert registry.watching(v1) == set()

    def test_dropping_a_mirror_leaves_other_mirrors_alone(self, registry):
        first, _ = registry.join(role="sharer", name="A")
        second, _ = registry.join(role="sharer", name="B")
        viewer, _ = registry.join(role="viewer")
        registry.publish(first, label="one")
        registry.publish(second, label="two")
        registry.subscribe(viewer, second)
        outbox = registry.unpublish(first)
        assert [m["streamId"] for m in by_target(outbox)[viewer]] == [first]
        assert [s["label"] for s in registry.roster()] == ["two"]
        assert registry.watching(viewer) == {second}

    def test_unpublish_without_a_stream_is_a_no_op(self, registry):
        sharer, _ = registry.join(role="sharer")
        assert registry.unpublish(sharer) == []

    def test_capacity_blocks_a_new_mirror_but_not_an_existing_one(self):
        registry = Registry(max_streams=1)
        first, _ = registry.join(role="sharer", name="A")
        second, _ = registry.join(role="sharer", name="B")
        viewer, _ = registry.join(role="viewer")
        registry.publish(first, label="one")
        with pytest.raises(RegistryError) as excinfo:
            registry.publish(second, label="two")
        assert excinfo.value.code == "capacity"
        assert excinfo.value.fatal is True
        # The incumbent may keep refreshing its own mirror.
        registry.publish(first, label="one", width=1920, height=1080)
        assert [s["label"] for s in registry.roster()] == ["one"]
        # Capacity counts mirrors; an audience never uses it up.
        assert registry.stats()["viewers"] == 1
        assert registry.watching(viewer) == set()


class TestSubscribe:
    def test_sharer_is_told_to_negotiate(self, mesh):
        sharer, v1, _v2, registry = mesh
        outbox = registry.subscribe(v1, sharer)
        joined = message_for(outbox, sharer, "peer_joined")
        assert joined["viewerId"] == v1
        assert joined["name"] == "Phone"
        assert message_for(outbox, v1, "stream_updated")["stream"]["viewers"] == 1

    def test_subscribing_twice_is_idempotent(self, mesh):
        sharer, v1, _v2, registry = mesh
        registry.subscribe(v1, sharer)
        assert registry.subscribe(v1, sharer) == []
        assert registry.streams[sharer].viewers == {v1}

    def test_unknown_stream(self, registry):
        viewer, _ = registry.join(role="viewer")
        with pytest.raises(RegistryError) as excinfo:
            registry.subscribe(viewer, "nope")
        assert excinfo.value.code == "unknown_stream"

    def test_a_sharer_cannot_even_watch_itself(self, mesh):
        sharer, _v1, _v2, registry = mesh
        with pytest.raises(RegistryError) as excinfo:
            registry.subscribe(sharer, sharer)
        assert excinfo.value.code == "not_viewer"

    def test_a_sharer_cannot_subscribe_like_a_viewer(self, mesh):
        sharer, _v1, _v2, registry = mesh
        other, _ = registry.join(role="sharer", name="B")
        registry.publish(other, label="B's screen")
        with pytest.raises(RegistryError) as excinfo:
            registry.subscribe(sharer, other)
        assert excinfo.value.code == "not_viewer"

    def test_unsubscribe_closes_the_leg(self, mesh):
        sharer, v1, v2, registry = mesh
        registry.subscribe(v1, sharer)
        registry.subscribe(v2, sharer)
        outbox = registry.unsubscribe(v1, sharer)
        assert message_for(outbox, sharer, "peer_left")["viewerId"] == v1
        assert message_for(outbox, v2, "stream_updated")["stream"]["viewers"] == 1
        assert registry.unsubscribe(v1, sharer) == []

    def test_unsubscribing_from_an_unknown_stream_is_quiet(self, registry):
        viewer, _ = registry.join(role="viewer")
        assert registry.unsubscribe(viewer, "ghost") == []


class TestSignalAuthorization:
    def test_sharer_may_reach_a_subscribed_viewer(self, mesh):
        sharer, v1, _v2, registry = mesh
        registry.subscribe(v1, sharer)
        outbox = registry.signal(sharer, v1, {"sdp": {"type": "offer"}})
        relay = message_for(outbox, v1, "signal")
        assert relay["from"] == sharer
        assert relay["payload"] == {"sdp": {"type": "offer"}}

    def test_viewer_may_answer_the_sharer_it_watches(self, mesh):
        sharer, v1, _v2, registry = mesh
        registry.subscribe(v1, sharer)
        assert registry.signal(v1, sharer, {"candidate": {"candidate": "x"}}) == [
            (
                sharer,
                {
                    "type": "signal",
                    "from": v1,
                    "to": sharer,
                    "payload": {"candidate": {"candidate": "x"}},
                },
            )
        ]

    def test_sharer_may_not_blindly_push_to_a_stranger(self, mesh):
        sharer, _v1, v2, registry = mesh
        with pytest.raises(RegistryError) as excinfo:
            registry.signal(sharer, v2, {"sdp": {"type": "offer"}})
        assert excinfo.value.code == "not_subscribed"

    def test_viewer_may_not_reach_a_sharer_it_never_subscribed_to(self, mesh):
        _sharer, v1, _v2, registry = mesh
        other, _ = registry.join(role="sharer", name="C")
        registry.publish(other, label="private")
        with pytest.raises(RegistryError) as excinfo:
            registry.signal(v1, other, {})
        assert excinfo.value.code == "not_subscribed"

    def test_peers_may_not_talk_to_each_other_directly(self, mesh):
        _sharer, v1, v2, registry = mesh
        with pytest.raises(RegistryError) as excinfo:
            registry.signal(v1, v2, {})
        assert excinfo.value.code == "peer_to_peer"

    def test_unknown_endpoints_are_refused(self, mesh):
        sharer, _v1, _v2, registry = mesh
        with pytest.raises(RegistryError) as excinfo:
            registry.signal(sharer, "ghost", {})
        assert excinfo.value.code == "unknown_peer"


class TestTeardown:
    def test_sharer_disconnect_removes_the_mirror(self, mesh):
        sharer, v1, v2, registry = mesh
        registry.subscribe(v1, sharer)
        registry.subscribe(v2, sharer)
        outbox = registry.leave(sharer)
        assert types_for(outbox, v1) == ["stream_removed"]
        assert types_for(outbox, v2) == ["stream_removed"]
        assert registry.streams == {}
        assert registry.watching(v1) == set()

    def test_viewer_disconnect_releases_the_sharer(self, mesh):
        sharer, v1, v2, registry = mesh
        registry.subscribe(v1, sharer)
        registry.subscribe(v2, sharer)
        outbox = registry.leave(v1)
        assert message_for(outbox, sharer, "peer_left")["viewerId"] == v1
        assert registry.streams[sharer].viewers == {v2}

    def test_leaving_twice_is_quiet(self, mesh):
        _sharer, v1, _v2, registry = mesh
        registry.leave(v1)
        assert registry.leave(v1) == []

    def test_sharer_disconnect_after_a_crash_still_cleans_subscriptions(self, mesh):
        sharer, v1, _v2, registry = mesh
        registry.subscribe(v1, sharer)
        registry.leave(sharer)
        # A stale viewer must not be able to signal the dead sharer.
        with pytest.raises(RegistryError):
            registry.signal(v1, sharer, {})


class TestLayout:
    def test_the_default_is_the_wall_not_fullscreen_with_zero_followers(self, registry):
        registry.join(role="viewer")
        assert registry.layout.staged is None
        assert registry.layout.fullscreen is False
        assert registry.layout_dto() == {
            "type": "layout",
            "staged": None,
            "fullscreen": False,
            "followers": 0,
        }

    def test_staging_broadcasts_to_viewers_and_the_sender_without_doubling(self, mesh):
        sharer, v1, v2, registry = mesh
        outbox = registry.set_layout(sharer, staged=sharer)
        assert {t for t, _ in outbox} == {sharer, v1, v2}
        for peer_id in (sharer, v1, v2):
            assert types_for(outbox, peer_id) == ["layout"]
        expected = {"type": "layout", "staged": sharer, "fullscreen": False, "followers": 0}
        assert all(m == expected for _t, m in outbox)
        assert len(outbox) == 3  # one frame per target; nobody receives it twice

    def test_a_partial_update_touches_only_the_named_fields(self, mesh):
        sharer, _v1, _v2, registry = mesh
        registry.set_layout(sharer, staged=sharer)
        outbox = registry.set_layout(sharer, fullscreen=True)
        dto = message_for(outbox, sharer, "layout")
        assert registry.layout.staged == sharer  # absent field left alone
        assert registry.layout.fullscreen is True
        assert dto == {"type": "layout", "staged": sharer, "fullscreen": True, "followers": 0}

    def test_an_explicit_null_clears_and_an_opinionless_arrange_is_ack_only(self, mesh):
        sharer, v1, v2, registry = mesh
        registry.set_layout(sharer, staged=sharer, fullscreen=True)
        outbox = registry.set_layout(v1, staged=None)
        assert registry.layout.staged is None
        assert registry.layout.fullscreen is True  # absent field left alone
        # The clearing is a real change: viewers plus the sender (deduped) are told.
        assert {t for t, _ in outbox} == {v1, v2}
        # No opinion at all: the sender is acked and nobody else hears anything.
        outbox = registry.set_layout(v2)
        assert outbox == [
            (v2, {"type": "layout", "staged": None, "fullscreen": True, "followers": 0})
        ]

    def test_an_unknown_staged_mirror_is_refused_and_changes_nothing(self, mesh):
        sharer, _v1, _v2, registry = mesh
        registry.set_layout(sharer, staged=sharer, fullscreen=True)
        with pytest.raises(RegistryError) as excinfo:
            registry.set_layout(sharer, staged="ghost", fullscreen=False)
        assert excinfo.value.code == "unknown_stream"
        assert registry.layout.staged == sharer
        assert registry.layout.fullscreen is True

    def test_repeating_the_same_state_replies_with_the_ack_only(self, mesh):
        sharer, _v1, _v2, registry = mesh
        registry.set_layout(sharer, staged=sharer)
        outbox = registry.set_layout(sharer, staged=sharer, fullscreen=False)
        assert outbox == [
            (sharer, {"type": "layout", "staged": sharer, "fullscreen": False, "followers": 0})
        ]

    def test_unpublishing_the_staged_mirror_falls_back_to_the_wall(self, mesh):
        sharer, v1, v2, registry = mesh
        registry.set_layout(sharer, staged=sharer)
        outbox = registry.unpublish(sharer)
        for peer_id in (v1, v2):
            # Exactly one layout frame, riding the same envelope set as the removal.
            assert types_for(outbox, peer_id) == ["stream_removed", "layout"]
            assert message_for(outbox, peer_id, "layout")["staged"] is None
        assert registry.layout.staged is None

    def test_a_sharer_disconnecting_falls_back_to_the_wall(self, mesh):
        sharer, v1, v2, registry = mesh
        registry.set_layout(sharer, staged=sharer)
        outbox = registry.leave(sharer)
        for peer_id in (v1, v2):
            assert types_for(outbox, peer_id) == ["stream_removed", "layout"]
            assert message_for(outbox, peer_id, "layout")["staged"] is None
        assert registry.layout.staged is None

    def test_a_replaced_stream_leaves_the_stage_cleared(self, mesh):
        sharer, v1, _v2, registry = mesh
        registry.set_layout(sharer, staged=sharer)
        registry.leave(sharer)  # the old mirror goes with its socket
        fresh, _ = registry.join(role="sharer", name="Linux Box")
        outbox = registry.publish(fresh, label="Terminal", width=1280, height=720)
        # The replacement has a new id; the stage must not still point at the
        # old one, and nothing auto-stages the newcomer.
        assert fresh != sharer
        assert registry.layout.staged is None
        assert "layout" not in types_for(outbox, v1)
        assert [s["id"] for s in registry.roster()] == [fresh]

    def test_the_stage_is_said_once_when_a_kiosk_sharer_leaves(self, registry):
        kiosk_sharer, _ = registry.join(role="sharer", kiosk=True)
        viewer, _ = registry.join(role="viewer")
        registry.publish(kiosk_sharer, label="Terminal")
        registry.set_layout(kiosk_sharer, staged=kiosk_sharer)
        outbox = registry.leave(kiosk_sharer)
        # The fallback and the follower change must not double the layout frame.
        assert types_for(outbox, viewer) == ["stream_removed", "layout"]

    def test_followers_counts_only_kiosk_peers(self, registry):
        registry.join(role="viewer")
        registry.join(role="viewer")
        registry.join(role="viewer", kiosk=True)
        registry.join(role="sharer")
        assert registry.layout_dto()["followers"] == 1

    def test_a_kiosk_joining_pushes_the_new_follower_count(self, mesh):
        _sharer, v1, v2, registry = mesh
        _id, outbox = registry.join(role="viewer", kiosk=True)
        # Told to the other viewers; the joiner got the state in its welcome,
        # not as a layout frame.
        assert {t for t, m in outbox if m["type"] == "layout"} == {v1, v2}
        assert types_for(outbox, _id) == ["welcome"]
        assert message_for(outbox, v1, "layout")["followers"] == 1
        assert message_for(outbox, v1, "layout") == message_for(outbox, v2, "layout")
        assert registry.layout_dto()["followers"] == 1

    def test_a_non_kiosk_join_says_nothing_about_the_layout(self, mesh):
        _sharer, v1, _v2, registry = mesh
        _id, outbox = registry.join(role="viewer")
        assert "layout" not in types_for(outbox, v1)

    def test_a_kiosk_leaving_pushes_the_new_follower_count(self, mesh):
        _sharer, v1, v2, registry = mesh
        kiosk, _ = registry.join(role="viewer", kiosk=True)
        assert registry.layout_dto()["followers"] == 1
        outbox = registry.leave(kiosk)
        assert {t for t, _ in outbox} == {v1, v2}
        assert message_for(outbox, v1, "layout")["followers"] == 0
        assert registry.layout_dto()["followers"] == 0

    def test_a_peer_joined_after_an_arrange_arrives_already_arranged(self, mesh):
        sharer, _v1, _v2, registry = mesh
        registry.set_layout(sharer, staged=sharer, fullscreen=True)
        late, outbox = registry.join(role="viewer", kiosk=True)
        welcome = message_for(outbox, late, "welcome")
        assert welcome["layout"] == {
            "type": "layout",
            "staged": sharer,
            "fullscreen": True,
            "followers": 1,
        }

    def test_a_dead_peer_cannot_arrange_the_wall(self, mesh):
        _sharer, _v1, _v2, registry = mesh
        with pytest.raises(RegistryError) as excinfo:
            registry.set_layout("ghost", staged="ghost")
        assert excinfo.value.code == "unknown_peer"


class TestRenameAndStats:
    def test_rename_refreshes_the_mirrors_that_show_it(self, mesh):
        sharer, v1, _v2, registry = mesh
        outbox = registry.rename(sharer, name="Meeting Room")
        assert message_for(outbox, v1, "stream_updated")["stream"]["name"] == "Meeting Room"
        assert registry.roster()[0]["name"] == "Meeting Room"

    def test_rename_to_the_same_name_is_quiet(self, mesh):
        sharer, _v1, _v2, registry = mesh
        assert registry.rename(sharer, name="Linux Box") == []

    def test_stats_count_every_role(self, mesh):
        sharer, v1, _v2, registry = mesh
        registry.subscribe(v1, sharer)
        assert registry.stats() == {
            "mirrors": 1,
            "sharers": 1,
            "viewers": 2,
            "connections": 3,
            "watching": 1,
        }

    def test_roster_is_oldest_first(self, registry):
        first, _ = registry.join(role="sharer", name="first")
        registry.publish(first, label="first")
        second, _ = registry.join(role="sharer", name="second")
        registry.publish(second, label="second")
        assert [s["label"] for s in registry.roster()] == ["first", "second"]