package hub

import (
	"context"
	"errors"
	"io"
	"log/slog"
	"testing"
	"time"
)

func TestAuthorizeIsTheAdmittedParticipationRule(t *testing.T) {
	now := time.Date(2026, 9, 10, 9, 0, 0, 0, time.UTC)
	h := testHub(&now)
	ctx := context.Background()
	a, _ := h.Open("r1", "sa", 1, "Ann", KindMember)
	if err := h.Authorize(ctx, "r1", "sa", a.Peer); !errors.Is(err, ErrNotAdmitted) {
		t.Fatalf("unjoined: want ErrNotAdmitted, got %v", err)
	}
	if err := h.Join(ctx, "r1", "sa", a.Peer); err != nil {
		t.Fatal(err)
	}
	if err := h.Authorize(ctx, "r1", "sa", a.Peer); err != nil {
		t.Fatalf("admitted member: %v", err)
	}
	if err := h.Authorize(ctx, "r1", "sb", a.Peer); !errors.Is(err, ErrUnknownPeer) {
		t.Fatalf("another session: want ErrUnknownPeer, got %v", err)
	}
	if err := h.Authorize(ctx, "r2", "sa", a.Peer); !errors.Is(err, ErrUnknownPeer) {
		t.Fatalf("another room: want ErrUnknownPeer, got %v", err)
	}
	// personID 100 is testHub's own guest threshold (personID < 100 is a
	// member, as TestMemberJoinsAndGuestWaits in admission_test.go
	// already relies on) — a personID of 2 here would derive as a
	// member and be admitted outright, proving nothing about a waiting
	// guest.
	g, _ := h.Open("r1", "sg", 100, "Gus", KindGuest)
	h.Join(ctx, "r1", "sg", g.Peer)
	if err := h.Authorize(ctx, "r1", "sg", g.Peer); !errors.Is(err, ErrNotAdmitted) {
		t.Fatalf("waiting guest: want ErrNotAdmitted, got %v", err)
	}
}

// TestAuthorizeDropsAMemberWhoseStandingIsGoneAndKeepsAnAdmittedGuest is
// §15.12 through Authorize, mirroring admission_test.go's
// TestJoinDropsAndAnnouncesAMemberWhoLostStanding: standing is a
// mutable map keyed on personID, moved without a tick running, so the
// only thing that could have refused the member is Authorize's own
// re-derivation. Bob is admitted as a guest (personID 100, testHub's
// own guest threshold) before his grant "expires" — ruling 14 says
// Authorize never even *asks* for a guest, which is asserted directly
// by counting StandingFor calls: standingLostLocked's own admitted-
// guest guard would still make the *outcome* (nil, participation kept)
// look right even if memberStandingGone's early return for a
// non-member kind were deleted and it called StandingFor for Bob
// anyway — so the outcome alone does not discriminate that mutation.
// The call count does.
func TestAuthorizeDropsAMemberWhoseStandingIsGoneAndKeepsAnAdmittedGuest(t *testing.T) {
	now := time.Date(2026, 9, 10, 9, 0, 0, 0, time.UTC)
	standing := map[int64]bool{1: true, 100: true}
	guestStandingCalls := 0
	h := New(Config{
		Now:    func() time.Time { return now },
		Logger: slog.New(slog.NewTextHandler(io.Discard, nil)),
		StandingFor: func(ctx context.Context, room string, id int64) (Kind, bool, error) {
			if id == 100 {
				guestStandingCalls++
				return KindGuest, standing[id], nil
			}
			return KindMember, standing[id], nil
		},
	})
	ctx := context.Background()
	a, _ := h.Open("r1", "sa", 1, "Ann", KindMember)
	if err := h.Join(ctx, "r1", "sa", a.Peer); err != nil {
		t.Fatal(err)
	}
	b, _ := h.Open("r1", "sb", 100, "Bob", KindGuest)
	if err := h.Join(ctx, "r1", "sb", b.Peer); err != nil {
		t.Fatal(err)
	}
	if err := h.Admit(ctx, "r1", "sa", a.Peer, b.Peer); err != nil {
		t.Fatal(err)
	}
	drain(a.Sub)
	drain(b.Sub)

	standing[1] = false // Ann taken off the team, no tick has run
	if err := h.Authorize(ctx, "r1", "sa", a.Peer); !errors.Is(err, ErrNotYours) {
		t.Fatalf("member whose standing is gone: want ErrNotYours, got %v", err)
	}
	if _, found := h.Find("r1", "sa", a.Peer); found {
		t.Fatal("Ann's participation should have ended")
	}
	bev := drain(b.Sub)
	if len(bev) == 0 || bev[len(bev)-1].Type != TypeGone || bev[len(bev)-1].From != a.Peer {
		t.Fatalf("Bob's stream got %v, want gone naming Ann last", types(bev))
	}

	standing[100] = false // Bob's grant has "expired"
	before := guestStandingCalls
	if err := h.Authorize(ctx, "r1", "sb", b.Peer); err != nil {
		t.Fatalf("admitted guest with a lapsed grant: %v", err)
	}
	if guestStandingCalls != before {
		t.Fatalf("Authorize asked StandingFor for a guest: %d calls during this Authorize, want 0", guestStandingCalls-before)
	}
}