package roomserver_test

import (
	"encoding/json"
	"errors"
	"testing"

	"github.com/dariuszjaniak/warp/server/internal/matrix/auth"
	"github.com/dariuszjaniak/warp/server/internal/matrix/event"
	"github.com/dariuszjaniak/warp/server/internal/roomserver"
)

func TestJoinPublicRoom(t *testing.T) {
	f := newFixture(t, nil)
	resp := f.createRoom(roomserver.CreateRoomRequest{Preset: roomserver.PresetPublicChat})

	joined, err := f.api.JoinRoom(t.Context(), roomserver.JoinRequest{
		RoomID: resp.RoomID,
		User:   bob,
	})
	if err != nil {
		t.Fatalf("JoinRoom: %v", err)
	}
	if joined != resp.RoomID {
		t.Errorf("JoinRoom returned %q, want %q", joined, resp.RoomID)
	}
	if got := f.membership(resp.RoomID, bob); got != event.MembershipJoin {
		t.Errorf("bob's membership is %q, want join", got)
	}

	// A second join is a no-op, not a second event: clients call /join to
	// make sure, and every extra membership event lands in everybody's
	// timeline.
	before, err := f.store.Event(t.Context(), resp.RoomID, f.memberEventID(resp.RoomID, bob))
	if err != nil {
		t.Fatalf("Event: %v", err)
	}
	if _, err := f.api.JoinRoom(t.Context(), roomserver.JoinRequest{
		RoomID: resp.RoomID, User: bob,
	}); err != nil {
		t.Fatalf("joining twice: %v", err)
	}
	after, err := f.store.Event(t.Context(), resp.RoomID, f.memberEventID(resp.RoomID, bob))
	if err != nil {
		t.Fatalf("Event: %v", err)
	}
	if after.EventID != before.EventID {
		t.Errorf("joining twice produced a second membership event")
	}

	// The joined-member count follows.
	summary, err := f.store.RoomSummary(t.Context(), resp.RoomID)
	if err != nil {
		t.Fatalf("RoomSummary: %v", err)
	}
	if summary.JoinedMembers != 2 {
		t.Errorf("the room has %d joined members, want 2", summary.JoinedMembers)
	}
}

// memberEventID is the event ID of a user's current membership event.
func (f *fixture) memberEventID(roomID, userID string) string {
	f.t.Helper()
	entry, err := f.store.Membership(f.t.Context(), roomID, userID)
	if err != nil {
		f.t.Fatalf("Membership: %v", err)
	}
	return entry.EventID
}

func TestJoinInviteOnlyRoom(t *testing.T) {
	f := newFixture(t, nil)
	resp := f.createRoom(roomserver.CreateRoomRequest{Preset: roomserver.PresetPrivateChat})

	// Without an invite the rules refuse the join. The refusal comes from
	// them, not from a check in this package.
	_, err := f.api.JoinRoom(t.Context(), roomserver.JoinRequest{
		RoomID: resp.RoomID, User: bob,
	})
	if !errors.Is(err, roomserver.ErrRejected) {
		t.Fatalf("joining an invite-only room = %v, want ErrRejected", err)
	}

	if err := f.api.InviteUser(t.Context(), roomserver.InviteRequest{
		RoomID: resp.RoomID, Sender: alice, Target: bob,
	}); err != nil {
		t.Fatalf("InviteUser: %v", err)
	}
	if got := f.membership(resp.RoomID, bob); got != event.MembershipInvite {
		t.Errorf("bob's membership after the invite is %q, want invite", got)
	}

	if _, err := f.api.JoinRoom(t.Context(), roomserver.JoinRequest{
		RoomID: resp.RoomID, User: bob,
	}); err != nil {
		t.Fatalf("joining after an invite: %v", err)
	}
	if got := f.membership(resp.RoomID, bob); got != event.MembershipJoin {
		t.Errorf("bob's membership after joining is %q, want join", got)
	}
}

// TestInviteRequiresPower is the rule a room's moderators rely on.
func TestInviteRequiresPower(t *testing.T) {
	f := newFixture(t, nil)
	resp := f.createRoom(roomserver.CreateRoomRequest{Preset: roomserver.PresetPublicChat})

	if _, err := f.api.JoinRoom(t.Context(), roomserver.JoinRequest{
		RoomID: resp.RoomID, User: bob,
	}); err != nil {
		t.Fatalf("bob joining: %v", err)
	}

	// The default invite level is 0, so bob can invite. Raise it and he
	// cannot.
	if _, err := f.api.SendEvent(t.Context(), roomserver.SendEventRequest{
		RoomID:   resp.RoomID,
		Sender:   alice,
		Type:     event.TypePowerLevels,
		StateKey: stringPtr(""),
		Content:  json.RawMessage(`{"invite":50,"users":{"` + alice + `":100}}`),
	}); err != nil {
		t.Fatalf("raising the invite level: %v", err)
	}

	err := f.api.InviteUser(t.Context(), roomserver.InviteRequest{
		RoomID: resp.RoomID, Sender: bob, Target: carol,
	})
	if !errors.Is(err, roomserver.ErrRejected) {
		t.Errorf("an invite without the power = %v, want ErrRejected", err)
	}
}

func TestLeaveAndRejectInvite(t *testing.T) {
	f := newFixture(t, nil)
	resp := f.createRoom(roomserver.CreateRoomRequest{Preset: roomserver.PresetPublicChat})

	if _, err := f.api.JoinRoom(t.Context(), roomserver.JoinRequest{
		RoomID: resp.RoomID, User: bob,
	}); err != nil {
		t.Fatalf("bob joining: %v", err)
	}
	if err := f.api.LeaveRoom(t.Context(), resp.RoomID, bob, "bye"); err != nil {
		t.Fatalf("LeaveRoom: %v", err)
	}
	if got := f.membership(resp.RoomID, bob); got != event.MembershipLeave {
		t.Errorf("bob's membership after leaving is %q, want leave", got)
	}

	// The same endpoint rejects an invite, which is why it has to work on
	// a room the caller was never joined to.
	if err := f.api.InviteUser(t.Context(), roomserver.InviteRequest{
		RoomID: resp.RoomID, Sender: alice, Target: carol,
	}); err != nil {
		t.Fatalf("InviteUser: %v", err)
	}
	if err := f.api.LeaveRoom(t.Context(), resp.RoomID, carol, "no thanks"); err != nil {
		t.Fatalf("rejecting an invite: %v", err)
	}
	if got := f.membership(resp.RoomID, carol); got != event.MembershipLeave {
		t.Errorf("carol's membership after rejecting is %q, want leave", got)
	}

	// Leaving a room you were never in is refused by the rules.
	err := f.api.LeaveRoom(t.Context(), resp.RoomID, "@dave:"+testServerName, "")
	if !errors.Is(err, roomserver.ErrRejected) {
		t.Errorf("leaving a room never joined = %v, want ErrRejected", err)
	}
}

func TestKickBanAndUnban(t *testing.T) {
	f := newFixture(t, nil)
	resp := f.createRoom(roomserver.CreateRoomRequest{Preset: roomserver.PresetPublicChat})

	join := func(user string) {
		t.Helper()
		if _, err := f.api.JoinRoom(t.Context(), roomserver.JoinRequest{
			RoomID: resp.RoomID, User: user,
		}); err != nil {
			t.Fatalf("%s joining: %v", user, err)
		}
	}
	join(bob)

	if err := f.api.KickUser(t.Context(), resp.RoomID, alice, bob, "behave"); err != nil {
		t.Fatalf("KickUser: %v", err)
	}
	if got := f.membership(resp.RoomID, bob); got != event.MembershipLeave {
		t.Errorf("bob's membership after the kick is %q, want leave", got)
	}
	// A kick is not a ban: bob can come back.
	join(bob)

	if err := f.api.BanUser(t.Context(), resp.RoomID, alice, bob, "enough"); err != nil {
		t.Fatalf("BanUser: %v", err)
	}
	if got := f.membership(resp.RoomID, bob); got != event.MembershipBan {
		t.Errorf("bob's membership after the ban is %q, want ban", got)
	}
	_, err := f.api.JoinRoom(t.Context(), roomserver.JoinRequest{
		RoomID: resp.RoomID, User: bob,
	})
	if !errors.Is(err, roomserver.ErrRejected) {
		t.Errorf("a banned user joining = %v, want ErrRejected", err)
	}

	if err := f.api.UnbanUser(t.Context(), resp.RoomID, alice, bob, ""); err != nil {
		t.Fatalf("UnbanUser: %v", err)
	}
	// Unbanning leaves the user outside the room, not in it.
	if got := f.membership(resp.RoomID, bob); got != event.MembershipLeave {
		t.Errorf("bob's membership after the unban is %q, want leave", got)
	}
	join(bob)

	// Unbanning somebody who is not banned says so rather than writing an
	// event that means nothing.
	err = f.api.UnbanUser(t.Context(), resp.RoomID, alice, bob, "")
	if !errors.Is(err, roomserver.ErrForbidden) {
		t.Errorf("unbanning a member = %v, want ErrForbidden", err)
	}
}

// TestKickRequiresPower checks that a member cannot remove a peer.
func TestKickRequiresPower(t *testing.T) {
	f := newFixture(t, nil)
	resp := f.createRoom(roomserver.CreateRoomRequest{Preset: roomserver.PresetPublicChat})

	for _, user := range []string{bob, carol} {
		if _, err := f.api.JoinRoom(t.Context(), roomserver.JoinRequest{
			RoomID: resp.RoomID, User: user,
		}); err != nil {
			t.Fatalf("%s joining: %v", user, err)
		}
	}

	err := f.api.KickUser(t.Context(), resp.RoomID, bob, carol, "")
	if !errors.Is(err, roomserver.ErrRejected) {
		t.Errorf("a kick without the power = %v, want ErrRejected", err)
	}
}

// TestMembershipRemoteUsersNeedFederation is the behaviour PLAN.md section 3
// asks for: a clear refusal rather than a bare M_FORBIDDEN.
func TestMembershipRemoteUsersNeedFederation(t *testing.T) {
	f := newFixture(t, nil)
	resp := f.createRoom(roomserver.CreateRoomRequest{})

	err := f.api.InviteUser(t.Context(), roomserver.InviteRequest{
		RoomID: resp.RoomID, Sender: alice, Target: "@eve:elsewhere.example",
	})
	if !errors.Is(err, roomserver.ErrFederationDisabled) {
		t.Errorf("inviting a remote user = %v, want ErrFederationDisabled", err)
	}

	_, err = f.api.JoinRoom(t.Context(), roomserver.JoinRequest{
		RoomID: "!elsewhere:elsewhere.example", User: alice,
	})
	if !errors.Is(err, roomserver.ErrFederationDisabled) {
		t.Errorf("joining a remote room = %v, want ErrFederationDisabled", err)
	}

	// With federation on it is still not implemented, and says so — but it
	// says it as a federation problem rather than as a missing room.
	g := newFixture(t, func(opts *roomserver.Options) {
		opts.FederationEnabled = func() bool { return true }
	})
	_, err = g.api.JoinRoom(t.Context(), roomserver.JoinRequest{
		RoomID: "!elsewhere:elsewhere.example", User: alice,
	})
	if !errors.Is(err, roomserver.ErrFederationDisabled) {
		t.Errorf("joining a remote room with federation on = %v, want ErrFederationDisabled", err)
	}
}

// TestRestrictedJoin is the one authorisation rule that needs a signature
// checked, and so the one that needs this server to vouch for a join.
func TestRestrictedJoin(t *testing.T) {
	f := newFixture(t, nil)

	// The space whose membership grants entry.
	space := f.createRoom(roomserver.CreateRoomRequest{Preset: roomserver.PresetPublicChat})

	restricted := f.createRoom(roomserver.CreateRoomRequest{
		Version: "11",
		InitialState: []roomserver.StateEvent{{
			Type: event.TypeJoinRules,
			Content: json.RawMessage(`{"join_rule":"restricted","allow":[` +
				`{"type":"m.room_membership","room_id":"` + space.RoomID + `"}]}`),
		}},
	})

	// Not in the space: no entry.
	_, err := f.api.JoinRoom(t.Context(), roomserver.JoinRequest{
		RoomID: restricted.RoomID, User: bob,
	})
	if !errors.Is(err, roomserver.ErrForbidden) {
		t.Fatalf("joining a restricted room from outside = %v, want ErrForbidden", err)
	}

	if _, err := f.api.JoinRoom(t.Context(), roomserver.JoinRequest{
		RoomID: space.RoomID, User: bob,
	}); err != nil {
		t.Fatalf("bob joining the space: %v", err)
	}

	// In the space: the join is authorised via a local user with the power
	// to invite, and the event carries their server's signature.
	if _, err := f.api.JoinRoom(t.Context(), roomserver.JoinRequest{
		RoomID: restricted.RoomID, User: bob,
	}); err != nil {
		t.Fatalf("joining a restricted room from the space: %v", err)
	}
	if got := f.membership(restricted.RoomID, bob); got != event.MembershipJoin {
		t.Errorf("bob's membership is %q, want join", got)
	}

	st := f.state(restricted.RoomID)
	member := st.Member(bob)
	if member == nil {
		t.Fatal("bob has no membership event")
	}
	var content struct {
		AuthorisedVia string `json:"join_authorised_via_users_server"`
	}
	if err := json.Unmarshal(member.Content(), &content); err != nil {
		t.Fatalf("the membership content is not an object: %v", err)
	}
	if content.AuthorisedVia != alice {
		t.Errorf("join_authorised_via_users_server = %q, want %q", content.AuthorisedVia, alice)
	}
}

func TestJoinedRoomsAndMembers(t *testing.T) {
	f := newFixture(t, nil)
	first := f.createRoom(roomserver.CreateRoomRequest{Preset: roomserver.PresetPublicChat})
	second := f.createRoom(roomserver.CreateRoomRequest{Preset: roomserver.PresetPublicChat})

	if _, err := f.api.JoinRoom(t.Context(), roomserver.JoinRequest{
		RoomID: first.RoomID, User: bob,
	}); err != nil {
		t.Fatalf("bob joining: %v", err)
	}

	rooms, err := f.api.JoinedRooms(t.Context(), bob)
	if err != nil {
		t.Fatalf("JoinedRooms: %v", err)
	}
	if len(rooms) != 1 || rooms[0] != first.RoomID {
		t.Errorf("bob's joined rooms = %v, want [%s]", rooms, first.RoomID)
	}

	aliceRooms, err := f.api.JoinedRooms(t.Context(), alice)
	if err != nil {
		t.Fatalf("JoinedRooms: %v", err)
	}
	if len(aliceRooms) != 2 {
		t.Errorf("alice is joined to %v, want both rooms", aliceRooms)
	}

	joined, err := f.api.JoinedMembers(t.Context(), first.RoomID, alice)
	if err != nil {
		t.Fatalf("JoinedMembers: %v", err)
	}
	if len(joined) != 2 {
		t.Fatalf("JoinedMembers returned %d members, want 2: %+v", len(joined), joined)
	}
	if joined[bob].DisplayName != "Bob" {
		t.Errorf("bob's display name is %q, want Bob", joined[bob].DisplayName)
	}

	// /joined_members is for members: a stranger is refused.
	if _, err := f.api.JoinedMembers(t.Context(), second.RoomID, bob); !errors.Is(err, roomserver.ErrForbidden) {
		t.Errorf("JoinedMembers for a stranger = %v, want ErrForbidden", err)
	}

	// /members includes the users who have left, unless filtered.
	if err := f.api.LeaveRoom(t.Context(), first.RoomID, bob, ""); err != nil {
		t.Fatalf("LeaveRoom: %v", err)
	}
	all, err := f.api.Members(t.Context(), roomserver.MembersRequest{
		RoomID: first.RoomID, User: alice,
	})
	if err != nil {
		t.Fatalf("Members: %v", err)
	}
	if len(all) != 2 {
		t.Errorf("Members returned %d events, want 2 (one of them a leave)", len(all))
	}
	onlyJoined, err := f.api.Members(t.Context(), roomserver.MembersRequest{
		RoomID: first.RoomID, User: alice, Membership: event.MembershipJoin,
	})
	if err != nil {
		t.Fatalf("Members with a filter: %v", err)
	}
	if len(onlyJoined) != 1 {
		t.Errorf("filtering by join returned %d events, want 1", len(onlyJoined))
	}
	notJoined, err := f.api.Members(t.Context(), roomserver.MembersRequest{
		RoomID: first.RoomID, User: alice, NotMembership: event.MembershipJoin,
	})
	if err != nil {
		t.Fatalf("Members with not_membership: %v", err)
	}
	if len(notJoined) != 1 {
		t.Errorf("not_membership=join returned %d events, want 1", len(notJoined))
	}
}

// TestStateVisibility is the room-level visibility check the read endpoints
// make: a member sees the room, a stranger does not, and anyone sees a
// world-readable one.
func TestStateVisibility(t *testing.T) {
	f := newFixture(t, nil)
	private := f.createRoom(roomserver.CreateRoomRequest{})

	if _, err := f.api.RoomState(t.Context(), private.RoomID, alice); err != nil {
		t.Errorf("the creator cannot read their own room's state: %v", err)
	}
	if _, err := f.api.RoomState(t.Context(), private.RoomID, bob); !errors.Is(err, roomserver.ErrForbidden) {
		t.Errorf("a stranger reading state = %v, want ErrForbidden", err)
	}

	readable := f.createRoom(roomserver.CreateRoomRequest{
		InitialState: []roomserver.StateEvent{{
			Type:    event.TypeHistoryVisibility,
			Content: json.RawMessage(`{"history_visibility":"world_readable"}`),
		}},
	})
	if _, err := f.api.RoomState(t.Context(), readable.RoomID, bob); err != nil {
		t.Errorf("a stranger cannot read a world-readable room's state: %v", err)
	}
}

// TestForceLeave is the admin escape hatch: it adds a real membership
// event, so the room's other members see what happened.
func TestForceLeave(t *testing.T) {
	f := newFixture(t, nil)
	resp := f.createRoom(roomserver.CreateRoomRequest{Preset: roomserver.PresetPublicChat})

	if _, err := f.api.JoinRoom(t.Context(), roomserver.JoinRequest{
		RoomID: resp.RoomID, User: bob,
	}); err != nil {
		t.Fatalf("bob joining: %v", err)
	}
	if err := f.api.ForceLeave(t.Context(), resp.RoomID, bob); err != nil {
		t.Fatalf("ForceLeave: %v", err)
	}
	if got := f.membership(resp.RoomID, bob); got != event.MembershipLeave {
		t.Errorf("bob's membership is %q, want leave", got)
	}

	// A user who is not in the room has nothing to leave.
	if err := f.api.ForceLeave(t.Context(), resp.RoomID, carol); !errors.Is(err, roomserver.ErrForbidden) {
		t.Errorf("force-leaving a stranger = %v, want ErrForbidden", err)
	}
}

// TestPowerLevelsCannotBeRaisedAboveYourOwn is the rule that keeps a
// moderator from promoting themselves.
func TestPowerLevelsCannotBeRaisedAboveYourOwn(t *testing.T) {
	f := newFixture(t, nil)
	resp := f.createRoom(roomserver.CreateRoomRequest{
		Version: "11",
		Preset:  roomserver.PresetPublicChat,
		PowerLevelContentOverride: json.RawMessage(
			`{"users":{"` + alice + `":100,"` + bob + `":50}}`),
	})

	if _, err := f.api.JoinRoom(t.Context(), roomserver.JoinRequest{
		RoomID: resp.RoomID, User: bob,
	}); err != nil {
		t.Fatalf("bob joining: %v", err)
	}

	_, err := f.api.SendEvent(t.Context(), roomserver.SendEventRequest{
		RoomID:   resp.RoomID,
		Sender:   bob,
		Type:     event.TypePowerLevels,
		StateKey: stringPtr(""),
		Content:  json.RawMessage(`{"users":{"` + alice + `":100,"` + bob + `":100}}`),
	})
	if !errors.Is(err, roomserver.ErrRejected) {
		t.Errorf("promoting yourself = %v, want ErrRejected", err)
	}

	st := f.state(resp.RoomID)
	powerLevels, err := auth.ResolvePowerLevels(st.PowerLevels(), st.Create(), st.Create().Rules())
	if err != nil {
		t.Fatalf("ResolvePowerLevels: %v", err)
	}
	if got := powerLevels.UserLevel(bob); got != 50 {
		t.Errorf("bob's power level is %d, want 50", got)
	}
}

// TestKickRequiresTheTargetToBeInTheRoom keeps a kick from adding a leave
// event for somebody who was never there — which the authorisation rules
// would accept, and which every member of the room would then see.
func TestKickRequiresTheTargetToBeInTheRoom(t *testing.T) {
	f := newFixture(t, nil)
	resp := f.createRoom(roomserver.CreateRoomRequest{Preset: roomserver.PresetPublicChat})

	err := f.api.KickUser(t.Context(), resp.RoomID, alice, bob, "")
	if !errors.Is(err, roomserver.ErrForbidden) {
		t.Errorf("kicking a stranger = %v, want ErrForbidden", err)
	}

	// An invite can be withdrawn with a kick, which is what the endpoint
	// is for as much as removing a member is.
	if err := f.api.InviteUser(t.Context(), roomserver.InviteRequest{
		RoomID: resp.RoomID, Sender: alice, Target: bob,
	}); err != nil {
		t.Fatalf("InviteUser: %v", err)
	}
	if err := f.api.KickUser(t.Context(), resp.RoomID, alice, bob, ""); err != nil {
		t.Fatalf("withdrawing an invite with a kick: %v", err)
	}
	if got := f.membership(resp.RoomID, bob); got != event.MembershipLeave {
		t.Errorf("bob's membership is %q, want leave", got)
	}

	// Lifting a ban is /unban, not a kick.
	if err := f.api.BanUser(t.Context(), resp.RoomID, alice, bob, ""); err != nil {
		t.Fatalf("BanUser: %v", err)
	}
	if err := f.api.KickUser(t.Context(), resp.RoomID, alice, bob, ""); !errors.Is(err, roomserver.ErrForbidden) {
		t.Errorf("kicking a banned user = %v, want ErrForbidden", err)
	}
}