Refactor EventTile using the MVVM pattern - #5b (#33600)

* Extract EventTile E2E padlock state

* Refactor EventTile E2E padlock rendering after review comments

apps/web/src/components/views/rooms/EventTile.tsx

@@ -22,7 +22,7 @@ import React, {
 } from "react";
 import classNames from "classnames";
 import {
-    EventStatus,
+    type EventStatus,
     EventType,
     type MatrixEvent,
     MatrixEventEvent,
@@ -38,9 +38,8 @@ import { logger } from "matrix-js-sdk/src/logger";
 import { CallErrorCode } from "matrix-js-sdk/src/webrtc/call";
 import {
     CryptoEvent,
-    DecryptionFailureCode,
     EventShieldColour,
-    EventShieldReason,
+    type EventShieldReason,
     type UserVerificationStatus,
 } from "matrix-js-sdk/src/crypto-api";
 import { Tooltip } from "@vector-im/compound-web";
@@ -49,8 +48,6 @@ import { CircleIcon, CheckCircleIcon, ThreadsIcon } from "@vector-im/compound-de
 import {
     useCreateAutoDisposedViewModel,
     ActionBarView,
-    E2ePadlock,
-    E2ePadlockIcon,
     MessageTimestampView,
     PinnedMessageBadge,
     ReactionsRowButtonView,
@@ -98,7 +95,8 @@ import { getLateEventInfo } from "../../structures/grouper/LateEventGrouper";
 import { Icon as LateIcon } from "../../../../res/img/sensor.svg";
 import PinningUtils from "../../../utils/PinningUtils";
 import { EventPreview } from "./EventPreview";
-import { E2eMessageSharedIcon } from "./EventTile/E2eMessageSharedIcon.tsx";
+import { E2eStandardPadlockIcon } from "./EventTile/E2eStandardPadlockIcon";
+import { E2eMessageSharedIcon } from "./EventTile/E2eMessageSharedIcon";
 import SettingsStore from "../../../settings/SettingsStore";
 import { CardContext } from "../right_panel/context";
 import { EventTileViewModel } from "../../../viewmodels/room/timeline/event-tile/EventTileViewModel";
@@ -144,6 +142,7 @@ import { ThreadListActionBarViewModel } from "../../../viewmodels/room/ThreadLis
 import { useMatrixClientContext } from "../../../contexts/MatrixClientContext";
 import { useSettingValue } from "../../../hooks/useSettings";
 import { DecryptionFailureBodyFactory, RedactedBodyFactory } from "../messages/MBodyFactory";
+import { getEventTileE2ePadlockViewState } from "../../../viewmodels/room/timeline/event-tile/EventTileE2eState";
 
 /** Relation lookup type retained for EventTile consumers. */
 export type { GetRelationsForEvent } from "../../../viewmodels/room/timeline/event-tile/reactions/EventTileReactionState";
@@ -728,120 +727,29 @@ export class UnwrappedEventTile extends React.Component<EventTileProps, IState>
     private renderE2EPadlock(): ReactNode {
         // if the event was edited, show the verification info for the edit, not
         // the original
-        const ev = this.props.mxEvent.replacingEvent() ?? this.props.mxEvent;
+        const verificationEvent = this.props.mxEvent.replacingEvent() ?? this.props.mxEvent;
+        const e2ePadlockViewState = getEventTileE2ePadlockViewState({
+            mxEvent: this.props.mxEvent,
+            verificationEvent,
+            shieldColour: this.state.shieldColour,
+            shieldReason: this.state.shieldReason,
+            isRoomEncrypted: this.context.isRoomEncrypted,
+            isLocalRoom: isLocalRoom(verificationEvent.getRoomId()!),
+        });
 
-        // no icon for local rooms
-        if (isLocalRoom(ev.getRoomId()!)) return null;
-
-        // event could not be decrypted
-        if (ev.isDecryptionFailure()) {
-            switch (ev.decryptionFailureReason) {
-                // These two errors get icons from DecryptionFailureBody, so we hide the padlock icon
-                case DecryptionFailureCode.SENDER_IDENTITY_PREVIOUSLY_VERIFIED:
-                case DecryptionFailureCode.UNSIGNED_SENDER_DEVICE:
-                    return null;
-                default:
-                    return <E2ePadlockDecryptionFailure />;
-            }
-        }
-
-        if (this.state.shieldReason === EventShieldReason.AUTHENTICITY_NOT_GUARANTEED) {
-            // This may happen if the message was forwarded to us by another user, in which case we can show a better message
-            const forwarder = this.props.mxEvent.getKeyForwardingUser();
-            if (forwarder) {
-                return <E2eMessageSharedIcon keyForwardingUserId={forwarder} roomId={ev.getRoomId()!} />;
-            }
-        }
-
-        if (this.state.shieldColour !== EventShieldColour.NONE) {
-            let shieldReasonMessage: string;
-            switch (this.state.shieldReason) {
-                case EventShieldReason.UNVERIFIED_IDENTITY:
-                    shieldReasonMessage = _t("encryption|event_shield_reason_unverified_identity");
-                    break;
-
-                case EventShieldReason.UNSIGNED_DEVICE:
-                    shieldReasonMessage = _t("encryption|event_shield_reason_unsigned_device");
-                    break;
-
-                case EventShieldReason.UNKNOWN_DEVICE:
-                    shieldReasonMessage = _t("encryption|event_shield_reason_unknown_device");
-                    break;
-
-                case EventShieldReason.AUTHENTICITY_NOT_GUARANTEED:
-                    shieldReasonMessage = _t("encryption|event_shield_reason_authenticity_not_guaranteed");
-                    break;
-
-                case EventShieldReason.MISMATCHED_SENDER_KEY:
-                    shieldReasonMessage = _t("encryption|event_shield_reason_mismatched_sender_key");
-                    break;
-
-                case EventShieldReason.SENT_IN_CLEAR:
-                    shieldReasonMessage = _t("common|unencrypted");
-                    break;
-
-                case EventShieldReason.VERIFICATION_VIOLATION:
-                    shieldReasonMessage = _t("timeline|decryption_failure|sender_identity_previously_verified");
-                    break;
-
-                case EventShieldReason.MISMATCHED_SENDER:
-                    shieldReasonMessage = _t("encryption|event_shield_reason_mismatched_sender");
-                    break;
-
-                default:
-                    shieldReasonMessage = _t("error|unknown");
-                    break;
-            }
-
-            if (this.state.shieldColour === EventShieldColour.GREY) {
+        switch (e2ePadlockViewState.kind) {
+            case "none":
+                return null;
+            case "messageShared":
                 return (
-                    <E2ePadlock
-                        className={
-                            // Timeline PCSS uses this app class as a layout hook for positioning and layout variants.
-                            "mx_EventTile_e2eIcon"
-                        }
-                        icon={E2ePadlockIcon.Normal}
-                        title={shieldReasonMessage}
+                    <E2eMessageSharedIcon
+                        keyForwardingUserId={e2ePadlockViewState.keyForwardingUserId}
+                        roomId={e2ePadlockViewState.roomId}
                     />
                 );
-            } else {
-                // red, by elimination
-                return (
-                    <E2ePadlock
-                        className={
-                            // Timeline PCSS uses this app class as a layout hook for positioning and layout variants.
-                            "mx_EventTile_e2eIcon"
-                        }
-                        icon={E2ePadlockIcon.Warning}
-                        title={shieldReasonMessage}
-                    />
-                );
-            }
+            case "icon":
+                return <E2eStandardPadlockIcon icon={e2ePadlockViewState.icon} title={e2ePadlockViewState.title} />;
         }
-
-        if (this.context.isRoomEncrypted) {
-            // else if room is encrypted
-            // and event is being encrypted or is not_sent (Unknown Devices/Network Error)
-            if (ev.status === EventStatus.ENCRYPTING) {
-                return null;
-            }
-            if (ev.status === EventStatus.NOT_SENT) {
-                return null;
-            }
-            if (ev.isState()) {
-                return null; // we expect this to be unencrypted
-            }
-            if (ev.isRedacted()) {
-                return null; // we expect this to be unencrypted
-            }
-            if (!ev.isEncrypted()) {
-                // if the event is not encrypted, but it's an e2e room, show a warning
-                return <E2ePadlockUnencrypted />;
-            }
-        }
-
-        // no padlock needed
-        return null;
     }
 
     private readonly onActionBarFocusChange = (actionBarFocused: boolean): void => {
@@ -1585,32 +1493,6 @@ const SafeEventTile = (props: EventTileProps): JSX.Element => {
 };
 export default SafeEventTile;
 
-function E2ePadlockUnencrypted(): JSX.Element {
-    return (
-        <E2ePadlock
-            className={
-                // Timeline PCSS uses this app class as a layout hook for positioning and layout variants.
-                "mx_EventTile_e2eIcon"
-            }
-            title={_t("common|unencrypted")}
-            icon={E2ePadlockIcon.Warning}
-        />
-    );
-}
-
-function E2ePadlockDecryptionFailure(): JSX.Element {
-    return (
-        <E2ePadlock
-            className={
-                // Timeline PCSS uses this app class as a layout hook for positioning and layout variants.
-                "mx_EventTile_e2eIcon"
-            }
-            title={_t("timeline|undecryptable_tooltip")}
-            icon={E2ePadlockIcon.DecryptionFailure}
-        />
-    );
-}
-
 interface ISentReceiptProps {
     messageState: EventStatus | undefined;
 }

apps/web/src/components/views/rooms/EventTile/E2eStandardPadlockIcon.tsx

@@ -0,0 +1,27 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE files in the repository root for full details.
+*/
+
+import React, { type JSX } from "react";
+import { E2ePadlock, type E2ePadlockIcon } from "@element-hq/web-shared-components";
+
+interface E2eStandardPadlockIconProps {
+    icon: E2ePadlockIcon;
+    title: string;
+}
+
+export function E2eStandardPadlockIcon({ icon, title }: Readonly<E2eStandardPadlockIconProps>): JSX.Element {
+    return (
+        <E2ePadlock
+            className={
+                // Timeline PCSS uses this app class as a layout hook for positioning and layout variants.
+                "mx_EventTile_e2eIcon"
+            }
+            title={title}
+            icon={icon}
+        />
+    );
+}

apps/web/src/viewmodels/room/timeline/event-tile/EventTileE2eState.ts

@@ -0,0 +1,211 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE files in the repository root for full details.
+*/
+
+import { EventStatus, type MatrixEvent } from "matrix-js-sdk/src/matrix";
+import { DecryptionFailureCode, EventShieldColour, EventShieldReason } from "matrix-js-sdk/src/crypto-api";
+import { E2ePadlockIcon } from "@element-hq/web-shared-components";
+
+import { _t } from "../../../../languageHandler";
+
+/** Display state for the EventTile E2E padlock area. */
+export type EventTileE2ePadlockState =
+    | {
+          /** No E2E padlock should render. */
+          kind: "none";
+      }
+    | {
+          /** Render the undecryptable padlock. */
+          kind: "decryptionFailure";
+      }
+    | {
+          /** Render the forwarded/shared message indicator. */
+          kind: "messageShared";
+          /** User ID that forwarded the message key. */
+          keyForwardingUserId: string;
+          /** Room ID used by the shared-message indicator. */
+          roomId: string;
+      }
+    | {
+          /** Render a trust shield padlock. */
+          kind: "shield";
+          /** Shield colour used to choose the rendered icon. */
+          shieldColour: EventShieldColour;
+          /** Shield reason used to choose the visible tooltip. */
+          shieldReason: EventShieldReason | null;
+      }
+    | {
+          /** Render the unencrypted warning in an encrypted room. */
+          kind: "unencrypted";
+      };
+
+/** Renderable display state for the EventTile E2E padlock area. */
+export type EventTileE2ePadlockViewState =
+    | {
+          /** No E2E padlock should render. */
+          kind: "none";
+      }
+    | {
+          /** Render the shared-message indicator. */
+          kind: "messageShared";
+          /** User ID that forwarded the message key. */
+          keyForwardingUserId: string;
+          /** Room ID used by the shared-message indicator. */
+          roomId: string;
+      }
+    | {
+          /** Render a standard E2E padlock icon. */
+          kind: "icon";
+          /** Icon variant to render. */
+          icon: E2ePadlockIcon;
+          /** Tooltip shown for the icon. */
+          title: string;
+      };
+
+/** Inputs for deriving EventTile E2E padlock display state. */
+export interface EventTileE2ePadlockStateInput {
+    /** Matrix event rendered by the tile. */
+    mxEvent: MatrixEvent;
+    /** Event used for verification decisions, usually the replacing event for edits. */
+    verificationEvent: MatrixEvent;
+    /** Current event shield colour. */
+    shieldColour: EventShieldColour;
+    /** Current event shield reason. */
+    shieldReason: EventShieldReason | null;
+    /** Whether the room is encrypted. */
+    isRoomEncrypted?: boolean | null;
+    /** Whether the event belongs to a local room. */
+    isLocalRoom: boolean;
+}
+
+/** Derives the E2E padlock display state for EventTile. */
+export function getEventTileE2ePadlockState({
+    mxEvent,
+    verificationEvent,
+    shieldColour,
+    shieldReason,
+    isRoomEncrypted,
+    isLocalRoom,
+}: EventTileE2ePadlockStateInput): EventTileE2ePadlockState {
+    if (isLocalRoom) {
+        return { kind: "none" };
+    }
+
+    if (verificationEvent.isDecryptionFailure()) {
+        switch (verificationEvent.decryptionFailureReason) {
+            case DecryptionFailureCode.SENDER_IDENTITY_PREVIOUSLY_VERIFIED:
+            case DecryptionFailureCode.UNSIGNED_SENDER_DEVICE:
+                return { kind: "none" };
+            default:
+                return { kind: "decryptionFailure" };
+        }
+    }
+
+    if (shieldReason === EventShieldReason.AUTHENTICITY_NOT_GUARANTEED) {
+        const keyForwardingUserId = mxEvent.getKeyForwardingUser();
+        if (keyForwardingUserId) {
+            return {
+                kind: "messageShared",
+                keyForwardingUserId,
+                roomId: verificationEvent.getRoomId()!,
+            };
+        }
+    }
+
+    if (shieldColour !== EventShieldColour.NONE) {
+        return {
+            kind: "shield",
+            shieldColour,
+            shieldReason,
+        };
+    }
+
+    if (isRoomEncrypted) {
+        if (
+            verificationEvent.status === EventStatus.ENCRYPTING ||
+            verificationEvent.status === EventStatus.NOT_SENT ||
+            verificationEvent.isState() ||
+            verificationEvent.isRedacted()
+        ) {
+            return { kind: "none" };
+        }
+
+        if (!verificationEvent.isEncrypted()) {
+            return { kind: "unencrypted" };
+        }
+    }
+
+    return { kind: "none" };
+}
+
+function getEventTileShieldReasonMessage(shieldReason: EventShieldReason | null): string {
+    switch (shieldReason) {
+        case EventShieldReason.UNVERIFIED_IDENTITY:
+            return _t("encryption|event_shield_reason_unverified_identity");
+
+        case EventShieldReason.UNSIGNED_DEVICE:
+            return _t("encryption|event_shield_reason_unsigned_device");
+
+        case EventShieldReason.UNKNOWN_DEVICE:
+            return _t("encryption|event_shield_reason_unknown_device");
+
+        case EventShieldReason.AUTHENTICITY_NOT_GUARANTEED:
+            return _t("encryption|event_shield_reason_authenticity_not_guaranteed");
+
+        case EventShieldReason.MISMATCHED_SENDER_KEY:
+            return _t("encryption|event_shield_reason_mismatched_sender_key");
+
+        case EventShieldReason.SENT_IN_CLEAR:
+            return _t("common|unencrypted");
+
+        case EventShieldReason.VERIFICATION_VIOLATION:
+            return _t("timeline|decryption_failure|sender_identity_previously_verified");
+
+        case EventShieldReason.MISMATCHED_SENDER:
+            return _t("encryption|event_shield_reason_mismatched_sender");
+
+        default:
+            return _t("error|unknown");
+    }
+}
+
+/** Derives renderable E2E padlock display state for EventTile. */
+export function getEventTileE2ePadlockViewState(input: EventTileE2ePadlockStateInput): EventTileE2ePadlockViewState {
+    const state = getEventTileE2ePadlockState(input);
+
+    switch (state.kind) {
+        case "none":
+            return { kind: "none" };
+
+        case "decryptionFailure":
+            return {
+                kind: "icon",
+                icon: E2ePadlockIcon.DecryptionFailure,
+                title: _t("timeline|undecryptable_tooltip"),
+            };
+
+        case "messageShared":
+            return {
+                kind: "messageShared",
+                keyForwardingUserId: state.keyForwardingUserId,
+                roomId: state.roomId,
+            };
+
+        case "unencrypted":
+            return {
+                kind: "icon",
+                icon: E2ePadlockIcon.Warning,
+                title: _t("common|unencrypted"),
+            };
+
+        case "shield":
+            return {
+                kind: "icon",
+                icon: state.shieldColour === EventShieldColour.GREY ? E2ePadlockIcon.Normal : E2ePadlockIcon.Warning,
+                title: getEventTileShieldReasonMessage(state.shieldReason),
+            };
+    }
+}

apps/web/test/viewmodels/event-tiles/EventTileE2eState-test.ts

@@ -0,0 +1,267 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE files in the repository root for full details.
+*/
+
+import { EventStatus, EventType, type MatrixEvent, MsgType } from "matrix-js-sdk/src/matrix";
+import { DecryptionFailureCode, EventShieldColour, EventShieldReason } from "matrix-js-sdk/src/crypto-api";
+import { E2ePadlockIcon } from "@element-hq/web-shared-components";
+
+import { mkEvent } from "../../test-utils";
+import {
+    getEventTileE2ePadlockState,
+    getEventTileE2ePadlockViewState,
+    type EventTileE2ePadlockStateInput,
+} from "../../../src/viewmodels/room/timeline/event-tile/EventTileE2eState";
+
+const roomId = "!room:example.org";
+const userId = "@alice:example.org";
+
+function makeEvent(): MatrixEvent {
+    return mkEvent({
+        event: true,
+        type: EventType.RoomMessage,
+        room: roomId,
+        user: userId,
+        content: {
+            msgtype: MsgType.Text,
+            body: "Hello",
+        },
+    });
+}
+
+function makeInput(overrides: Partial<EventTileE2ePadlockStateInput> = {}): EventTileE2ePadlockStateInput {
+    const mxEvent = overrides.mxEvent ?? makeEvent();
+
+    return {
+        mxEvent,
+        verificationEvent: overrides.verificationEvent ?? mxEvent,
+        shieldColour: EventShieldColour.NONE,
+        shieldReason: null,
+        isRoomEncrypted: false,
+        isLocalRoom: false,
+        ...overrides,
+    };
+}
+
+function mockDecryptionFailure(mxEvent: MatrixEvent, reason: DecryptionFailureCode): void {
+    jest.spyOn(mxEvent, "isDecryptionFailure").mockReturnValue(true);
+    Object.defineProperty(mxEvent, "decryptionFailureReason", {
+        configurable: true,
+        value: reason,
+    });
+}
+
+describe("EventTileE2eState", () => {
+    it("does not show a padlock for local rooms", () => {
+        const state = getEventTileE2ePadlockState(makeInput({ isLocalRoom: true }));
+
+        expect(state.kind).toBe("none");
+    });
+
+    it("shows a decryption failure padlock for generic decryption failures", () => {
+        const mxEvent = makeEvent();
+        mockDecryptionFailure(mxEvent, DecryptionFailureCode.UNKNOWN_ERROR);
+
+        const state = getEventTileE2ePadlockState(makeInput({ mxEvent }));
+
+        expect(state.kind).toBe("decryptionFailure");
+    });
+
+    it("uses the verification event for edited event padlock decisions", () => {
+        const mxEvent = makeEvent();
+        const verificationEvent = makeEvent();
+        mockDecryptionFailure(verificationEvent, DecryptionFailureCode.UNKNOWN_ERROR);
+
+        const state = getEventTileE2ePadlockState(makeInput({ mxEvent, verificationEvent }));
+
+        expect(state.kind).toBe("decryptionFailure");
+    });
+
+    it.each([DecryptionFailureCode.SENDER_IDENTITY_PREVIOUSLY_VERIFIED, DecryptionFailureCode.UNSIGNED_SENDER_DEVICE])(
+        "does not show a padlock for %s decryption failures",
+        (reason) => {
+            const mxEvent = makeEvent();
+            mockDecryptionFailure(mxEvent, reason);
+
+            const state = getEventTileE2ePadlockState(makeInput({ mxEvent }));
+
+            expect(state.kind).toBe("none");
+        },
+    );
+
+    it("shows a message-shared state when the authenticity warning has a key forwarding user", () => {
+        const mxEvent = makeEvent();
+        jest.spyOn(mxEvent, "getKeyForwardingUser").mockReturnValue("@bob:example.org");
+
+        const state = getEventTileE2ePadlockState(
+            makeInput({
+                mxEvent,
+                shieldColour: EventShieldColour.GREY,
+                shieldReason: EventShieldReason.AUTHENTICITY_NOT_GUARANTEED,
+            }),
+        );
+
+        expect(state).toEqual({
+            kind: "messageShared",
+            keyForwardingUserId: "@bob:example.org",
+            roomId,
+        });
+    });
+
+    it("shows a normal shield for grey shield state", () => {
+        const state = getEventTileE2ePadlockState(
+            makeInput({
+                shieldColour: EventShieldColour.GREY,
+                shieldReason: EventShieldReason.UNSIGNED_DEVICE,
+            }),
+        );
+
+        expect(state).toEqual({
+            kind: "shield",
+            shieldColour: EventShieldColour.GREY,
+            shieldReason: EventShieldReason.UNSIGNED_DEVICE,
+        });
+    });
+
+    it("shows a warning shield for red shield state", () => {
+        const state = getEventTileE2ePadlockState(
+            makeInput({
+                shieldColour: EventShieldColour.RED,
+                shieldReason: EventShieldReason.UNKNOWN_DEVICE,
+            }),
+        );
+
+        expect(state).toEqual({
+            kind: "shield",
+            shieldColour: EventShieldColour.RED,
+            shieldReason: EventShieldReason.UNKNOWN_DEVICE,
+        });
+    });
+
+    it("shows an unencrypted warning for unencrypted events in encrypted rooms", () => {
+        const state = getEventTileE2ePadlockState(makeInput({ isRoomEncrypted: true }));
+
+        expect(state.kind).toBe("unencrypted");
+    });
+
+    it.each([EventStatus.ENCRYPTING, EventStatus.NOT_SENT])(
+        "does not show an unencrypted warning for %s local echo state",
+        (status) => {
+            const mxEvent = makeEvent();
+            mxEvent.status = status;
+
+            const state = getEventTileE2ePadlockState(makeInput({ mxEvent, isRoomEncrypted: true }));
+
+            expect(state.kind).toBe("none");
+        },
+    );
+
+    it("does not show an unencrypted warning for state events in encrypted rooms", () => {
+        const mxEvent = makeEvent();
+        jest.spyOn(mxEvent, "isState").mockReturnValue(true);
+
+        const state = getEventTileE2ePadlockState(makeInput({ mxEvent, isRoomEncrypted: true }));
+
+        expect(state.kind).toBe("none");
+    });
+
+    it("does not show an unencrypted warning for redacted events in encrypted rooms", () => {
+        const mxEvent = makeEvent();
+        jest.spyOn(mxEvent, "isRedacted").mockReturnValue(true);
+
+        const state = getEventTileE2ePadlockState(makeInput({ mxEvent, isRoomEncrypted: true }));
+
+        expect(state.kind).toBe("none");
+    });
+
+    it("does not show an unencrypted warning for encrypted events", () => {
+        const mxEvent = makeEvent();
+        jest.spyOn(mxEvent, "isEncrypted").mockReturnValue(true);
+
+        const state = getEventTileE2ePadlockState(makeInput({ mxEvent, isRoomEncrypted: true }));
+
+        expect(state.kind).toBe("none");
+    });
+
+    it("maps decryption failure state to the decryption failure icon view state", () => {
+        const mxEvent = makeEvent();
+        mockDecryptionFailure(mxEvent, DecryptionFailureCode.UNKNOWN_ERROR);
+
+        const state = getEventTileE2ePadlockViewState(makeInput({ mxEvent }));
+
+        expect(state).toEqual({
+            kind: "icon",
+            icon: E2ePadlockIcon.DecryptionFailure,
+            title: "This message could not be decrypted",
+        });
+    });
+
+    it("maps unencrypted state to the warning icon view state", () => {
+        const state = getEventTileE2ePadlockViewState(makeInput({ isRoomEncrypted: true }));
+
+        expect(state).toEqual({
+            kind: "icon",
+            icon: E2ePadlockIcon.Warning,
+            title: "Not encrypted",
+        });
+    });
+
+    it.each([
+        [EventShieldReason.UNKNOWN, E2ePadlockIcon.Normal, "Unknown error"],
+        [EventShieldReason.UNVERIFIED_IDENTITY, E2ePadlockIcon.Normal, "Encrypted by an unverified user."],
+        [EventShieldReason.UNSIGNED_DEVICE, E2ePadlockIcon.Normal, "Encrypted by a device not verified by its owner."],
+        [EventShieldReason.UNKNOWN_DEVICE, E2ePadlockIcon.Normal, "Encrypted by an unknown or deleted device."],
+        [
+            EventShieldReason.AUTHENTICITY_NOT_GUARANTEED,
+            E2ePadlockIcon.Warning,
+            "The authenticity of this encrypted message can't be guaranteed on this device.",
+        ],
+        [EventShieldReason.MISMATCHED_SENDER_KEY, E2ePadlockIcon.Warning, "Encrypted by an unverified session"],
+        [EventShieldReason.SENT_IN_CLEAR, E2ePadlockIcon.Warning, "Not encrypted"],
+        [
+            EventShieldReason.VERIFICATION_VIOLATION,
+            E2ePadlockIcon.Warning,
+            "Sender's verified digital identity was reset",
+        ],
+        [
+            EventShieldReason.MISMATCHED_SENDER,
+            E2ePadlockIcon.Warning,
+            "The sender of the event does not match the owner of the device that sent it.",
+        ],
+    ])("maps shield reason %s to an icon view state", (shieldReason, expectedIcon, expectedTitle) => {
+        const state = getEventTileE2ePadlockViewState(
+            makeInput({
+                shieldColour: expectedIcon === E2ePadlockIcon.Normal ? EventShieldColour.GREY : EventShieldColour.RED,
+                shieldReason,
+            }),
+        );
+
+        expect(state).toEqual({
+            kind: "icon",
+            icon: expectedIcon,
+            title: expectedTitle,
+        });
+    });
+
+    it("keeps forwarded-message state renderable by the shared-message indicator", () => {
+        const mxEvent = makeEvent();
+        jest.spyOn(mxEvent, "getKeyForwardingUser").mockReturnValue("@bob:example.org");
+
+        const state = getEventTileE2ePadlockViewState(
+            makeInput({
+                mxEvent,
+                shieldColour: EventShieldColour.GREY,
+                shieldReason: EventShieldReason.AUTHENTICITY_NOT_GUARANTEED,
+            }),
+        );
+
+        expect(state).toEqual({
+            kind: "messageShared",
+            keyForwardingUserId: "@bob:example.org",
+            roomId,
+        });
+    });
+});