feat(chat): show end-to-end encryption status in DMs and groups

apps/flipcash/app/src/main/kotlin/com/flipcash/app/internal/ui/navigation/AppScreenContent.kt

@@ -36,6 +36,7 @@ import com.flipcash.app.currency.RegionSelectionScreen
 import com.flipcash.app.deposit.DepositFlowScreen
 import com.flipcash.app.invite.InviteContactScreen
 import com.flipcash.app.messenger.ChatFlowScreen
+import com.flipcash.app.messenger.E2eeLearnMoreScreen
 import com.flipcash.app.messenger.MuteChatScreen
 import com.flipcash.app.messenger.ProfileScreen
 import com.flipcash.app.messenger.ReportFlowScreen
@@ -127,6 +128,8 @@ fun appEntryProvider(
         ReportFlowScreen(route = key, resultStateRegistry = resultStateRegistry)
     }
     annotatedEntry<AppRoute.Messaging.MuteChat> { key -> MuteChatScreen(key.chatId, key.chatType) }
+    annotatedEntry<AppRoute.Messaging.E2eeDmInfo> { E2eeLearnMoreScreen(forGroup = false) }
+    annotatedEntry<AppRoute.Messaging.E2eeGroupInfo> { E2eeLearnMoreScreen(forGroup = true) }
 
     // Tokens
     annotatedEntry<AppRoute.Token.Info>(testTag = "token_info_screen") { key ->

apps/flipcash/core/src/main/kotlin/com/flipcash/app/core/AppRoute.kt

@@ -436,6 +436,25 @@ sealed interface AppRoute : NavKey, Parcelable {
             Messaging,
             com.getcode.navigation.Sheet,
             com.getcode.navigation.WrapContentSheet
+
+        /**
+         * What end-to-end encryption covers in a DM, opened from the DM profile's footer. A
+         * [com.getcode.navigation.WrapContentSheet], for the reason [MuteChat] is one.
+         */
+        @Serializable
+        @Parcelize
+        data object E2eeDmInfo :
+            Messaging,
+            com.getcode.navigation.Sheet,
+            com.getcode.navigation.WrapContentSheet
+
+        /** The group counterpart of [E2eeDmInfo], opened from Group Info's footer. */
+        @Serializable
+        @Parcelize
+        data object E2eeGroupInfo :
+            Messaging,
+            com.getcode.navigation.Sheet,
+            com.getcode.navigation.WrapContentSheet
     }
 
     @Serializable

apps/flipcash/core/src/main/res/values/strings.xml

@@ -979,7 +979,30 @@
     <string name="label_edited">Edited</string>
     <string name="label_messageDeletedByYou">You deleted this message</string>
     <string name="label_messageDeleted">This message was deleted</string>
-    <string name="label_messageUnsupported">This message isn\'t supported on this version</string>
+    <string name="label_messageUndecryptable">This message can\'t be displayed</string>
+    <string name="hint_messageUndecryptable_update">Update Flipcash to see it</string>
+    <string name="hint_messageUndecryptable_askToResend">Ask %1$s to send it again</string>
+    <string name="hint_messageUndecryptable_tryAgain">Try sending it again</string>
+
+    <string name="label_e2eeFooter_dm">Messages are end-to-end encrypted</string>
+    <string name="label_e2eeFooter_group">Group chats aren\'t end-to-end encrypted</string>
+    <string name="action_learnMore">Learn More</string>
+
+    <string name="title_e2eeSheet_dm">Your messages are private</string>
+    <string name="subtitle_e2eeSheet_dm">Messages and photos in this chat are end-to-end encrypted. Only you and the person you\'re chatting with can read them. Not even Flipcash can.</string>
+    <string name="title_e2eeSheet_group">Group chats aren\'t encrypted</string>
+    <string name="subtitle_e2eeSheet_group">End-to-end encryption covers chats between two people. Messages in group chats are stored on Flipcash servers in a form Flipcash can read.</string>
+    <string name="header_e2eeSheet_encrypted">ENCRYPTED</string>
+    <string name="header_e2eeSheet_notEncrypted">NOT ENCRYPTED</string>
+    <string name="item_e2eeSheet_textAndReplies">Text messages and replies</string>
+    <string name="item_e2eeSheet_photos">Photos you send</string>
+    <string name="item_e2eeSheet_tipsAndPayments">Tips and payments, which are recorded on Solana</string>
+    <string name="item_e2eeSheet_reactions">Reactions, and who sent them</string>
+    <string name="item_e2eeSheet_editedOrDeleted">That a message was edited or deleted</string>
+    <string name="item_e2eeSheet_groupChats">Group chats</string>
+    <string name="item_e2eeSheet_beforeEncryption">Messages sent before encryption was turned on</string>
+    <string name="item_e2eeSheet_messagesInDms">Messages in DMs</string>
+    <string name="item_e2eeSheet_groupChatsIncludingThis">Group chats, including this one</string>
 
     <!-- Cash link card: the state of the link a message carries, read without claiming it -->
     <string name="label_linkCard_cash">Cash</string>

apps/flipcash/features/messenger/src/main/kotlin/com/flipcash/app/messenger/E2eeLearnMoreScreen.kt

@@ -0,0 +1,19 @@
+package com.flipcash.app.messenger
+
+import androidx.compose.runtime.Composable
+import com.flipcash.app.messenger.internal.screens.E2eeLearnMoreSheet
+import com.flipcash.app.messenger.internal.screens.E2eeSheetKind
+import com.getcode.navigation.scenes.LocalBottomSheetDismissDispatcher
+
+/**
+ * The DM or group encryption explainer, behind `AppRoute.Messaging.E2eeDmInfo` and `E2eeGroupInfo`.
+ */
+@Composable
+fun E2eeLearnMoreScreen(forGroup: Boolean) {
+    // Exit through the sheet so it animates down rather than having its scene deleted mid-frame.
+    val dismissSheet = LocalBottomSheetDismissDispatcher.current
+    E2eeLearnMoreSheet(
+        kind = if (forGroup) E2eeSheetKind.Group else E2eeSheetKind.Dm,
+        onDismiss = dismissSheet,
+    )
+}

apps/flipcash/features/messenger/src/main/kotlin/com/flipcash/app/messenger/internal/ChatViewModel.kt

@@ -53,6 +53,7 @@ import com.flipcash.app.tokens.TokenCoordinator
 import com.flipcash.app.userflags.UserFlagsCoordinator
 import com.flipcash.features.messenger.R
 import com.flipcash.libs.coroutines.DispatcherProvider
+import com.flipcash.services.chat.E2eePolicy
 import com.flipcash.services.models.JoinChatError
 import com.flipcash.services.models.TipAction
 import com.flipcash.services.models.TipOrigin
@@ -183,6 +184,7 @@ data class TypingConstraints(
 @HiltViewModel
 internal class ChatViewModel @Inject constructor(
     private val chatCoordinator: ChatCoordinator,
+    private val e2eePolicy: E2eePolicy,
     private val contactCoordinator: ContactCoordinator,
     private val contactPaymentDelegate: ContactPaymentDelegate,
     private val tipPaymentDelegate: TipPaymentDelegate,
@@ -241,6 +243,8 @@ internal class ChatViewModel @Inject constructor(
         // bottom bar read it to render the correct (condensed vs expanded) presentation immediately
         // instead of flashing the expanded white pill while a tip profile loads.
         val chatType: ChatType = ChatType.UNKNOWN,
+        /** Whether [E2eePolicy] says this chat's messages are end-to-end encrypted. */
+        val isEncrypted: Boolean = false,
         val chatInputState: TextFieldState = TextFieldState(),
         val typists: Set<ActiveTypist> = emptySet(),
         /** What the typing indicator draws ahead of its dots. See [typingAvatars]. */
@@ -561,6 +565,8 @@ internal class ChatViewModel @Inject constructor(
         /** This chat's viewer state moved, from the stream or from the viewer's own request. */
         data class OnViewerStateResolved(val viewerState: ViewerState?) : Event
 
+        data class OnEncryptionResolved(val isEncrypted: Boolean) : Event
+
         data class OnCurrencySymbolUpdated(val symbol: String): Event
         data class OnChatInitFeeUpdated(val formatted: String?) : Event
         data class OnSendCashReadinessChanged(val ready: Boolean) : Event
@@ -1546,6 +1552,16 @@ internal class ChatViewModel @Inject constructor(
             .onEach { dispatchEvent(Event.OnViewerStateResolved(it)) }
             .launchIn(viewModelScope)
 
+        // The profile footer's claim. Decided by the policy from the chat's metadata, so the
+        // screen never reads the server's flag itself.
+        stateFlow.mapNotNull { it.chatId }
+            .distinctUntilChanged()
+            .flatMapLatest { chatCoordinator.observeMetadata(it) }
+            .map { it?.metadata?.let(e2eePolicy::shouldEncrypt) ?: false }
+            .distinctUntilChanged()
+            .onEach { dispatchEvent(Event.OnEncryptionResolved(it)) }
+            .launchIn(viewModelScope)
+
         // Observed rather than read once: the rule can change under an open screen, and a buy
         // hydrates a fresher copy of the token. See observeRuleToken for why it fetches as well.
         stateFlow.map { state ->
@@ -2650,6 +2666,8 @@ internal class ChatViewModel @Inject constructor(
                         )
                     )
                 }
+                is Event.OnEncryptionResolved -> { state -> state.copy(isEncrypted = event.isEncrypted) }
+
                 is Event.OnViewerStateResolved -> { state ->
                     state.copy(viewerState = event.viewerState)
                 }

apps/flipcash/features/messenger/src/main/kotlin/com/flipcash/app/messenger/internal/screens/E2eeLearnMoreSheet.kt

@@ -0,0 +1,199 @@
+package com.flipcash.app.messenger.internal.screens
+
+import androidx.annotation.DrawableRes
+import androidx.annotation.StringRes
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.navigationBarsPadding
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Lock
+import androidx.compose.material.icons.filled.LockOpen
+import androidx.compose.material3.Icon
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.res.painterResource
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.tooling.preview.Preview
+import androidx.compose.ui.tooling.preview.PreviewWrapper
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import com.flipcash.app.theme.FlipcashThemeWrapper
+import com.flipcash.features.messenger.R
+import com.getcode.theme.CodeTheme
+import com.getcode.ui.components.AppBarDefaults
+import com.getcode.ui.components.AppBarWithTitle
+import com.getcode.ui.components.BulletRow
+
+/** Which chat kind the learn-more sheet explains. */
+internal enum class E2eeSheetKind { Dm, Group }
+
+/**
+ * What end-to-end encryption does and doesn't cover, opened from the profile footer. One layout
+ * for both kinds, with the DM's and the group's own words (nodes 10416:1533, 10557:1412).
+ */
+@Composable
+internal fun E2eeLearnMoreSheet(
+    kind: E2eeSheetKind,
+    onDismiss: () -> Unit,
+) {
+    val isDm = kind == E2eeSheetKind.Dm
+    val encrypted = if (isDm) {
+        listOf(R.string.item_e2eeSheet_textAndReplies, R.string.item_e2eeSheet_photos)
+    } else {
+        listOf(R.string.item_e2eeSheet_messagesInDms)
+    }
+    val notEncrypted = if (isDm) {
+        listOf(
+            R.string.item_e2eeSheet_tipsAndPayments,
+            R.string.item_e2eeSheet_reactions,
+            R.string.item_e2eeSheet_editedOrDeleted,
+            R.string.item_e2eeSheet_groupChats,
+            R.string.item_e2eeSheet_beforeEncryption,
+        )
+    } else {
+        listOf(
+            R.string.item_e2eeSheet_groupChatsIncludingThis,
+            R.string.item_e2eeSheet_tipsAndPayments,
+        )
+    }
+
+    Column(
+        modifier = Modifier
+            .fillMaxWidth()
+            .navigationBarsPadding(),
+        horizontalAlignment = Alignment.CenterHorizontally,
+    ) {
+        AppBarWithTitle(
+            endContent = { AppBarDefaults.Close(onClick = onDismiss) },
+        )
+
+        Box(
+            modifier = Modifier
+                .padding(top = 10.dp)
+                .size(70.dp)
+                .background(Color.White.copy(alpha = 0.08f), CircleShape),
+            contentAlignment = Alignment.Center,
+        ) {
+            Icon(
+                modifier = Modifier.size(32.dp),
+                imageVector = if (isDm) Icons.Filled.Lock else Icons.Filled.LockOpen,
+                contentDescription = null,
+                tint = Color.White.copy(alpha = 0.7f),
+            )
+        }
+
+        Text(
+            modifier = Modifier
+                .padding(horizontal = CodeTheme.dimens.inset)
+                .padding(top = 20.dp),
+            text = stringResource(
+                if (isDm) R.string.title_e2eeSheet_dm else R.string.title_e2eeSheet_group
+            ),
+            style = CodeTheme.typography.textLarge.copy(
+                fontSize = 22.sp,
+                fontWeight = FontWeight.SemiBold,
+            ),
+            color = CodeTheme.colors.textMain,
+            textAlign = TextAlign.Center,
+        )
+        Text(
+            modifier = Modifier
+                .padding(horizontal = 24.dp)
+                .padding(top = 16.dp),
+            text = stringResource(
+                if (isDm) R.string.subtitle_e2eeSheet_dm else R.string.subtitle_e2eeSheet_group
+            ),
+            style = CodeTheme.typography.textSmall.copy(
+                fontSize = 15.sp,
+                lineHeight = 21.sp,
+                fontWeight = FontWeight.Medium,
+            ),
+            color = Color.White.copy(alpha = 0.7f),
+            textAlign = TextAlign.Center,
+        )
+
+        Column(
+            modifier = Modifier
+                .fillMaxWidth()
+                .padding(horizontal = 14.dp)
+                .padding(top = 40.dp, bottom = 24.dp),
+            verticalArrangement = Arrangement.spacedBy(16.dp),
+        ) {
+            SheetSection(
+                header = R.string.header_e2eeSheet_encrypted,
+                items = encrypted,
+                icon = R.drawable.ic_e2ee_included,
+            )
+            SheetSection(
+                header = R.string.header_e2eeSheet_notEncrypted,
+                items = notEncrypted,
+                icon = R.drawable.ic_e2ee_excluded,
+            )
+        }
+    }
+}
+
+@Composable
+private fun SheetSection(
+    @StringRes header: Int,
+    items: List<Int>,
+    @DrawableRes icon: Int,
+) {
+    Column(
+        modifier = Modifier
+            .fillMaxWidth()
+            .background(Color.White.copy(alpha = 0.04f), RoundedCornerShape(6.dp))
+            .padding(16.dp),
+        verticalArrangement = Arrangement.spacedBy(12.dp),
+    ) {
+        Text(
+            text = stringResource(header),
+            style = CodeTheme.typography.caption.copy(
+                fontSize = 11.sp,
+                fontWeight = FontWeight.SemiBold,
+                letterSpacing = 0.44.sp,
+            ),
+            color = Color.White.copy(alpha = 0.45f),
+        )
+        for (item in items) {
+            BulletRow(
+                painter = painterResource(icon),
+                text = stringResource(item),
+                textStyle = CodeTheme.typography.textSmall.copy(
+                    fontSize = 15.sp,
+                    fontWeight = FontWeight.Medium,
+                ),
+                textColor = Color.White.copy(alpha = 0.9f),
+                // The exported glyphs carry their own colours.
+                iconTint = Color.Unspecified,
+                spacing = 12.dp,
+            )
+        }
+    }
+}
+
+@Preview(heightDp = 817)
+@PreviewWrapper(FlipcashThemeWrapper::class)
+@Composable
+private fun Preview_E2eeSheet_Dm() {
+    E2eeLearnMoreSheet(kind = E2eeSheetKind.Dm, onDismiss = {})
+}
+
+@Preview(heightDp = 817)
+@PreviewWrapper(FlipcashThemeWrapper::class)
+@Composable
+private fun Preview_E2eeSheet_Group() {
+    E2eeLearnMoreSheet(kind = E2eeSheetKind.Group, onDismiss = {})
+}

apps/flipcash/features/messenger/src/main/kotlin/com/flipcash/app/messenger/internal/screens/profile/ChatProfileScreen.kt

@@ -88,6 +88,7 @@ internal fun ChatProfileScreen(
             chatId = chatState.chatId,
             chatType = chatState.chatType,
             viewerState = chatState.viewerState,
+            isEncrypted = chatState.isEncrypted,
         ),
         cashSymbol = chatState.cashSymbol,
         onBack = { flowNavigator.back() },
@@ -103,8 +104,9 @@ internal fun profileChat(
     chatId: ChatId?,
     chatType: ChatType,
     viewerState: ViewerState?,
+    isEncrypted: Boolean = false,
 ): ProfileChat? = when (origin) {
-    ProfileOrigin.Chat -> ProfileChat(chatId, chatType, viewerState)
+    ProfileOrigin.Chat -> ProfileChat(chatId, chatType, viewerState, isEncrypted)
     ProfileOrigin.Mention -> null
 }
 
@@ -116,6 +118,8 @@ internal data class ProfileChat(
     val chatId: ChatId?,
     val chatType: ChatType,
     val viewerState: ViewerState?,
+    /** [com.flipcash.services.chat.E2eePolicy]'s answer for this chat; the footer follows it. */
+    val isEncrypted: Boolean = false,
 )
 
 /**
@@ -142,6 +146,14 @@ internal fun PersonProfileScreen(
         topBar = {
             AppBarWithTitle(onBackIconClicked = onBack)
         },
+        bottomBar = {
+            if (chat?.isEncrypted == true) {
+                E2eeFooter(
+                    isEncrypted = true,
+                    onLearnMore = { navigator.push(AppRoute.Messaging.E2eeDmInfo) },
+                )
+            }
+        },
     ) { innerPadding ->
         MenuList(
             modifier = Modifier