block creation or sending of duplicate channels. (#3913)

app/src/main/java/com/geeksville/mesh/ui/sharing/Channel.kt

@@ -96,6 +96,7 @@ import kotlinx.coroutines.launch
 import org.jetbrains.compose.resources.stringResource
 import org.meshtastic.core.model.Channel
 import org.meshtastic.core.model.util.getChannelUrl
+import org.meshtastic.core.model.util.hasDuplicateKeys
 import org.meshtastic.core.model.util.qrCode
 import org.meshtastic.core.model.util.toChannelSet
 import org.meshtastic.core.navigation.Route
@@ -107,6 +108,7 @@ import org.meshtastic.core.strings.are_you_sure_change_default
 import org.meshtastic.core.strings.cancel
 import org.meshtastic.core.strings.cant_change_no_radio
 import org.meshtastic.core.strings.channel_invalid
+import org.meshtastic.core.strings.channel_key_already_in_use
 import org.meshtastic.core.strings.copy
 import org.meshtastic.core.strings.edit
 import org.meshtastic.core.strings.modem_preset
@@ -231,6 +233,12 @@ fun ChannelScreen(
 
     // Send new channel settings to the device
     fun installSettings(newChannelSet: ChannelSet) {
+        // Check for duplicate keys before installing
+        if (newChannelSet.hasDuplicateKeys()) {
+            scope.launch { context.showToast(Res.string.channel_key_already_in_use) }
+            return
+        }
+
         // Try to change the radio, if it fails, tell the user why and throw away their edits
         try {
             viewModel.setChannels(newChannelSet)

core/model/src/main/kotlin/org/meshtastic/core/model/util/ChannelSet.kt

@@ -89,3 +89,21 @@ fun ChannelSet.qrCode(shouldAdd: Boolean): Bitmap? = try {
     Timber.e("URL was too complex to render as barcode")
     null
 }
+
+/**
+ * Check if the ChannelSet contains any duplicate PSKs.
+ *
+ * @return true if there are duplicate PSKs, false otherwise
+ */
+fun ChannelSet.hasDuplicateKeys(): Boolean {
+    val pskList = mutableListOf<ByteArray>()
+    for (setting in settingsList) {
+        val channel = Channel(setting, loraConfig)
+        val pskBytes = channel.psk.toByteArray()
+        if (pskList.any { it contentEquals pskBytes }) {
+            return true
+        }
+        pskList.add(pskBytes)
+    }
+    return false
+}

core/strings/src/commonMain/composeResources/values/strings.xml

@@ -218,6 +218,7 @@
     <string name="meshtastic_service_notifications">Service notifications</string>
     <string name="about">About</string>
     <string name="channel_invalid">This Channel URL is invalid and can not be used</string>
+    <string name="channel_key_already_in_use">A channel with this key is already in use</string>
     <string name="contact_invalid">This contact is invalid and can not be added</string>
     <string name="debug_panel">Debug Panel</string>
     <string name="debug_decoded_payload">Decoded Payload:</string>

core/ui/src/main/kotlin/org/meshtastic/core/ui/qr/ScannedQrCodeDialog.kt

@@ -40,9 +40,11 @@ import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateListOf
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.tooling.preview.PreviewScreenSizes
 import androidx.compose.ui.unit.dp
@@ -50,15 +52,19 @@ import androidx.compose.ui.window.Dialog
 import androidx.compose.ui.window.DialogProperties
 import androidx.hilt.lifecycle.viewmodel.compose.hiltViewModel
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import kotlinx.coroutines.launch
 import org.jetbrains.compose.resources.stringResource
 import org.meshtastic.core.model.Channel
+import org.meshtastic.core.model.util.hasDuplicateKeys
 import org.meshtastic.core.strings.Res
 import org.meshtastic.core.strings.accept
 import org.meshtastic.core.strings.add
 import org.meshtastic.core.strings.cancel
+import org.meshtastic.core.strings.channel_key_already_in_use
 import org.meshtastic.core.strings.new_channel_rcvd
 import org.meshtastic.core.strings.replace
 import org.meshtastic.core.ui.component.ChannelSelection
+import org.meshtastic.core.ui.util.showToast
 import org.meshtastic.proto.AppOnlyProtos.ChannelSet
 import org.meshtastic.proto.ConfigProtos.Config.LoRaConfig.ModemPreset
 import org.meshtastic.proto.channelSet
@@ -290,10 +296,16 @@ fun ScannedQrCodeDialog(
                             )
                         }
 
+                        val context = LocalContext.current
+                        val coroutineScope = rememberCoroutineScope()
                         TextButton(
                             onClick = {
-                                onDismiss()
-                                onConfirm(selectedChannelSet)
+                                if (selectedChannelSet.hasDuplicateKeys()) {
+                                    coroutineScope.launch { context.showToast(Res.string.channel_key_already_in_use) }
+                                } else {
+                                    onDismiss()
+                                    onConfirm(selectedChannelSet)
+                                }
                             },
                             enabled = selectedChannelSet.settingsCount in 1..8,
                         ) {

feature/settings/src/main/kotlin/org/meshtastic/feature/settings/radio/channel/ChannelConfigScreen.kt

@@ -37,27 +37,33 @@ import androidx.compose.material3.Icon
 import androidx.compose.material3.Scaffold
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.saveable.listSaver
 import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.runtime.setValue
 import androidx.compose.runtime.toMutableStateList
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.platform.LocalFocusManager
 import androidx.compose.ui.platform.LocalHapticFeedback
 import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import kotlinx.coroutines.launch
 import org.jetbrains.compose.resources.stringResource
 import org.meshtastic.core.model.Channel
 import org.meshtastic.core.model.DeviceVersion
+import org.meshtastic.core.model.util.hasDuplicateKeys
 import org.meshtastic.core.strings.Res
 import org.meshtastic.core.strings.add
 import org.meshtastic.core.strings.cancel
+import org.meshtastic.core.strings.channel_key_already_in_use
 import org.meshtastic.core.strings.channel_name
 import org.meshtastic.core.strings.channels
 import org.meshtastic.core.strings.press_and_drag
@@ -67,6 +73,7 @@ import org.meshtastic.core.ui.component.PreferenceFooter
 import org.meshtastic.core.ui.component.dragContainer
 import org.meshtastic.core.ui.component.dragDropItemsIndexed
 import org.meshtastic.core.ui.component.rememberDragDropState
+import org.meshtastic.core.ui.util.showToast
 import org.meshtastic.feature.settings.radio.RadioConfigViewModel
 import org.meshtastic.feature.settings.radio.channel.component.ChannelCard
 import org.meshtastic.feature.settings.radio.channel.component.ChannelConfigHeader
@@ -75,6 +82,7 @@ import org.meshtastic.feature.settings.radio.channel.component.ChannelLegendDial
 import org.meshtastic.feature.settings.radio.channel.component.EditChannelDialog
 import org.meshtastic.feature.settings.radio.channel.component.SECONDARY_CHANNEL_EPOCH
 import org.meshtastic.feature.settings.radio.component.PacketResponseStateDialog
+import org.meshtastic.proto.AppOnlyProtos
 import org.meshtastic.proto.ChannelProtos.ChannelSettings
 import org.meshtastic.proto.ConfigProtos.Config.LoRaConfig
 import org.meshtastic.proto.channelSettings
@@ -135,21 +143,69 @@ private fun ChannelConfigScreen(
         settingsList.size != settingsListInput.size ||
             settingsList.zip(settingsListInput).any { (item1, item2) -> item1 != item2 }
 
+    // Check if the current channel list has duplicate PSKs - recompute when list changes
+    var hasDuplicateKeys by remember { mutableStateOf(false) }
+    LaunchedEffect(settingsListInput.size, settingsListInput.toList(), loraConfig) {
+        val channelSet =
+            AppOnlyProtos.ChannelSet.newBuilder()
+                .apply {
+                    addAllSettings(settingsListInput.toList())
+                    setLoraConfig(loraConfig)
+                }
+                .build()
+        hasDuplicateKeys = channelSet.hasDuplicateKeys()
+    }
+
     var showEditChannelDialog: Int? by rememberSaveable { mutableStateOf(null) }
     var showChannelLegendDialog by rememberSaveable { mutableStateOf(false) }
 
+    val context = LocalContext.current
+    val coroutineScope = rememberCoroutineScope()
+
     if (showEditChannelDialog != null) {
         val index = showEditChannelDialog ?: return
         EditChannelDialog(
             channelSettings = with(settingsListInput) { if (size > index) get(index) else channelSettings {} },
             modemPresetName = modemPresetName,
-            onAddClick = {
-                if (settingsListInput.size > index) {
-                    settingsListInput[index] = it
+            onAddClick = { newChannelSettings ->
+                val isEditing = index < settingsListInput.size
+
+                // Build a temporary list to check for duplicates
+                val tempList = settingsListInput.toMutableList()
+                if (isEditing) {
+                    tempList[index] = newChannelSettings
                 } else {
-                    settingsListInput.add(it)
+                    tempList.add(newChannelSettings)
+                }
+
+                // Check for duplicates in the temporary list
+                val tempChannelSet =
+                    AppOnlyProtos.ChannelSet.newBuilder()
+                        .apply {
+                            addAllSettings(tempList)
+                            setLoraConfig(loraConfig)
+                        }
+                        .build()
+
+                val hasDuplicate = tempChannelSet.hasDuplicateKeys()
+
+                if (hasDuplicate) {
+                    coroutineScope.launch { context.showToast(Res.string.channel_key_already_in_use) }
+                    // If this was a new channel added by FAB (at the end), remove it
+                    // FAB adds channel then opens dialog, so index will be lastIndex
+                    if (index == settingsListInput.size - 1 && index >= 0) {
+                        settingsListInput.removeAt(index)
+                        showEditChannelDialog = null
+                    }
+                    // If editing existing channel, don't update - keep original and dialog open
+                } else {
+                    if (isEditing) {
+                        settingsListInput[index] = newChannelSettings
+                    } else {
+                        settingsListInput.add(newChannelSettings)
+                    }
+                    showEditChannelDialog = null
                 }
-                showEditChannelDialog = null
             },
             onDismissRequest = { showEditChannelDialog = null },
         )
@@ -238,7 +294,7 @@ private fun ChannelConfigScreen(
                     item { Spacer(modifier = Modifier.weight(1f)) }
                     item {
                         PreferenceFooter(
-                            enabled = enabled && isEditing,
+                            enabled = enabled && isEditing && !hasDuplicateKeys,
                             negativeText = stringResource(Res.string.cancel),
                             onNegativeClicked = {
                                 focusManager.clearFocus()
@@ -248,7 +304,11 @@ private fun ChannelConfigScreen(
                             positiveText = stringResource(Res.string.send),
                             onPositiveClicked = {
                                 focusManager.clearFocus()
-                                onPositiveClicked(settingsListInput)
+                                if (hasDuplicateKeys) {
+                                    coroutineScope.launch { context.showToast(Res.string.channel_key_already_in_use) }
+                                } else {
+                                    onPositiveClicked(settingsListInput)
+                                }
                             },
                         )
                     }