feat(message-list): mark message as read when clicked

Author: rafaeltonholo

feature/mail/message/list/api/src/main/kotlin/net/thunderbird/feature/mail/message/list/ui/state/MessageItemUi.kt

@@ -1,6 +1,7 @@
 package net.thunderbird.feature.mail.message.list.ui.state
 
 import androidx.compose.runtime.Immutable
+import kotlinx.collections.immutable.toPersistentList
 
 /**
  * Represents the UI state of a single message item in a message list.
@@ -65,3 +66,29 @@ data class MessageItemUi(
         Unread,
     }
 }
+
+/**
+ * Create a copy of this message item with the updated [state] and refreshed sender
+ * display name styling.
+ *
+ * @param state The new state to apply.
+ * @return A new [MessageItemUi] instance with the updated state and styling.
+ */
+fun MessageItemUi.withState(state: MessageItemUi.State): MessageItemUi {
+    val styles = buildList {
+        when (val separatorIndex = senders.displayName.indexOf(',')) {
+            -1 if state != MessageItemUi.State.Read -> add(ComposedAddressStyle.Bold(start = 0))
+            in 0..Int.MAX_VALUE if state != MessageItemUi.State.Read -> {
+                add(ComposedAddressStyle.Bold(start = 0, end = separatorIndex))
+                add(ComposedAddressStyle.Regular(start = separatorIndex))
+            }
+
+            else -> add(ComposedAddressStyle.Regular(start = 0))
+        }
+    }.toPersistentList()
+
+    return copy(
+        senders = senders.copy(displayNameStyles = styles),
+        state = state,
+    )
+}

feature/mail/message/list/internal/src/main/kotlin/net/thunderbird/feature/mail/message/list/internal/ui/state/machine/SetupLoadedMessagesState.kt

@@ -5,7 +5,9 @@ import net.thunderbird.core.common.state.builder.StateMachineBuilder
 import net.thunderbird.feature.mail.message.list.ui.event.MessageItemEvent
 import net.thunderbird.feature.mail.message.list.ui.event.MessageListEvent
 import net.thunderbird.feature.mail.message.list.ui.event.MessageListSearchEvent
+import net.thunderbird.feature.mail.message.list.ui.state.MessageItemUi
 import net.thunderbird.feature.mail.message.list.ui.state.MessageListState
+import net.thunderbird.feature.mail.message.list.ui.state.withState
 
 /**
  * Defines the state transitions for the [MessageListState.LoadedMessages] state.
@@ -59,7 +61,14 @@ internal fun StateMachineBuilder<MessageListState, MessageListEvent>.loadedMessa
         transition<MessageItemEvent.OnMessageClick> { state, event ->
             state
                 .mapMessages { message ->
-                    message.copy(active = message.id == event.message.id)
+                    val isCurrent = message.id == event.message.id
+                    message.copy(active = isCurrent).withState(
+                        if (isCurrent && message.state != MessageItemUi.State.Read) {
+                            MessageItemUi.State.Read
+                        } else {
+                            message.state
+                        },
+                    )
                 }
                 .withMetadata { copy(activeMessage = event.message) }
         }