remember the last used SIM card on a per-number basis

app/src/main/kotlin/com/simplemobiletools/smsmessenger/activities/ThreadActivity.kt

@@ -1,5 +1,6 @@
 package com.simplemobiletools.smsmessenger.activities
 
+import android.annotation.SuppressLint
 import android.app.Activity
 import android.content.Intent
 import android.graphics.BitmapFactory
@@ -146,6 +147,8 @@ class ThreadActivity : SimpleActivity() {
                     window.setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE)
                     thread_type_message.requestFocus()
                 }
+
+                setupSIMSelector()
             }
         }
         setupButtons()
@@ -265,7 +268,10 @@ class ThreadActivity : SimpleActivity() {
                 addAttachment(it)
             }
         }
+    }
 
+    @SuppressLint("MissingPermission")
+    private fun setupSIMSelector() {
         val availableSIMs = SubscriptionManager.from(this).activeSubscriptionInfoList
         if (availableSIMs.size > 1) {
             availableSIMs.forEachIndexed { index, subscriptionInfo ->
@@ -277,8 +283,10 @@ class ThreadActivity : SimpleActivity() {
                 availableSIMCards.add(SIMCard)
             }
 
-            currentSIMCardIndex = 0
+            val numbers = participants.map { it.phoneNumber }.toTypedArray()
-            thread_select_sim_icon.applyColorFilter(textColor)
+            currentSIMCardIndex = availableSIMs.indexOfFirstOrNull { it.subscriptionId == config.getUseSIMIdAtNumber(numbers.first()) } ?: 0
+
+            thread_select_sim_icon.applyColorFilter(config.textColor)
             thread_select_sim_icon.beVisible()
             thread_select_sim_number.beVisible()
 
@@ -291,8 +299,8 @@ class ThreadActivity : SimpleActivity() {
                 }
             }
 
-            thread_select_sim_number.setTextColor(textColor.getContrastColor())
+            thread_select_sim_number.setTextColor(config.textColor.getContrastColor())
-            thread_select_sim_number.text = "1"
+            thread_select_sim_number.text = (availableSIMCards[currentSIMCardIndex].id).toString()
         }
     }
 
@@ -469,6 +477,9 @@ class ThreadActivity : SimpleActivity() {
         val SIMId = availableSIMCards.getOrNull(currentSIMCardIndex)?.subscriptionId
         if (SIMId != null) {
             settings.subscriptionId = SIMId
+            numbers.forEach {
+                config.saveUseSIMIdAtNumber(it, SIMId)
+            }
         }
 
         val transaction = Transaction(this, settings)

app/src/main/kotlin/com/simplemobiletools/smsmessenger/extensions/Collections.kt

@@ -0,0 +1,11 @@
+package com.simplemobiletools.smsmessenger.extensions
+
+inline fun <T> List<T>.indexOfFirstOrNull(predicate: (T) -> Boolean): Int? {
+    var index = 0
+    for (item in this) {
+        if (predicate(item))
+            return index
+        index++
+    }
+    return null
+}

app/src/main/kotlin/com/simplemobiletools/smsmessenger/helpers/Config.kt

@@ -7,4 +7,10 @@ class Config(context: Context) : BaseConfig(context) {
     companion object {
         fun newInstance(context: Context) = Config(context)
     }
+
+    fun saveUseSIMIdAtNumber(number: String, SIMId: Int) {
+        prefs.edit().putInt(USE_SIM_ID_PREFIX + number, SIMId).apply()
+    }
+
+    fun getUseSIMIdAtNumber(number: String) = prefs.getInt(USE_SIM_ID_PREFIX + number, 0)
 }

app/src/main/kotlin/com/simplemobiletools/smsmessenger/helpers/Constants.kt

@@ -9,6 +9,7 @@ const val THREAD_TEXT = "thread_text"
 const val THREAD_NUMBER = "thread_number"
 const val THREAD_ATTACHMENT_URI = "thread_attachment_uri"
 const val THREAD_ATTACHMENT_URIS = "thread_attachment_uris"
+const val USE_SIM_ID_PREFIX = "use_sim_id_"
 
 // view types for the thread list view
 const val THREAD_DATE_TIME = 1
@@ -16,10 +17,6 @@ const val THREAD_RECEIVED_MESSAGE = 2
 const val THREAD_SENT_MESSAGE = 3
 const val THREAD_SENT_MESSAGE_ERROR = 4
 
-// constants used at passing info to SmsSentReceiver
-const val MESSAGE_BODY = "message_body"
-const val MESSAGE_ADDRESS = "message_address"
-
 fun refreshMessages() {
     EventBus.getDefault().post(Events.RefreshMessages())
 }