Add translation to variable

android/engine/src/main/java/org/smartregister/fhircore/engine/ui/base/BaseMultiLanguageActivity.kt

@@ -46,8 +46,8 @@ abstract class BaseMultiLanguageActivity : AppCompatActivity() {
     val lang =
       baseContext
         .getSharedPreferences(SharedPreferencesHelper.PREFS_NAME, Context.MODE_PRIVATE)
-        .getString(SharedPreferenceKey.LANG.name, Locale.ENGLISH.toLanguageTag())
-        ?: Locale.ENGLISH.toLanguageTag()
+        .getString(SharedPreferenceKey.LANG.name, Locale.getDefault().toLanguageTag())
+        ?: Locale.getDefault().toLanguageTag()
     baseContext.setAppLocale(lang).run {
       super.attachBaseContext(baseContext)
       applyOverrideConfiguration(this)

android/engine/src/main/java/org/smartregister/fhircore/engine/util/LanguageBasicUtil.kt

@@ -0,0 +1,101 @@
+/*
+ * Copyright 2021-2024 Ona Systems, Inc
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.smartregister.fhircore.engine.util
+
+import java.util.Locale
+import org.hl7.fhir.r4.model.Basic
+import org.hl7.fhir.r4.model.CodeableConcept
+import org.hl7.fhir.r4.model.Coding
+import timber.log.Timber
+
+/**
+ * Utility class for creating and managing a FHIR Basic resource that represents the current device
+ * language. This resource is used as a launch context in questionnaires, allowing variable
+ * definitions to conditionally display text based on the device's language setting.
+ *
+ * The Basic resource contains language information using ISO 639-1 language codes (e.g., en, es,
+ * fr).
+ */
+object LanguageBasicUtil {
+  /**
+   * Fixed identifier for the device language resource. This ensures the resource can be
+   * consistently referenced and updated.
+   */
+  const val LANGUAGE_BASIC_ID = "device-language"
+
+  /**
+   * Creates a Basic FHIR resource representing the current device language.
+   *
+   * @return A Basic FHIR resource configured with the current device language information.
+   *
+   * Example usage:
+   * ```kotlin
+   * val languageBasic = LanguageBasicUtil.createLanguageBasic()
+   * // languageBasic can then be used as a launch context in questionnaires
+   * ```
+   */
+  fun createLanguageBasic(): Basic {
+    val languageCode = getCurrentLanguageCode()
+    val languageDisplay = getCurrentLanguageDisplay()
+
+    return Basic().apply {
+      id = LANGUAGE_BASIC_ID
+
+      code =
+        CodeableConcept()
+          .addCoding(
+            Coding(
+              "urn:ietf:bcp:47",
+              languageCode,
+              languageDisplay,
+            ),
+          )
+
+      Timber.d("Created language basic resource with language code: $languageCode")
+    }
+  }
+
+  /**
+   * Retrieves the current device language code in ISO 639-1 format (e.g., en, es, fr).
+   *
+   * @return The ISO 639-1 language code of the device's current locale.
+   */
+  private fun getCurrentLanguageCode(): String {
+    return Locale.getDefault().language
+  }
+
+  /**
+   * Retrieves the display name for the current device language.
+   *
+   * @return The display name of the device's language (e.g., "English", "Spanish", "French").
+   */
+  private fun getCurrentLanguageDisplay(): String {
+    return Locale.getDefault().displayLanguage
+  }
+
+  /**
+   * Checks if a language code matches the current device language.
+   *
+   * This is useful for FHIRPath expressions that need to conditionally evaluate based on language.
+   *
+   * @param languageCode The ISO 639-1 language code to check (e.g., "en", "es", "fr").
+   * @return True if the device language matches the provided code, false otherwise.
+   */
+  fun isLanguage(languageCode: String): Boolean {
+    return getCurrentLanguageCode() == languageCode
+  }
+}

android/engine/src/test/kotlin/org/smartregister/fhircore/engine/util/LanguageBasicUtilTest.kt

@@ -0,0 +1,87 @@
+/*
+ * Copyright 2021-2024 Ona Systems, Inc
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.smartregister.fhircore.engine.util
+
+import org.junit.Assert
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.RobolectricTestRunner
+import org.smartregister.fhircore.engine.robolectric.RobolectricTest
+
+/**
+ * Unit tests for [LanguageBasicUtil].
+ *
+ * Tests the creation and management of the Basic FHIR resource representing the device language,
+ * and the ability to check language codes.
+ */
+@RunWith(RobolectricTestRunner::class)
+class LanguageBasicUtilTest : RobolectricTest() {
+
+  @Test
+  fun testCreateLanguageBasicReturnsValidBasic() {
+    val basic = LanguageBasicUtil.createLanguageBasic()
+
+    // Verify the basic resource is created with the correct ID
+    Assert.assertEquals(LanguageBasicUtil.LANGUAGE_BASIC_ID, basic.id)
+
+    // Verify the basic resource has a code
+    Assert.assertNotNull(basic.code)
+    Assert.assertFalse(basic.code.coding.isEmpty())
+  }
+
+  @Test
+  fun testCreateLanguageBasicHasLanguageCode() {
+    val basic = LanguageBasicUtil.createLanguageBasic()
+
+    // Verify the basic resource has a code field with coding
+    Assert.assertNotNull(basic.code)
+    Assert.assertFalse(basic.code.coding.isEmpty())
+
+    // Verify the coding has the correct system
+    val languageCoding = basic.code.coding.first()
+    Assert.assertEquals("urn:ietf:bcp:47", languageCoding.system)
+
+    // Verify the language code is in ISO 639-1 format (2-letter code)
+    Assert.assertNotNull(languageCoding.code)
+    Assert.assertTrue(languageCoding.code.matches(Regex("[a-z]{2}")))
+
+    // Verify the language display is not empty
+    Assert.assertNotNull(languageCoding.display)
+    Assert.assertFalse(languageCoding.display.isEmpty())
+  }
+
+  @Test
+  fun testDeviceLanguageIdConstant() {
+    // Verify the constant ID is set correctly
+    Assert.assertEquals("device-language", LanguageBasicUtil.LANGUAGE_BASIC_ID)
+  }
+
+  @Test
+  fun testIsLanguageWithExactMatch() {
+    // Test with the current device language
+    val currentLanguage = java.util.Locale.getDefault().language
+    Assert.assertTrue(LanguageBasicUtil.isLanguage(currentLanguage))
+  }
+
+  @Test
+  fun testIsLanguageWithNonMatchingLanguage() {
+    // Test with a language that's not the current device language
+    // Using a different language code that's unlikely to be the device language
+    val nonMatchingLanguage = if (java.util.Locale.getDefault().language != "ja") "ja" else "es"
+    Assert.assertFalse(LanguageBasicUtil.isLanguage(nonMatchingLanguage))
+  }
+}

android/quest/src/main/java/org/smartregister/fhircore/quest/ui/questionnaire/QuestionnaireActivity.kt

@@ -60,6 +60,7 @@ import org.smartregister.fhircore.engine.ui.base.AlertDialogue
 import org.smartregister.fhircore.engine.ui.base.AlertIntent
 import org.smartregister.fhircore.engine.ui.base.BaseMultiLanguageActivity
 import org.smartregister.fhircore.engine.util.DispatcherProvider
+import org.smartregister.fhircore.engine.util.LanguageBasicUtil
 import org.smartregister.fhircore.engine.util.extension.encodeResourceToString
 import org.smartregister.fhircore.engine.util.extension.parcelable
 import org.smartregister.fhircore.engine.util.extension.parcelableArrayList
@@ -455,8 +456,10 @@ class QuestionnaireActivity : BaseMultiLanguageActivity() {
               ?: showToast(getString(R.string.error_populating_questionnaire))
           }
 
+          val languageBasic = LanguageBasicUtil.createLanguageBasic()
           launchContextResources
             .associate { Pair(it.resourceType.name.lowercase(), it.json()) }
+            .plus(LANGUAGE_VARIABLE_NAME to languageBasic.json())
             .takeIf { it.isNotEmpty() }
             ?.let { setQuestionnaireLaunchContextMap(it) }
         }
@@ -615,6 +618,7 @@ class QuestionnaireActivity : BaseMultiLanguageActivity() {
     const val QUESTIONNAIRE_SUBMISSION_EXTRACTED_RESOURCE_IDS = "questionnaireExtractedResourceIds"
     const val QUESTIONNAIRE_RESPONSE = "questionnaireResponse"
     const val QUESTIONNAIRE_ACTION_PARAMETERS = "questionnaireActionParameters"
+    const val LANGUAGE_VARIABLE_NAME = "language"
 
     fun intentBundle(
       questionnaireConfig: QuestionnaireConfig,

android/quest/src/main/java/org/smartregister/fhircore/quest/ui/questionnaire/QuestionnaireViewModel.kt

@@ -78,6 +78,7 @@ import org.smartregister.fhircore.engine.domain.model.isSummary
 import org.smartregister.fhircore.engine.rulesengine.RulesExecutor
 import org.smartregister.fhircore.engine.task.FhirCarePlanGenerator
 import org.smartregister.fhircore.engine.util.DispatcherProvider
+import org.smartregister.fhircore.engine.util.LanguageBasicUtil
 import org.smartregister.fhircore.engine.util.SharedPreferenceKey
 import org.smartregister.fhircore.engine.util.SharedPreferencesHelper
 import org.smartregister.fhircore.engine.util.extension.allItems
@@ -1162,8 +1163,10 @@ constructor(
 
       val launchContextResources =
         launchContextResources(resourceType, resourceIdentifier, actionParameters)
-      val launchContexts = launchContextResources.associateBy { it.resourceType.name.lowercase() }
-
+      val languageBasic = LanguageBasicUtil.createLanguageBasic()
+      val launchContexts =
+        launchContextResources.associateBy { it.resourceType.name.lowercase() }.toMutableMap()
+      launchContexts["language"] = languageBasic
       // Populate questionnaire with initial default values
       ResourceMapper.populate(
         questionnaire,