Support evaluation of variables, launchContext and other FHIR contexts for cqf-calculatedValue expressions

datacapture/src/main/java/com/google/android/fhir/datacapture/QuestionnaireViewModel.kt

@@ -30,20 +30,21 @@ import com.google.android.fhir.datacapture.expressions.EnabledAnswerOptionsEvalu
 import com.google.android.fhir.datacapture.extensions.EntryMode
 import com.google.android.fhir.datacapture.extensions.addNestedItemsToAnswer
 import com.google.android.fhir.datacapture.extensions.allItems
-import com.google.android.fhir.datacapture.extensions.cqfCalculatedValueExpression
 import com.google.android.fhir.datacapture.extensions.cqfExpression
 import com.google.android.fhir.datacapture.extensions.createQuestionnaireResponseItem
 import com.google.android.fhir.datacapture.extensions.entryMode
 import com.google.android.fhir.datacapture.extensions.filterByCodeInNameExtension
 import com.google.android.fhir.datacapture.extensions.flattened
 import com.google.android.fhir.datacapture.extensions.hasDifferentAnswerSet
-import com.google.android.fhir.datacapture.extensions.isCqfCalculatedValue
 import com.google.android.fhir.datacapture.extensions.isDisplayItem
-import com.google.android.fhir.datacapture.extensions.isFhirPath
 import com.google.android.fhir.datacapture.extensions.isHelpCode
 import com.google.android.fhir.datacapture.extensions.isHidden
 import com.google.android.fhir.datacapture.extensions.isPaginated
 import com.google.android.fhir.datacapture.extensions.localizedTextSpanned
+import com.google.android.fhir.datacapture.extensions.maxValue
+import com.google.android.fhir.datacapture.extensions.maxValueCqfCalculatedValueExpression
+import com.google.android.fhir.datacapture.extensions.minValue
+import com.google.android.fhir.datacapture.extensions.minValueCqfCalculatedValueExpression
 import com.google.android.fhir.datacapture.extensions.packRepeatedGroups
 import com.google.android.fhir.datacapture.extensions.questionnaireLaunchContexts
 import com.google.android.fhir.datacapture.extensions.shouldHaveNestedItemsUnderAnswers
@@ -71,15 +72,12 @@ import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.flow.withIndex
 import kotlinx.coroutines.launch
-import org.hl7.fhir.r4.model.Base
-import org.hl7.fhir.r4.model.Expression
 import org.hl7.fhir.r4.model.Questionnaire
 import org.hl7.fhir.r4.model.Questionnaire.QuestionnaireItemComponent
 import org.hl7.fhir.r4.model.QuestionnaireResponse
 import org.hl7.fhir.r4.model.QuestionnaireResponse.QuestionnaireResponseItemAnswerComponent
 import org.hl7.fhir.r4.model.QuestionnaireResponse.QuestionnaireResponseItemComponent
 import org.hl7.fhir.r4.model.Resource
-import org.hl7.fhir.r4.model.Type
 import timber.log.Timber
 
 internal class QuestionnaireViewModel(application: Application, state: SavedStateHandle) :
@@ -594,23 +592,6 @@ internal class QuestionnaireViewModel(application: Application, state: SavedStat
       }
   }
 
-  private fun resolveExpression(
-    questionnaireItem: QuestionnaireItemComponent,
-    questionnaireResponseItem: QuestionnaireResponseItemComponent,
-    expression: Expression,
-  ): Base? {
-    if (!expression.isFhirPath) {
-      throw UnsupportedOperationException("${expression.language} not supported yet")
-    }
-    return expressionEvaluator
-      .evaluateExpression(
-        questionnaireItem,
-        questionnaireResponseItem,
-        expression,
-      )
-      .singleOrNull()
-  }
-
   private fun removeDisabledAnswers(
     questionnaireItem: QuestionnaireItemComponent,
     questionnaireResponseItem: QuestionnaireResponseItemComponent,
@@ -703,27 +684,6 @@ internal class QuestionnaireViewModel(application: Application, state: SavedStat
     )
   }
 
-  private fun resolveCqfCalculatedValueExpressions(
-    questionnaireItem: QuestionnaireItemComponent,
-    questionnaireResponseItem: QuestionnaireResponseItemComponent,
-  ) {
-    questionnaireItem.extension
-      .filter { it.hasValue() && it.value.isCqfCalculatedValue }
-      .forEach { extension ->
-        val currentExtensionValue = extension.value
-        val currentExtensionValueExtensions = currentExtensionValue.extension
-        val evaluatedCqfCalculatedValue =
-          currentExtensionValue.cqfCalculatedValueExpression?.let {
-            resolveExpression(questionnaireItem, questionnaireResponseItem, it) as? Type
-          }
-        // add previous extensions to the evaluated value
-        evaluatedCqfCalculatedValue?.setExtension(currentExtensionValueExtensions)
-        if (evaluatedCqfCalculatedValue != null) {
-          extension.setValue(evaluatedCqfCalculatedValue)
-        }
-      }
-  }
-
   /**
    * Returns the list of [QuestionnaireViewItem]s generated for the questionnaire items and
    * questionnaire response items.
@@ -762,9 +722,6 @@ internal class QuestionnaireViewModel(application: Application, state: SavedStat
 
     restoreFromDisabledQuestionnaireItemAnswersCache(questionnaireResponseItem)
 
-    // Evaluate cqf-calculatedValues
-    resolveCqfCalculatedValueExpressions(questionnaireItem, questionnaireResponseItem)
-
     // Determine the validation result, which will be displayed on the item itself
     val validationResult =
       if (
@@ -775,15 +732,22 @@ internal class QuestionnaireViewModel(application: Application, state: SavedStat
         QuestionnaireResponseItemValidator.validate(
           questionnaireItem,
           questionnaireResponseItem.answer,
-          context = this@QuestionnaireViewModel.getApplication(),
-        )
+          this@QuestionnaireViewModel.getApplication(),
+        ) {
+          expressionEvaluator.evaluateExpressionValue(
+            questionnaireItem,
+            questionnaireResponseItem,
+            it,
+          )
+        }
       } else {
         NotValidated
       }
 
     // Set question text dynamically from CQL expression
     questionnaireItem.textElement.cqfExpression?.let { expression ->
-      resolveExpression(questionnaireItem, questionnaireResponseItem, expression)
+      expressionEvaluator
+        .evaluateExpressionValue(questionnaireItem, questionnaireResponseItem, expression)
         ?.primitiveValue()
         ?.let { questionnaireResponseItem.text = it }
     }
@@ -814,6 +778,24 @@ internal class QuestionnaireViewModel(application: Application, state: SavedStat
             validationResult = validationResult,
             answersChangedCallback = answersChangedCallback,
             enabledAnswerOptions = enabledQuestionnaireAnswerOptions,
+            minAnswerValue =
+              questionnaireItem.minValueCqfCalculatedValueExpression?.let {
+                expressionEvaluator.evaluateExpressionValue(
+                  questionnaireItem,
+                  questionnaireResponseItem,
+                  it,
+                )
+              }
+                ?: questionnaireItem.minValue,
+            maxAnswerValue =
+              questionnaireItem.maxValueCqfCalculatedValueExpression?.let {
+                expressionEvaluator.evaluateExpressionValue(
+                  questionnaireItem,
+                  questionnaireResponseItem,
+                  it,
+                )
+              }
+                ?: questionnaireItem.maxValue,
             draftAnswer = draftAnswerMap[questionnaireResponseItem],
             enabledDisplayItems =
               questionnaireItem.item.filter {

datacapture/src/main/java/com/google/android/fhir/datacapture/extensions/MoreQuestionnaireItemComponents.kt

@@ -293,13 +293,17 @@ val Questionnaire.QuestionnaireItemComponent.sliderStepValue: Int?
     return null
   }
 
-/** The inclusive lower bound on the range of allowed answer values. */
 internal val Questionnaire.QuestionnaireItemComponent.minValue
-  get() = getExtensionByUrl(MIN_VALUE_EXTENSION_URL)?.value?.valueOrCalculateValue()
+  get() = getExtensionByUrl(MIN_VALUE_EXTENSION_URL)?.value
+
+internal val Questionnaire.QuestionnaireItemComponent.minValueCqfCalculatedValueExpression
+  get() = getExtensionByUrl(MIN_VALUE_EXTENSION_URL)?.value?.cqfCalculatedValueExpression
 
-/** The inclusive upper bound on the range of allowed answer values. */
 internal val Questionnaire.QuestionnaireItemComponent.maxValue
-  get() = getExtensionByUrl(MAX_VALUE_EXTENSION_URL)?.value?.valueOrCalculateValue()
+  get() = getExtensionByUrl(MAX_VALUE_EXTENSION_URL)?.value
+
+internal val Questionnaire.QuestionnaireItemComponent.maxValueCqfCalculatedValueExpression
+  get() = getExtensionByUrl(MAX_VALUE_EXTENSION_URL)?.value?.cqfCalculatedValueExpression
 
 // ********************************************************************************************** //
 //                                                                                                //

datacapture/src/main/java/com/google/android/fhir/datacapture/extensions/MoreQuestionnaires.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2023 Google LLC
+ * Copyright 2023-2024 Google LLC
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -94,7 +94,7 @@ private fun validateLaunchContextExtension(launchExtension: Extension) {
       false
     }
 
-  if (nameCoding.system != EXTENSION_LAUNCH_CONTEXT || !isValidResourceType) {
+  if (nameCoding.system != CODE_SYSTEM_LAUNCH_CONTEXT || !isValidResourceType) {
     error(
       "The extension:name and/or extension:type do not follow the format specified in $EXTENSION_SDC_QUESTIONNAIRE_LAUNCH_CONTEXT",
     )
@@ -139,7 +139,8 @@ internal const val EXTENSION_ENTRY_MODE_URL: String =
 internal const val EXTENSION_SDC_QUESTIONNAIRE_LAUNCH_CONTEXT =
   "http://hl7.org/fhir/uv/sdc/StructureDefinition/sdc-questionnaire-launchContext"
 
-internal const val EXTENSION_LAUNCH_CONTEXT = "http://hl7.org/fhir/uv/sdc/CodeSystem/launchContext"
+internal const val CODE_SYSTEM_LAUNCH_CONTEXT =
+  "http://hl7.org/fhir/uv/sdc/CodeSystem/launchContext"
 
 val Questionnaire.entryMode: EntryMode?
   get() {

datacapture/src/main/java/com/google/android/fhir/datacapture/extensions/MoreTypes.kt

@@ -18,11 +18,9 @@ package com.google.android.fhir.datacapture.extensions
 
 import android.content.Context
 import com.google.android.fhir.datacapture.R
-import com.google.android.fhir.datacapture.fhirpath.evaluateToBase
 import com.google.android.fhir.datacapture.views.factories.localDate
 import com.google.android.fhir.datacapture.views.factories.localTime
 import com.google.android.fhir.getLocalizedText
-import org.hl7.fhir.exceptions.FHIRException
 import org.hl7.fhir.r4.model.Attachment
 import org.hl7.fhir.r4.model.BooleanType
 import org.hl7.fhir.r4.model.CodeType
@@ -39,7 +37,6 @@ import org.hl7.fhir.r4.model.Reference
 import org.hl7.fhir.r4.model.StringType
 import org.hl7.fhir.r4.model.Type
 import org.hl7.fhir.r4.model.UriType
-import timber.log.Timber
 
 /**
  * Returns the string representation of a [PrimitiveType].
@@ -97,11 +94,13 @@ private fun getDisplayString(type: Type, context: Context): String? =
     else -> (type as? PrimitiveType<*>)?.valueAsString
   }
 
+/**
+ * Returns the string representation for [PrimitiveType] or [Quantity], otherwise defaults to null
+ */
 private fun getValueString(type: Type): String? =
   when (type) {
-    is StringType -> type.getLocalizedText() ?: type.valueAsString
-    is Quantity -> type.takeIf { it.hasValue() }?.value?.toString()
-    else -> (type as? PrimitiveType<*>)?.valueAsString
+    is Quantity -> type.value?.toString()
+    else -> (type as? PrimitiveType<*>)?.asStringValue()
   }
 
 /** Converts StringType to toUriType. */
@@ -132,30 +131,10 @@ internal fun Quantity.toCoding(): Coding {
   return Coding(this.system, this.code, this.unit)
 }
 
-fun Type.valueOrCalculateValue(): Type {
-  return if (getValueString(this) != null) {
-    this
-  } else {
-    this.cqfCalculatedValueExpression?.let { expression ->
-      try {
-        fhirPathEngine.evaluate(this, expression.expression).singleOrNull() as? Type
-      } catch (e: FHIRException) {
-        Timber.w("Could not evaluate expression with FHIRPathEngine", e)
-        null
-      }
-    }
-      ?: this
-  }
-}
-
-internal val Type.isCqfCalculatedValue
-  get() = this.hasExtension(EXTENSION_CQF_CALCULATED_VALUE_URL)
+internal fun Type.hasValue(): Boolean = !getValueString(this).isNullOrBlank()
 
 internal val Type.cqfCalculatedValueExpression
-  get() =
-    this.takeIf { isCqfCalculatedValue }
-      ?.getExtensionByUrl(EXTENSION_CQF_CALCULATED_VALUE_URL)
-      ?.value as? Expression
+  get() = this.getExtensionByUrl(EXTENSION_CQF_CALCULATED_VALUE_URL)?.value as? Expression
 
 internal const val EXTENSION_CQF_CALCULATED_VALUE_URL: String =
   "http://hl7.org/fhir/StructureDefinition/cqf-calculatedValue"

datacapture/src/main/java/com/google/android/fhir/datacapture/fhirpath/ExpressionEvaluator.kt

@@ -141,6 +141,24 @@ internal class ExpressionEvaluator(
     )
   }
 
+  /** Returns the evaluation result of an expression as a [Type] value */
+  suspend fun evaluateExpressionValue(
+    questionnaireItem: QuestionnaireItemComponent,
+    questionnaireResponseItem: QuestionnaireResponseItemComponent?,
+    expression: Expression,
+  ): Type? {
+    if (!expression.isFhirPath) {
+      throw UnsupportedOperationException("${expression.language} not supported yet")
+    }
+    return try {
+      evaluateExpression(questionnaireItem, questionnaireResponseItem, expression).singleOrNull()
+        as? Type
+    } catch (e: Exception) {
+      Timber.w("Could not evaluate expression ${expression.expression} with FHIRPathEngine", e)
+      null
+    }
+  }
+
   /**
    * Returns a list of pair of item and the calculated and evaluated value for all items with
    * calculated expression extension, which is dependent on value of updated response

datacapture/src/main/java/com/google/android/fhir/datacapture/fhirpath/FhirPathUtil.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2022-2023 Google LLC
+ * Copyright 2022-2024 Google LLC
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -24,7 +24,6 @@ import org.hl7.fhir.r4.model.ExpressionNode
 import org.hl7.fhir.r4.model.QuestionnaireResponse
 import org.hl7.fhir.r4.model.QuestionnaireResponse.QuestionnaireResponseItemComponent
 import org.hl7.fhir.r4.model.Resource
-import org.hl7.fhir.r4.model.Type
 import org.hl7.fhir.r4.utils.FHIRPathEngine
 
 private val fhirPathEngine: FHIRPathEngine =
@@ -101,9 +100,9 @@ internal fun evaluateToBase(
 }
 
 /** Evaluates the given expression and returns list of [Base] */
-internal fun evaluateToBase(type: Type, expression: String): List<Base> {
+internal fun evaluateToBase(base: Base, expression: String): List<Base> {
   return fhirPathEngine.evaluate(
-    /* base = */ type,
+    /* base = */ base,
     /* path = */ expression,
   )
 }

datacapture/src/main/java/com/google/android/fhir/datacapture/validation/AnswerConstraintValidator.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2022-2023 Google LLC
+ * Copyright 2022-2024 Google LLC
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,8 +17,10 @@
 package com.google.android.fhir.datacapture.validation
 
 import android.content.Context
+import org.hl7.fhir.r4.model.Expression
 import org.hl7.fhir.r4.model.Questionnaire
 import org.hl7.fhir.r4.model.QuestionnaireResponse
+import org.hl7.fhir.r4.model.Type
 
 /**
  * Validates [QuestionnaireResponse.QuestionnaireResponseItemComponent] against a particular
@@ -35,10 +37,11 @@ internal interface AnswerConstraintValidator {
    *
    * [Learn more](https://www.hl7.org/fhir/questionnaireresponse.html#link).
    */
-  fun validate(
+  suspend fun validate(
     questionnaireItem: Questionnaire.QuestionnaireItemComponent,
     answer: QuestionnaireResponse.QuestionnaireResponseItemAnswerComponent,
     context: Context,
+    expressionEvaluator: suspend (Expression) -> Type?,
   ): Result
 
   /**