use codegen for indexing (#773)

* use codegen for indexing

* move code-generation to separate module

Signed-off-by: epicadk <[email protected]>

* code cleanup

Co-authored-by: Jing Tang <[email protected]>

buildSrc/src/main/kotlin/Dependencies.kt

@@ -82,6 +82,7 @@ object Dependencies {
   const val http = "com.squareup.okhttp3:okhttp:${Versions.http}"
   const val jsonToolsPatch = "com.github.java-json-tools:json-patch:${Versions.jsonToolsPatch}"
   const val material = "com.google.android.material:material:${Versions.material}"
+  const val kotlinPoet = "com.squareup:kotlinpoet:${Versions.kotlinPoet}"
 
   // Dependencies for testing go here
   object AndroidxTest {
@@ -144,6 +145,7 @@ object Dependencies {
     const val retrofit = "2.7.2"
     const val truth = "1.0.1"
     const val flexBox = "3.0.0"
+    const val kotlinPoet = "1.9.0"
 
     object AndroidxTest {
       const val core = "1.2.0"

buildSrc/src/main/kotlin/Plugins.kt

@@ -22,6 +22,8 @@ object Plugins {
     const val kotlinAndroid = "kotlin-android"
     const val kotlinKapt = "kotlin-kapt"
     const val mavenPublish = "maven-publish"
+    const val javaLibrary = "java-library"
+    const val kotlin = "kotlin"
     const val navSafeArgs = "androidx.navigation.safeargs.kotlin"
     const val spotless = "com.diffplug.spotless"
   }

codegen/.gitignore

@@ -0,0 +1 @@
+/build

codegen/build.gradle.kts

@@ -0,0 +1,15 @@
+plugins {
+  id(Plugins.BuildPlugins.javaLibrary)
+  id(Plugins.BuildPlugins.kotlin)
+}
+
+java {
+  sourceCompatibility = JavaVersion.VERSION_1_8
+  targetCompatibility = JavaVersion.VERSION_1_8
+}
+
+dependencies {
+  api(Dependencies.HapiFhir.structuresR4) { exclude(module = "junit") }
+
+  implementation(Dependencies.kotlinPoet)
+}

codegen/src/main/java/com/google/android/fhir/codegen/SearchParameterRepositoryGenerator.kt

@@ -0,0 +1,134 @@
+/*
+ * Copyright 2020 Google LLC
+ *
+ * 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 com.google.android.fhir.codegen
+
+import ca.uhn.fhir.context.FhirContext
+import com.squareup.kotlinpoet.ClassName
+import com.squareup.kotlinpoet.CodeBlock
+import com.squareup.kotlinpoet.FileSpec
+import com.squareup.kotlinpoet.FunSpec
+import com.squareup.kotlinpoet.KModifier
+import com.squareup.kotlinpoet.ParameterizedTypeName.Companion.parameterizedBy
+import java.io.File
+import java.util.Locale
+import kotlin.collections.HashMap
+import org.hl7.fhir.r4.model.Bundle
+import org.hl7.fhir.r4.model.Enumerations
+import org.hl7.fhir.r4.model.Resource
+import org.hl7.fhir.r4.model.SearchParameter
+
+/**
+ * Generates the file `SearchParameterRepositoryGenerated.kt`.
+ *
+ * The search parameter definitions are in the file `codegen/src/main/res/search-parameters.json`.
+ * This file should be kept up-to-date with the HL7 specifications at
+ * `http://www.hl7.org/fhir/search-parameters.json` and the `SearchParameterRepositoryGenerated.kt`
+ * should be regenerated to reflect any change.
+ *
+ * To do this, replace the content of the file `codegen/src/main/res/search-parameters.json` with
+ * the content at `http://www.hl7.org/fhir/search-parameters.json` and run the `main` function in
+ * the `codegen` module.
+ */
+object SearchParameterRepositoryGenerator {
+
+  private const val indexPackage = "com.google.android.fhir.index"
+  private const val hapiPackage = "org.hl7.fhir.r4.model"
+  private const val generatedClassName = "SearchParameterRepositoryGenerated"
+
+  private val searchParamMap: HashMap<String, CodeBlock.Builder> = HashMap()
+  private val searchParamDefinitionClass = ClassName(indexPackage, "SearchParamDefinition")
+
+  fun generate(bundle: Bundle, outputPath: String) {
+    for (entry in bundle.entry) {
+      val searchParameter = entry.resource as SearchParameter
+      if (searchParameter.expression.isNullOrEmpty()) continue
+
+      for (path in getResourceToPathMap(searchParameter.expression)) {
+        val hashMapKey = path.key
+        if (!searchParamMap.containsKey(hashMapKey)) {
+          searchParamMap[hashMapKey] = CodeBlock.builder().add("%S -> listOf(", hashMapKey)
+        }
+        searchParamMap[hashMapKey]!!.add(
+          "%T(%S,%T.%L,%S),\n",
+          searchParamDefinitionClass,
+          searchParameter.name,
+          Enumerations.SearchParamType::class,
+          searchParameter.type.toCode().uppercase(Locale.ROOT),
+          path.value
+        )
+      }
+    }
+
+    val fileSpec = FileSpec.builder(indexPackage, generatedClassName)
+
+    val function =
+      FunSpec.builder("getSearchParamList")
+        .addParameter("resource", Resource::class)
+        .returns(
+          ClassName("kotlin.collections", "List").parameterizedBy(searchParamDefinitionClass)
+        )
+        .addModifiers(KModifier.INTERNAL)
+        .addKdoc(
+          "This File is Generated from com.google.android.fhir.codegen.SearchParameterRepositoryGenerator all changes to this file must be made through the aforementioned file only"
+        )
+        .beginControlFlow("return when (resource.fhirType())")
+
+    for (resource in searchParamMap.keys) {
+      val resourceClass = ClassName(hapiPackage, resource.toHapiName())
+      try {
+        Class.forName(resourceClass.reflectionName())
+      } catch (e: ClassNotFoundException) {
+        // TODO handle alias and name (InsurancePlan)
+        println("Class not found $resource ")
+        continue
+      }
+      function.addCode(searchParamMap[resource]!!.add(")\n").build())
+    }
+    function.addStatement("else -> emptyList()").endControlFlow()
+    fileSpec.addFunction(function.build()).build().writeTo(File(outputPath))
+  }
+
+  /**
+   * @return the resource names mapped to their respective paths in the expression.
+   *
+   * @param expression an expression that contains the paths of a given search param
+   *
+   * This is necessary because the path expressions are not necessarily grouped by resource type
+   *
+   * For example an expression of "AllergyIntolerance.code | AllergyIntolerance.reaction.substance |
+   * Condition.code" will return "AllergyIntolerance" -> "AllergyIntolerance.code |
+   * AllergyIntolerance.reaction.substance" , "Condition" -> "Condition.code"
+   */
+  private fun getResourceToPathMap(expression: String): Map<String, String> {
+    return expression
+      .split("|")
+      .groupBy { splitString -> splitString.split(".").first().trim().removePrefix("(") }
+      .mapValues { it.value.joinToString(" | ") { join -> join.trim() } }
+  }
+
+  private fun String.toHapiName() = if (this == "List") "ListResource" else this
+}
+
+private const val inputFilePath = "codegen/src/main/res/search-parameters.json"
+private const val outputFilePath = "engine/src/main/java"
+
+fun main() {
+  val sp = File(inputFilePath)
+  val bundle =
+    FhirContext.forR4().newJsonParser().parseResource(Bundle::class.java, sp.inputStream())
+  SearchParameterRepositoryGenerator.generate(bundle, outputFilePath)
+}