[DRAFT WORK IN PROGRESS] Prototype of JSON schema codegen

build.gradle

@@ -35,7 +35,7 @@ buildscript {
     }
     dependencies {
         classpath "androidx.navigation:navigation-safe-args-gradle-plugin:$navigationVersion"
-        classpath 'com.android.tools.build:gradle:8.2.0'
+        classpath 'com.android.tools.build:gradle:8.2.1'
         classpath 'com.google.gms:google-services:4.3.15'
         classpath "com.pascalwelsch.gitversioner:gitversioner:0.5.0"
 

ground/build.gradle

@@ -313,6 +313,8 @@ dependencies {
     stagingImplementation "androidx.fragment:fragment-testing:$fragmentVersion"
 
     implementation "com.google.guava:guava:31.1-android"
+
+    implementation project(":shared")
 }
 
 // Allow references to generated code.

ground/src/main/java/com/google/android/ground/persistence/remote/firebase/ObjectMapper.kt

@@ -0,0 +1,91 @@
+/*
+ * Copyright 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.
+ * You may obtain a copy of the License at
+ *
+ *     https://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.ground.persistence.remote.firebase
+
+import com.google.ground.shared.schema.GeometryObject
+import com.google.ground.shared.schema.MultiPolygonObject
+import com.google.ground.shared.schema.PointObject
+import com.google.ground.shared.schema.PolygonObject
+import com.google.gson.GsonBuilder
+import com.google.gson.JsonArray
+import com.google.gson.JsonDeserializationContext
+import com.google.gson.JsonDeserializer
+import com.google.gson.JsonElement
+import com.google.gson.JsonNull
+import com.google.gson.JsonObject
+import com.google.gson.JsonParseException
+import com.google.gson.JsonPrimitive
+import java.lang.reflect.Type
+import kotlin.reflect.KClass
+
+class ObjectMapper {
+  fun <T : Any> toObject(map: Map<String, Any>, kotlinClass: KClass<T>): T {
+
+    val gson =
+      GsonBuilder().registerTypeAdapter(GeometryObject::class.java, GeometryDeserializer()).create()
+    val json = map.toJsonElement()
+    return gson.fromJson(json, kotlinClass.java)
+  }
+
+  private fun Any?.toJsonElement(): JsonElement =
+    when (this) {
+      null -> JsonNull.INSTANCE
+      is JsonElement -> this
+      is Number -> JsonPrimitive(this)
+      is Boolean -> JsonPrimitive(this)
+      is String -> JsonPrimitive(this)
+      is Array<*> -> toJsonArray()
+      is List<*> -> toJsonArray()
+      // TODO: Add annotations for nested arrays.
+      is Map<*, *> -> toJsonObject()
+      else -> error("Unsupported type ${this.javaClass}")
+    }
+
+  private fun List<*>.toJsonArray(): JsonArray {
+    val arr = JsonArray(size)
+    forEach { arr.add(it.toJsonElement()) }
+    return arr
+  }
+
+  private fun Array<*>.toJsonArray() = arrayListOf(this).toJsonArray()
+
+  private fun Map<*, *>.toJsonObject(): JsonObject {
+    val obj = JsonObject()
+    entries.forEach { (k, v) -> obj.add(k.toString(), v.toJsonElement()) }
+    return obj
+  }
+}
+
+class GeometryDeserializer : JsonDeserializer<GeometryObject> {
+  override fun deserialize(
+    json: JsonElement,
+    typeOfT: Type,
+    context: JsonDeserializationContext
+  ): GeometryObject {
+    val type = json.asJsonObject["type"].asString
+    val kotlinClass =
+      geometryClassesByType[type] ?: throw JsonParseException("Unknown geometry type $type")
+    return context.deserialize(json, kotlinClass.java)
+  }
+}
+
+internal val geometryClassesByType =
+  mapOf(
+    "Point" to PointObject::class,
+    "Polygon" to PolygonObject::class,
+    "MultiPolygon" to MultiPolygonObject::class
+  )

ground/src/test/java/com/google/android/ground/persistence/remote/firebase/ObjectMapperTest.kt

@@ -0,0 +1,96 @@
+package com.google.android.ground.persistence.remote.firebase
+
+import com.google.firebase.firestore.GeoPoint
+import com.google.ground.shared.schema.LinearRingObject
+import com.google.ground.shared.schema.LoiDocument
+import com.google.ground.shared.schema.PointObject
+import com.google.ground.shared.schema.PolygonObject
+import com.google.gson.Gson
+import com.google.gson.reflect.TypeToken
+import kotlin.test.assertEquals
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.mockito.junit.MockitoJUnitRunner
+
+@RunWith(MockitoJUnitRunner::class)
+class ObjectMapperTest {
+  @Test
+  fun `Converts Point LOI`() {
+    val json =
+      """
+        {
+          "jobId": "123",
+          "customId": "foo",
+          "submissionCount": 42,
+          "geometry": {
+            "type": "Point",
+            "coordinates": {"latitude": 12.34, "longitude": 56.78}
+          }
+        }
+        """
+        .trimIndent()
+    val expected =
+      LoiDocument(
+        jobId = "123",
+        customId = "foo",
+        submissionCount = 42,
+        geometry =
+          PointObject(coordinates = GeoPoint(/* latitude= */ 12.34, /* longitude= */ 56.78))
+      )
+    val actual = ObjectMapper().toObject(json.toMap(), LoiDocument::class)
+    assertEquals(expected, actual)
+  }
+
+  @Test
+  fun `Converts basic Polygon LOI`() {
+    // TODO: Test Polygon with holes.
+    val json =
+      """
+        {
+          "jobId": "123",
+          "customId": "foo",
+          "submissionCount": 42,
+          "geometry": {
+            "type": "Polygon",
+            "coordinates": [
+              {
+                "$": [
+                  {"latitude": 0.0, "longitude": 0.0},
+                  {"latitude": 0.0, "longitude": 1.0},
+                  {"latitude": 1.0, "longitude": 1.0},              
+                  {"latitude": 0.0, "longitude": 0.0}
+                ]
+              }
+            ]
+          }
+        }
+        """
+        .trimIndent()
+    val expected =
+      LoiDocument(
+        jobId = "123",
+        customId = "foo",
+        submissionCount = 42,
+        geometry =
+          PolygonObject(
+            coordinates =
+              listOf(
+                LinearRingObject(
+                  listOf(
+                    GeoPoint(/* latitude= */ 0.0, /* longitude= */ 0.0),
+                    GeoPoint(/* latitude= */ 0.0, /* longitude= */ 1.0),
+                    GeoPoint(/* latitude= */ 1.0, /* longitude= */ 1.0),
+                    GeoPoint(/* latitude= */ 0.0, /* longitude= */ 0.0)
+                  )
+                )
+              )
+          )
+      )
+    val actual = ObjectMapper().toObject(json.toMap(), LoiDocument::class)
+    assertEquals(expected, actual)
+  }
+}
+
+internal object MapTypeToken : TypeToken<Map<String, Any>>()
+
+internal fun String.toMap(): Map<String, Any> = Gson().fromJson(this, MapTypeToken.type)

settings.gradle

@@ -2,5 +2,5 @@ plugins {
     id 'org.gradle.toolchains.foojay-resolver-convention' version '0.4.0'
 }
 
-include ':ground', ':sharedTest'
+include ':shared', ':ground', ':sharedTest'
 

shared/build.gradle.kts

@@ -0,0 +1,72 @@
+/*
+ * Copyright 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.
+ * You may obtain a copy of the License at
+ *
+ *     https://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.
+ */
+
+import net.pwall.json.kotlin.codegen.gradle.JSONSchemaCodegen
+import net.pwall.json.kotlin.codegen.gradle.JSONSchemaCodegenPlugin
+
+plugins {
+  // Android library plugin.
+  id("com.android.library")
+  // Kotlin plugins for Gradle.
+  id("kotlin-android")
+}
+
+android {
+  namespace = "com.google.ground.shared.schema"
+  // TODO(#2206): Manage compileSdk version centrally.
+  compileSdk = 34
+  sourceSets { getByName("main").java.srcDirs("build/generated-sources/kotlin") }
+}
+
+// TODO(#2206): Manage version centrally (e.g., via rootProject.jvmToolchainVersion).
+kotlin { jvmToolchain(17) }
+
+// TODO(#2206): Manage version centrally.
+dependencies {
+  implementation("org.jetbrains.kotlin", "kotlin-stdlib", "1.9.20")
+  implementation(platform("com.google.firebase:firebase-bom:32.4.1"))
+  implementation("com.google.firebase:firebase-firestore")
+}
+
+buildscript {
+  repositories { mavenCentral() }
+  dependencies { classpath("net.pwall.json:json-kotlin-gradle:0.102") }
+}
+
+apply<JSONSchemaCodegenPlugin>()
+
+configure<JSONSchemaCodegen> {
+  configFile.set(file("json-schema-codegen/config.json")) // if not in the default location
+  //    inputs { inputFile(file("src/main/resources/schema")) }
+  val base = "../../ground-platform/schema/src"
+  inputs {
+    inputFile(file("$base/loi-document.json"))
+    inputFile(file("$base/geometry-object.json"))
+    inputFile(file("$base/point-object.json"))
+    inputFile(file("$base/polygon-object.json"))
+    inputFile(file("$base/multi-polygon-object.json"))
+    inputFile(file("$base/linear-ring-array-wrapper.json"))
+    inputFile(file("$base/coordinates-object.json"))
+
+    inputFile(file("$base/submission-document.json"))
+    inputFile(file("$base/audit-info-object.json"))
+  }
+    // TODO:
+  //        codeGenerator.addCustomClassByURI(URI("http://pwall.net/test#/properties/price"),
+  // "com.example.Money")
+  outputDir.set(file("build/generated-sources/kotlin"))
+  packageName.set("com.google.ground.shared.schema")
+}

shared/json-schema-codegen/config.json

@@ -0,0 +1,13 @@
+{
+  "classNames": {
+    "urn:jsonschema:PolygonObject:coordinates": "PolygonCoordinates"
+  },
+  "customClasses": {
+    "extension": {
+      "x-kt-type": {
+        "SubmissionDataObject": "com.google.ground.shared.schema.SubmissionDataObject",
+        "GeoPoint": "com.google.firebase.firestore.GeoPoint"
+      }
+    }
+  }
+}

shared/src/main/kotlin/com/google/ground/shared/schema/SubmissionDataObject.kt

@@ -0,0 +1,20 @@
+/*
+ * Copyright 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.
+ * You may obtain a copy of the License at
+ *
+ *     https://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.ground.shared.schema
+
+// TODO(#2256): Update schema so that values can be strongly typed.
+typealias SubmissionDataObject = Map<String, Any>