feat: Add gradle task to automatically copy the codegen artifacts for paper (#2168)

## Description

When changing native props on Fabric, codegen generates corresponding
interfaces and delegates. To make sure both implementations are
consistent, we implement those interfaces on Paper too. Currently, after
generating interfaces using codegen, developer needs to copy
corresponding files for paper manually. This task adds Gradle task, that
automates this.

## Changes

Add new task to build Gradle and necessary properties: 
- codegen artifacts dir and paper dir 
- flag in both fabric apps that indicates that copying should be
performed (we do want this task to be performed only when developing the
library)

## Test code and steps to reproduce

Remove `textColor` from `src/fabric/SearchBarNativeComponent.ts` and run
` ./gradlew generateCodegenArtifactsFromSchema` in
`/react-native-screens/FabricExample/android`. That should automatically
copy regenerated files to paper directory.

---------

Co-authored-by: Kacper Kafara <kacper.kafara@swmansion.com>

Author: maciekstosio

Example/android/gradle.properties

@@ -49,3 +49,5 @@ hermesEnabled=true
 # This is necessary, because the code checking for multiple instances
 # detects package versions from other example applications in the repository.
 disableMultipleInstancesCheck=true
+
+isScreensExampleApp=true

FabricExample/android/gradle.properties

@@ -39,3 +39,5 @@ newArchEnabled=true
 # Use this property to enable or disable the Hermes JS engine.
 # If set to false, you will be using JSC instead.
 hermesEnabled=true
+
+isScreensExampleApp=true

FabricTestExample/android/gradle.properties

@@ -41,3 +41,5 @@ newArchEnabled=true
 hermesEnabled=true
 
 disableMultipleInstancesCheck=true
+
+isScreensExampleApp=true

TVOSExample/android/gradle.properties

@@ -26,3 +26,5 @@ android.enableJetifier=true
 
 # Version of flipper SDK to use with React Native
 FLIPPER_VERSION=0.75.1
+
+isScreensExampleApp=true

TestsExample/android/gradle.properties

@@ -41,3 +41,5 @@ newArchEnabled=false
 hermesEnabled=true
 
 disableMultipleInstancesCheck=true
+
+isScreensExampleApp=true

android/build.gradle

@@ -192,3 +192,79 @@ dependencies {
         }
     }
 }
+
+def isScreensExampleApp() {
+    return project.hasProperty('isScreensExampleApp') && project.property('isScreensExampleApp') == "true"
+}
+
+def getAbsoluteCodegenArtifactsPaperDestination() {
+    if (!project.hasProperty('codegenArtifactsPaperDestination')) {
+        throw new Exception('[RNScreens] Please fill codegenArtifactsPaperDestination variable in android/gradle.properties correct path to paper paper destination')
+    }
+
+    return "${project.rootDir}/../../${project.property('codegenArtifactsPaperDestination')}"
+}
+
+def getAbsoluteCodegenArtifactsSource() {
+    if (!project.hasProperty('codegenArtifactsSource')) {
+        throw new Exception('[RNScreens] Please fill codegenArtifactsSource variable in android/gradle.properties correct path to codegenerated artifacts')
+    }
+
+    return "${project.rootDir}/../../${project.property('codegenArtifactsSource')}"
+}
+
+
+tasks.register("copyCodegenArtifacts") {
+    group 'After build tasks'
+    description 'Tasks which copy codegen artifacts to paper architecture'
+    
+    if (!isScreensExampleApp() || !isNewArchitectureEnabled()) {
+        return
+    }
+
+    dependsOn tasks.generateCodegenArtifactsFromSchema
+
+    doLast {
+
+        def absoluteCodegenArtifactsPaperDestination = getAbsoluteCodegenArtifactsPaperDestination()
+        def absoluteCodegenArtifactsSource = getAbsoluteCodegenArtifactsSource()
+
+        def existingFiles = fileTree(absoluteCodegenArtifactsPaperDestination).matching {
+            include '**/*.java'
+        }
+
+        def generatedFiles = fileTree(absoluteCodegenArtifactsSource).matching {
+            include '**/*.java'
+        }
+
+        def existingFilesMap = [:]
+
+        existingFiles.forEach { existingFile ->
+            existingFilesMap[existingFile.name] = 1
+        }
+
+        generatedFiles.forEach { generatedFile -> 
+            if (!existingFilesMap.containsKey(generatedFile.name)) {
+                logger.warn("[RNScreens] ${generatedFile.name} not found in paper dir, if it's used in Android you need to copy it manually and implement yourself before using auto-copy feature")
+            }
+        }
+
+        if (existingFiles.size() == 0) {
+            logger.warn("[RNScreens] Paper destination with codegen interfaces is empty. This might be okay if you don't have any interfaces/delegates used in Android, if that's not the case please check if codegenArtifactsPaperDestination in android/gradle.properties is correct")
+        }
+
+        if (existingFiles.size() > generatedFiles.size()) {
+            throw new Exception("[RNScreens] Number od generated artifacts should be greather then or equal to paper interfaces. Please check if codegenArtifactsSource in android/gradle.properties is correct")
+        }
+
+        copy {
+            from absoluteCodegenArtifactsSource
+            include existingFiles.collect { it.name }
+            into absoluteCodegenArtifactsPaperDestination
+        }
+    }
+}
+
+if (isScreensExampleApp() && isNewArchitectureEnabled()) {
+    tasks.generateCodegenArtifactsFromSchema.finalizedBy('copyCodegenArtifacts')
+}

android/gradle.properties

@@ -21,3 +21,10 @@ android.useAndroidX=true
 android.enableJetifier=true
 
 kotlin.code.style=official
+
+# Path to codegen output directory with this library view manager's interfaces & delegates. Used by `copyCodegenArtifacts` task that helps to synchronise newly generated files with their Paper conterparts.
+codegenArtifactsSource=android/build/generated/source/codegen/java/com/facebook/react/viewmanagers
+
+# Path to directory with view manager's interfaces & delegates used while running on Paper architecture. This property is used as output path for `copyCodegenArtifacts` task.
+# Used for task (copyCodegenArtifacts) that automates copying those interfaces/delegates when codegen is run
+codegenArtifactsPaperDestination=android/src/paper/java/com/facebook/react/viewmanagers/