feat: introduce spotless/ktlint (#39)

* feat: introduce spotless + ktlint

* chore: run `spotlessApply` to format the code

* chore: exclude `examples` module

* fix: PROJECT_VERSION variable name

* fix: remove @Preview from Gallery

* chore: fix conflict

* build: add spotless CI

* chore: run spotlessApply to format the code

* build: remove examples module from settings.gradle.kts configuration

* chore: remove detekt.yml

* refactor: change the project indentation to 4 spaces

Author: whitescent

Diff for: .editorconfig

@@ -0,0 +1,28 @@
+root = true
+
+[*]
+charset = utf-8
+indent_size = 4
+indent_style = space
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.{kt,kts}]
+ij_kotlin_imports_layout = *
+ij_kotlin_allow_trailing_comma = true
+ij_kotlin_allow_trailing_comma_on_call_site = true
+ij_kotlin_line_break_after_multiline_when_entry = false
+ij_kotlin_name_count_to_use_star_import = 2147483647
+ij_kotlin_name_count_to_use_star_import_for_members = 2147483647
+ij_kotlin_packages_to_use_import_on_demand = unset
+ktlint_code_style = intellij_idea
+ktlint_function_naming_ignore_when_annotated_with = Composable
+ktlint_standard_function-expression-body = disabled
+ktlint_standard_filename = disabled
+ktlint_compose_modifier-missing-check = disabled
+
+[*.md]
+trim_trailing_whitespace = false
+
+[*.xml]
+indent_size = 4

Diff for: .github/workflows/spotless.yaml

@@ -0,0 +1,27 @@
+name: Spotless Check
+
+on:
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  spotless:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v3
+
+      - name: Set up JDK
+        uses: actions/setup-java@v3
+        with:
+          java-version: '17'
+          distribution: 'temurin'
+          cache: gradle
+
+      - name: Grant execute permission for gradlew
+        run: chmod +x ./gradlew
+
+      - name: Run Spotless Check
+        run: ./gradlew spotlessCheck

Diff for: build.gradle.kts

@@ -1,35 +1,61 @@
+import com.diffplug.gradle.spotless.SpotlessExtension
+
 plugins {
-  // this is necessary to avoid the plugins to be loaded multiple times
-  // in each subproject's classloader
-  alias(libs.plugins.androidApplication) apply false
-  alias(libs.plugins.androidLibrary) apply false
-  alias(libs.plugins.jetbrainsCompose) apply false
-  alias(libs.plugins.kotlinMultiplatform) apply false
-  alias(libs.plugins.compose.compiler) apply false
-  alias(libs.plugins.kotlin.jvm) apply false
-  alias(libs.plugins.dokka) apply false
+    // this is necessary to avoid the plugins to be loaded multiple times
+    // in each subproject's classloader
+    alias(libs.plugins.androidApplication) apply false
+    alias(libs.plugins.androidLibrary) apply false
+    alias(libs.plugins.jetbrainsCompose) apply false
+    alias(libs.plugins.kotlinMultiplatform) apply false
+    alias(libs.plugins.compose.compiler) apply false
+    alias(libs.plugins.kotlin.jvm) apply false
+    alias(libs.plugins.dokka) apply false
+    alias(libs.plugins.spotless) apply false
 }
 
 subprojects {
-  version = findProperty("storytale.deploy.version")
-    ?: error("'storytale.deploy.version' was not set")
+    version = findProperty("storytale.deploy.version")
+        ?: error("'storytale.deploy.version' was not set")
 
-  plugins.withId("maven-publish") {
-    configureIfExists<PublishingExtension> {
-      repositories {
-        maven {
-          name = "ComposeRepo"
-          setUrl(System.getenv("COMPOSE_REPO_URL"))
-          credentials {
-            username = System.getenv("COMPOSE_REPO_USERNAME")
-            password = System.getenv("COMPOSE_REPO_KEY")
-          }
+    plugins.withId("maven-publish") {
+        configureIfExists<PublishingExtension> {
+            repositories {
+                maven {
+                    name = "ComposeRepo"
+                    setUrl(System.getenv("COMPOSE_REPO_URL"))
+                    credentials {
+                        username = System.getenv("COMPOSE_REPO_USERNAME")
+                        password = System.getenv("COMPOSE_REPO_KEY")
+                    }
+                }
+            }
+        }
+    }
+    plugins.apply(rootProject.libs.plugins.spotless.get().pluginId)
+    extensions.configure<SpotlessExtension> {
+        kotlin {
+            target("src/**/*.kt")
+            targetExclude("src/test/resources/**")
+            ktlint(libs.ktlint.get().version)
+                .editorConfigOverride(
+                    mapOf(
+                        "indent_size" to "4",
+                        "ktlint_compose_modifier-missing-check" to "disabled",
+                        "ktlint_compose_compositionlocal-allowlist" to "disabled",
+                    ),
+                )
+                .customRuleSets(listOf(libs.composeRules.get().toString()))
+        }
+        kotlinGradle {
+            target("*.gradle.kts")
+            ktlint(libs.ktlint.get().version)
+                .editorConfigOverride(
+                    mapOf("indent_size" to "4"),
+                )
         }
-      }
     }
-  }
 }
 
 inline fun <reified T> Project.configureIfExists(fn: T.() -> Unit) {
-  extensions.findByType(T::class.java)?.fn()
-}
+    extensions.findByType(T::class.java)?.fn()
+}

Diff for: detekt.yml

@@ -40,7 +40,7 @@ kotlin {
   listOf(
     iosX64(),
     iosArm64(),
-    iosSimulatorArm64()
+    iosSimulatorArm64(),
   ).forEach { iosTarget ->
     iosTarget.binaries.framework {
       baseName = "ComposeApp"

Diff for: examples/build.gradle.kts

@@ -4,4 +4,4 @@ class AndroidPlatform : Platform {
   override val name: String = "Android ${Build.VERSION.SDK_INT}"
 }
 
-actual fun getPlatform(): Platform = AndroidPlatform()
+actual fun getPlatform(): Platform = AndroidPlatform()

Diff for: examples/src/androidMain/kotlin/Platform.android.kt

@@ -19,6 +19,6 @@ class MainActivity : ComponentActivity() {
 
 @Preview
 @Composable
-fun AppAndroidPreview() {
+private fun AppAndroidPreview() {
   App()
-}
+}