buildSrc/src/main/kotlin/androidx/build/Ktlint.kt

/*
 * Copyright 2019 The Android Open Source Project
 *
 * 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 androidx.build

import androidx.build.uptodatedness.cacheEvenIfNoOutputs
import org.gradle.api.Project
import org.gradle.api.artifacts.Configuration
import org.gradle.api.tasks.Input
import org.gradle.api.tasks.JavaExec
import org.gradle.api.tasks.StopExecutionException
import org.gradle.api.tasks.options.Option

private fun Project.getKtlintConfiguration(): Configuration {
    return configurations.findByName("ktlint") ?: configurations.create("ktlint") {
        val dependency = dependencies.create("com.pinterest:ktlint:0.39.0")
        it.dependencies.add(dependency)
    }
}

private val DisabledRules = listOf(
    // does not match IJ default ordering
    "import-ordering",
    // not useful for our projects
    "final-newline",
).joinToString(",")

fun Project.configureKtlint() {
    val outputDir = "${project.buildDir}/reports/ktlint/"
    val inputDir = "src"
    val includeFiles = "**/*.kt"
    val excludeFiles = "**/test-data/**/*.kt"
    val inputFiles = project.fileTree(
        mutableMapOf(
            "dir" to inputDir, "include" to includeFiles,
            "exclude" to excludeFiles
        )
    )
    val outputFile = "${outputDir}ktlint-checkstyle-report.xml"

    val lintProvider = tasks.register("ktlint", JavaExec::class.java) { task ->
        task.inputs.files(inputFiles)
        task.cacheEvenIfNoOutputs()
        task.description = "Check Kotlin code style."
        task.group = "Verification"
        task.classpath = getKtlintConfiguration()
        task.main = "com.pinterest.ktlint.Main"
        task.args = listOf(
            "--android",
            "--disabled_rules",
            DisabledRules,
            "--reporter=plain",
            "--reporter=checkstyle,output=$outputFile",
            "$inputDir/$includeFiles",
            "!$inputDir/$excludeFiles"
        )
    }

    // afterEvaluate because Gradle's default "check" task doesn't exist yet
    afterEvaluate {
        addToCheckTask(lintProvider)
    }
    addToBuildOnServer(lintProvider)

    tasks.register("ktlintFormat", JavaExec::class.java) { task ->
        task.inputs.files(inputFiles)
        task.outputs.file(outputFile)
        task.description = "Fix Kotlin code style deviations."
        task.group = "formatting"
        task.classpath = getKtlintConfiguration()
        task.main = "com.pinterest.ktlint.Main"
        task.args = listOf(
            "--android",
            "-F",
            "--disabled_rules",
            DisabledRules,
            "--reporter=plain",
            "--reporter=checkstyle,output=$outputFile",
            "$inputDir/$includeFiles",
            "!$inputDir/$excludeFiles"
        )
    }
}

open class KtlintCheckFileTask : JavaExec() {
    @get:Input
    @set:Option(
        option = "file",
        description = "File to check. This option can be used multiple times: --file file1.kt " +
            "--file file2.kt"
    )
    var files: List<String> = emptyList()

    @get:Input
    @set:Option(
        option = "format",
        description = "Use --format to auto-correct style violations (if some errors cannot be " +
            "fixed automatically they will be printed to stderr)"
    )
    var format = false
}

fun Project.configureKtlintCheckFile() {
    tasks.register("ktlintCheckFile", KtlintCheckFileTask::class.java) { task ->
        task.description = "Check Kotlin code style."
        task.group = "Verification"
        task.classpath = getKtlintConfiguration()
        task.main = "com.pinterest.ktlint.Main"

        task.doFirst {
            if (task.files.isEmpty()) {
                throw StopExecutionException()
            }
            val kotlinFiles = task.files.filter { file ->
                file.endsWith(".kt") || file.endsWith(".ktx")
            }
            if (kotlinFiles.isNullOrEmpty()) {
                throw StopExecutionException()
            }
            val args = mutableListOf(
                "--android",
                "--disabled_rules",
                DisabledRules
            )
            args.addAll(kotlinFiles)
            if (task.format) {
                args.add("-F")
            }
            task.args = args
        }
    }
}