/*
 * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
 *
 * 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 de.undercouch.gradle.tasks.download.Download
import de.undercouch.gradle.tasks.download.Verify
import java.nio.file.*
import java.util.UUID
import kotlin.io.path.createDirectories

plugins { id("de.undercouch.download") }

val buildInfo = project.extensions.getByType<BuildInfo>()

val BuildInfo.GraalVm.downloadFile
  get(): File {
    val extension = if (buildInfo.os.isWindows) "zip" else "tar.gz"
    return file(homeDir).resolve("${baseName}.$extension")
  }

// tries to minimize chance of corruption by download-to-temp-file-and-move
val downloadGraalVmAarch64 by
  tasks.registering(Download::class) { configureDownloadGraalVm(buildInfo.graalVmAarch64) }

val downloadGraalVmAmd64 by
  tasks.registering(Download::class) { configureDownloadGraalVm(buildInfo.graalVmAmd64) }

fun Download.configureDownloadGraalVm(graalvm: BuildInfo.GraalVm) {
  onlyIf { !graalvm.installDir.exists() }
  doLast { println("Downloaded GraalVm to ${graalvm.downloadFile}") }

  src(graalvm.downloadUrl)
  dest(graalvm.downloadFile)
  overwrite(false)
  tempAndMove(true)
}

val verifyGraalVmAarch64 by
  tasks.registering(Verify::class) {
    configureVerifyGraalVm(buildInfo.graalVmAarch64)
    dependsOn(downloadGraalVmAarch64)
  }

val verifyGraalVmAmd64 by
  tasks.registering(Verify::class) {
    configureVerifyGraalVm(buildInfo.graalVmAmd64)
    dependsOn(downloadGraalVmAmd64)
  }

fun Verify.configureVerifyGraalVm(graalvm: BuildInfo.GraalVm) {
  onlyIf { !graalvm.installDir.exists() }

  src(graalvm.downloadFile)
  checksum(
    buildInfo.libs.findVersion("graalVmSha256-${graalvm.osName}-${graalvm.arch}").get().toString()
  )
  algorithm("SHA-256")
}

// minimize chance of corruption by extract-to-random-dir-and-flip-symlink
val installGraalVmAarch64 by
  tasks.registering {
    dependsOn(verifyGraalVmAarch64)
    configureInstallGraalVm(buildInfo.graalVmAarch64)
  }

// minimize chance of corruption by extract-to-random-dir-and-flip-symlink
val installGraalVmAmd64 by
  tasks.registering {
    dependsOn(verifyGraalVmAmd64)
    configureInstallGraalVm(buildInfo.graalVmAmd64)
  }

fun Task.configureInstallGraalVm(graalVm: BuildInfo.GraalVm) {
  onlyIf { !graalVm.installDir.exists() }

  doLast {
    val distroDir = Paths.get(graalVm.homeDir, UUID.randomUUID().toString())

    try {
      distroDir.createDirectories()
      println("Extracting ${graalVm.downloadFile} into $distroDir")
      // faster and more reliable than Gradle's `copy { from tarTree() }`
      exec {
        workingDir = file(distroDir)
        executable = "tar"
        args("--strip-components=1", "-xzf", graalVm.downloadFile)
      }

      val distroBinDir =
        if (buildInfo.os.isMacOsX) distroDir.resolve("Contents/Home/bin")
        else distroDir.resolve("bin")

      println("Installing native-image into $distroDir")
      exec {
        val executableName = if (buildInfo.os.isWindows) "gu.cmd" else "gu"
        executable = distroBinDir.resolve(executableName).toString()
        args("install", "--no-progress", "native-image")
      }

      println("Creating symlink ${graalVm.installDir} for $distroDir")
      val tempLink = Paths.get(graalVm.homeDir, UUID.randomUUID().toString())
      Files.createSymbolicLink(tempLink, distroDir)
      try {
        Files.move(tempLink, graalVm.installDir.toPath(), StandardCopyOption.ATOMIC_MOVE)
      } catch (e: Exception) {
        try {
          delete(tempLink.toFile())
        } catch (ignored: Exception) {}
        throw e
      }
    } catch (e: Exception) {
      try {
        delete(distroDir)
      } catch (ignored: Exception) {}
      throw e
    }
  }
}