Function assetsDownload

app/build.gradle.kts:1271–1322

}

fun assetsDownload(
	assets: List<Asset>,
	projectDir: File,
) {
	val checksumDir = File(projectDir, ".checksum")
	checksumDir.mkdirs()

	assets.forEach { asset ->
		val target = File(projectDir, asset.localPath)
		target.parentFile.mkdirs()

		// Path for checksum file
		val canonicalName = asset.localPath.replace("/", "_")
		val checksumFile = File(checksumDir, "${asset.variant}-$canonicalName.md5")

		// Load previous checksum (empty string if missing)
		val previousChecksum: String =
			if (checksumFile.exists()) {
				checksumFile.readText()
			} else {
				""
			}

		val remoteChecksum = assetsFileChecksum(asset)

		val needsDownload = (previousChecksum != remoteChecksum) || previousChecksum.isEmpty()

		if (needsDownload) {
			project.logger.lifecycle("Downloading ${asset.url} → ${asset.localPath}")

			assetsFileDownload(asset, File(rootProject.projectDir, asset.localPath))
			// Recompute checksum after download
			val digest = MessageDigest.getInstance("MD5")
			target.inputStream().use { input ->
				val buffer = ByteArray(8192)
				var read: Int
				while (input.read(buffer).also { read = it } > 0) {
					digest.update(buffer, 0, read)
				}
			}
			val newChecksum = digest.digest().joinToString("") { "%02x".format(it) }
			if (!remoteChecksum.isNullOrEmpty() && newChecksum != remoteChecksum) {
				throw GradleException("Check sum mismatch for ${asset.localPath} (expected $remoteChecksum, got $newChecksum)")
			}

			checksumFile.writeText(newChecksum)
			project.logger.lifecycle("Updated checksum stored: ${checksumFile.absolutePath}")
		} else {
			project.logger.lifecycle("File ${asset.localPath} is up-to-date (checksum matches).")
		}
	}
}

tasks.register("assetsDownloadDebug") {
	group = "setup"