import com.android.build.gradle.api.ApplicationVariant
import com.android.build.gradle.api.BaseVariantOutput
import com.android.build.gradle.internal.api.BaseVariantOutputImpl

android {
    //...
    
    applicationVariants.all(ApplicationVariantAction())
}

class ApplicationVariantAction : Action<ApplicationVariant> {
    override fun execute(variant: ApplicationVariant) {
        val fileName = createFileName(variant)
        variant.outputs.all(VariantOutputAction(fileName))
    }

    private fun createFileName(variant: ApplicationVariant): String {
        return "YourAppName" +
                "_${variant.name}" +
                "_verCode${Android.versionCode}" +
                "_${getDateTimeFormat()}.apk"
    }

    private fun getDateTimeFormat(): String {
        val simpleDateFormat = SimpleDateFormat("yyMdHms", Locale.US)
        return simpleDateFormat.format(Date())
    }

    class VariantOutputAction(
        private val fileName: String
    ) : Action<BaseVariantOutput> {
        override fun execute(output: BaseVariantOutput) {
            if (output is BaseVariantOutputImpl) {
                output.outputFileName = fileName
            }
        }
    }
}