Kotlin Embedded Config

DeploymentEnvironment.kt

open class DeploymentEnvironment<T : Any>(
    val base: T,
    vararg val profiles: Pair<String, (T) -> T>
) {
    companion object {

        fun <T : Any> config(clazz: Class<T>, name: String, profiles: Iterable<String> = emptyList()): T {
            return (Class.forName(clazz.`package`.name + "." + name).kotlin.objectInstance as DeploymentEnvironment<T>)
                .config(profiles)
        }
    }

    fun config(profiles: Iterable<String> = emptyList()): T =
        profiles.fold(base) { config, profile ->
            this.profiles.first { it.first == profile }.second(config)
        }
}

DeploymentEnvironmentTestTest.kt

data class FooConfig(
    val name: String,
    val value: Int
)

object dev : DeploymentEnvironment<FooConfig>(
    FooConfig("dev", 1),
    "p2" to { config: FooConfig -> config.copy(value = 2) },
    "p3" to { config: FooConfig -> config.copy(value = 3) }
)

class DeploymentEnvironmentTest {
    @Test
    fun config() {
        assertEquals(
            dev.base,
            DeploymentEnvironment.get(FooConfig::class.java, "dev")
        )
    }

    @Test
    fun profileOverrideConfig() {
        assertEquals(
            dev.base.let(dev.profiles[0].second),
            DeploymentEnvironment.get(FooConfig::class.java, "dev", listOf("p2"))
        )
    }

    @Test
    fun laterProfileOverridePrior() {
        assertEquals(
            dev.base.let(dev.profiles[0].second).let(dev.profiles[1].second),
            DeploymentEnvironment.get(FooConfig::class.java, "dev", listOf("p2", "p3"))
        )
    }
}