import kotlinx.browser.window
import kotlinx.coroutines.await
import kotlinx.serialization.Serializable
import kotlinx.serialization.json.Json
import org.w3c.fetch.RequestInit

private val AppJson = Json { ignoreUnknownKeys = true }

@Serializable
data class AppConfig(
  val apiBaseUrl: String,
  val keycloakUrl: String? = null // Optional, da nicht immer vorhanden
)

suspend fun loadAppConfig(): AppConfig {
    return try {
        // ?_nocache erzwingt einen SW-bypassing Request (SW sieht andere URL → Cache-Miss → Netzwerk)
      val response = window.fetch("/config.json?_nocache=1", RequestInit()).await()
        if (!response.ok) {
            console.warn("[Config] Failed to load config.json, falling back to globalThis")
            return fallbackFromGlobal()
        }
        val text = response.text().await()
      AppJson.decodeFromString(AppConfig.serializer(), text)
    } catch (e: dynamic) {
        console.error("[Config] Error loading config:", e)
        // Fallback: Caddy-injizierte Werte aus index.html (globalThis.API_BASE_URL / KEYCLOAK_URL)
        fallbackFromGlobal()
    }
}

private fun fallbackFromGlobal(): AppConfig {
    val apiBase = (js("globalThis.API_BASE_URL") as? String)
      ?.takeIf { it.isNotBlank() && !it.startsWith($$"${") }
        ?: window.location.origin
    val kcUrl = (js("globalThis.KEYCLOAK_URL") as? String)
      ?.takeIf { it.isNotBlank() && !it.startsWith($$"${") }
    console.log("[Config] Fallback: apiBaseUrl=$apiBase, keycloakUrl=$kcUrl")
    return AppConfig(apiBaseUrl = apiBase, keycloakUrl = kcUrl)
}