import { instanceUrl } from "./transport"

type Settings = {
    API_BASE_URL?: string;
    ENCRYPTION_KEY?: string;
    FEDEO_PUBLIC_URL?: string;
    FEDEO_FEDERATION_URL?: string;
    FEDEO_FEDERATION_ENABLED?: string;
}

/** Existing deployment settings are sufficient; extra URLs are optional overrides. */
export function collaborationConfig(settings: Settings) {
    const configuredApi = settings.API_BASE_URL?.trim() || ""
    let apiUrl = (settings.FEDEO_FEDERATION_URL?.trim() || configuredApi).replace(/\/+$/, "")
    let publicUrl = settings.FEDEO_PUBLIC_URL?.trim().replace(/\/+$/, "") || ""
    if (!publicUrl) {
        try { publicUrl = new URL(configuredApi || apiUrl).origin } catch { /* Local development may have no public URL. */ }
    }
    const mode = settings.FEDEO_FEDERATION_ENABLED?.trim().toLowerCase() || "auto"
    if (!["auto", "true", "false"].includes(mode)) throw new Error("FEDEO_FEDERATION_ENABLED muss auto, true oder false sein")
    if (mode === "false") return { apiUrl, publicUrl, enabled: false, disabledReason: "Die Föderation wurde vom Betreiber deaktiviert." }

    let disabledReason: string | undefined
    try { apiUrl = instanceUrl(apiUrl) }
    catch { disabledReason = "Föderation benötigt eine gültige öffentliche HTTPS-API_BASE_URL auf Port 443." }
    if (!disabledReason && !/^[a-f0-9]{64}$/i.test(settings.ENCRYPTION_KEY || "")) {
        disabledReason = "Föderation benötigt einen gültigen ENCRYPTION_KEY mit 64 Hex-Zeichen." }
    if (mode === "true" && disabledReason) throw new Error(disabledReason)
    return { apiUrl, publicUrl, enabled: !disabledReason, disabledReason }
}