(ns example.factory.aws.cloudformation)

(defn apply-stack-fn
  [create-fn update-fn]
  (fn apply-stack
    [payload]
    (try
      (create-fn payload)
      (catch AlreadyExistsException e
        (update-fn payload)))))

(defn expand-params
  [params-hash]
  ; something pure
  )

(defn deploy-stack-fn
  [apply-fn]
  (fn deploy-stack
    [stack-name template-hash params-hash]
    (apply-fn :stack-name stack-name
              :template-body (json/write-str template-hash)
              :parameters (expand-params params-hash))))

(ns example.aws.cloudformation
  (:require [example.factory.aws.cloudformation :as factory]))

(def apply-stack
  (factory/apply-stack-fn cloudformation/create-stack
                          cloudformation/update-stack))

(def deploy-stack
  (factory/deploy-stack-fn apply-stack))