launch-reply.clj

(ns launch-reply.core
  (:require
    [clojure.java.io :as io]
    )
  (:import
    [java.nio.file WatchService StandardWatchEventKinds FileSystems Path Paths]
    [java.io File]
    )
  )

(def port-file-name ".nrepl-port")

(defn launch-reply
  [port]
  (require '[reply.main])
  (let [cmd `(reply.main/-main "--attach" ~(str "localhost:" port))]
    (println cmd)
    (eval cmd))
  )

(defn watch-and-launch
  []
  (let [watchService (.newWatchService (FileSystems/getDefault))
        cwd (File. ".")
        directory (Paths/get (.toURI cwd))
        watchKey  (.register directory watchService (into-array [StandardWatchEventKinds/ENTRY_MODIFY]))
        content (atom nil)
        ]
    (if (.exists (io/file port-file-name))
      (launch-reply (slurp port-file-name))
      (do
        (println "Watching" (.getCanonicalPath cwd) "for" port-file-name)
        ;; from https://gist.github.com/yogthos/911e6aba9802ceacd83c#file-file_watcher-clj-L30
        (while (not @content)
          (let [k (.take watchService)]
            (doseq [event (.pollEvents k)]
              (when (= port-file-name (.toString (.getFileName (.context event))))
                (reset! content (slurp (.toFile (.context event))))
                (println port-file-name "written with" @content)
                )
              )))
        (launch-reply @content)
        ))
    ))

(defn -main [& args]
  (watch-and-launch))

(comment
  (Paths/get ".")
  (.get Paths ".")
  (println  StandardWatchEventKinds/ENTRY_CREATE)
  (into-array [StandardWatchEventKinds/ENTRY_CREATE])
  )