(ns rewrite-clj.zip.base
  (:refer-clojure :exclude [print])
  (:require [rewrite-clj.node :as node]
            [rewrite-clj.parser :as p]
            [rewrite-clj.zip.whitespace :as ws]
            [clojure.zip :as z]))

;; ## Zipper

(defn edn*
  "Create zipper over the given Clojure/EDN node."
  [node]
  (z/zipper
    node/inner?
    (comp seq node/children)
    node/replace-children
    node))

(defn edn
  "Create zipper over the given Clojure/EDN node and move
   to the first non-whitespace/non-comment child."
  [node]
  (if (= (node/tag node) :forms)
    (let [top (edn* node)]
      (or (-> top z/down ws/skip-whitespace)
          top))
    (recur (node/forms-node [node]))))

;; ## Inspection

(defn tag
  "Get tag of node at the current zipper location."
  [zloc]
  (some-> zloc z/node node/tag))

(defn sexpr
  "Get sexpr represented by the given node."
  [zloc]
  (some-> zloc z/node node/sexpr))

(defn child-sexprs
  "Get children as s-expressions."
  [zloc]
  (some-> zloc z/node node/child-sexprs))

(defn length
  "Get length of printable string for the given zipper location."
  [zloc]
  (or (some-> zloc z/node node/length) 0))


;; ## Read

(defn of-string
  "Create zipper from String."
  [s]
  (some-> s p/parse-string-all edn))


;; ## Write

(defn string
  "Create string representing the current zipper location."
  [zloc]
  (some-> zloc z/node node/string))

(defn root-string
  "Create string representing the zipped-up zipper."
  [zloc]
  (some-> zloc z/root node/string))

;; (defn- print!
;;   [s writer]
;;   (if writer
;;     (.write ^java.io.Writer writer s)
;;     (recur s *out*)))

;; (defn print
;;   "Print current zipper location."
;;   [zloc & [writer]]
;;   (some-> zloc
;;           string
;;           (print! writer)))

;; (defn print-root
;;   "Zip up and print root node."
;;   [zloc & [writer]]
;;   (some-> zloc
;;           root-string
;;           (print! writer)))