(ns cryogen-core.sass
  (:require [clojure.java.shell :as shell]
            [clojure.java.io :as io]
            [text-decoration.core :refer :all]
            [cryogen-core.io :refer [ignore match-re-filter]]))

(defmacro sh
  [& args]
  (let [valid-args (remove nil? args)]
    `(shell/sh ~@valid-args)))

(defn sass-installed?
  "Checks for the installation of Sass."
  []
  (= 0 (:exit (sh "sass" "--version"))))

(defn compass-installed?
  "Checks for the installation of Compass."
  []
  (try
    (= 0 (:exit (sh "compass" "--version")))
    (catch java.io.IOException _
      false)))

(defn find-sass-files
  "Given a Diretory, gets files, Filtered to those having scss or sass
  extention. Ignores files matching any ignored regexps."
  [base-dir dir ignored-files]
  (let [^java.io.FilenameFilter filename-filter (match-re-filter #"(?i:s[ca]ss$)")]
    (->> (.listFiles (io/file base-dir dir) filename-filter)
         (filter #(not (.isDirectory ^java.io.File %)))
         (filter (ignore ignored-files))
         (map #(.getName ^java.io.File %)))))

(defn compile-sass-file!
  "Given a sass file which might be in src-sass directory,
  output the resulting css in dest-sass. All error handling is
    done by sh / launching the sass command."
  [{:keys [src-sass
           dest-sass
           base-dir]}]
  (shell/with-sh-dir base-dir
    (if (compass-installed?)
      (sh "sass" "--compass" "--update" (str src-sass ":" dest-sass))
      (sh "sass" "--update" (str src-sass ":" dest-sass)))))

(defn compile-sass->css!
  "Given a directory src-sass, looks for all sass files and compiles them into
dest-sass. Prompts you to install sass if he finds sass files and can't find
the command. Shows you any problems it comes across when compiling. "
  [{:keys [src-sass
           dest-sass
           ignored-files
           base-dir] :as opts}]
  (when-let [sass-files (seq (find-sass-files base-dir src-sass ignored-files))]
    (if (sass-installed?)
      ;; I found sass files,
      ;; If sass is installed
      (do
        (println "\t" (cyan src-sass) "-->" (cyan dest-sass))
        (let [result (compile-sass-file! opts)]
          (if (zero? (:exit result))
            ;; no problems in sass compilation
            (println "Successfully compiled sass files")
            ;; else I show the error
            (println (red (:err result))
                     (red (:out result))))))
      ;; Else I prompt to install Sass
      (println "Sass seems not to be installed, but you have scss / sass files in "
               src-sass
               " - You might want to install it here: sass-lang.com"))))