(defvar pcmpl-emerge-package-completions '()
  "Cache for emerge package completions.")

(defvar pcmpl-emerge-options '("--sync" "--info" "--help" "-h" "--depclean" "-c"
			       "--check-news" "--clean" "-av" "-avuDN"
			       "--config" "--deselect" "-W" "--prune" "-P" "--regen"
			       "--resume" "-r" "--searchdesc" "-S" "--unmerge" "-C"
			       "--version" "-V" "--accept-properties=" "--accept-restrict="
			       "--alert" "-A" "--alphabetical" "--ask" "-a" "--autounmask-backtrack"
			       "--autounmask" "--autounmask-only" "--autounmask-continue"
			       "--autounmask-unrestricted-atoms" "--autounmask-keep-keywords"
			       "--autounmask-keep-masks" "--autounmask-license" "--autounmask-use"
			       "--autounmask-write" "--binpkg-changed-deps" "--binpkg-respect-use"
			       "--buildpkg" "-b" "--buildpkg-exclude" "--buildpkgonly" "-B"))


(defun pcmpl-emerge-list-packages-in-repo (repo)
  "Return a list of package paths in REPO."
  (let (result)
    (setf result (split-string (shell-command-to-string
				(format "find %s -mindepth 2 -maxdepth 2 -type d -not -path '*/\.*'" repo))
			       "\n" t))
    (setf result (mapcar
		  (lambda (str) (string-remove-prefix (concat "/var/db/repos/" (file-name-nondirectory repo) "/") str))
		  result))
    result))

(defun pcmpl-emerge-update-completions ()
  "Update the completions cache."
  (let ((top-dir "/var/db/repos/")
        paths)
    (cl-loop for repo in (seq-filter (lambda (f) (not (string-match-p "\\.git$" f)))
                                     (directory-files top-dir t directory-files-no-dot-files-regexp))
             do (setf paths (append paths (seq-filter 
                                            (lambda (str) 
                                              (not (string-match-p "/\\.git/" str)))
                                            (pcmpl-emerge-list-packages-in-repo repo)))))
    (setf pcmpl-emerge-package-completions (seq-uniq paths))))

;;;###autoload
(defun pcomplete/emerge ()
  "Completion rules for the 'emerge' command."
  (unless pcmpl-emerge-package-completions
    (pcmpl-emerge-update-completions))
  (pcomplete-here* pcmpl-emerge-options)
  (pcomplete-here* pcmpl-emerge-package-completions))

(provide 'pcmpl-emerge)