;;; alidist-mode.el --- Major mode for alidist recipes
;;; Commentary:
;;; alidist recipes are shell scripts with a YAML header in front.
;;; We want both these parts highlighted properly, and to lint the
;;; whole thing with a custom script that glues together yamllint and
;;; shellcheck with a few custom checks.
;;; Code:

(require 'flycheck)
(require 'sh-script)
(require 'mmm-auto)

(flycheck-def-executable-var alidist "alidistlint")

(flycheck-define-checker alidist
  "A syntax checker and linter for alidist recipes."
  ;; `flycheck-alidist-executable' automatically overrides the car of the
  ;; :command list if set and non-nil.
  :command ("alidistlint" "--format=gcc" source)
  :error-patterns
  ((error line-start (file-name) ":" line ":" column ": error: " (message)
          " [" (id (minimal-match (one-or-more not-newline))) "]" line-end)
   (warning line-start (file-name) ":" line ":" column ": warning: " (message)
            " [" (id (minimal-match (one-or-more not-newline))) "]" line-end)
   (info line-start (file-name) ":" line ":" column ": note: " (message)
         " [" (id (minimal-match (one-or-more not-newline))) "]" line-end))
  :modes (alidist-mode alidist-script-mode))

(add-to-list 'flycheck-checkers 'alidist)

(defvar-local alidist-mode-mmm-refresh-timer nil
  "An idle timer for the current buffer, to make `mmm-mode' reparse it.")
(put 'alidist-mode-mmm-refresh-timer 'risky-local-variable t)

(defun alidist-mode-cancel-refresh-timer ()
  "Cancel and delete the timer that reparses the buffer.
It is stored in `alidist-mode-mmm-refresh-timer'."
  (when alidist-mode-mmm-refresh-timer
    (cancel-timer alidist-mode-mmm-refresh-timer)
    (setq alidist-mode-mmm-refresh-timer nil)))

(define-derived-mode alidist-mode yaml-mode "alidist"
  "An outer mode for alidist recipes, handling the metadata."
  (mmm-mode)
  ;; `mmm-mode' doesn't refresh its submodes when the buffer changes (e.g. when
  ;; a *_recipe key is added to the YAML header), so refresh manually when idle.
  (alidist-mode-cancel-refresh-timer)
  (add-hook 'kill-buffer-hook #'alidist-mode-cancel-refresh-timer 0 t)
  (setq alidist-mode-mmm-refresh-timer
        (run-with-idle-timer
         2 t (lambda (original-buffer)
               (when (eq original-buffer (current-buffer))
                 ;; Silence `mmm-parse-buffer''s annoying message.
                 (let ((inhibit-message t))
                   (mmm-parse-buffer))))
         ;; Idle timers are global, so make sure we only run the timer in the
         ;; right buffer. Save the buffer now to enable this, and compare every
         ;; time the timer ticks over.
         (current-buffer))))

(define-derived-mode alidist-script-mode sh-mode "Script"
  "A mode for scripts in alidist recipes with some default settings."
  (sh-set-shell "bash"))

(mmm-add-group 'alidist-recipe
  '((alidist-main-script
     :submode alidist-script-mode
     :face mmm-default-submode-face
     :front "^---\n"
     :back "\\'")   ; end of buffer
    (alidist-option-script
     :submode alidist-script-mode
     :face mmm-default-submode-face
     ;; Any *_recipe key with a multiline string value is probably a script.
     :front "^[[:space:]]*[a-z_]+_recipe: [|>]-?\n"
     ;; End of YAML header, or another YAML key.
     :back "^---\n\\|^[[:space:]]*[a-z_]+:\\($\\| \\)")))

;; Add sh-mode's indentation variables to mmm-mode's list.
(setq mmm-save-local-variables
      `(,@(mapcar
           (lambda (var) `(,var () (sh-mode)))
           sh-var-list)
        . ,mmm-save-local-variables))

(mmm-add-mode-ext-class 'alidist-mode nil 'alidist-recipe)
(add-to-list 'auto-mode-alist (cons "\\(\\`\\|/\\)alidist/.+\\.sh\\'"
                                    #'alidist-mode))

(provide 'alidist-mode)
;;; alidist-mode.el ends here