;;; build.el --- Project build, set up for Evil -*- lexical-binding: t; -*-
;;; Commentary:
;; Loaded from init.el after Evil.
;;
;;   :build        Run ./build.sh from the nearest ancestor dir containing it.
;;   :build ARGS   Run ./build.sh ARGS, e.g. :build release -v
;;
;; If no build.sh is found (or it isn't executable), report it and do nothing.
;;
;; The compilation buffer opens at the bottom (45% height, full width) and
;; takes focus when the build starts. ANSI colours are rendered.
;; Kill a running build with M-x kill-compilation.
;;; Code:

(setq compilation-read-command nil          ; run without prompting
      compilation-ask-about-save nil
      compilation-scroll-output t)

(add-hook 'compilation-filter-hook #'ansi-color-compilation-filter)

;; Compilation buffer at the bottom, full frame width.
(add-to-list 'display-buffer-alist
             '((derived-mode . compilation-mode)
               (display-buffer-reuse-window display-buffer-at-bottom)
               (window-height . 0.45)))

;; Focus the compilation window when a build starts.
(add-hook 'compilation-start-hook
          (lambda (proc)
            (when-let* ((win (get-buffer-window (process-buffer proc))))
              (select-window win))))

;; :build runs ./build.sh; :build ARGS appends ARGS.
(evil-define-command my/ex-build (args)
  "Run `./build.sh ARGS' from the nearest directory containing build.sh."
  (interactive "<a>")
  (let ((root (locate-dominating-file default-directory "build.sh")))
    (unless root
      (user-error "No build.sh found"))
    (let ((default-directory root))
      (unless (file-executable-p "build.sh")
        (user-error "build.sh is not executable"))
      (compile (string-trim (concat "./build.sh " args))))))   ; nil args -> ""

(evil-ex-define-cmd "build" #'my/ex-build)

;;; build.el ends here