;;; syd-eshell.el -*- lexical-binding: t; -*-

(require 'ring)
(require 'cl-lib)

(defvar eshell-buffer-name "*eshell*")

(defvar syd-eshell-buffers (make-ring 25)
  "List of open eshell buffers.")

(defun syd-eshell-buffers ()
  "TODO"
  (ring-elements syd-eshell-buffers))

;;;###autoload
(defun syd-eshell-run-command (command &optional buffer)
  "TODO"
  (let ((buffer
         (or buffer
             (if (eq major-mode 'eshell-mode)
                 (current-buffer)
               (cl-find-if #'buffer-live-p (syd-eshell-buffers))))))
    (unless buffer
      (user-error "No living eshell buffers available"))
    (unless (buffer-live-p buffer)
      (user-error "Cannot operate on a dead buffer"))
    (with-current-buffer buffer
      (goto-char eshell-last-output-end)
      (goto-char (line-end-position))
      (insert command)
      (eshell-send-input nil t))))

;;;###autoload
(defun syd-eshell/toggle (arg &optional command)
  "Toggle eshell popup window."
  (interactive "P")
  (let ((eshell-buffer
         (get-buffer-create
          (format "*eshell-popup:%s*"
                  (if (bound-and-true-p persp-mode)
                      (safe-persp-name (get-current-persp))
                    "main"))))
        confirm-kill-processes
        current-prefix-arg)
    (when arg
      (when-let* ((win (get-buffer-window eshell-buffer)))
        (delete-window win))
      (when (buffer-live-p eshell-buffer)
        (with-current-buffer eshell-buffer
          (fundamental-mode)
          (erase-buffer))))
    (if-let* ((win (get-buffer-window eshell-buffer)))
        (let (confirm-kill-processes)
          (delete-window win)
          (ignore-errors (kill-buffer eshell-buffer)))
      (with-current-buffer eshell-buffer
        (syd-mark-buffer-as-real)
        (if (eq major-mode 'eshell-mode)
            (run-hooks 'eshell-mode-hook)
          (eshell-mode))
        (when command
          (syd-eshell-run-command command eshell-buffer)))
      (pop-to-buffer eshell-buffer))))

(use-package eshell
  :custom
  ((eshell-banner-message
    '(format "🦌 %s %s }:3\n"
      (propertize (format " %s " (string-trim (buffer-name)))
                  'face 'mode-line-highlight)
      (propertize (current-time-string)
                  'face 'font-lock-keyword-face)))
   (eshell-scroll-to-bottom-on-input 'all)
   (eshell-scroll-to-bottom-on-output 'all)
   (eshell-kill-processes-on-exit t)
   (eshell-hist-ignoredups t)
   (eshell-glob-case-insensitive t)
   (eshell-error-if-no-glob t)
   (eshell-history-file-name (file-name-concat
                              syd-data-dir "eshell" "history"))
   (eshell-last-dir-ring-file-name (file-name-concat
                                    syd-data-dir "eshell" "lastdir")))
  :general
  (:keymaps 'syd-leader-open-map
            "e" #'syd-eshell/toggle)
  (:keymaps 'eshell-mode-map
   :states '(normal insert)
   "C-j" #'eshell-next-matching-input-from-input
   "C-k" #'eshell-previous-matching-input-from-input)

  :config
  (require 'syd-buffers)

  (add-hook 'eshell-mode-hook #'syd-mark-buffer-as-real)

  ;; UI enhancements.
  (defun syd-eshell-remove-fringes-h ()
    (set-window-fringes nil 0 0)
    (set-window-margins nil 1 nil))
  (defun syd-eshell-enable-text-wrapping-h ()
    (visual-line-mode +1)
    (set-display-table-slot standard-display-table 0 ?\ ))
  (add-hook 'eshell-mode-hook #'syd-eshell-remove-fringes-h)
  (add-hook 'eshell-mode-hook #'syd-eshell-enable-text-wrapping-h)

  (with-eval-after-load 'hide-mode-line
    (add-hook 'eshell-mode-hook #'hide-mode-line-mode))

  ;; Remove hscroll-margin in shells, otherwise you get jumpiness when the
  ;; cursor comes close to the left/right edges of the window.
  (defun syd-eshell-disable-hscroll-margin ()
    (setq hscroll-margin 0))
  (add-hook 'eshell-mode-hook #'syd-eshell-disable-hscroll-margin))

(set-popup-rule! "^\\*eshell-popup"
       :vslot -5 :size 0.35 :select t :modeline nil :quit nil :ttl nil)

(provide 'syd-eshell)