;;; shell.el -*- lexical-binding: t; -*-
;;;
;;; Author:  Jakob L. Kreuze <zerodaysfordays@sdf.org>
;;; URL:     https://git.sr.ht/~jakob/.emacs.d/
;;;
;;; `shell' is sometimes clunky, and I can't get `alacritty' to work on my
;;; Pinebook Pro anymore, so I've been experimenting with `vterm'. Thus far, it
;;; is a nice medium between the two, so I am considering dropping `shell'
;;; altogether, albeit with a very slow transition-out.
;;;

;; Global variable that we use for the custom modeline.
(defvar vterm-buffer-titles (make-hash-table)
  "Title set by shell program.")

;; Some niceties for creating VTerm buffers with descriptive names.
(defun vterm-create-session-interactively (&optional ARG)
  "Wrapper around `vterm' to _always_ create a new session.

Possibly with a user-specified distinctive name."
  (interactive "p")
  (if (/= ARG 1)
      (vterm (format "*vterm*<%s>" (read-string "Name of buffer: ")))
    (vterm 't)))

(defun vterm-cycle-buffers ()
  "Switch to a vterm buffer in a cyclic order.

If a vterm buffer is currently open, choose the next in the ring.
Otherwise, switch to the first available vterm buffer."
  (interactive)
  (let* ((buffer-names (mapcar #'buffer-name (buffer-list)))
         (candidates (seq-filter (lambda (x) (string-search "*vterm*" x)) buffer-names))
         (cur-idx (or (cl-position-if (lambda (x)
                                        (string= x (buffer-name (current-buffer))))
                                      candidates)
                      -1))
         (idx (if (= (1+ cur-idx) (length candidates))
                  0
                (1+ cur-idx))))
    (switch-to-buffer (elt candidates idx))))

(use-package vterm
  ;; Hook into `vterm--set-title' for updating our custom modeline.
  :config
  (defun vterm--set-title (title)
    "Use TITLE to set the buffer name according to `vterm-buffer-name-string'."
    (puthash (current-buffer) title vterm-buffer-titles))

  ;; Custom keybindings for cycling through open VTerm buffers.
  :bind
  (:map vterm-mode-map ("M-s-p" . vterm-cycle-buffers))

  :bind
  ("s-<return>" . (lambda ()
                    (interactive)
                    (vterm-create-session-interactively 2))))