;;; my-eshell.el --- Configure eshell
;;; Commentary:

;;; Code:

(require 'use-package)
(require 'cl-seq)
(require 'magit)

(require 'eshell)
(require 'esh-mode)
(require 'esh-module)

(setq eshell-modules-list
      '(eshell-alias
        eshell-basic
        eshell-cmpl
        eshell-dirs
        eshell-glob
        eshell-hist
        eshell-ls
        eshell-pred
        eshell-prompt
        eshell-script
        eshell-term
        eshell-tramp
        eshell-unix))

(require 'em-alias)
(require 'em-basic)
(require 'em-dirs)
(require 'em-glob)
(require 'em-hist)
(require 'em-smart)
(require 'em-term)
(require 'em-tramp)
(require 'em-prompt)

(defun my/eshell-mode-setup ()
  "Configures various aliases for eshell."
  (eshell/alias "e" "find-file $1")
  (eshell/alias "emacs" "find-file $1")
  (eshell/alias "ee" "find-file-other-window $1")
  (eshell/alias "ll" "ls -l")
  (eshell/alias "d" "dired $1")
  (eshell/alias "gs" "magit-status")
  (eshell/alias "gd" "magit-diff-unstaged")
  (eshell/alias "gds" "magit-diff-staged")
  (eshell/alias "rg" "counsel-rg")
  (eshell/alias "cal" "calendar")
  (eshell/alias "agenda" "org-agenda"))

(defun my/eshell--open-or-cd (path)
  "Cd to PATH if path is a directory, otherwise open PATH via `find-file'."
  (interactive)
  (if (file-directory-p path)
      (progn
        (goto-char (point-max))
        (insert (concat "cd " path))
        (eshell-send-input)
        (insert (concat "ls -l"))
        (eshell-send-input))
    (find-file path)))

(defun my/eshell-open-file-at-point ()
  "Open the file at point in a buffer."
  (interactive)
  (let ((filename (symbol-name (symbol-at-point))))
    (cond
     ((file-readable-p filename)
      (my/eshell--open-or-cd filename))
     ((file-readable-p (expand-file-name filename))
      (my/eshell--open-or-cd (expand-file-name filename))))))

(defun my/eshell-here ()
  "Opens a new shell in the directory associated with the current buffer's file.
The eshell is renamed to match that directory to make multiple
eshell windows easier."
  (interactive)
  (let* ((parent (if (buffer-file-name)
                     (file-name-directory (buffer-file-name))
                   default-directory))
         (name (car (last (split-string parent "/" t)))))
    (split-window-horizontally)
    (other-window 1)
    (eshell "new")
    (rename-buffer (concat "*eshell: " name "*"))
    (insert (concat "ls " "-lh"))
    (eshell-send-input)))

(defvar-local my/eshell-output-buffer "*Exported eshell output*"
  "Name of buffer with the last output of Eshell command.")

(defvar-local my/eshell-output-delimiter "---"
  "Delimiter for successive `prot-eshell-export' outputs.")

(defun my/eshell--command-prompt-output ()
  "Capture last command prompt and its output."
  (let ((beg (save-excursion
               (goto-char (eshell-beginning-of-input))
               (goto-char (point-at-bol)))))
  (when (derived-mode-p 'eshell-mode)
    (buffer-substring-no-properties beg (eshell-end-of-output)))))

;; https://gitlab.com/protesilaos/dotfiles/-/blob/master/emacs/.emacs.d/prot-lisp/prot-eshell.el#L114
(defun my/eshell-export ()
  "Produce a buffer with output of the last Eshell command.
If `my/eshell-output-buffer' does not exist, create it.  Else
append to it, while separating multiple outputs with
`my/eshell-output-delimiter'."
  (interactive)
  (let ((eshell-output (my/eshell--command-prompt-output)))
    (with-current-buffer (get-buffer-create my/eshell-output-buffer)
      (goto-char (point-max))
      (unless (eq (point-min) (point-max))
        (insert (format "\n%s\n\n" my/eshell-output-delimiter)))
      (goto-char (point-at-bol))
      (insert eshell-output)
      (switch-to-buffer-other-window (current-buffer)))))

;; eshell time and notification
(defvar-local eshell-current-command-start-time nil)

;; https://www.birkey.co/2021-06-20-why-eshell-part-1.html
(defun my/eshell-current-command-start ()
  "Capture the time for when the command is started."
  (setq eshell-current-command-start-time (current-time)))

(defun my/eshell-current-command-stop ()
  "Calculate how long the command took to run."
  (when eshell-current-command-start-time
    (let ((elapsed-time (float-time
			 (time-subtract (current-time)
					eshell-current-command-start-time))))
      (if (> elapsed-time 5)
          (eshell-interactive-print
	   (format "Finished in: %.0fs\n" elapsed-time)))))
  (setq eshell-current-command-start-time nil))

(defun my/eshell-current-command-time-track ()
  "Track how long command takes to run."
  (add-hook 'eshell-pre-command-hook #'my/eshell-current-command-start nil t)
  (add-hook 'eshell-post-command-hook #'my/eshell-current-command-stop nil t))

(use-package eshell
  :hook ((eshell-mode . my/eshell-mode-setup)
         (eshell-mode . my/eshell-current-command-time-track)
         (eshell-mode . eshell-smart-initialize))
  :commands (eshell eshell-command)
  :bind (("C-c e h" . my/eshell-here)
         ("C-c e e" . my/eshell-export)
         ("C-c r"   . counsel-esh-history)
         :map eshell-mode-map
         ("C-o" . my/eshell-open-file-at-point))
  :custom
  (eshell-scroll-to-bottom-on-input 'all)
  (eshell-error-if-no-glob t)
  (eshell-hist-ignoredups t)
  (eshell-save-history-on-exit t)
  (eshell-cd-on-directory t)
  (eshell-prefer-lisp-functions nil)
  (eshell-where-to-jump 'begin)
  (eshell-review-quick-commands nil)
  (eshell-smart-space-goes-to-end t)
  (eshell-prompt-function 'my/eshell-prompt)
  (tramp-shell-prompt-pattern "^[^$>\n]*[#$%>] *\\(\[[0-9;]*[a-zA-Z] *\\)*")
  (eshell-destroy-buffer-when-process-dies t))

(use-package eshell-bookmark
  :ensure t
  :hook (eshell-mode . eshell-bookmark-setup))

(provide 'my-eshell)
;;; my-eshell.el ends here