;;; Provides functions to make reading novels in eww easier.

(defun eww-new-buffer ()
  "open new empty eww buffer"
  (interactive)
  (switch-to-buffer (generate-new-buffer "*eww*"))
  (eww-mode))

(defun next-chapter ()
  "eww follow link to next chapter"
  (interactive)
  (defvar-local next-chapter-heur "[nN]ext.*?[cC]hapter")
  (if (re-search-forward next-chapter-heur nil t)
      (progn
	(backward-char)
	(eww-follow-link))
    (message "next chapter link not found")))

(defun prev-chapter ()
  "eww follow link to previous chapter"
  (interactive)
  (defvar-local prev-chapter-heur "[pP]rev.*?[cC]hapter")
  (if (re-search-forward prev-chapter-heur nil t)
      (progn
	(backward-char)
	(eww-follow-link))
    (message "prev chapter link not found")))

(defun goto-chapter ()
  "move cursor to next occurence of chapter"
  (interactive)  
  ;; (defvar-local chapter-heur "^.*chapter.*[[:digit:]].*")
  (defvar-local chapter-heur "^chapter.*[[:digit:]].*")
  (re-search-forward chapter-heur (buffer-end 1) t)
  (recenter-top-bottom 0))

(defun re-seq (regexp string)
  "Get a list of all regexp matches in a string"
  (save-match-data
    (let ((pos 0)
          matches)
      (while (string-match regexp string pos)
        (push (match-string 0 string) matches)
        (setq pos (match-end 0)))
      matches)))

(defun map-insert-columnized (SEQ &optional cols)
  "insert sequence in columnized form"
  (unless cols
    (setq-local cols 8))
  (setq-local counter 0)
  (while SEQ
    (insert (car SEQ))
    (setq-local SEQ (cdr SEQ))
    (setq-local counter (+ counter 1))
    (if (eq counter cols)
	(progn
	  (insert "\n")
	  (setq-local counter 0)))))

(defun xah-clean-whitespace ()
  "Delete trailing whitespace, and replace repeated blank lines to just 1.
Only space and tab is considered whitespace here.
Works on whole buffer or text selection, respects `narrow-to-region'.

URL `http://ergoemacs.org/emacs/elisp_compact_empty_lines.html'
Version 2017-09-22"
  (interactive)
  (let ($begin $end)
    (if (region-active-p)
        (setq $begin (region-beginning) $end (region-end))
      (setq $begin (point-min) $end (point-max)))
    (save-excursion
      (save-restriction
        (narrow-to-region $begin $end)
        (progn
          (goto-char (point-min))
          (while (re-search-forward "[ \t]+\n" nil "move")
            (replace-match "\n")))
        (progn
          (goto-char (point-min))
          (while (re-search-forward "\n\n\n+" nil "move")
            (replace-match "\n\n")))
        (progn
          (goto-char (point-max))
          (while (equal (char-before) 32) ; char 32 is space
            (delete-char -1))))
      (message "white space cleaned"))))

(defun my-clean-whitespace ()
  "Performs xah-clean-whitespace on read only buffers."
  (interactive)
  (if buffer-read-only
      (progn
	(read-only-mode 0)
	(xah-clean-whitespace)
	(read-only-mode 1))
    (progn
      (xah-clean-whitespace))))

(defun eww-open-url-in-new-buffer (&optional URL)
  "Opens given url new new eww buffer."
  (interactive)
  (or URL
      (setq URL
  	    (read-string "URL: ")))
  (eww-new-buffer)
  (eww URL))

(defun eww-bookmark-browse-in-new-buffer ()
  "Browse the bookmark under point in new eww buffer."
  (interactive)
  (let ((bookmark (get-text-property (line-beginning-position) 'eww-bookmark)))
    (unless bookmark
      (user-error "No bookmark on the current line"))
    (quit-window)
    (eww-new-buffer)
    (eww-browse-url (plist-get bookmark :url))))

(provide 'nov)