; FIXME: Do as a minor mode like mouse-sel / mouse-copy / mouse-drag ???

; 0

(setq transient-mark-mode t)

; 1

(setq mouse-drag-copy-region nil)

;2 

;;; Like x-select-enable-clipboard

(defcustom x-select-enable-primary t
  "Non-nil means cutting and pasting uses the primary selection."
  :type 'boolean
  :group 'killing)

(setq x-select-enable-clipboard t)

(setq x-select-enable-primary nil)


;;; modified from term/x-win.el
;;; cut and pasted, change is basically just an extra (when...

(defun x-select-text* (text &optional push)
  "Make TEXT, a string, the primary or clipboard or both X selection,
depending on value of x-select-enable-clipboard and x-select-enable-primary
Also, set the value of X cut buffer 0, for backward compatibility
with older X applications."
  ;; Don't send the cut buffer too much text.
  ;; It becomes slow, and if really big it causes errors.
  (cond ((>= (length text) x-cut-buffer-max)
	 (x-set-cut-buffer "" push)
	 (setq x-last-selected-text-cut ""
	       x-last-selected-text-cut-encoded ""))
	(t
	 (setq x-last-selected-text-cut text
	       x-last-cut-buffer-coding 'iso-latin-1
	       x-last-selected-text-cut-encoded
	       ;; ICCCM says cut buffer always contain ISO-Latin-1
	       (encode-coding-string text 'iso-latin-1))
	 (x-set-cut-buffer x-last-selected-text-cut-encoded push)))
  (when x-select-enable-primary
    (x-set-selection 'PRIMARY text)
    (setq x-last-selected-text-primary text))
  (when x-select-enable-clipboard
    (x-set-selection 'CLIPBOARD text)
    (setq x-last-selected-text-clipboard text))
  )


;;; modified from term/x-win.el
;;; cut and pasted, change is basically just an extra (when ...

;; Return a value of one of the current X selections.
;; Consult the selections, and the cut buffer.  Treat empty strings
;; as if they were unset.
;; If this function is called twice and finds the same text,
;; it returns nil the second time.  This is so that a single
;; selection won't be added to the kill ring over and over.
(defun x-cut-buffer-or-selection-value* ()
  (let (clip-text primary-text cut-text)
    (when x-select-enable-clipboard
      (setq clip-text (x-selection-value 'CLIPBOARD))
      (if (string= clip-text "") (setq clip-text nil))

      ;; Check the CLIPBOARD selection for 'newness', is it different
      ;; from what we remebered them to be last time we did a
      ;; cut/paste operation.
      (setq clip-text
	    (cond;; check clipboard
	     ((or (not clip-text) (string= clip-text ""))
	      (setq x-last-selected-text-clipboard nil))
	     ((eq      clip-text x-last-selected-text-clipboard) nil)
	     ((string= clip-text x-last-selected-text-clipboard)
	      ;; Record the newer string,
	      ;; so subsequent calls can use the `eq' test.
	      (setq x-last-selected-text-clipboard clip-text)
	      nil)
	     (t
	      (setq x-last-selected-text-clipboard clip-text))))
      )
    (when x-select-enable-primary
      (setq primary-text (x-selection-value 'PRIMARY))
      ;; Check the PRIMARY selection for 'newness', is it different
      ;; from what we remebered them to be last time we did a
      ;; cut/paste operation.
      (setq primary-text
	    (cond;; check primary selection
	     ((or (not primary-text) (string= primary-text ""))
	      (setq x-last-selected-text-primary nil))
	     ((eq      primary-text x-last-selected-text-primary) nil)
	     ((string= primary-text x-last-selected-text-primary)
	      ;; Record the newer string,
	      ;; so subsequent calls can use the `eq' test.
	      (setq x-last-selected-text-primary primary-text)
	      nil)
	     (t
	      (setq x-last-selected-text-primary primary-text))))
      )

    (setq cut-text (x-get-cut-buffer 0))

    ;; Check the x cut buffer for 'newness', is it different
    ;; from what we remebered them to be last time we did a
    ;; cut/paste operation.
    (setq cut-text
	  (let ((next-coding (or next-selection-coding-system 'iso-latin-1)))
	    (cond;; check cut buffer
	     ((or (not cut-text) (string= cut-text ""))
	      (setq x-last-selected-text-cut nil))
	     ;; This short cut doesn't work because x-get-cut-buffer 	 
	     ;; always returns a newly created string. 	 
	     ;; ((eq      cut-text x-last-selected-text-cut) nil) 	 
	     ((and (string= cut-text x-last-selected-text-cut-encoded)
		   (eq x-last-cut-buffer-coding next-coding))
	      ;; See the comment above.  No need of this recording. 	 
	      ;; Record the newer string, 	 
	      ;; so subsequent calls can use the `eq' test. 	 
	      ;; (setq x-last-selected-text-cut cut-text) 	 
	      nil)
	     (t
	      (setq x-last-selected-text-cut-encoded cut-text
		  x-last-cut-buffer-coding next-coding
		  x-last-selected-text-cut
		  ;; ICCCM says cut buffer always contain ISO-Latin-1, but
		  ;; use next-selection-coding-system if not nil.
		  (decode-coding-string 
		   cut-text next-coding))))))

    ;; As we have done one selection, clear this now.
    (setq next-selection-coding-system nil)

    ;; At this point we have recorded the current values for the
    ;; selection from clipboard (if we are supposed to) primary,
    ;; and cut buffer.  So return the first one that has changed
    ;; (which is the first non-null one).
    ;;
    ;; NOTE: There will be cases where more than one of these has
    ;; changed and the new values differ.  This indicates that
    ;; something like the following has happened since the last time
    ;; we looked at the selections: Application X set all the
    ;; selections, then Application Y set only one or two of them (say
    ;; just the cut-buffer).  In this case since we don't have
    ;; timestamps there is no way to know what the 'correct' value to
    ;; return is.  The nice thing to do would be to tell the user we
    ;; saw multiple possible selections and ask the user which was the
    ;; one they wanted.
    ;; This code is still a big improvement because now the user can
    ;; futz with the current selection and get emacs to pay attention
    ;; to the cut buffer again (previously as soon as clipboard or
    ;; primary had been set the cut buffer would essentially never be
    ;; checked again).
    (or clip-text primary-text cut-text)
    ))



(setf interprogram-cut-function 'x-select-text*)
(setf interprogram-paste-function 'x-cut-buffer-or-selection-value*)

; 3

; x-set-selection nil == primary. 
(add-hook 'activate-mark-hook 
	  (function (lambda ()
		      (x-set-selection nil (buffer-substring (region-beginning) (region-end))))))


; 4

;;; based on mouse.el/mouse-yank-secondary

(defun mouse-yank-primary (click)
  "Insert the primary selection at the position clicked on.
Move point to the end of the inserted text.
If `mouse-yank-at-point' is non-nil, insert at point
regardless of where you click."
  (interactive "e")
  ;; Give temporary modes such as isearch a chance to turn off.
  (run-hooks 'mouse-leave-buffer-hook)
  (or mouse-yank-at-point (mouse-set-point click))
  (let ((secondary (x-get-selection 'PRIMARY)))
    (if secondary
        (insert (x-get-selection 'PRIMARY))
      (error "No primary selection"))))

(global-set-key [mouse-2] 'mouse-yank-primary)