;
;   unidiff.el -- major mode for diff files in unified format.
;
;   Copyright (c) Andrew W. Nosenko <awn@bcs.zp.ua>, 2000-2001
;
;   You can redistribute this file and/or modify it under the terms of
;   the GNU General Public License as published by the Free Software
;   Foundation; either version 2, or (at your option) any later version.
;
;   How to add to auto-mode alist (example): insert next code
;   into ~/.emacs file:
;
;       (setq auto-mode-alist
;             (append '(("diff$" . unidiff-mode)
;                       ("\\.patch$" . unidiff-mode)
;                       ("^patch-" . unidiff-mode))
;                     auto-mode-alist))
;
(defvar unidiff-mode-map nil
  "Unidiff mode keymap")   ; Create a mode-specific keymap.
(if unidiff-mode-map
    ()    ; don't change mode-map if already set
  (setq unidiff-mode-map (make-sparse-keymap))
  (define-key unidiff-mode-map "\M-p" 'unidiff-go-prev-chunk)
  (define-key unidiff-mode-map "\M-n" 'unidiff-go-next-chunk)
  (define-key unidiff-mode-map "\M-{" 'unidiff-go-prev-file)
  (define-key unidiff-mode-map "\M-}" 'unidiff-go-next-file)
  )

(defvar unidiff-mode-abbrev-table nil "Unidiff mode abbrev table")


(defgroup unidiff-faces
  ()  ; initial members
  "Unidiff Mode Faces"
  :group 'faces
)
  
(defface unidiff-minus-line-face
  '((((class color)) (:foreground "red4")))
  "Face for \"minus\" lines"
  :group 'unidiff-faces
)

(defface unidiff-plus-line-face
  '((((class color)) (:foreground "blue4")))
  "Face for \"plus\" lines"
  :group 'unidiff-faces
)

(defface unidiff-index-line-face
  '((((class color)) (:foreground "green4")))
  "Face for \"Index:\" lines"
  :group 'unidiff-faces
)

(defface unidiff-file-line-face
  '((((class color)) (:foreground "green4")))
  "Face for file name lines"
  :group 'unidiff-faces
)

(defface unidiff-begin-chunk-face
  '((((class color)) (:foreground "magenta4")))
  "Face for begin of chunk lines"
  :group 'unidiff-faces
)

(defface unidiff-ancor-line-face
  '((((class color)) (:foreground "gray50")))
  "Face for ancor lines"
  :group 'unidiff-faces
)

(defvar unidiff-font-lock-keywords
  '(
   ("^--- .*\n\\+\\+\\+ .*$" . unidiff-file-line-face)
   ("^@@.*$" . unidiff-begin-chunk-face)
   ("^\\(Index: .*\n\\(=*\nRCS file: .*\nretrieving revision.*\n\\(retrieving revision.*\n\\)?\\)?\\)?diff .*$" .
     unidiff-index-line-face)
   ("^\\+.*$" . unidiff-plus-line-face)
   ("^-.*$" . unidiff-minus-line-face)
   ("^ .*$" . unidiff-ancor-line-face)
   )
  )

  
(defvar unidiff-begin-chunk-regexp
  "^@@.*$"
  "Regexp for catch begin of chunk. Not affect for font-lock."
  )

(defvar unidiff-begin-file-regexp
  "^--- .*\n\\+\\+\\+ .*$"
  "Regexp for catch begin of file. Not affect for font-lock."
  )


;;;###autoload
(defun unidiff-mode ()
  "Major mode for view/edit unidiff files

Key bindings:
\\{unidiff-mode-map}"
  (interactive)
  (kill-all-local-variables)
  (setq major-mode 'unidiff-mode
	mode-name "Unidiff"
	local-abbrev-table unidiff-mode-abbrev-table
        )
  (use-local-map unidiff-mode-map)
  (put 'unidiff-mode 'mode-class 'special)
  (set (make-local-variable 'font-lock-keywords-only) t)
  (run-hooks 'unidiff-mode-hook)
)

(defun unidiff-go-next-chunk ()
  (interactive)

  (make-local-variable 'unidiff-saved-position)
  (set 'unidiff-saved-position (point))
  (goto-char (+ unidiff-saved-position 1))
  (if (not (re-search-forward unidiff-begin-chunk-regexp nil t))
      (progn
        (goto-char unidiff-saved-position)
        (message "no next chunk")
        (beep)
        )
    (goto-char (match-beginning 0))
    )
  )

(defun unidiff-go-prev-chunk ()
  (interactive)

  (make-local-variable 'unidiff-saved-position)
  (set 'unidiff-saved-position (point))
  (goto-char (+ unidiff-saved-position 1))
  (if (not (re-search-backward unidiff-begin-chunk-regexp nil t))
      (progn
        (goto-char unidiff-saved-position)
        (message "no previous chunk")
        (beep)
        )
    (goto-char (match-beginning 0))
    )
)

(defun unidiff-go-next-file ()
  (interactive)
  (make-local-variable 'unidiff-saved-position)
  (set 'unidiff-saved-position (point))
  (goto-char (+ unidiff-saved-position 1))
  (if (not
       (re-search-forward
        unidiff-begin-file-regexp
        nil
        t))
      (progn
        (goto-char unidiff-saved-position)
        (message "no next file")
        (beep)
        )
    (goto-char (match-beginning 0))
    )
)

(defun unidiff-go-prev-file ()
  (interactive)
  (make-local-variable 'unidiff-saved-position)
  (set 'unidiff-saved-position (point))
  (goto-char (+ unidiff-saved-position 1))
  (if (not
       (re-search-backward
        unidiff-begin-file-regexp
        nil
        t))
      (progn
        (goto-char unidiff-saved-position)
        (message "no previous file")
        (beep)
        )
    (goto-char (match-beginning 0))
    )
)