;;; bzr-gnus.el --- bzr dvc integration to gnus

;; Copyright (C) 2008 by all contributors

;; Author: Stefan Reichoer <stefan@xsteve.at>

;; DVC is free software; you can redistribute it 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.

;; DVC is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to
;; the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.

;;; Commentary:

;; gnus is optional. Load it at compile-time to avoid warnings.
(eval-when-compile
  (condition-case nil
      (progn
        (require 'gnus)
        (require 'gnus-art)
        (require 'gnus-sum))
    (error nil)))

;;;###autoload
(defun bzr-insinuate-gnus ()
  "Integrate bzr into Gnus."
  (interactive)
  ;; there is nothing special to do yet...
  )

(defun bzr-gnus-article-view-patch (n)
  "View MIME part N in a gnus article, as a bzr changeset.
The patch can be embedded or external.  If external, the
parameter N is ignored."
  (interactive)
  (let ((num-of-mime-parts
         (save-window-excursion
           (gnus-summary-select-article-buffer)
           (gnus-article-mime-total-parts))))
    (if (> num-of-mime-parts 1)
        (bzr-gnus-article-view-attached-patch 2)
      (bzr-gnus-article-view-external-patch))))

(defun bzr-gnus-article-view-attached-patch (n)
  "View MIME part N, as bzr patchset."
  (interactive "p")
  (error "bzr-gnus-article-view-attached-patch not yet implemented"))

(defun bzr-gnus-article-view-external-patch ()
  "View an external patch that is referenced in this mail.

The mail must contain a line starting with 'Committed revision ' and ending
with the branch location."
  (interactive)
  (let ((revnr)
        (archive-location)
        (diff-buffer)
        (window-conf (current-window-configuration)))
    (gnus-summary-select-article-buffer)
    (split-window-vertically)
    (goto-char (point-min))
    ;; Committed revision 129 to http://my-arch.org/branch1
    (when (re-search-forward "Committed revision \\([0-9]+\\) to \\(.+\\)$" nil t)
      (setq revnr (match-string-no-properties 1))
      (setq archive-location (match-string-no-properties 2)))
    (gnus-article-show-summary)
    (if (and revnr archive-location)
        (progn
          (message "Viewing bzr revison: %s, location: %s" revnr archive-location)
          ;; bzr diff -r128..129 http://my-arch.org/branch1
          ;; Note: this command needs at least bzr v1.1
          (setq diff-buffer
                (bzr-delta `(bzr (revision (local "" ,(- (string-to-number revnr) 1))))
                           `(bzr (revision (local "" ,(string-to-number revnr))))
                           nil
                           archive-location))
          (save-excursion
            (set-buffer diff-buffer)
            (dvc-buffer-push-previous-window-config window-conf)))
      (message "No external bzr patch found in this article.")
      (set-window-configuration window-conf))))

(defun bzr-gnus-article-merge-bundle (n)
  "Merge MIME part N, as bzr merge bundle."
  (interactive "p")
  (unless current-prefix-arg
    (setq n 2))
  (gnus-article-part-wrapper n 'bzr-gnus-merge-bundle))

(defvar bzr-merge-bundle-mapping nil
  "*Project in which bzr bundles should be applied.

An alist of rules to map email addresses to target directories.

This is used by the `bzr-gnus-merge-bundle' function.
Example setting: '((\"dvc-dev@gna.org\" \"~/work/bzr/dvc\"))"
  )
;; e.g.: (setq bzr-merge-bundle-mapping '(("dvc-dev@gna.org" "~/work/bzr/dvc")))
(defun bzr-gnus-merge-bundle (handle)
  "Merge a bzr merge bundle via gnus.  HANDLE should be the handle of the part."
  (let ((patch-file-name (concat (dvc-make-temp-name "gnus-bzr-merge-") ".patch"))
        (window-conf (current-window-configuration))
        (to-addr (message-fetch-field "To"))
        (import-dir))
    (gnus-summary-select-article-buffer)
    (dvc-gnus-article-extract-log-message)
    (mm-save-part-to-file handle patch-file-name)

    (dolist (m bzr-merge-bundle-mapping)
      (when (string-match (regexp-quote (car m)) to-addr)
        (setq import-dir (dvc-uniquify-file-name (cadr m)))))
    (delete-other-windows)
    (dvc-buffer-push-previous-window-config)
    (find-file patch-file-name)
    (setq import-dir (dvc-read-directory-name "Merge bzr bundle to: " nil nil t import-dir))
    (when import-dir
      (let ((default-directory import-dir))
        (bzr-merge-bundle patch-file-name)))
    (delete-file patch-file-name)
    (kill-buffer (current-buffer)) ;; the patch file
    (set-window-configuration window-conf)
    (when (and import-dir (y-or-n-p "Run bzr status in merged tree? "))
      (let ((default-directory import-dir))
        (bzr-status)
        (delete-other-windows)))))

(defun bzr-gnus-article-pull-bundle-in-branch (n)
  "Merge MIME part N, as bzr merge bundle."
  (interactive "p")
  (unless current-prefix-arg
    (setq n 2))
  (gnus-article-part-wrapper n 'bzr-gnus-pull-bundle-in-branch))

(defun bzr-gnus-pull-bundle-in-branch (handle)
  "Merge a bzr merge bundle via gnus.  HANDLE should be the handle of the part."
  (let ((patch-file-name (concat (dvc-make-temp-name "gnus-bzr-pull-bundle-") ".patch"))
        (window-conf (current-window-configuration))
        (to-addr (message-fetch-field "To"))
        (import-dir))
    (gnus-summary-select-article-buffer)
    (dvc-gnus-article-extract-log-message)
    (mm-save-part-to-file handle patch-file-name)
    (message "bzr-gnus-pull-bundle-in-branch: implementation not finished (saved patch to %s)" patch-file-name)))


(provide 'bzr-gnus)
;;; bzr-gnus.el ends here