[stgit] / contrib / stgit.el

;; stgit.el: An emacs mode for StGit
;;
;; Copyright (C) 2007 David Kågedal <davidk@lysator.liu.se>
;;
;; To install: put this file on the load-path and place the following
;; in your .emacs file:
;;
;;    (require 'stgit)
;;
;; To start: `M-x stgit'

(require 'git nil t)
(require 'cl)
(require 'ewoc)

(defun stgit (dir)
  "Manage StGit patches for the tree in DIR."
  (interactive "DDirectory: \n")
  (switch-to-stgit-buffer (git-get-top-dir dir))
  (stgit-reload))

(unless (fboundp 'git-get-top-dir)
  (defun git-get-top-dir (dir)
    "Retrieve the top-level directory of a git tree."
    (let ((cdup (with-output-to-string
                  (with-current-buffer standard-output
                    (cd dir)
                    (unless (eq 0 (call-process "git" nil t nil
                                                "rev-parse" "--show-cdup"))
                      (error "Cannot find top-level git tree for %s" dir))))))
      (expand-file-name (concat (file-name-as-directory dir)
                                (car (split-string cdup "\n")))))))

(defun stgit-refresh-git-status (&optional dir)
  "If it exists, refresh the `git-status' buffer belonging to
directory DIR or `default-directory'"
  (when (and (fboundp 'git-find-status-buffer)
             (fboundp 'git-refresh-status))
    (let* ((top-dir (git-get-top-dir (or dir default-directory)))
           (git-status-buffer (and top-dir (git-find-status-buffer top-dir))))
      (when git-status-buffer
        (with-current-buffer git-status-buffer
          (git-refresh-status))))))

(defun stgit-find-buffer (dir)
  "Return the buffer displaying StGit patches for DIR, or nil if none."
  (setq dir (file-name-as-directory dir))
  (let ((buffers (buffer-list)))
    (while (and buffers
                (not (with-current-buffer (car buffers)
                       (and (eq major-mode 'stgit-mode)
                            (string= default-directory dir)))))
      (setq buffers (cdr buffers)))
    (and buffers (car buffers))))

(defun switch-to-stgit-buffer (dir)
  "Switch to a (possibly new) buffer displaying StGit patches for DIR."
  (setq dir (file-name-as-directory dir))
  (let ((buffer (stgit-find-buffer dir)))
    (switch-to-buffer (or buffer
			  (create-stgit-buffer dir)))))

(defstruct (stgit-patch)
  status name desc empty files-ewoc)

(defun stgit-patch-pp (patch)
  (let ((status (stgit-patch-status patch))
        (start (point))
        (name (stgit-patch-name patch)))
    (case name
       (:index (insert (propertize "  Index" 'face 'italic)))
       (:work (insert (propertize "  Work tree" 'face 'italic)))
       (t (insert (case status
                    ('applied "+")
                    ('top ">")
                    ('unapplied "-"))
                  (if (memq name stgit-marked-patches)
                      "*" " ")
                  (propertize (format "%-30s"
                                      (symbol-name name))
                              'face (case status
                                      ('applied 'stgit-applied-patch-face)
                                      ('top 'stgit-top-patch-face)
                                      ('unapplied 'stgit-unapplied-patch-face)
                                      ('index nil)
                                      ('work nil)))
                  "  "
                  (if (stgit-patch-empty patch) "(empty) " "")
                  (propertize (or (stgit-patch-desc patch) "")
                              'face 'stgit-description-face))))
    (put-text-property start (point) 'entry-type 'patch)
    (when (memq name stgit-expanded-patches)
      (stgit-insert-patch-files patch))
    (put-text-property start (point) 'patch-data patch)))

(defun create-stgit-buffer (dir)
  "Create a buffer for showing StGit patches.
Argument DIR is the repository path."
  (let ((buf (create-file-buffer (concat dir "*stgit*")))
        (inhibit-read-only t))
    (with-current-buffer buf
      (setq default-directory dir)
      (stgit-mode)
      (set (make-local-variable 'stgit-ewoc)
           (ewoc-create #'stgit-patch-pp "Branch:\n" "--"))
      (setq buffer-read-only t))
    buf))

(defmacro stgit-capture-output (name &rest body)
  "Capture StGit output and, if there was any output, show it in a window
at the end.
Returns nil if there was no output."
  (declare (debug ([&or stringp null] body))
           (indent 1))
  `(let ((output-buf (get-buffer-create ,(or name "*StGit output*")))
         (stgit-dir default-directory)
         (inhibit-read-only t))
     (with-current-buffer output-buf
       (erase-buffer)
       (setq default-directory stgit-dir)
       (setq buffer-read-only t))
     (let ((standard-output output-buf))
       ,@body)
     (with-current-buffer output-buf
       (set-buffer-modified-p nil)
       (setq buffer-read-only t)
       (if (< (point-min) (point-max))
           (display-buffer output-buf t)))))

(defun stgit-make-run-args (args)
  "Return a copy of ARGS with its elements converted to strings."
  (mapcar (lambda (x)
            ;; don't use (format "%s" ...) to limit type errors
            (cond ((stringp x) x)
                  ((integerp x) (number-to-string x))
                  ((symbolp x) (symbol-name x))
                  (t
                   (error "Bad element in stgit-make-run-args args: %S" x))))
          args))

(defun stgit-run-silent (&rest args)
  (setq args (stgit-make-run-args args))
  (apply 'call-process "stg" nil standard-output nil args))

(defun stgit-run (&rest args)
  (setq args (stgit-make-run-args args))
  (let ((msgcmd (mapconcat #'identity args " ")))
    (message "Running stg %s..." msgcmd)
    (apply 'call-process "stg" nil standard-output nil args)
    (message "Running stg %s...done" msgcmd)))

(defun stgit-run-git (&rest args)
  (setq args (stgit-make-run-args args))
  (let ((msgcmd (mapconcat #'identity args " ")))
    (message "Running git %s..." msgcmd)
    (apply 'call-process "git" nil standard-output nil args)
    (message "Running git %s...done" msgcmd)))

(defun stgit-run-git-silent (&rest args)
  (setq args (stgit-make-run-args args))
  (apply 'call-process "git" nil standard-output nil args))

(defun stgit-index-empty-p ()
  "Returns non-nil if the index contains no changes from HEAD."
  (zerop (stgit-run-git-silent "diff-index" "--cached" "--quiet" "HEAD")))

(defun stgit-run-series (ewoc)
  (let ((first-line t))
    (with-temp-buffer
      (let ((exit-status (stgit-run-silent "series" "--description" "--empty")))
        (goto-char (point-min))
        (if (not (zerop exit-status))
            (cond ((looking-at "stg series: \\(.*\\)")
                   (ewoc-set-hf ewoc (car (ewoc-get-hf ewoc))
                                "-- not initialized (run M-x stgit-init)"))
                  ((looking-at ".*")
                   (error "Error running stg: %s"
                          (match-string 0))))
          (while (not (eobp))
            (unless (looking-at
                     "\\([0 ]\\)\\([>+-]\\)\\( \\)\\([^ ]+\\) *[|#] \\(.*\\)")
              (error "Syntax error in output from stg series"))
            (let* ((state-str (match-string 2))
                   (state (cond ((string= state-str ">") 'top)
                                ((string= state-str "+") 'applied)
                                ((string= state-str "-") 'unapplied))))
              (ewoc-enter-last ewoc
                               (make-stgit-patch
                                :status state
                                :name (intern (match-string 4))
                                :desc (match-string 5)
                                :empty (string= (match-string 1) "0"))))
            (setq first-line nil)
            (forward-line 1)))))
    (when stgit-show-worktree
      (ewoc-enter-last ewoc
                       (make-stgit-patch
                        :status 'index
                        :name :index
                        :desc nil
                        :empty nil))
      (ewoc-enter-last ewoc
                       (make-stgit-patch
                        :status 'work
                        :name :work
                        :desc nil
                        :empty nil)))))


(defun stgit-reload ()
  "Update the contents of the StGit buffer."
  (interactive)
  (let ((inhibit-read-only t)
        (curline (line-number-at-pos))
        (curpatch (stgit-patch-name-at-point)))
    (ewoc-filter stgit-ewoc #'(lambda (x) nil))
    (ewoc-set-hf stgit-ewoc
                 (concat "Branch: "
                         (propertize
                          (with-temp-buffer
                            (stgit-run-silent "branch")
                            (buffer-substring (point-min) (1- (point-max))))
                          'face 'bold)
                         "\n")
                 (if stgit-show-worktree
                     "--"
                   (propertize
                    (substitute-command-keys "--\n\"\\[stgit-toggle-worktree]\"\
 shows the working tree\n")
                   'face 'stgit-description-face)))
    (stgit-run-series stgit-ewoc)
    (if curpatch
        (stgit-goto-patch curpatch)
      (goto-line curline)))
  (stgit-refresh-git-status))

(defgroup stgit nil
  "A user interface for the StGit patch maintenance tool."
  :group 'tools)

(defface stgit-description-face
  '((((background dark)) (:foreground "tan"))
    (((background light)) (:foreground "dark red")))
  "The face used for StGit descriptions"
  :group 'stgit)

(defface stgit-top-patch-face
  '((((background dark)) (:weight bold :foreground "yellow"))
    (((background light)) (:weight bold :foreground "purple"))
    (t (:weight bold)))
  "The face used for the top patch names"
  :group 'stgit)

(defface stgit-applied-patch-face
  '((((background dark)) (:foreground "light yellow"))
    (((background light)) (:foreground "purple"))
    (t ()))
  "The face used for applied patch names"
  :group 'stgit)

(defface stgit-unapplied-patch-face
  '((((background dark)) (:foreground "gray80"))
    (((background light)) (:foreground "orchid"))
    (t ()))
  "The face used for unapplied patch names"
  :group 'stgit)

(defface stgit-modified-file-face
  '((((class color) (background light)) (:foreground "purple"))
    (((class color) (background dark)) (:foreground "salmon")))
  "StGit mode face used for modified file status"
  :group 'stgit)

(defface stgit-unmerged-file-face
  '((((class color) (background light)) (:foreground "red" :bold t))
    (((class color) (background dark)) (:foreground "red" :bold t)))
  "StGit mode face used for unmerged file status"
  :group 'stgit)

(defface stgit-unknown-file-face
  '((((class color) (background light)) (:foreground "goldenrod" :bold t))
    (((class color) (background dark)) (:foreground "goldenrod" :bold t)))
  "StGit mode face used for unknown file status"
  :group 'stgit)

(defface stgit-file-permission-face
  '((((class color) (background light)) (:foreground "green" :bold t))
    (((class color) (background dark)) (:foreground "green" :bold t)))
  "StGit mode face used for permission changes."
  :group 'stgit)

(defcustom stgit-expand-find-copies-harder
  nil
  "Try harder to find copied files when listing patches.

When not nil, runs git diff-tree with the --find-copies-harder
flag, which reduces performance."
  :type 'boolean
  :group 'stgit)

(defconst stgit-file-status-code-strings
  (mapcar (lambda (arg)
            (cons (car arg)
                  (propertize (cadr arg) 'face (car (cddr arg)))))
          '((add         "Added"       stgit-modified-file-face)
            (copy        "Copied"      stgit-modified-file-face)
            (delete      "Deleted"     stgit-modified-file-face)
            (modify      "Modified"    stgit-modified-file-face)
            (rename      "Renamed"     stgit-modified-file-face)
            (mode-change "Mode change" stgit-modified-file-face)
            (unmerged    "Unmerged"    stgit-unmerged-file-face)
            (unknown     "Unknown"     stgit-unknown-file-face)))
  "Alist of code symbols to description strings")

(defun stgit-file-status-code-as-string (file)
  "Return stgit status code for FILE as a string"
  (let* ((code (assq (stgit-file-status file)
                     stgit-file-status-code-strings))
         (score (stgit-file-cr-score file)))
    (when code
      (format "%-11s  "
              (if (and score (/= score 100))
                  (format "%s %s" (cdr code)
                          (propertize (format "%d%%" score)
                                      'face 'stgit-description-face))
                (cdr code))))))

(defun stgit-file-status-code (str &optional score)
  "Return stgit status code from git status string"
  (let ((code (assoc str '(("A" . add)
                           ("C" . copy)
                           ("D" . delete)
                           ("M" . modify)
                           ("R" . rename)
                           ("T" . mode-change)
                           ("U" . unmerged)
                           ("X" . unknown)))))
    (setq code (if code (cdr code) 'unknown))
    (when (stringp score)
      (if (> (length score) 0)
          (setq score (string-to-number score))
        (setq score nil)))
    (if score (cons code score) code)))

(defconst stgit-file-type-strings
  '((#o100 . "file")
    (#o120 . "symlink")
    (#o160 . "subproject"))
  "Alist of names of file types")

(defun stgit-file-type-string (type)
  "Return string describing file type TYPE (the high bits of file permission).
Cf. `stgit-file-type-strings' and `stgit-file-type-change-string'."
  (let ((type-str (assoc type stgit-file-type-strings)))
    (or (and type-str (cdr type-str))
	(format "unknown type %o" type))))

(defun stgit-file-type-change-string (old-perm new-perm)
  "Return string describing file type change from OLD-PERM to NEW-PERM.
Cf. `stgit-file-type-string'."
  (let ((old-type (lsh old-perm -9))
        (new-type (lsh new-perm -9)))
    (cond ((= old-type new-type) "")
          ((zerop new-type) "")
          ((zerop old-type)
           (if (= new-type #o100)
               ""
             (format "   (%s)" (stgit-file-type-string new-type))))
          (t (format "   (%s -> %s)"
                     (stgit-file-type-string old-type)
                     (stgit-file-type-string new-type))))))

(defun stgit-file-mode-change-string (old-perm new-perm)
  "Return string describing file mode change from OLD-PERM to NEW-PERM.
Cf. `stgit-file-type-change-string'."
  (setq old-perm (logand old-perm #o777)
        new-perm (logand new-perm #o777))
  (if (or (= old-perm new-perm)
          (zerop old-perm)
          (zerop new-perm))
      ""
    (let* ((modified       (logxor old-perm new-perm))
	   (not-x-modified (logand (logxor old-perm new-perm) #o666)))
      (cond ((zerop modified) "")
            ((and (zerop not-x-modified)
                  (or (and (eq #o111 (logand old-perm #o111))
                           (propertize "-x" 'face 'stgit-file-permission-face))
                      (and (eq #o111 (logand new-perm #o111))
                           (propertize "+x" 'face
                                       'stgit-file-permission-face)))))
            (t (concat (propertize (format "%o" old-perm)
                                   'face 'stgit-file-permission-face)
                       (propertize " -> "
                                   'face 'stgit-description-face)
                       (propertize (format "%o" new-perm)
                                   'face 'stgit-file-permission-face)))))))

(defstruct (stgit-file)
  old-perm new-perm copy-or-rename cr-score cr-from cr-to status file)

(defun stgit-file-pp (file)
  (let ((status (stgit-file-status file))
        (name (if (stgit-file-copy-or-rename file)
                  (concat (stgit-file-cr-from file)
                          (propertize " -> "
                                      'face 'stgit-description-face)
                          (stgit-file-cr-to file))
                (stgit-file-file file)))
        (mode-change (stgit-file-mode-change-string
                      (stgit-file-old-perm file)
                      (stgit-file-new-perm file)))
        (start (point)))
    (insert (format "    %-12s%1s%s%s\n"
                    (stgit-file-status-code-as-string file)
                    mode-change
                    name
                    (propertize (stgit-file-type-change-string
                                 (stgit-file-old-perm file)
                                 (stgit-file-new-perm file))
                                'face 'stgit-description-face)))
    (add-text-properties start (point)
                         (list 'entry-type 'file
                               'file-data file))))

(defun stgit-insert-patch-files (patch)
  "Expand (show modification of) the patch with name PATCHSYM (a
symbol) after the line at point.
`stgit-expand-find-copies-harder' controls how hard to try to
find copied files."
  (insert "\n")
  (let* ((patchsym (stgit-patch-name patch))
         (end (progn (insert "#") (prog1 (point-marker) (forward-char -1))))
         (args (list "-z" (if stgit-expand-find-copies-harder
                              "--find-copies-harder"
                            "-C")))
         (ewoc (ewoc-create #'stgit-file-pp nil nil t)))
    (setf (stgit-patch-files-ewoc patch) ewoc)
    (with-temp-buffer
      (apply 'stgit-run-git
             (cond ((eq patchsym :work)
                    `("diff-files" ,@args))
                   ((eq patchsym :index)
                    `("diff-index" ,@args "--cached" "HEAD"))
                   (t
                    `("diff-tree" ,@args "-r" ,(stgit-id patchsym)))))
      (goto-char (point-min))
      (unless (or (eobp) (memq patchsym '(:work :index)))
        (forward-char 41))
      (while (looking-at ":\\([0-7]+\\) \\([0-7]+\\) [0-9A-Fa-f]\\{40\\} [0-9A-Fa-f]\\{40\\} ")
        (let ((old-perm (string-to-number (match-string 1) 8))
              (new-perm (string-to-number (match-string 2) 8)))
          (goto-char (match-end 0))
          (let ((file
                 (cond ((looking-at
                         "\\([CR]\\)\\([0-9]*\\)\0\\([^\0]*\\)\0\\([^\0]*\\)\0")
                        (make-stgit-file
                         :old-perm       old-perm
                         :new-perm       new-perm
                         :copy-or-rename t
                         :cr-score       (string-to-number (match-string 2))
                         :cr-from        (match-string 3)
                         :cr-to          (match-string 4)
                         :status         (stgit-file-status-code (match-string 1))
                         :file           (match-string 3)))
                       ((looking-at "\\([ABD-QS-Z]\\)\0\\([^\0]*\\)\0")
                        (make-stgit-file
                         :old-perm       old-perm
                         :new-perm       new-perm
                         :copy-or-rename nil
                         :cr-score       nil
                         :cr-from        nil
                         :cr-to          nil
                         :status         (stgit-file-status-code (match-string 1))
                         :file           (match-string 2))))))
            (ewoc-enter-last ewoc file))
          (goto-char (match-end 0))))
      (unless (ewoc-nth ewoc 0)
        (ewoc-set-hf ewoc "" (propertize "    <no files>\n"
                                         'face 'stgit-description-face))))
    (goto-char end)
    (delete-char -2)))

(defun stgit-select-file ()
  (let ((filename (expand-file-name
                   (stgit-file-file (stgit-patched-file-at-point)))))
    (unless (file-exists-p filename)
      (error "File does not exist"))
    (find-file filename)))

(defun stgit-select-patch ()
  (let ((patchname (stgit-patch-name-at-point)))
    (if (memq patchname stgit-expanded-patches)
        (setq stgit-expanded-patches (delq patchname stgit-expanded-patches))
      (setq stgit-expanded-patches (cons patchname stgit-expanded-patches)))
    (ewoc-invalidate stgit-ewoc (ewoc-locate stgit-ewoc)))
  (move-to-column (stgit-goal-column)))

(defun stgit-select ()
  "Expand or collapse the current entry"
  (interactive)
  (case (get-text-property (point) 'entry-type)
    ('patch
     (stgit-select-patch))
    ('file
     (stgit-select-file))
    (t
     (error "No patch or file on line"))))

(defun stgit-find-file-other-window ()
  "Open file at point in other window"
  (interactive)
  (let ((patched-file (stgit-patched-file-at-point)))
    (unless patched-file
      (error "No file on the current line"))
    (let ((filename (expand-file-name (stgit-file-file patched-file))))
      (unless (file-exists-p filename)
        (error "File does not exist"))
      (find-file-other-window filename))))

(defun stgit-quit ()
  "Hide the stgit buffer."
  (interactive)
  (bury-buffer))

(defun stgit-git-status ()
  "Show status using `git-status'."
  (interactive)
  (unless (fboundp 'git-status)
    (error "The stgit-git-status command requires git-status"))
  (let ((dir default-directory))
    (save-selected-window
      (pop-to-buffer nil)
      (git-status dir))))

(defun stgit-goal-column ()
  "Return goal column for the current line"
  (case (get-text-property (point) 'entry-type)
    ('patch 2)
    ('file 4)
    (t 0)))

(defun stgit-next-line (&optional arg)
  "Move cursor vertically down ARG lines"
  (interactive "p")
  (next-line arg)
  (move-to-column (stgit-goal-column)))

(defun stgit-previous-line (&optional arg)
  "Move cursor vertically up ARG lines"
  (interactive "p")
  (previous-line arg)
  (move-to-column (stgit-goal-column)))

(defun stgit-next-patch (&optional arg)
  "Move cursor down ARG patches."
  (interactive "p")
  (ewoc-goto-next stgit-ewoc (or arg 1))
  (move-to-column goal-column))

(defun stgit-previous-patch (&optional arg)
  "Move cursor up ARG patches."
  (interactive "p")
  (ewoc-goto-prev stgit-ewoc (or arg 1))
  (move-to-column goal-column))

(defvar stgit-mode-hook nil
  "Run after `stgit-mode' is setup.")

(defvar stgit-mode-map nil
  "Keymap for StGit major mode.")

(unless stgit-mode-map
  (let ((toggle-map (make-keymap)))
    (suppress-keymap toggle-map)
    (mapc (lambda (arg) (define-key toggle-map (car arg) (cdr arg)))
          '(("t" .        stgit-toggle-worktree)))
    (setq stgit-mode-map (make-keymap))
    (suppress-keymap stgit-mode-map)
    (mapc (lambda (arg) (define-key stgit-mode-map (car arg) (cdr arg)))
          `((" " .        stgit-mark)
            ("m" .        stgit-mark)
            ("\d" .       stgit-unmark-up)
            ("u" .        stgit-unmark-down)
            ("?" .        stgit-help)
            ("h" .        stgit-help)
            ("\C-p" .     stgit-previous-line)
            ("\C-n" .     stgit-next-line)
            ([up] .       stgit-previous-line)
            ([down] .     stgit-next-line)
            ("p" .        stgit-previous-patch)
            ("n" .        stgit-next-patch)
            ("\M-{" .     stgit-previous-patch)
            ("\M-}" .     stgit-next-patch)
            ("s" .        stgit-git-status)
            ("g" .        stgit-reload)
            ("r" .        stgit-refresh)
            ("\C-c\C-r" . stgit-rename)
            ("e" .        stgit-edit)
            ("M" .        stgit-move-patches)
            ("S" .        stgit-squash)
            ("N" .        stgit-new)
            ("R" .        stgit-repair)
            ("C" .        stgit-commit)
            ("U" .        stgit-uncommit)
            ("\r" .       stgit-select)
            ("o" .        stgit-find-file-other-window)
            ("i" .        stgit-file-toggle-index)
            (">" .        stgit-push-next)
            ("<" .        stgit-pop-next)
            ("P" .        stgit-push-or-pop)
            ("G" .        stgit-goto)
            ("=" .        stgit-show)
            ("D" .        stgit-delete)
            ([(control ?/)] . stgit-undo)
            ("\C-_" .     stgit-undo)
            ("B" .        stgit-branch)
            ("t" .        ,toggle-map)
            ("q" .        stgit-quit)))))

(defun stgit-mode ()
  "Major mode for interacting with StGit.
Commands:
\\{stgit-mode-map}"
  (kill-all-local-variables)
  (buffer-disable-undo)
  (setq mode-name "StGit"
        major-mode 'stgit-mode
        goal-column 2)
  (use-local-map stgit-mode-map)
  (set (make-local-variable 'list-buffers-directory) default-directory)
  (set (make-local-variable 'stgit-marked-patches) nil)
  (set (make-local-variable 'stgit-expanded-patches) nil)
  (set (make-local-variable 'stgit-show-worktree) stgit-default-show-worktree)
  (set-variable 'truncate-lines 't)
  (add-hook 'after-save-hook 'stgit-update-saved-file)
  (run-hooks 'stgit-mode-hook))

(defun stgit-update-saved-file ()
  (let* ((file (expand-file-name buffer-file-name))
         (dir (file-name-directory file))
         (gitdir (condition-case nil (git-get-top-dir dir)
                   (error nil)))
	 (buffer (and gitdir (stgit-find-buffer gitdir))))
    (when buffer
      (with-current-buffer buffer
        ;; FIXME: just invalidate ewoc node
	(stgit-reload)))))

(defun stgit-add-mark (patchsym)
  "Mark the patch PATCHSYM."
  (setq stgit-marked-patches (cons patchsym stgit-marked-patches)))

(defun stgit-remove-mark (patchsym)
  "Unmark the patch PATCHSYM."
  (setq stgit-marked-patches (delq patchsym stgit-marked-patches)))

(defun stgit-clear-marks ()
  "Unmark all patches."
  (setq stgit-marked-patches '()))

(defun stgit-patch-at-point (&optional cause-error)
  (get-text-property (point) 'patch-data))

(defun stgit-patch-name-at-point (&optional cause-error)
  "Return the patch name on the current line as a symbol.
If CAUSE-ERROR is not nil, signal an error if none found."
  (let ((patch (stgit-patch-at-point)))
    (cond (patch
           (stgit-patch-name patch))
          (cause-error
           (error "No patch on this line")))))

(defun stgit-patched-file-at-point ()
  (get-text-property (point) 'file-data))

(defun stgit-patches-marked-or-at-point ()
  "Return the symbols of the marked patches, or the patch on the current line."
  (if stgit-marked-patches
      stgit-marked-patches
    (let ((patch (stgit-patch-name-at-point)))
      (if patch
          (list patch)
        '()))))

(defun stgit-goto-patch (patchsym)
  "Move point to the line containing patch PATCHSYM.
If that patch cannot be found, do nothing."
  (let ((node (ewoc-nth stgit-ewoc 0)))
    (while (and node (not (eq (stgit-patch-name (ewoc-data node))
                              patchsym)))
      (setq node (ewoc-next stgit-ewoc node)))
    (when node
      (ewoc-goto-node stgit-ewoc node)
      (move-to-column goal-column))))

(defun stgit-init ()
  "Run stg init."
  (interactive)
  (stgit-capture-output nil
    (stgit-run "init"))
  (stgit-reload))

(defun stgit-mark ()
  "Mark the patch under point."
  (interactive)
  (let* ((node (ewoc-locate stgit-ewoc))
         (patch (ewoc-data node)))
    (stgit-add-mark (stgit-patch-name patch))
    (ewoc-invalidate stgit-ewoc node))
  (stgit-next-patch))

(defun stgit-unmark-up ()
  "Remove mark from the patch on the previous line."
  (interactive)
  (stgit-previous-patch)
  (let* ((node (ewoc-locate stgit-ewoc))
         (patch (ewoc-data node)))
    (stgit-remove-mark (stgit-patch-name patch))
    (ewoc-invalidate stgit-ewoc node))
  (move-to-column (stgit-goal-column)))

(defun stgit-unmark-down ()
  "Remove mark from the patch on the current line."
  (interactive)
  (let* ((node (ewoc-locate stgit-ewoc))
         (patch (ewoc-data node)))
    (stgit-remove-mark (stgit-patch-name patch))
    (ewoc-invalidate stgit-ewoc node))
  (stgit-next-patch))

(defun stgit-rename (name)
  "Rename the patch under point to NAME."
  (interactive (list (read-string "Patch name: "
                                  (symbol-name (stgit-patch-name-at-point t)))))
  (let ((old-patchsym (stgit-patch-name-at-point t)))
    (stgit-capture-output nil
      (stgit-run "rename" old-patchsym name))
    (let ((name-sym (intern name)))
      (when (memq old-patchsym stgit-expanded-patches)
        (setq stgit-expanded-patches
            (cons name-sym (delq old-patchsym stgit-expanded-patches))))
      (when (memq old-patchsym stgit-marked-patches)
        (setq stgit-marked-patches
            (cons name-sym (delq old-patchsym stgit-marked-patches))))
      (stgit-reload)
      (stgit-goto-patch name-sym))))

(defun stgit-repair ()
  "Run stg repair."
  (interactive)
  (stgit-capture-output nil
    (stgit-run "repair"))
  (stgit-reload))

(defun stgit-available-branches ()
  "Returns a list of the available stg branches"
  (let ((output (with-output-to-string
                  (stgit-run "branch" "--list")))
        (start 0)
        result)
    (while (string-match "^>?\\s-+s\\s-+\\(\\S-+\\)" output start)
      (setq result (cons (match-string 1 output) result))
      (setq start (match-end 0)))
    result))

(defun stgit-branch (branch)
  "Switch to branch BRANCH."
  (interactive (list (completing-read "Switch to branch: "
                                      (stgit-available-branches))))
  (stgit-capture-output nil (stgit-run "branch" "--" branch))
  (stgit-reload))

(defun stgit-commit (count)
  "Run stg commit on COUNT commits.
Interactively, the prefix argument is used as COUNT."
  (interactive "p")
  (stgit-capture-output nil (stgit-run "commit" "-n" count))
  (stgit-reload))

(defun stgit-uncommit (count)
  "Run stg uncommit on COUNT commits.
Interactively, the prefix argument is used as COUNT."
  (interactive "p")
  (stgit-capture-output nil (stgit-run "uncommit" "-n" count))
  (stgit-reload))

(defun stgit-push-next (npatches)
  "Push the first unapplied patch.
With numeric prefix argument, push that many patches."
  (interactive "p")
  (stgit-capture-output nil (stgit-run "push" "-n" npatches))
  (stgit-reload)
  (stgit-refresh-git-status))

(defun stgit-pop-next (npatches)
  "Pop the topmost applied patch.
With numeric prefix argument, pop that many patches."
  (interactive "p")
  (stgit-capture-output nil (stgit-run "pop" "-n" npatches))
  (stgit-reload)
  (stgit-refresh-git-status))

(defun stgit-applied-at-point ()
  "Is the patch on the current line applied?"
  (save-excursion
    (beginning-of-line)
    (looking-at "[>+]")))

(defun stgit-push-or-pop ()
  "Push or pop the patch on the current line."
  (interactive)
  (let ((patchsym (stgit-patch-name-at-point t))
        (applied (stgit-applied-at-point)))
    (stgit-capture-output nil
      (stgit-run (if applied "pop" "push") patchsym))
    (stgit-reload)))

(defun stgit-goto ()
  "Go to the patch on the current line."
  (interactive)
  (let ((patchsym (stgit-patch-name-at-point t)))
    (stgit-capture-output nil
      (stgit-run "goto" patchsym))
    (stgit-reload)))

(defun stgit-id (patchsym)
  "Return the git commit id for PATCHSYM.
If PATCHSYM is a keyword, returns PATCHSYM unmodified."
  (if (keywordp patchsym)
      patchsym
    (let ((result (with-output-to-string
		    (stgit-run-silent "id" patchsym))))
      (unless (string-match "^\\([0-9A-Fa-f]\\{40\\}\\)$" result)
	(error "Cannot find commit id for %s" patchsym))
      (match-string 1 result))))

(defun stgit-show ()
  "Show the patch on the current line."
  (interactive)
  (stgit-capture-output "*StGit patch*"
    (case (get-text-property (point) 'entry-type)
      ('file
       (let* ((patched-file (stgit-patched-file-at-point))
              (patch-name (stgit-patch-name-at-point))
              (patch-id (stgit-id patch-name))
              (args (append (and (stgit-file-cr-from patched-file)
                                 (if stgit-expand-find-copies-harder
                                     '("--find-copies-harder")
                                   '("-C")))
                            (cond ((eq patch-id :index)
                                   '("--cached"))
                                  ((eq patch-id :work)
                                   nil)
                                  (t
                                   (list (concat patch-id "^") patch-id)))
                            '("--")
                              (if (stgit-file-copy-or-rename patched-file)
                                  (list (stgit-file-cr-from patched-file)
                                        (stgit-file-cr-to patched-file))
                                (list (stgit-file-file patched-file))))))
         (apply 'stgit-run-git "diff" args)))
      ('patch
       (stgit-run "show" "-O" "--patch-with-stat" "-O" "-M"
                  (stgit-patch-name-at-point)))
      (t
       (error "No patch or file at point")))
    (with-current-buffer standard-output
      (goto-char (point-min))
      (diff-mode))))

(defun stgit-move-change-to-index (file status)
  "Copies the workspace state of FILE to index, using git add or git rm"
  (let ((op (if (file-exists-p file) "add" "rm")))
    (stgit-capture-output "*git output*"
      (stgit-run-git op "--" file))))

(defun stgit-remove-change-from-index (file status)
  "Unstages the change in FILE from the index"
  (stgit-capture-output "*git output*"
    (stgit-run-git "reset" "-q" "--" file)))

(defun stgit-file-toggle-index ()
  "Move modified file in or out of the index."
  (interactive)
  (let ((patched-file (stgit-patched-file-at-point)))
    (unless patched-file
      (error "No file on the current line"))
    (let ((patch-name (stgit-patch-name-at-point)))
      (cond ((eq patch-name :work)
             (stgit-move-change-to-index (stgit-file-file patched-file)
                                         (stgit-file-status patched-file)))
            ((eq patch-name :index)
             (stgit-remove-change-from-index (stgit-file-file patched-file)
                                             (stgit-file-status patched-file)))
            (t
             (error "Can only move files in the working tree to index")))))
  ;; FIXME: invalidate ewoc
  (stgit-reload))

(defun stgit-edit ()
  "Edit the patch on the current line."
  (interactive)
  (let ((patchsym (stgit-patch-name-at-point t))
        (edit-buf (get-buffer-create "*StGit edit*"))
        (dir default-directory))
    (log-edit 'stgit-confirm-edit t nil edit-buf)
    (set (make-local-variable 'stgit-edit-patchsym) patchsym)
    (setq default-directory dir)
    (let ((standard-output edit-buf))
      (stgit-run-silent "edit" "--save-template=-" patchsym))))

(defun stgit-confirm-edit ()
  (interactive)
  (let ((file (make-temp-file "stgit-edit-")))
    (write-region (point-min) (point-max) file)
    (stgit-capture-output nil
      (stgit-run "edit" "-f" file stgit-edit-patchsym))
    (with-current-buffer log-edit-parent-buffer
      (stgit-reload))))

(defun stgit-new (add-sign)
  "Create a new patch.
With a prefix argument, include a \"Signed-off-by:\" line at the
end of the patch."
  (interactive "P")
  (let ((edit-buf (get-buffer-create "*StGit edit*"))
        (dir default-directory))
    (log-edit 'stgit-confirm-new t nil edit-buf)
    (setq default-directory dir)
    (when add-sign
      (save-excursion
        (let ((standard-output (current-buffer)))
          (stgit-run-silent "new" "--sign" "--save-template=-"))))))

(defun stgit-confirm-new ()
  (interactive)
  (let ((file (make-temp-file "stgit-edit-")))
    (write-region (point-min) (point-max) file)
    (stgit-capture-output nil
      (stgit-run "new" "-f" file))
    (with-current-buffer log-edit-parent-buffer
      (stgit-reload))))

(defun stgit-create-patch-name (description)
  "Create a patch name from a long description"
  (let ((patch ""))
    (while (> (length description) 0)
      (cond ((string-match "\\`[a-zA-Z_-]+" description)
             (setq patch (downcase (concat patch
                                           (match-string 0 description))))
             (setq description (substring description (match-end 0))))
            ((string-match "\\` +" description)
             (setq patch (concat patch "-"))
             (setq description (substring description (match-end 0))))
            ((string-match "\\`[^a-zA-Z_-]+" description)
             (setq description (substring description (match-end 0))))))
    (cond ((= (length patch) 0)
           "patch")
          ((> (length patch) 20)
           (substring patch 0 20))
          (t patch))))

(defun stgit-delete (patchsyms &optional spill-p)
  "Delete the patches in PATCHSYMS.
Interactively, delete the marked patches, or the patch at point.

With a prefix argument, or SPILL-P, spill the patch contents to
the work tree and index."
  (interactive (list (stgit-patches-marked-or-at-point)
                     current-prefix-arg))
  (unless patchsyms
    (error "No patches to delete"))
  (let ((npatches (length patchsyms)))
    (when (yes-or-no-p (format "Really delete %d patch%s%s? "
			       npatches
			       (if (= 1 npatches) "" "es")
                               (if spill-p
                                   " (spilling contents to index)"
                                 "")))
      (let ((args (if spill-p 
                      (cons "--spill" patchsyms)
                    patchsyms)))
        (stgit-capture-output nil
          (apply 'stgit-run "delete" args))
        (stgit-reload)))))

(defun stgit-move-patches-target ()
  "Return the patchsym indicating a target patch for
`stgit-move-patches'.

This is either the patch at point, or one of :top and :bottom, if
the point is after or before the applied patches."

  (let ((patchsym (stgit-patch-name-at-point)))
    (cond (patchsym patchsym)
	  ((save-excursion (re-search-backward "^>" nil t)) :top)
	  (t :bottom))))

(defun stgit-sort-patches (patchsyms)
  "Returns the list of patches in PATCHSYMS sorted according to
their position in the patch series, bottommost first.

PATCHSYMS may not contain duplicate entries."
  (let (sorted-patchsyms
        (series (with-output-to-string
                  (with-current-buffer standard-output
                    (stgit-run-silent "series" "--noprefix"))))
        start)
    (while (string-match "^\\(.+\\)" series start)
      (let ((patchsym (intern (match-string 1 series))))
        (when (memq patchsym patchsyms)
          (setq sorted-patchsyms (cons patchsym sorted-patchsyms))))
      (setq start (match-end 0)))
    (setq sorted-patchsyms (nreverse sorted-patchsyms))

    (unless (= (length patchsyms) (length sorted-patchsyms))
      (error "Internal error"))

    sorted-patchsyms))

(defun stgit-move-patches (patchsyms target-patch)
  "Move the patches in PATCHSYMS to below TARGET-PATCH.
If TARGET-PATCH is :bottom or :top, move the patches to the
bottom or top of the stack, respectively.

Interactively, move the marked patches to where the point is."
  (interactive (list stgit-marked-patches
                     (stgit-move-patches-target)))
  (unless patchsyms
    (error "Need at least one patch to move"))

  (unless target-patch
    (error "Point not at a patch"))

  (if (eq target-patch :top)
      (stgit-capture-output nil
        (apply 'stgit-run "float" patchsyms))

    ;; need to have patchsyms sorted by position in the stack
    (let ((sorted-patchsyms (stgit-sort-patches patchsyms)))
      (while sorted-patchsyms
        (setq sorted-patchsyms
              (and (stgit-capture-output nil
                     (if (eq target-patch :bottom)
                         (stgit-run "sink" "--" (car sorted-patchsyms))
                       (stgit-run "sink" "--to" target-patch "--"
                                  (car sorted-patchsyms))))
                   (cdr sorted-patchsyms))))))
  (stgit-reload))

(defun stgit-squash (patchsyms)
  "Squash the patches in PATCHSYMS.
Interactively, squash the marked patches.

Unless there are any conflicts, the patches will be merged into
one patch, which will occupy the same spot in the series as the
deepest patch had before the squash."
  (interactive (list stgit-marked-patches))
  (when (< (length patchsyms) 2)
    (error "Need at least two patches to squash"))
  (let ((stgit-buffer (current-buffer))
        (edit-buf (get-buffer-create "*StGit edit*"))
        (dir default-directory)
        (sorted-patchsyms (stgit-sort-patches patchsyms)))
    (log-edit 'stgit-confirm-squash t nil edit-buf)
    (set (make-local-variable 'stgit-patchsyms) sorted-patchsyms)
    (setq default-directory dir)
    (let ((result (let ((standard-output edit-buf))
                    (apply 'stgit-run-silent "squash"
                           "--save-template=-" sorted-patchsyms))))

      ;; stg squash may have reordered the patches or caused conflicts
      (with-current-buffer stgit-buffer
        (stgit-reload))

      (unless (eq 0 result)
        (fundamental-mode)
        (rename-buffer "*StGit error*")
        (resize-temp-buffer-window)
        (switch-to-buffer-other-window stgit-buffer)
        (error "stg squash failed")))))

(defun stgit-confirm-squash ()
  (interactive)
  (let ((file (make-temp-file "stgit-edit-")))
    (write-region (point-min) (point-max) file)
    (stgit-capture-output nil
      (apply 'stgit-run "squash" "-f" file stgit-patchsyms))
    (with-current-buffer log-edit-parent-buffer
      (stgit-clear-marks)
      ;; Go to first marked patch and stay there
      (goto-char (point-min))
      (re-search-forward (concat "^[>+-]\\*") nil t)
      (move-to-column goal-column)
      (let ((pos (point)))
        (stgit-reload)
        (goto-char pos)))))

(defun stgit-help ()
  "Display help for the StGit mode."
  (interactive)
  (describe-function 'stgit-mode))

(defun stgit-undo (&optional arg)
  "Run stg undo.
With prefix argument, run it with the --hard flag."
  (interactive "P")
  (stgit-capture-output nil
    (if arg
        (stgit-run "undo" "--hard")
      (stgit-run "undo")))
  (stgit-reload))

(defun stgit-refresh (&optional arg)
  "Run stg refresh.
With prefix argument, refresh the marked patch or the patch under point."
  (interactive "P")
  (let ((patchargs (if arg
                       (let ((patches (stgit-patches-marked-or-at-point)))
                         (cond ((null patches)
                                (error "No patch to update"))
                               ((> (length patches) 1)
                                (error "Too many patches selected"))
                               (t
                                (cons "-p" patches))))
                     nil)))
    (stgit-capture-output nil
      (apply 'stgit-run "refresh" patchargs))
    (stgit-refresh-git-status))
  (stgit-reload))

(defcustom stgit-default-show-worktree
  nil
  "Set to non-nil to by default show the working tree in a new stgit buffer.

This value is used as the default value for `stgit-show-worktree'."
  :type 'boolean
  :group 'stgit)

(defvar stgit-show-worktree nil
  "Show work tree and index in the stgit buffer.

See `stgit-default-show-worktree' for its default value.")

(defun stgit-toggle-worktree (&optional arg)
  "Toggle the visibility of the work tree.
With arg, show the work tree if arg is positive.

Its initial setting is controlled by `stgit-default-show-worktree'."
  (interactive)
  (setq stgit-show-worktree
        (if (numberp arg)
            (> arg 0)
          (not stgit-show-worktree)))
  (stgit-reload))

(provide 'stgit)