;;; magit-files.el --- finding files  -*- lexical-binding: t -*-

;; Copyright (C) 2010-2017  The Magit Project Contributors
;;
;; You should have received a copy of the AUTHORS.md file which
;; lists all contributors.  If not, see http://magit.vc/authors.

;; Author: Jonas Bernoulli <jonas@bernoul.li>
;; Maintainer: Jonas Bernoulli <jonas@bernoul.li>

;; Magit 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 3, or (at your option)
;; any later version.
;;
;; Magit 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 Magit.  If not, see http://www.gnu.org/licenses.

;;; Commentary:

;; This library implements support for finding blobs, staged files,
;; and Git configuration files.  It also implements modes useful in
;; buffers visiting files and blobs, and the commands used by those
;; modes.

;;; Code:

(require 'magit)

;;; Find Blob

(defvar magit-find-file-hook nil)
(add-hook 'magit-find-file-hook #'magit-blob-mode)

;;;###autoload
(defun magit-find-file (rev file)
  "View FILE from REV.
Switch to a buffer visiting blob REV:FILE,
creating one if none already exists."
  (interactive (magit-find-file-read-args "Find file"))
  (switch-to-buffer (magit-find-file-noselect rev file)))

;;;###autoload
(defun magit-find-file-other-window (rev file)
  "View FILE from REV, in another window.
Like `magit-find-file', but create a new window or reuse an
existing one."
  (interactive (magit-find-file-read-args "Find file in other window"))
  (switch-to-buffer-other-window (magit-find-file-noselect rev file)))

(defun magit-find-file-read-args (prompt)
  (let  ((rev (magit-read-branch-or-commit "Find file from revision")))
    (list rev (magit-read-file-from-rev rev prompt))))

(defun magit-find-file-noselect (rev file)
  "Read FILE from REV into a buffer and return the buffer.
FILE must be relative to the top directory of the repository."
  (magit-find-file-noselect-1 rev file 'magit-find-file-hook))

(defun magit-find-file-noselect-1 (rev file hookvar &optional revert)
  "Read FILE from REV into a buffer and return the buffer.
FILE must be relative to the top directory of the repository.
An empty REV stands for index."
  (let ((topdir (magit-toplevel)))
    (when (file-name-absolute-p file)
      (setq file (file-relative-name file topdir)))
    (with-current-buffer (magit-get-revision-buffer-create rev file)
      (when (or (not magit-buffer-file-name)
                (if (eq revert 'ask-revert)
                    (y-or-n-p (format "%s already exists; revert it? "
                                      (buffer-name))))
                revert)
        (setq magit-buffer-revision
              (if (string= rev "") "{index}" (magit-rev-format "%H" rev)))
        (setq magit-buffer-refname rev)
        (setq magit-buffer-file-name (expand-file-name file topdir))
        (setq default-directory
              (let ((dir (file-name-directory magit-buffer-file-name)))
                (if (file-exists-p dir) dir topdir)))
        (setq-local revert-buffer-function #'magit-revert-rev-file-buffer)
        (revert-buffer t t)
        (run-hooks hookvar))
      (current-buffer))))

(defun magit-get-revision-buffer-create (rev file)
  (magit-get-revision-buffer rev file t))

(defun magit-get-revision-buffer (rev file &optional create)
  (funcall (if create 'get-buffer-create 'get-buffer)
           (format "%s.~%s~" file (if (equal rev "") "index"
                                    (subst-char-in-string ?/ ?_ rev)))))

(defun magit-revert-rev-file-buffer (_ignore-auto noconfirm)
  (when (or noconfirm
            (and (not (buffer-modified-p))
                 (catch 'found
                   (dolist (regexp revert-without-query)
                     (when (string-match regexp magit-buffer-file-name)
                       (throw 'found t)))))
            (yes-or-no-p (format "Revert buffer from git %s? "
                                 (if (equal magit-buffer-refname "") "{index}"
                                   (concat "revision " magit-buffer-refname)))))
    (let* ((inhibit-read-only t)
           (default-directory (magit-toplevel))
           (file (file-relative-name magit-buffer-file-name))
           (coding-system-for-read (or coding-system-for-read 'undecided)))
      (erase-buffer)
      (magit-git-insert "cat-file" "-p" (concat magit-buffer-refname ":" file))
      (setq buffer-file-coding-system last-coding-system-used))
    (let ((buffer-file-name magit-buffer-file-name)
          (after-change-major-mode-hook
           (remq 'global-diff-hl-mode-enable-in-buffers
                 after-change-major-mode-hook)))
      (normal-mode t))
    (setq buffer-read-only t)
    (set-buffer-modified-p nil)
    (goto-char (point-min))))

;;; Find Index

(defvar magit-find-index-hook nil)

(defun magit-find-file-index-noselect (file &optional revert)
  "Read FILE from the index into a buffer and return the buffer.
FILE must to be relative to the top directory of the repository."
  (magit-find-file-noselect-1 "" file 'magit-find-index-hook
                              (or revert 'ask-revert)))

(defun magit-update-index ()
  "Update the index with the contents of the current buffer.
The current buffer has to be visiting a file in the index, which
is done using `magit-find-index-noselect'."
  (interactive)
  (let ((file (magit-file-relative-name)))
    (unless (equal magit-buffer-refname "")
      (user-error "%s isn't visiting the index" file))
    (if (y-or-n-p (format "Update index with contents of %s" (buffer-name)))
        (let ((index (make-temp-file "index"))
              (buffer (current-buffer)))
          (when magit-wip-before-change-mode
            (magit-wip-commit-before-change (list file) " before un-/stage"))
          (let ((coding-system-for-write buffer-file-coding-system))
            (with-temp-file index
              (insert-buffer-substring buffer)))
          (magit-with-toplevel
            (magit-call-git "update-index" "--cacheinfo"
                            (substring (magit-git-string "ls-files" "-s" file)
                                       0 6)
                            (magit-git-string "hash-object" "-t" "blob" "-w"
                                              (concat "--path=" file)
                                              "--" index)
                            file))
          (set-buffer-modified-p nil)
          (when magit-wip-after-apply-mode
            (magit-wip-commit-after-apply (list file) " after un-/stage")))
      (message "Abort")))
  (--when-let (magit-mode-get-buffer 'magit-status-mode)
    (with-current-buffer it (magit-refresh)))
  t)

;;; Find Config File

(defun magit-find-git-config-file (filename &optional wildcards)
  "Edit a file located in the current repository's git directory.

When \".git\", located at the root of the working tree, is a
regular file, then that makes it cumbersome to open a file
located in the actual git directory.

This command is like `find-file', except that it temporarily
binds `default-directory' to the actual git directory, while
reading the FILENAME."
  (interactive
   (let ((default-directory (magit-git-dir)))
     (find-file-read-args "Find file: "
                          (confirm-nonexistent-file-or-buffer))))
  (find-file filename wildcards))

(defun magit-find-git-config-file-other-window (filename &optional wildcards)
  "Edit a file located in the current repository's git directory, in another window.

When \".git\", located at the root of the working tree, is a
regular file, then that makes it cumbersome to open a file
located in the actual git directory.

This command is like `find-file-other-window', except that it
temporarily binds `default-directory' to the actual git
directory, while reading the FILENAME."
  (interactive
   (let ((default-directory (magit-git-dir)))
     (find-file-read-args "Find file in other window: "
                          (confirm-nonexistent-file-or-buffer))))
  (find-file-other-window filename wildcards))

(defun magit-find-git-config-file-other-frame (filename &optional wildcards)
  "Edit a file located in the current repository's git directory, in another frame.

When \".git\", located at the root of the working tree, is a
regular file, then that makes it cumbersome to open a file
located in the actual git directory.

This command is like `find-file-other-frame', except that it
temporarily binds `default-directory' to the actual git
directory, while reading the FILENAME."
  (interactive
   (let ((default-directory (magit-git-dir)))
     (find-file-read-args "Find file in other frame: "
                          (confirm-nonexistent-file-or-buffer))))
  (find-file-other-frame filename wildcards))

;;; File Mode

(defvar magit-file-mode-map
  (let ((map (make-sparse-keymap)))
    (define-key map "\C-xg"    'magit-status)
    (define-key map "\C-x\M-g" 'magit-dispatch-popup)
    (define-key map "\C-c\M-g" 'magit-file-popup)
    map)
  "Keymap for `magit-file-mode'.")

;;;###autoload (autoload 'magit-file-popup "magit" nil t)
(magit-define-popup magit-file-popup
  "Popup console for Magit commands in file-visiting buffers."
  :actions '((?s "Stage"     magit-stage-file)
             (?d "Diff"      magit-diff-buffer-file)
             (?l "Log"       magit-log-buffer-file)
             (?b "Blame"     magit-blame-popup)
             (?u "Unstage"   magit-unstage-file)
             (?D "Diff..."   magit-diff-buffer-file-popup)
             (?L "Log..."    magit-log-buffer-file-popup)
             (?p "Find blob" magit-blob-previous)
             (?c "Commit"    magit-commit-popup))
  :max-action-columns 4)

(defvar magit-file-mode-lighter "")

(define-minor-mode magit-file-mode
  "Enable some Magit features in a file-visiting buffer.

Currently this only adds the following key bindings.
\n\\{magit-file-mode-map}"
  :package-version '(magit . "2.2.0")
  :lighter magit-file-mode-lighter
  :keymap  magit-file-mode-map)

(defun magit-file-mode-turn-on ()
  (and buffer-file-name
       (ignore-errors (magit-inside-worktree-p))
       (magit-file-mode)))

;;;###autoload
(define-globalized-minor-mode global-magit-file-mode
  magit-file-mode magit-file-mode-turn-on
  :package-version '(magit . "2.2.0")
  :link '(info-link "(magit)Minor Mode for Buffers Visiting Files")
  :group 'magit-essentials
  :group 'magit-modes)

;;; Blob Mode

(defvar magit-blob-mode-map
  (let ((map (make-sparse-keymap)))
    (cond ((featurep 'jkl)
           (define-key map "i" 'magit-blob-previous)
           (define-key map "k" 'magit-blob-next))
          (t
           (define-key map "p" 'magit-blob-previous)
           (define-key map "n" 'magit-blob-next)))
    (define-key map "q" 'magit-kill-this-buffer)
    map)
  "Keymap for `magit-blob-mode'.")

(define-minor-mode magit-blob-mode
  "Enable some Magit features in blob-visiting buffers.

Currently this only adds the following key bindings.
\n\\{magit-blob-mode-map}"
  :package-version '(magit . "2.3.0"))

(defun magit-blob-next ()
  "Visit the next blob which modified the current file."
  (interactive)
  (if magit-buffer-file-name
      (magit-blob-visit (or (magit-blob-successor magit-buffer-revision
                                                  magit-buffer-file-name)
                            magit-buffer-file-name)
                        (line-number-at-pos))
    (if (buffer-file-name (buffer-base-buffer))
        (user-error "You have reached the end of time")
      (user-error "Buffer isn't visiting a file or blob"))))

(defun magit-blob-previous ()
  "Visit the previous blob which modified the current file."
  (interactive)
  (-if-let (file (or magit-buffer-file-name
                     (buffer-file-name (buffer-base-buffer))))
      (--if-let (magit-blob-ancestor magit-buffer-revision file)
          (magit-blob-visit it (line-number-at-pos))
        (user-error "You have reached the beginning of time"))
    (user-error "Buffer isn't visiting a file or blob")))

(defun magit-blob-visit (blob-or-file line)
  (if (stringp blob-or-file)
      (find-file blob-or-file)
    (-let [(rev file) blob-or-file]
      (magit-find-file rev file)
      (apply #'message "%s (%s %s ago)"
             (magit-rev-format "%s" rev)
             (magit--age (magit-rev-format "%ct" rev)))))
  (goto-char (point-min))
  (forward-line (1- line)))

(defun magit-blob-ancestor (rev file)
  (let ((lines (magit-with-toplevel
                 (magit-git-lines "log" "-2" "--format=%H" "--name-only"
                                  "--follow" (or rev "HEAD") "--" file))))
    (if rev (cddr lines) (butlast lines 2))))

(defun magit-blob-successor (rev file)
  (let ((lines (magit-with-toplevel
                 (magit-git-lines "log" "--format=%H" "--name-only" "--follow"
                                  "HEAD" "--" file))))
    (catch 'found
      (while lines
        (if (equal (nth 2 lines) rev)
            (throw 'found (list (nth 0 lines) (nth 1 lines)))
          (setq lines (nthcdr 2 lines)))))))

;;; File Commands

(defun magit-file-rename (file newname)
  "Rename the FILE to NEWNAME.
If FILE isn't tracked in Git, fallback to using `rename-file'."
  (interactive
   (let* ((file (magit-read-file "Rename file"))
          (newname (read-file-name (format "Rename %s to file: " file))))
     (list (expand-file-name file (magit-toplevel))
           (expand-file-name newname))))
  (if (magit-file-tracked-p file)
      (let ((oldbuf (get-file-buffer file)))
        (when (and oldbuf (buffer-modified-p oldbuf))
          (user-error "Save %s before moving it" file))
        (when (file-exists-p newname)
          (user-error "%s already exists" newname))
        (magit-run-git "mv" file newname)
        (when oldbuf
          (with-current-buffer oldbuf
            (let ((buffer-read-only buffer-read-only))
              (set-visited-file-name newname))
            (if (fboundp 'vc-refresh-state)
                (vc-refresh-state)
              (with-no-warnings
                (vc-find-file-hook))))))
    (rename-file file newname current-prefix-arg)
    (magit-refresh)))

(defun magit-file-untrack (file)
  "Untrack FILE.
Stop tracking FILE in Git but do not remove it from the working
tree."
  (interactive (list (magit-read-tracked-file "Untrack file")))
  (magit-run-git "rm" "--cached" "--" file))

(defun magit-file-delete (file &optional force)
  "Delete FILE.
With a prefix argument FORCE do so even when FILE has uncommitted
changes.

If FILE isn't tracked in Git, fallback to using `delete-file'."
  (interactive (list (magit-read-file "Delete file")))
  (if (magit-file-tracked-p file)
      (magit-run-git "rm" (and force "--force") "--" file)
    (delete-file (expand-file-name file (magit-toplevel)) t)
    (magit-refresh)))

;;;###autoload
(defun magit-file-checkout (rev file)
  "Checkout FILE from REV."
  (interactive
   (let ((rev (magit-read-branch-or-commit
               "Checkout from revision" magit-buffer-revision)))
     (list rev (magit-read-file-from-rev rev "Checkout file"))))
  (magit-with-toplevel
    (magit-run-git "checkout" rev "--" file)))

;;; Read File

(defvar magit-read-file-hist nil)

(defun magit-read-file-from-rev (rev prompt &optional default)
  (let ((files (magit-revision-files rev)))
    (magit-completing-read
     prompt files nil t nil 'magit-read-file-hist
     (car (member (or default (magit-current-file)) files)))))

(defun magit-read-file (prompt &optional tracked-only)
  (let ((choices (nconc (magit-list-files)
                        (unless tracked-only (magit-untracked-files)))))
    (magit-completing-read prompt choices nil t nil nil
                           (car (member (or (magit-section-when (file submodule))
                                            (magit-file-relative-name
                                             nil tracked-only))
                                        choices)))))

(defun magit-read-tracked-file (prompt)
  (magit-read-file prompt t))

(defun magit-read-file-choice (prompt files &optional error default)
  "Read file from FILES.

If FILES has only one member, return that instead of prompting.
If FILES has no members, give a user error.  ERROR can be given
to provide a more informative error.

If DEFAULT is non-nil, use this as the default value instead of
`magit-current-file'."
  (pcase (length files)
    (0 (user-error (or error "No file choices")))
    (1 (car files))
    (_ (magit-completing-read
        prompt files nil t nil 'magit-read-file-hist
        (car (member (or default (magit-current-file)) files))))))

(defun magit-read-changed-file (rev-or-range prompt &optional default)
  (magit-read-file-choice
   prompt
   (magit-changed-files rev-or-range)
   default
   (concat "No file changed in " rev-or-range)))

(defun magit-read-files (prompt initial-contents)
  (mapconcat 'identity
             (completing-read-multiple (or prompt "File,s: ")
                                       (magit-list-files)
                                       nil nil initial-contents) ","))

(provide 'magit-files)
;;; magit-files.el ends here