From b0e4215ec52acc07b1ff15b1bcc7562e1cdbf7c3 Mon Sep 17 00:00:00 2001
From: Florian Fischer <florian.fischer@muhq.space>
Date: Sat, 4 May 2024 14:38:49 +0200
Subject: restore the previous file on abort

This feature requires a vis build supporting changing a window's
file from Lua.
To enable it set the module's change_file_on_abort member to true.
---
 init.lua | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/init.lua b/init.lua
index ce5145c..af96399 100644
--- a/init.lua
+++ b/init.lua
@@ -20,6 +20,8 @@ local lockfiles = dofile(script_path .. 'lockfiles.lua')
 local M = {}
 M.directory = '${XDG_STATE_HOME:-${HOME}/.local/state}/vis/locks'
 M.directory_expanded = nil
+-- Enable this if vis supports changing a window's file from Lua
+M.change_file_on_abort = false
 
 -- Detect available backends
 if os.execute('command -v whiptail') then
@@ -66,6 +68,12 @@ local function prompt_backend(path, lfile_path, pid, backend)
   return (status == 0) and output:sub(1, 1)
 end
 
+local cur_file
+vis.events.subscribe(vis.events.FILE_OPEN, function()
+  -- remember the current file to reopen it when aborting an edit attempt
+  cur_file = vis.win and vis.win.file and (vis.win.file.path or vis.win.file.name)
+end)
+
 -- get a user confirmation
 -- return true if user wants to edit the locked file
 local function prompt(path, lfile_path, pid)
@@ -76,10 +84,6 @@ local function prompt(path, lfile_path, pid)
   elseif output == 'q' then
     vis:exit(1)
   end
-
-  -- else 'abort' or dialog canceled
-  vis:command('q')
-  vis:command('new')
 end
 
 local created_locks = {}
@@ -97,7 +101,18 @@ vis.events.subscribe(vis.events.WIN_OPEN, function(win)
     created_locks[file.path] = lfile_path
   else
     if not prompt(file.path, lfile_path, lock_pid) then
-      -- return ~= nil to stop further event handling since we closed the window
+      -- 'abort' or dialog canceled
+      if cur_file and M.change_file_on_abort then
+        -- restore the previous file
+        win.file = cur_file
+        -- fire a new WIN_OPEN event because we changed the file
+        vis.events.emit(vis.events.WIN_OPEN, win)
+      else
+        vis:command('q')
+        vis:command('new')
+      end
+      -- stop handling the old FILE_OPEN event either we closed it
+      -- or changed its file and emitted a new WIN_OPEN event
       return true
     end
   end
-- 
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