Open previous file in last book folder (#13424)

frontend/apps/filemanager/filemanager.lua

@@ -1615,4 +1615,19 @@ function FileManager:onSetMixedSorting(toggle)
     return true
 end
 
+function FileManager:onOpenNextOrPreviousFileInFolder(prev)
+    local last_file = G_reader_settings:readSetting("lastfile")
+    if not last_file then return true end
+    local file = self.file_chooser:getNextOrPreviousFileInFolder(last_file, prev)
+    if file then
+        self:openFile(file)
+    else
+        UIManager:show(InfoMessage:new{
+            text = prev and _("Last book is the first file in the folder. No previous file to open.")
+                         or _("Last book is the last file in the folder. No next file to open."),
+        })
+    end
+    return true
+end
+
 return FileManager

frontend/apps/reader/modules/readerstatus.lua

@@ -171,20 +171,24 @@ function ReaderStatus:openFileBrowser()
     self.ui:showFileManager(file)
 end
 
-function ReaderStatus:onOpenNextDocumentInFolder()
+function ReaderStatus:onOpenNextOrPreviousFileInFolder(prev)
+    local collate = G_reader_settings:readSetting("collate")
+    if collate == "access" or collate == "date" then return true end
     local FileChooser = require("ui/widget/filechooser")
-    local next_file = FileChooser:getNextFile(self.document.file)
-    if next_file then
+    local file = FileChooser:getNextOrPreviousFileInFolder(self.document.file, prev)
+    if file then
         -- Delay until the next tick, as this will destroy the Document instance,
         -- but we may not be the final Event caught by said Document...
         UIManager:nextTick(function()
-            self.ui:switchDocument(next_file)
+            self.ui:switchDocument(file)
         end)
     else
         UIManager:show(InfoMessage:new{
-            text = _("This is the last file in the current folder. No next file to open."),
+            text = prev and _("This is the first file in the folder. No previous file to open.")
+                         or _("This is the last file in the folder. No next file to open."),
         })
     end
+    return true
 end
 
 function ReaderStatus:deleteFile()

frontend/dispatcher.lua

@@ -63,6 +63,8 @@ local settingsList = {
     ----
     show_menu = {category="none", event="ShowMenu", title=_("Show menu"), general=true},
     menu_search = {category="none", event="MenuSearch", title=_("Menu search"), general=true},
+    open_next_document_in_folder = {category="none", event="OpenNextOrPreviousFileInFolder", title=_("Open next file in last book folder"), general=true},
+    open_previous_document_in_folder = {category="none", event="OpenNextOrPreviousFileInFolder", arg=true, title=_("Open previous file in last book folder"), general=true},
     notebook_file = {category="none", event="ShowNotebookFile", title=_("Notebook file"), general=true},
     screenshot = {category="none", event="Screenshot", title=_("Screenshot"), general=true, separator=true},
     ----
@@ -145,8 +147,6 @@ local settingsList = {
     ----
 
     -- Reader
-    open_next_document_in_folder = {category="none", event="OpenNextDocumentInFolder", title=_("Open next document in folder"), reader=true, separator=true},
-    ----
     show_config_menu = {category="none", event="ShowConfigMenu", title=_("Show bottom menu"), reader=true},
     toggle_status_bar = {category="none", event="ToggleFooterMode", title=_("Toggle status bar"), reader=true},
     toggle_chapter_progress_bar = {category="none", event="ToggleChapterProgressBar", title=_("Toggle chapter progress bar"), reader=true, separator=true},
@@ -298,6 +298,8 @@ local dispatcher_menu_order = {
     ----
     "show_menu",
     "menu_search",
+    "open_next_document_in_folder",
+    "open_previous_document_in_folder",
     "notebook_file",
     "screenshot",
     ----
@@ -380,8 +382,6 @@ local dispatcher_menu_order = {
     ----
 
     -- Reader
-    "open_next_document_in_folder",
-    ----
     "show_config_menu",
     "toggle_status_bar",
     "toggle_chapter_progress_bar",

frontend/ui/widget/filechooser.lua

@@ -430,23 +430,29 @@ function FileChooser:onFileHold(item)
     return true
 end
 
--- Used in ReaderStatus:onOpenNextDocumentInFolder().
-function FileChooser:getNextFile(curr_file)
+function FileChooser:getNextOrPreviousFileInFolder(curr_file, prev)
     local show_finished = FileChooser.show_finished
     FileChooser.show_finished = true
     local curr_path = curr_file:match(".*/"):gsub("/$", "")
     local item_table = self:genItemTableFromPath(curr_path)
     FileChooser.show_finished = show_finished
-    local is_curr_file_found
-    for i, item in ipairs(item_table) do
-        if not is_curr_file_found and item.path == curr_file then
+    local top_i, step, is_curr_file_found
+    if prev then
+        top_i = #item_table + 1
+        step = -1
+    else
+        step = 1
+    end
+    for i = 1, #item_table do
+        local idx = prev and top_i - i or i
+        if not is_curr_file_found and item_table[idx].path == curr_file then
             is_curr_file_found = true
         end
         if is_curr_file_found then
-            local next_file = item_table[i+1]
-            if next_file and next_file.is_file and DocumentRegistry:hasProvider(next_file.path)
-                    and BookList.getBookStatus(next_file.path) ~= "complete" then
-                return next_file.path
+            local file = item_table[idx + step]
+            if file and file.is_file and DocumentRegistry:hasProvider(file.path)
+                    and BookList.getBookStatus(file.path) ~= "complete" then
+                return file.path
             end
         end
     end