Add ReaderHandmade: support for custom TOC and hidden flows

Checkboxes under TOC>Settings> allow enabling Custom TOC
and Custom hidden flows (similar to "Hide non-linear fragments"
available with some EPUBs).
Handled by a new ReaderHandmade module.
Adding and removing TOC chapters is done in PageBrowser
with long-press on a page thumbnail, and for chapters also
in the popup dialog after selecting some text in a page.

ReaderToc: add a symbol in title when the TOC is the
alternative TOC or the custom TOC.

frontend/apps/reader/modules/readertoc.lua

@@ -29,9 +29,8 @@ local ReaderToc = InputContainer:extend{
     collapsed_toc = nil, -- table
     collapse_depth = 2,
     expanded_nodes = nil, -- table
-    toc_menu_title = _("Table of contents"),
-    alt_toc_menu_title = _("Table of contents *"),
     toc_items_per_page_default = 14,
+    alt_toc_symbol = "\u{E298}" -- two-folders in circle (custom toc uses a pen in square symbol)
 }
 
 function ReaderToc:init()
@@ -66,6 +65,17 @@ function ReaderToc:registerKeyEvents()
     end
 end
 
+function ReaderToc:getTitle()
+    local title = _("Table of contents")
+    -- Handmade ToC has precedence over alternative ToC
+    if self.ui.handmade:isHandmadeTocEnabled() then
+        title = title .. " " .. self.ui.handmade.custom_toc_symbol
+    elseif self.ui.document:isTocAlternativeToc() then
+        title = title .. " " .. self.alt_toc_symbol
+    end
+    return title
+end
+
 ReaderToc.onPhysicalKeyboardConnected = ReaderToc.registerKeyEvents
 
 function ReaderToc:onReadSettings(config)
@@ -756,7 +766,7 @@ function ReaderToc:onShowToc()
     --       This yields *slightly* better alignment between state & mandatory (in terms of effective margins).
     local button_size = self.expand_button:getSize()
     local toc_menu = Menu:new{
-        title = _("Table of Contents"),
+        title = self:getTitle(),
         item_table = self.collapsed_toc,
         state_w = can_collapse and button_size.w or 0,
         ui = self.ui,
@@ -938,7 +948,7 @@ function ReaderToc:addToMainMenu(menu_items)
     -- insert table to main reader menu
     menu_items.table_of_contents = {
         text_func = function()
-            return self.ui.document:isTocAlternativeToc() and self.alt_toc_menu_title or self.toc_menu_title
+            return self:getTitle()
         end,
         callback = function()
             self:onShowToc()
@@ -951,13 +961,22 @@ function ReaderToc:addToMainMenu(menu_items)
     -- Alternative ToC (only available with CRE documents)
     if self.ui.document:canHaveAlternativeToc() then
         menu_items.toc_alt_toc = {
-            text = _("Alternative table of contents"),
-            help_text = _([[
+            text = _("Alternative table of contents") .. " " .. self.alt_toc_symbol,
+            help_text_func = function()
+                local help_text = _([[
 An alternative table of contents can be built from document headings <H1> to <H6>.
 If the document contains no headings, or all are ignored, the alternative ToC will be built from document fragments and will point to the start of each individual HTML file in the EPUB.
 
 Some of the headings can be ignored, and hints can be set to other non-heading elements in a user style tweak, so they can be used as ToC items.
-See Style tweaks → Miscellaneous → Alternative ToC hints.]]),
+See Style tweaks → Miscellaneous → Alternative ToC hints.]])
+                if self.ui.handmade:isHandmadeTocEnabled() then
+                    help_text = _([[To use the alternative ToC, disable your custom table of contents first.]]) .. "\n\n" .. help_text
+                end
+                return help_text
+            end,
+            enabled_func = function()
+                return not self.ui.handmade:isHandmadeTocEnabled()
+            end,
             checked_func = function()
                 return self.ui.document:isTocAlternativeToc()
             end,