improved merge on favourites refresh

1 files changed, 21 insertions, 25 deletions

diff --git a/main.lua b/main.lua
index ffb7707..2c9e405 100644
--- a/main.lua
+++ b/main.lua
@@ -473,11 +473,9 @@ local function set_menu_sort(menu, bool)
 end
 
 -- refresh options when navigating up the stack to a previous favourites menu.
--- existing menu options are never removed, even if unfavourited. if the order
--- of still-favourited items is unchanged and no new favourites have been added
--- before the last still-favourited item, the existing order is kept and all
--- new favourites are appended to the end of the menu. otherwise, the new order
--- is used and any unfavourited options are moved to the end.
+-- existing menu options are never removed, even if unfavourited. the new order
+-- is always respected, while still preserving the relative order of existing
+-- options when possible.
 local function refresh_favourites_menu()
 	local menu = menus[depth]
 	local opt = menu.options[menu.cursor]
@@ -487,36 +485,34 @@ local function refresh_favourites_menu()
 	end
 
 	local options = group_menu_options(catalogue:get(menu.group_id))
+	local pos = {}
+	for i, v in ipairs(options) do
+		pos[v.id] = i
+	end
+
+	local res = {}
 	local seen = {}
-	for _, v in ipairs(options) do
-		seen[v.id] = true
+	local function append(v)
+		if not seen[v.id] then
+			res[#res+1] = v
+			seen[v.id] = true
+		end
 	end
 
-	local same = true
 	local ind = 1
 	for _, v in ipairs(menu.options) do
-		if seen[v.id] then
-			if v.id == options[ind].id then
+		if pos[v.id] then
+			while ind <= pos[v.id] do
+				append(options[ind])
 				ind = ind + 1
-			else
-				same = false
-				break
 			end
 		end
+		append(v)
 	end
-
-	if same then
-		for i = ind, #options do
-			menu.options[#menu.options+1] = options[i]
-		end
-	else
-		for _, v in ipairs(menu.options) do
-			if not seen[v.id] then
-				options[#options+1] = v
-			end
-		end
-		menu.options = options
+	for i = ind, #options do
+		append(options[i])
 	end
+	menu.options = res
 
 	if sorted then
 		set_menu_sort(menu, true)