Embed co-owner data into the area itself

api.lua

@@ -128,8 +128,10 @@ function areas:canInteract(pos, name)
 	end
 	local owned = false
 	for _, area in pairs(areas_list) do
-		-- Player owns the area or area is open
-		if area.owner == name or area.open then
+		-- Player owns the area, area is open, or player is a co-owner
+		if area.owner == name
+			or area.open
+			or (area.co_owners and area.co_owners[name]) then
 			return true
 		elseif areas.factions_available and area.faction_open then
 			if (factions.version or 0) < 2 then

chatcommands.lua

@@ -286,6 +286,7 @@ minetest.register_chatcommand("change_owner", {
 					.." or is not owned by you.", id)
 		end
 		areas.areas[id].owner = newOwner
+		areas:removeCoOwner(id, newOwner)
 		areas:save()
 		minetest.chat_send_player(newOwner,
 			S("@1 has given you control over the area \"@2\" (ID @3).",
@@ -294,6 +295,90 @@ minetest.register_chatcommand("change_owner", {
 	end
 })
 
+minetest.register_chatcommand("add_co_owner", {
+	params = S("<ID>").." "..S("<CoOwner>"),
+	description = S("Add a co-owner to an area"),
+	func = function(name, param)
+		local id, coOwner = param:match("^(%d+)%s(%S+)$")
+		if not id then
+			return false, S("Invalid usage, see"
+					.." /help @1.", "add_co_owner")
+		end
+
+		if not areas:player_exists(coOwner) then
+			return false, S("The player \"@1\" does not exist.", coOwner)
+		end
+
+		id = tonumber(id)
+		if not areas:isAreaOwner(id, name) then
+			return false, S("Area @1 does not exist"
+					.." or is not owned by you.", id)
+		end
+		areas:addCoOwner(id, coOwner)
+		areas:save()
+		minetest.chat_send_player(coOwner,
+			S("@1 has added you as a co-owner of the area \"@2\" (ID @3).",
+				name, areas.areas[id].name, id))
+		return true, S("Co-owner added.")
+	end
+})
+
+minetest.register_chatcommand("remove_co_owner", {
+	params = S("<ID>").." "..S("<CoOwner>"),
+	description = S("Remove a co-owner from an area"),
+	func = function(name, param)
+		local id, coOwner = param:match("^(%d+)%s(%S+)$")
+		if not id then
+			return false, S("Invalid usage, see"
+					.." /help @1.", "remove_co_owner")
+		end
+
+		if not areas:player_exists(coOwner) then
+			return false, S("The player \"@1\" does not exist.", coOwner)
+		end
+
+		id = tonumber(id)
+		if not areas:isAreaOwner(id, name) then
+			return false, S("Area @1 does not exist"
+					.." or is not owned by you.", id)
+		end
+		areas:removeCoOwner(id, coOwner)
+		areas:save()
+		minetest.chat_send_player(coOwner,
+			S("@1 has removed you from the list of co-owners of the area \"@2\" (ID @3).",
+				name, areas.areas[id].name, id))
+		return true, S("Co-owner removed.")
+	end
+})
+
+minetest.register_chatcommand("list_co_owners", {
+	params = S("<ID>"),
+	description = S("List co-owners of an area"),
+	func = function(name, param)
+		local id = tonumber(param)
+		if not id then
+			return false, S("Invalid usage, see /help @1.", "area_open")
+		end
+
+		local entry = areas.areas[id]
+		if not entry then
+			return false, S("The area @1 does not exist.", id)
+		end
+
+		local coOwners = {}
+		for coOwner in pairs(areas:listCoOwners(id)) do
+			coOwners[#coOwners+1] = coOwner
+		end
+
+		if #coOwners == 0 then
+			return true, S("The area \"@1\" (ID @2) have no co-owners.", entry.name, id)
+		end
+
+		return true, S("Co-owners of area \"@1\" (ID @2): @3",
+			entry.name, id, table.concat(coOwners, ", "))
+	end
+})
+
 
 minetest.register_chatcommand("area_open", {
 	params = S("<ID>"),

hud.lua

@@ -42,10 +42,16 @@ minetest.register_globalstep(function(dtime)
 				end
 			end
 
-			table.insert(areaStrings, ("%s [%u] (%s%s%s)")
+			local coOwnersCount = 0
+			for _ in pairs(areas:listCoOwners(id)) do
+				coOwnersCount = coOwnersCount + 1
+			end
+
+			table.insert(areaStrings, ("%s [%u] (%s%s%s)%s")
 					:format(area.name, id, area.owner,
 					area.open and S(":open") or "",
-					faction_info and ": "..faction_info or ""))
+					faction_info and ": "..faction_info or "",
+					coOwnersCount ~= 0 and " +" .. coOwnersCount or ""))
 		end
 
 		for i, area in pairs(areas:getExternalHudEntries(pos)) do

internal.lua

@@ -217,6 +217,30 @@ function areas:getChildren(id)
 	return children
 end
 
+-- Add a co-owner to an area
+function areas:addCoOwner(id, name)
+	local entry = self.areas[id]
+	entry.co_owners = entry.co_owners or {}
+	entry.co_owners[name] = true
+end
+
+-- Remove a co-owner from an area
+function areas:removeCoOwner(id, name)
+	local entry = self.areas[id]
+	if entry.co_owners then
+		entry.co_owners[name] = nil
+		if next(entry.co_owners) == nil then
+			entry.co_owners = nil
+		end
+	end
+end
+
+-- Return the list of co-owners
+function areas:listCoOwners(id)
+	local entry = self.areas[id]
+	return entry.co_owners and table.copy(entry.co_owners) or {}
+end
+
 -- checks all possible restrictions registered with
 -- areas:registerProtectionCondition
 -- builtin callbacks below