WC2: Downgrade scenario from 4p to 3p

~ Part 2 ~

The player who lost his leader probably does not want to play anymore.
When the level is won, transition to the 3p version.
This could actually be done for all scenarios,
until reaching the 1p.

data/campaigns/World_Conquest/lua/game_mechanics/promote_commander.lua

@@ -30,6 +30,7 @@ on_event("die", function(cx)
 			-- For 4p, one player is allowed to be defeated, without all players losing the scenario.
 			wml.variables.wc2_defeated_side = u.side
 			wml.variables.wc2_player_count = wml.variables.wc2_player_count - 1
+			wesnoth.scenario.next = "WC_II_3p"
 			wesnoth.wml_actions.item {
 				x = u.x,
 				y = u.y,
@@ -47,3 +48,8 @@ on_event("die", function(cx)
 		end
 	end
 end)
+
+-- clear variable from previous scenario
+on_event("start", function()
+	wml.variables.wc2_defeated_side = nil
+end

data/campaigns/World_Conquest/lua/map/scenario_utils/side_definitions.lua

@@ -69,6 +69,10 @@ local function add_player_side(scenario, scenario_num, gold)
 		side.faction_lock = false
 		side.leader_lock = false
 	end
+	if side_num == wml.variables.wc2_defeated_side then
+		side.save_id = "wc2_leader4"
+		side.id = "wc2_leader4"
+	end
 	table.insert(scenario.side, side)
 end