--[[
   Copyright (c) The OpenRA Developers and Contributors
   This file is part of OpenRA, which is free software. It is made
   available to you under the terms of the GNU General Public License
   as published by the Free Software Foundation, either version 3 of
   the License, or (at your option) any later version. For more
   information, see COPYING.
]]

--- This mission's human player.
local USSR = Player.GetPlayer("USSR")

--- Owner of the inactive Soviet bases.
local BadGuy = Player.GetPlayer("BadGuy")

--- Owner of most hostile Allied forces.
--- (France guards crates near the west edge.)
local Greece = Player.GetPlayer("Greece")

--- Owner of the green smoke signals.
local England = Player.GetPlayer("England")

--- Both Soviet players, grouped here for later targeting.
local SovietPlayers = { BadGuy, USSR }

---@type integer USSR must defend the Tech Center.
local TechObjective

---@type integer USSR must reach the Sub Pen.
local PenObjective

---@type integer USSR must wipe out all intruders owned by Greece.
local IntruderObjective

---@type integer USSR may quickly capture an Airfield for a bonus.
local AirfieldObjective

local TimerColor = HSLColor.White
local DefeatStarted = false
local VictoryStarted = false
local NavalBaseFound = false
local CruisersArrived = false
local CruisersKilled = false
local TanyaReinforced = false
local FirstAirfieldCaptured = false

--- Prefix for the player messages.
local BattlefieldControl = UserInterface.GetFluentMessage("battlefield-control")

--[[
	Ticks until certain teams reinforce after the service base is regained.
	The Normal event timings should overall be a decent match for the RA1
	version, but they will differ.
	
	The original Cruiser-activated footprints can not be relied upon because
	ORA movement speed is different. The RA1 Cruisers and Longbows had delays
	of ~300/~600 seconds at 5/7 speed.
]]
local EndTeamDelays =
{
	easy =
	{
		cruisers = DateTime.Seconds(450),
		longbows = DateTime.Seconds(600),
		sea7_sea8 = DateTime.Seconds(454),
		end1 = DateTime.Seconds(493),
		end2_end5 = DateTime.Seconds(524)
	},
	normal =
	{
		cruisers = DateTime.Seconds(390),
		longbows = DateTime.Seconds(600),
		sea7_sea8 = DateTime.Seconds(394),
		end1 = DateTime.Seconds(433),
		end2_end5 = DateTime.Seconds(464)
	},
	hard =
	{
		cruisers = DateTime.Seconds(330),
		longbows = DateTime.Seconds(300),
		sea7_sea8 = DateTime.Seconds(334),
		end1 = DateTime.Seconds(373),
		end2_end5 = DateTime.Seconds(404)
	}
}

--- A collection of LST attackers scheduled once the Service Depot is regained.
local EndTransportTeams =
{
	end1 =
	{
		types = { "e3", "e3", "e3", "e3", "e3" },
		path = { Waypoint90.Location, NavalRocketUnload.Location },
	},
	end2 =
	{
		types = { "2tnk", "2tnk", "arty" },
		path = { Waypoint93.Location, Waypoint95.Location }
	},
	end5 =
	{
		types = { "2tnk", "2tnk", "2tnk" },
		path = { Waypoint65.Location, Waypoint66.Location }
	},
	sea7 =
	{
		types = { "1tnk", "1tnk", "arty", "arty" },
		path = { Waypoint94.Location, Waypoint67.Location }
	},
	sea8 =
	{
		types = { "1tnk", "1tnk", "1tnk", "arty" },
		path = { Waypoint65.Location, Waypoint66.Location }
	}
}

local Footprints =
{
	--- Beach rescue trigger by Waypoint 74.
	atk2 =
	{
		CPos.New(91, 92),
		CPos.New(91, 93),
		CPos.New(91, 94),
		CPos.New(91, 95),
		CPos.New(91, 96)
	},
	--- Outside the starting base by Waypoint 75.
	atk6 =
	{
		CPos.New(71, 72),
		CPos.New(71, 73),
		CPos.New(71, 74),
		CPos.New(71, 75),
		CPos.New(71, 76),
		CPos.New(71, 77),
		CPos.New(71, 78),
		CPos.New(71, 79)
	},
	--- Cells north/northeast of the mining outpost.
	atk7 =
	{
		--- Ore patch cells.
		CPos.New(83, 51),
		CPos.New(84, 51),
		CPos.New(85, 51),
		CPos.New(86, 51),
		CPos.New(87, 51),
		CPos.New(88, 51),
		CPos.New(89, 51),
		CPos.New(90, 51),
		CPos.New(91, 51),
		CPos.New(92, 51),
		CPos.New(93, 51),
		--- Path to NE corner base.
		CPos.New(98, 56),
		CPos.New(99, 56),
		CPos.New(99, 57),
		CPos.New(100, 57),
		CPos.New(101, 57),
		CPos.New(101, 58),
		CPos.New(102, 58),
		CPos.New(103, 58),
		CPos.New(103, 59),
		CPos.New(104, 59),
		CPos.New(104, 60)
	},
	--- Land approach to the airbase.
	des3 =
	{
		--- West end.
		CPos.New(20, 18),
		CPos.New(20, 19),
		CPos.New(20, 20),
		CPos.New(20, 21),
		CPos.New(20, 22),
		CPos.New(20, 23),
		CPos.New(20, 24),
		CPos.New(20, 25),
		CPos.New(20, 26),
		CPos.New(20, 27),
		CPos.New(20, 28),
		CPos.New(20, 29),
		--- South end.
		CPos.New(21, 29),
		CPos.New(22, 29),
		CPos.New(23, 29),
		CPos.New(24, 29),
		CPos.New(25, 29),
		CPos.New(26, 29),
		CPos.New(27, 29),
		CPos.New(28, 29),
		CPos.New(29, 29),
		CPos.New(30, 29),
		CPos.New(31, 29),
		CPos.New(32, 29),
		CPos.New(33, 29),
		CPos.New(34, 29),
		--- East end.
		CPos.New(34, 28),
		CPos.New(34, 27),
		CPos.New(34, 26),
		CPos.New(34, 25),
		CPos.New(34, 24),
		CPos.New(34, 23),
		CPos.New(34, 22),
		CPos.New(33, 22),
		CPos.New(33, 21),
		CPos.New(33, 20),
		CPos.New(33, 19),
		CPos.New(33, 18)
	},
	--- River between waypoints 73 and 84.
	ent2 =
	{
		CPos.New(35, 44),
		CPos.New(35, 45),
		CPos.New(36, 45),
		CPos.New(36, 46),
		CPos.New(37, 46),
		CPos.New(37, 47),
		CPos.New(38, 47),
		CPos.New(38, 48),
		CPos.New(38, 48),
		CPos.New(39, 48),
		CPos.New(39, 49),
		CPos.New(39, 50)
	},
	--- Small strip of coast west of Waypoint 57.
	ent3 =
	{
		CPos.New(69, 18),
		CPos.New(69, 19),
		CPos.New(69, 20),
		CPos.New(69, 21),
		CPos.New(69, 22),
		CPos.New(69, 23)
	},
	--- River between waypoints 73 and 76.
	ent4 =
	{
		CPos.New(21, 62),
		CPos.New(22, 62),
		CPos.New(23, 62),
		CPos.New(24, 62),
		CPos.New(25, 62),
		CPos.New(26, 62),
		CPos.New(27, 62),
		CPos.New(28, 62),
		CPos.New(29, 62),
		CPos.New(30, 62)
	},
	--- River between waypoints 76 and 53.
	ent5 =
	{
		CPos.New(19, 82),
		CPos.New(20, 82),
		CPos.New(21, 82),
		CPos.New(22, 82),
		CPos.New(23, 82),
		CPos.New(24, 82),
		CPos.New(25, 82),
		CPos.New(26, 82),
		CPos.New(27, 82),
		CPos.New(28, 82),
		CPos.New(29, 82)
	},
	--- River between waypoints 53 and 72.
	ent6 =
	{
		CPos.New(19, 101),
		CPos.New(20, 101),
		CPos.New(21, 101),
		CPos.New(22, 101),
		CPos.New(23, 101),
		CPos.New(24, 101),
		CPos.New(25, 101),
		CPos.New(26, 101),
		CPos.New(27, 101),
		CPos.New(28, 101),
		CPos.New(29, 101),
		CPos.New(30, 101)
	},
	--- River between waypoints 73 and 84.
	rev3 =
	{
		CPos.New(33, 45),
		CPos.New(33, 46),
		CPos.New(33, 47),
		CPos.New(34, 47),
		CPos.New(34, 48),
		CPos.New(35, 48),
		CPos.New(35, 49),
		CPos.New(36, 48),
		CPos.New(36, 49),
		CPos.New(36, 50),
		CPos.New(37, 49),
		CPos.New(37, 50),
		CPos.New(37, 51)
	},
	--- River near Waypoint 84.
	rev4 =
	{
		CPos.New(49, 34),
		CPos.New(48, 35),
		CPos.New(49, 35),
		CPos.New(47, 36),
		CPos.New(48, 36),
		CPos.New(46, 37),
		CPos.New(47, 37),
		CPos.New(45, 38),
		CPos.New(46, 38)
	},
	--- Between the first flare and a beach to its south. Non-original.
	tanya =
	{
		CPos.New(92, 90),
		CPos.New(93, 90),
		CPos.New(94, 90),
		CPos.New(95, 90),
		CPos.New(96, 90)
	}
}

local function FinishCountdown()
	DateTime.TimeLimit = 0
	TimerColor = USSR.Color
	local text = UserInterface.GetFluentMessage("cruisers-arrived")

	for i = 0, 5 do
		local flash

		if i % 2 == 0 then
			flash = HSLColor.White
		end

		Trigger.AfterDelay(DateTime.Seconds(i), function()
			UserInterface.SetMissionText(text, flash or TimerColor)
		end)
	end

	Trigger.AfterDelay(DateTime.Seconds(6), function()
		UserInterface.SetMissionText("")
	end)
end

---@param ticks integer
---@param interval integer
local function UpdateCountdown(ticks, interval)
	if ticks < 1 then
		return
	end

	local text = UserInterface.GetFluentMessage("cruisers-arrive-in", { ["time"] = Utils.FormatTime(ticks)})
	UserInterface.SetMissionText(text, TimerColor)

	Trigger.AfterDelay(interval, function()
		UpdateCountdown(ticks - interval, interval)
	end)
end

---@param duration integer
local function StartCountdown(duration)
	DateTime.TimeLimit = duration
	Media.PlaySpeechNotification(USSR, "TimerStarted")
	UpdateCountdown(duration, DateTime.Seconds(1))
	Trigger.OnTimerExpired(FinishCountdown)

	Trigger.AfterDelay(duration - DateTime.Seconds(120), function()
		TimerColor = USSR.Color
	end)
end

---@param speech string Speech notification to play.
---@param delay integer Ticks until the speech plays.
local function PlayDelayedSpeech(speech, delay)
	Trigger.AfterDelay(delay, function()
		Media.PlaySpeechNotification(USSR, speech)
	end)
end

local function AnnounceSovietVictory()
	if VictoryStarted then
		return
	end

	VictoryStarted = true
	PlayDelayedSpeech("ObjectiveMet", DateTime.Seconds(1))

	-- Like the original, it is possible to destroy Greece without naval units.
	-- For that, PenObjective is marked here (for a second time in most cases).
	local objectives = { PenObjective, IntruderObjective, TechObjective }

	Trigger.AfterDelay(DateTime.Seconds(2), function()
		Utils.Do(objectives, USSR.MarkCompletedObjective)
	end)
end

---@param objective integer ID of the failed objective.
---@param delay? integer Delay until the failed objective is marked.
---@param speech? string Notification speech to be played.
---@param speechDelay? integer Delay until the speech is started.
local function AnnounceSovietDefeat(objective, delay, speech, speechDelay)
	if DefeatStarted or VictoryStarted then
		return
	end
	DefeatStarted = true

	if speech then
		PlayDelayedSpeech(speech, speechDelay or DateTime.Seconds(1))
	end

	Trigger.AfterDelay(delay or DateTime.Seconds(2), function()
		USSR.MarkFailedObjective(objective)
	end)
end

---@param player player
local function StartFireSale(player)
	local buildings = Utils.Where(player.GetActors(), function(actor)
		return actor.HasProperty("StartBuildingRepairs") end)

	if #buildings == 0 then
		Utils.Do(player.GetGroundAttackers(), IdleHunt)
		return
	end

	Utils.Do(buildings, function(b)
		b.Sell()
	end)

	-- Delay until all sales (and potential actor spawns from them) are done.
	Trigger.OnAllRemovedFromWorld(buildings, function()
		Utils.Do(player.GetGroundAttackers(), IdleHunt)
	end)
end

---@param actor actor Actor to be removed.
---@param delay? integer Ticks to delay removal.
local function RemoveActor(actor, delay)
	if delay then
		Trigger.AfterDelay(delay, function()
			RemoveActor(actor)
		end)

		return
	end

	if actor and actor.IsInWorld then
		actor.Destroy()
	end
end

---@param type string Type of the new actor.
---@param owner player Owner of the new actor.
---@param location? cpos Location of the new actor.
---@param duration? integer Ticks to delay the actor's removal, after creation.
---@param delay? integer Ticks to delay adding the new actor to the world.
---@return actor
local function SpawnMiscActor(type, owner, location, duration, delay)
	delay = delay or 0
	local actor = Actor.Create(type, delay <= 0, { Owner = owner, Location = location or CPos.Zero })

	if delay > 0 then
		Trigger.AfterDelay(delay, function()
			actor.IsInWorld = true
		end)
	end

	if duration and duration > 0 then
		RemoveActor(actor, delay + duration)
	end

	return actor
end

---@param location cpos
---@return actor
local function SpawnSignalFlare(location)
	return SpawnMiscActor("flare", England, location, -1)
end

---@param location cpos Cell to use as the camera's center.
---@param duration? integer Ticks for the camera to linger (after delay, if any).
---@param type? string Camera's actor type.
---@param delay? integer Ticks to delay the camera's creation.
---@return actor
local function SpawnRevealCamera(location, duration, type, delay)
	duration = duration or DateTime.Seconds(6)
	type = type or "camera"
	return SpawnMiscActor(type, USSR, location, duration, delay)
end

--- Drop some Soviets near France's storage area. Non-original.
local function ReinforceCrateParatroopers()
	local crates = { MoneyCrate1, MoneyCrate2, HealCrate }
	local cratesAcquired = Utils.All(crates, function(c)
		return not c.IsInWorld end)

	if cratesAcquired then
		return
	end

	local revealed = false
	local proxy = Actor.Create("powerproxy.flametroopers", false, { Owner = USSR })
	local targetPos = Map.CenterOfCell(CPos.New(30, 43))
	local planes = proxy.TargetParatroopers(targetPos, Angle.New(384))

	Utils.Do(planes, function(plane)
		Trigger.OnPassengerExited(plane, function()
			if revealed then
				return
			end

			revealed = true
			SpawnRevealCamera(HealCrateRevealMark.Location, 85, "camera.paradrop")
		end)
	end)
end

--- Send some non-original units to support the starting base. This
--- is intended to compensate for the inability to build defenses there.
local function SendTechGuards()
	local types =
	{
		default = { "apc.techguard", "apc.techguard" },
		easy = { "3tnk", "e4", "3tnk", "e4", "apc.techguard" }
	}
	local path = { TechGuardEntry.Location, Waypoint67.Location }
	local guards = Reinforcements.ReinforceWithTransport(USSR, "lst.reinforcement", types[Difficulty] or types.default, path, { path[1] })[2]
	local speechPlayed = false
	local flipped = false
	local goals = { [true] = TechGuardGoalWest.Location, [false] = TechGuardGoalEast.Location }

	Utils.Do(guards, function(guard)
		Trigger.OnAddedToWorld(guard, function()
			guard.Move(goals[flipped], 2)
			flipped = not flipped

			if guard.HasProperty("UnloadPassengers") then
				guard.UnloadPassengers()
			end

			if speechPlayed then
				return
			end

			speechPlayed = true
			Media.PlaySpeechNotification(USSR, "ReinforcementsArrived")
			Beacon.New(England, TechGuardGoalEast.CenterPosition)
		end)
	end)
end

---@param types string[]
---@param path cpos[]
local function ReinforceBasicBoatTeam(types, path)
	local boatTeam = Reinforcements.ReinforceWithTransport(Greece, "lst", types, path, { path[1] })
	local boat, passengers = boatTeam[1], boatTeam[2]
	Utils.Do(passengers, IdleHunt)

	return boat, passengers
end

---@param transport actor Transport to reveal.
---@param location cpos Spawn location for the camera and trigger.
---@param hold? integer Ticks to continue revealing once the unload is done.
---@param type? string Type of camera to spawn.
---@param range? wdist Distance at which the transport triggers the reveal.
local function PrepareTransportReveal(transport, location, hold, type, range)
	range = range or WDist.FromCells(6)
	local pos = Map.CenterOfCell(location)
	local activated = false

	Trigger.OnEnteredProximityTrigger(pos, range, function(actor, id)
		if activated or actor ~= transport then
			return
		end

		activated = true
		Trigger.RemoveProximityTrigger(id)
		local camera = SpawnRevealCamera(location, -1, type)

		Trigger.OnPassengerExited(transport, function()
			if transport.HasPassengers then
				return
			end

			RemoveActor(camera, hold)
		end)

		Trigger.OnKilled(transport, function()
			RemoveActor(camera, hold)
		end)
	end)
end

---@param actors actor[]
---@param action fun()
local function OnAllAddedToWorld(actors, action)
	local i = 0

	Utils.Do(actors, function(actor)
		Trigger.OnAddedToWorld(actor, function()
			i = i + 1

			if i == #actors then
				action()
			end
		end)
	end)
end

---@param actor actor
---@return boolean
local function IsEastOfCenterRidge(actor)
	return actor.Location.X > Waypoint99.Location.X
end

---@param actor actor
---@return boolean
local function IsWall(actor)
	return actor.Type == "brik" or actor.Type == "cycl" or actor.Type == "fenc"
end

---@param actor actor
local function IsMobileSoviet(actor)
	return actor.Owner == USSR and actor.HasProperty("Move")
end

---@param actor actor
local function IsCruiser(actor)
	return actor.Owner == Greece and actor.Type == "ca"
end

---@param posA wpos
---@param posB wpos
---@return integer
local function SquaredDistance(posA, posB)
	local diffX = posA.X - posB.X
	local diffY = posA.Y - posB.Y
	return diffX * diffX + diffY * diffY
end

---@param origin wpos Point from which distances are measured.
---@param types string[] Target types to find.
---@param enemyPlayers player[] Players who will have their actors targeted.
---@param filter? fun(actor: actor):boolean Filter applied to actors after type and owner.
---@return actor[]
local function TargetsByDistance(origin, types, enemyPlayers, filter)
	local targets = { }
	local sort = table.sort

	Utils.Do(enemyPlayers, function(player)
		targets = Utils.Concat(targets, player.GetActorsByTypes(types))
	end)

	if filter then
		targets = Utils.Where(targets, filter)
	end

	sort(targets, function(a, b)
		return SquaredDistance(origin, a.CenterPosition) < SquaredDistance(origin, b.CenterPosition)
	end)

	return targets
end

---@param target actor
---@param harasser actor
---@return boolean
local function IsValidHarassTarget(target, harasser)
	return target and not target.IsDead and not target.Owner.IsAlliedWith(harasser.Owner)
end

---@param harasser actor Unit finished with harassment.
---@param onFinished? fun(harasser: actor) Called after OnIdle is clear.
local function ClearIdleHarass(harasser, onFinished)
	Trigger.Clear(harasser, "OnIdle")

	if onFinished then
		-- Delay in case the next function adds another OnIdle.
		Trigger.AfterDelay(1, function()
			if harasser.IsDead then
				return
			end

			onFinished(harasser)
		end)
	end
end

--- Give a list of targets to a unit, and orders for interacting with each.
--- When idle, the unit performs these orders until no valid targets remain.
---@param harasser actor Unit taking orders.
---@param types string[] Target types to find.
---@param enemyPlayers player[] Players who will have their actors targeted.
---@param filter? fun(a: actor):boolean Filter applied to actors after type and owner.
---@param onNewTarget fun(harasser: actor, target: actor) Called when a new target is selected.
---@param onFinished? fun(harasser: actor) Called once no more targets can be found.
local function IdleHarass(harasser, types, enemyPlayers, filter, onNewTarget, onFinished)
	if harasser.IsDead then
		return
	end

	Trigger.OnIdle(harasser, function()
		local tbd = TargetsByDistance(harasser.CenterPosition, types, enemyPlayers, filter)
		-- Cap the list size to limit how outdated it may become.
		local targets = Utils.Take(5, tbd)

		if #targets == 0 then
			ClearIdleHarass(harasser, onFinished)
			return
		end

		Utils.Do(targets, function(target)
			harasser.CallFunc(function()
				-- Target outdated? Assume a list refresh is needed.
				if not IsValidHarassTarget(target, harasser) then
					targets = { }
					return
				end

				onNewTarget(harasser, target)
			end)
		end)
	end)
end

--- Order units to harass when idle, each with their own initial target.
--- The intent is to reduce or stagger TargetsByDistance calls from groups.
---@param harassers actor[] Units taking orders.
---@param types string[] Target types to find.
---@param enemyPlayers player[] Players who will have their actors targeted.
---@param filter? fun(a: actor):boolean Filter applied to actors after type and owner.
---@param onNewTarget fun(harasser: actor, target: actor) Called when a new target is selected.
---@param onFinished? fun(harasser: actor) Called once no more targets can be found.
local function GroupHarass(harassers, types, enemyPlayers, filter, onNewTarget, onFinished)
	local targets
	local targetId = 1

	Utils.Do(harassers, function(harasser)
		IdleHarass(harasser, types, enemyPlayers, filter, onNewTarget, onFinished)

		if not harasser.IsInWorld then
			return
		end

		targets = targets or TargetsByDistance(harasser.CenterPosition, types, enemyPlayers, filter)

		if targets[targetId] then
			onNewTarget(harasser, targets[targetId])
			targetId = targetId + 1
		end
	end)
end

---@param plane actor Plane that will attack.
---@param types string[] Enemy types to attack, ordered by high to low priority.
---@param enemyPlayer player Owner of the enemy types.
---@return actor
local function NewPlaneTarget(plane, types, enemyPlayer)
	local enemies = enemyPlayer.GetActorsByTypes(types)
	local target

	Utils.Do(types, function(type)
		if target then
			return
		end

		local matches = Utils.Where(enemies, function(enemy)
			return enemy.Type == type and plane.CanTarget(enemy) end)

		if #matches > 0 then
			target = Utils.Random(matches)
		end
	end)

	return target
end

---@param plane actor Plane that will attack.
---@param types string[] Enemy types to attack, ordered by high to low priority.
---@param enemyPlayer player Owner of the enemy types.
local function IdlePlaneHarass(plane, types, enemyPlayer)
	local target

	Trigger.OnIdle(plane, function()
		local ammoStarved = plane.AmmoCount() == 0 and not plane.Owner.HasPrerequisites({ "afld" })

		if ammoStarved then
			plane.Move(Waypoint64.Location)
			plane.Destroy()
			return
		end

		target = target or NewPlaneTarget(plane, types, enemyPlayer)

		if not target or target.IsDead then
			plane.ReturnToBase()
			target = nil
			return
		end

		-- Ensure vision for targeting.
		SpawnMiscActor("camera.spotter", plane.Owner, target.Location, 3)

		Trigger.AfterDelay(1, function()
			if not target or target.IsDead or plane.IsDead or not plane.CanTarget(target) then
				target = nil
				return
			end

			plane.Attack(target)
		end)
	end)
end

---@param types string[] Plane types to spawn.
---@param targetTypes string[] Enemy types to attack, ordered by high to low priority.
local function SendAlliedPlanes(types, targetTypes)
	if not Greece.HasPrerequisites({ "afld"}) then
		return
	end

	-- The RA1 planes were set to reinforce from Waypoint 95 but because that
	-- sat on a land tile, the edge directly south was (and is) used instead.
	local path = { AlliedPlaneEntry.Location }
	local planes = Reinforcements.Reinforce(Greece, types, path)

	Utils.Do(planes, function(plane)
		IdlePlaneHarass(plane, targetTypes, USSR)
		Trigger.OnCapture(plane, Trigger.ClearAll)
	end)

	if Difficulty ~= "hard" then
		return
	end

	local delay = Actor.BuildTime(planes[1].Type) * 2 * #types

	Trigger.OnAllKilled(planes, function()
		Trigger.AfterDelay(delay, function()
			SendAlliedPlanes(types, targetTypes)
		end)
	end)
end

--- Reinforce a pair of Yak planes, based on RA1 team "air1".
local function SendYaks()
	local priorityList = { "4tnk", "3tnk", "silo", "harv" }
	SendAlliedPlanes({ "yak", "yak" }, priorityList)
end

--- Reinforce a MiG bomber, based on RA1 team "air2".
local function SendJet()
	local priorityList = { "4tnk", "3tnk", "powr", "silo", "v2rl", "mnly", "harv" }
	SendAlliedPlanes({ "mig" }, priorityList)
end

local function ReinforceLongbows()
	local types = { "heli", "heli", "heli", "heli" }
	-- This offset arranges them in a spread formation before the attack order.
	local offset = CVec.New(-5, 10)
	local path = { Waypoint94.Location, Waypoint94.Location + offset }

	return Reinforcements.Reinforce(Greece, types, path, 20)
end

--- Prepare an area trigger that will dispose of retreating Longbows.
--- Their repulsion trait makes the usual Move + Destroy orders unreliable.
---@param units actor[]
local function PrepareLongbowDisposal(units)
	local disposal = Trigger.OnEnteredProximityTrigger(AlliedHeliDisposal.CenterPosition, WDist.FromCells(2), function(actor)
		if actor.Type ~= "heli" then
			return
		end

		actor.Stop()
		actor.Destroy()
	end)

	Trigger.OnAllRemovedFromWorld(units, function()
		Trigger.RemoveProximityTrigger(disposal)
	end)
end

--- Send a Longbow team, based on the RA1 trigger "ent1".
--- The starting base is the normal target, but the depot is possible.
local function SendLongbows()
	if CruisersKilled then
		return
	end

	local targetTypes = { "ftur", "tsla", "apwr", "sam" }
	local longbows = ReinforceLongbows()
	PrepareLongbowDisposal(longbows)

	OnAllAddedToWorld(longbows, function()
		local targets = TargetsByDistance(Waypoint94.CenterPosition, targetTypes, SovietPlayers, IsEastOfCenterRidge)

		-- Ensure vision for targeting.
		SpawnMiscActor("camera", Greece, Waypoint67.Location, DateTime.Seconds(1))

		Utils.Do(longbows, function(longbow)
			if longbow.IsDead then
				return
			end

			longbow.Stop()
			local samFound = false

			Utils.Do(targets, function(target)
				if samFound or target.Type == "sam" then
					samFound = true
					return
				end

				longbow.Attack(target)
			end)

			Trigger.OnIdle(longbow, function()
				longbow.Move(AlliedHeliDisposal.Location)
			end)
		end)
	end)
end

--- Reveal the tech center to nearby Cruisers to ensure targeting.
---@param cruiser actor
local function OnCruiserReachedTech(cruiser)
	if TechCenter.IsDead then
		return
	end

	local camera = SpawnMiscActor("camera", Greece, Waypoint89.Location)
	Trigger.OnKilled(cruiser, camera.Destroy)
end

local function OnAllCruisersKilled()
	CruisersKilled = true
	local attackers = Greece.GetGroundAttackers()
	local navyPath = { EndBoatPatrol1.Location, EndBoatPatrol2.Location, EndBoatPatrol3.Location, EndBoatPatrol4.Location }

	if #attackers == 0 then
		-- Done in RA1 when Greece lost all current infantry & ground vehicles.
		StartFireSale(Greece)
		return
	end

	Utils.Do(attackers, function(a)
		if a.Type == "dd" or a.Type == "dd.escort" then
			a.Patrol(navyPath, true)
			return
		end

		-- Mostly for any remaining east edge tanks.
		IdleHunt(a)
	end)

	Trigger.OnAllKilled(attackers, function()
		StartFireSale(Greece)
	end)
end

--- Send ships ahead of the Cruisers, based on RA1 trigger "des2".
local function SendCruiserEscorts()
	local types = { "dd.escort", "dd.escort" }
	local path = { Waypoint90.Location, Waypoint83.Location }

	Reinforcements.Reinforce(Greece, types, path, DateTime.Seconds(1), function(escort)
		Trigger.OnIdle(escort, function()
			escort.Stance = "AttackAnything"
			local cruisers = Greece.GetActorsByType("ca")

			if #cruisers == 0 then
				escort.Hunt()
				return
			end

			Utils.Do(cruisers, escort.Guard)
		end)
	end)
end

--- Send in the Allies' Cruisers, based on trigger "crus".
local function SendCruisers()
	if not FirstAirfieldCaptured then
		USSR.MarkFailedObjective(AirfieldObjective)
	end

	Trigger.AfterDelay(DateTime.Seconds(9), SendCruiserEscorts)
	PlayDelayedSpeech("AlliedForcesApproaching", 20)
	Media.DisplayMessage(UserInterface.GetFluentMessage("unauthorized-naval-units"), BattlefieldControl, USSR.Color)

	Trigger.AfterDelay(DateTime.Seconds(4), function()
		Media.DisplayMessage(UserInterface.GetFluentMessage("protect-our-tech-center-at-all-costs"), BattlefieldControl, USSR.Color)
	end)

	local path =
	{
		Waypoint90.Location,
		Waypoint85.Location,
		Waypoint86.Location,
		Waypoint84.Location,
		Waypoint73.Location,
		Waypoint72.Location,
		Waypoint71.Location
	}

	local cruisers = Reinforcements.Reinforce(Greece, { "ca", "ca" }, path, DateTime.Seconds(2))
	Trigger.OnAllKilled(cruisers, OnAllCruisersKilled)
	SpawnRevealCamera(cruisers[1].Location)

	Utils.Do(cruisers, function(cruiser)
		Trigger.OnIdle(cruiser, function()
			if cruiser.Location == path[#path] then
				Trigger.Clear(cruiser, "OnIdle")
				return
			end

			cruiser.Move(path[#path])
		end)

		Trigger.OnEnteredProximityTrigger(Waypoint72.CenterPosition, WDist.FromCells(3), function(actor, id)
			if actor ~= cruiser then
				return
			end

			Trigger.RemoveProximityTrigger(id)
			OnCruiserReachedTech(cruiser)
		end)
	end)

	Trigger.AfterDelay(DateTime.Seconds(6), function()
		CruisersArrived = true
	end)
end

--- Send tanks to guard a path between the refineries and vehicle depot.
--- The original team was "end4" from trigger "des3".
local function SendEastEdgeTanks()
	local path = { Waypoint68.Location, Waypoint69.Location }
	local types = { "2tnk.widescan", "2tnk.widescan", "2tnk.widescan" }
	local passengers = Reinforcements.ReinforceWithTransport(Greece, "lst", types, path, { path[1] })[2]

	Utils.Do(passengers, function(p)
		Trigger.OnAddedToWorld(p, function()
			p.AttackMove(Waypoint63.Location, 2)
		end)
	end)
end

---@return actor[]
local function NavalWallTargets()
	local sort = table.sort
	local nw, se = NavalRocketScanWest.CenterPosition, NavalRocketScanEast.CenterPosition
	local walls = Map.ActorsInBox(nw, se, IsWall)

	-- Ensure our target list is ordered from west to east.
	sort(walls, function(a, b)
		return a.Location.X < b.Location.X
	end)

	return walls
end

--- Unload rockets to attack the Soviet pen, based on RA1's "ent4" trigger.
--- They can't outrange towers like RA1; a wall breach is attempted on Hard.
local function SendNavalRockets(types, path)
	if not NavalBaseFound then
		-- Cruisers are halfway down the river and the player seems
		-- to be running late. Delay this attack as a small courtesy.
		Trigger.OnObjectiveCompleted(USSR, function(_, id)
			if id ~= PenObjective then
				return
			end

			SendNavalRockets(types, path)
		end)

		return
	end

	local rockets = Reinforcements.ReinforceWithTransport(Greece, "lst", types, path, { path[1] })[2]

	if Difficulty ~= "hard" then
		Utils.Do(rockets, IdleHunt)
		return
	end

	local walls = NavalWallTargets()

	Utils.Do(rockets, function(rocket)
		Trigger.OnAddedToWorld(rocket, function()
			rocket.AttackMove(NavalRocketScanWest.Location, 4)

			Utils.Do(walls, function(wall)
				rocket.Attack(wall)
				rocket.AttackMove(wall.Location, 1)
			end)

			rocket.AttackMove(Waypoint52.Location, 2)
			IdleHunt(rocket)
		end)
	end)
end

local function ScheduleEndTransports()
	local events =
	{
		{
			teams = { EndTransportTeams.sea7, EndTransportTeams.sea8 },
			delay = EndTeamDelays[Difficulty].sea7_sea8
		},
		{
			teams = { EndTransportTeams.end1 },
			delay = EndTeamDelays[Difficulty].end1,
			teamFunc = SendNavalRockets,
		},
		{
			teams = { EndTransportTeams.end2, EndTransportTeams.end5 },
			delay = EndTeamDelays[Difficulty].end2_end5
		}
	}

	Utils.Do(events, function(event)
		local teamFunc = event.teamFunc or ReinforceBasicBoatTeam

		Trigger.AfterDelay(event.delay, function()
			if CruisersKilled then
				return
			end

			Utils.Do(event.teams, function(team)
				teamFunc(team.types, team.path)
			end)
		end)
	end)
end

--- The Soviet naval base has died, possibly while still in shroud.
--- Under normal circumstances, it should remain intact until regained.
local function OnNavalBaseKilled()
	if VictoryStarted or NavalBaseFound then
		return
	end

	SpawnRevealCamera(Waypoint52.Location, -1)
	AnnounceSovietDefeat(PenObjective, DateTime.Seconds(2), "ObjectiveNotMet", DateTime.Seconds(1))
	Media.DisplayMessage(UserInterface.GetFluentMessage("naval-base-destroyed"), BattlefieldControl, USSR.Color)
	Media.PlaySoundNotification(USSR, "AlertBleep")
end

local function OnStartAttackersRemoved()
	if DefeatStarted then
		return
	end

	Trigger.AfterDelay(DateTime.Seconds(4), function()
		Media.DisplayMessage(UserInterface.GetFluentMessage("scouts-mark-the-way-to-bases"), BattlefieldControl, USSR.Color)
	end)

	Trigger.AfterDelay(DateTime.Seconds(8), function()
		Media.PlaySpeechNotification(USSR, "SignalFlare")
		Beacon.New(USSR, Waypoint0.CenterPosition)
	end)
end

local function OnTechCenterLost()
	SpawnRevealCamera(Waypoint89.Location, -1)
	AnnounceSovietDefeat(TechObjective, DateTime.Seconds(2), "ObjectiveNotMet", DateTime.Seconds(1))
	Media.PlaySoundNotification(USSR, "AlertBleep")

	if TechCenter.IsDead then
		Media.DisplayMessage(UserInterface.GetFluentMessage("our-tech-center-destroyed"), BattlefieldControl, USSR.Color)
		return
	end

	Media.DisplayMessage(UserInterface.GetFluentMessage("our-tech-center-captured"), BattlefieldControl, USSR.Color)

	Trigger.AfterDelay(DateTime.Seconds(2), function()
		if TechCenter.IsInWorld then
			TechCenter.Sell()
		end
	end)
end

---@param actors actor[]
local function RegainBase(actors)
	Utils.Do(actors, function(actor)
		if actor.IsDead then
			return
		end

		actor.Owner = USSR

		if actor.Type == "harv" then
			actor.FindResources()
		end
	end)
end

local function OnMineBaseReached()
	local trucks = { MineTruck1, MineTruck2, MineTruck3 }
	local structures = { MineRefinery1, MineRefinery2, MineRefinery3, MinePower1, MinePower2, MinePower3, MinePower4, MineSilo1, MineSilo2, MineSilo3, MineSilo4, MineSilo5, MineSilo6, MineSilo7, MineSilo8 }
	RegainBase(structures)
	RegainBase(trucks)

	Media.DisplayMessage(UserInterface.GetFluentMessage("mining-outpost-reached"), BattlefieldControl, USSR.Color)

	Trigger.AfterDelay(DateTime.Seconds(4), function()
		Media.PlaySpeechNotification(USSR, "SignalFlareNorth")
		Beacon.New(USSR, Waypoint1.CenterPosition)
	end)

	if Difficulty == "hard" then
		Trigger.AfterDelay(DateTime.Seconds(60), SendYaks)
		Trigger.AfterDelay(DateTime.Seconds(120), SendJet)
		return
	end

	if Difficulty == "easy" then
		local proxy = Actor.Create("powerproxy.paratroopers", false, { Owner = USSR })
		proxy.TargetParatroopers(Waypoint55.CenterPosition, Angle.New(896))
	end
end

local function OnServiceBaseReached()
	local base = { ServiceDepot, ServiceFactory, ServiceFlame1, ServiceFlame2, ServiceFlame3, ServiceFlame4, ServicePower1, ServicePower2, ServiceCommand, ServiceEngineer1, ServiceEngineer2 }
	RegainBase(base)
	Media.DisplayMessage(UserInterface.GetFluentMessage("vehicle-depot-reached"), BattlefieldControl, USSR.Color)
	SpawnRevealCamera(Waypoint1.Location)

	Trigger.AfterDelay(DateTime.Seconds(4), function()
		Media.PlaySpeechNotification(USSR, "SignalFlareWest")
		Beacon.New(USSR, Waypoint2.CenterPosition)
		AirfieldObjective = AirfieldObjective or AddSecondaryObjective(USSR, "capture-airfield-before-cruisers")
	end)

	ScheduleEndTransports()
	Trigger.AfterDelay(EndTeamDelays[Difficulty].cruisers, SendCruisers)
	Trigger.AfterDelay(EndTeamDelays[Difficulty].longbows, SendLongbows)
	Trigger.AfterDelay(DateTime.Seconds(60), SendTechGuards)

	Trigger.AfterDelay(DateTime.Seconds(20), function()
		StartCountdown(EndTeamDelays[Difficulty].cruisers - DateTime.Seconds(20))
	end)

	-- On Hard, planes will already be triggered from the mining base.
	if Difficulty == "hard" then
		return
	end

	Trigger.AfterDelay(DateTime.Seconds(60), SendYaks)
	Trigger.AfterDelay(DateTime.Seconds(120), SendJet)

	if Difficulty == "easy" and not ServiceFactory.IsDead then
		local tankType = "4tnk"
		ServiceFactory.Produce(tankType)

		Trigger.AfterDelay(1, function()
			RegainBase(BadGuy.GetActorsByType(tankType))
		end)
	end
end

local function OnAirbaseReached()
	SpawnRevealCamera(Waypoint2.Location)

	if NavalBaseFound then
		return
	end

	Media.DisplayMessage(UserInterface.GetFluentMessage("airfields-reached"), BattlefieldControl, USSR.Color)

	Trigger.AfterDelay(DateTime.Seconds(4), function()
		Media.PlaySpeechNotification(USSR, "SignalFlareSouth")
		Beacon.New(USSR, Waypoint3.CenterPosition)
	end)
end

local function OnAirfieldCaptured()
	if FirstAirfieldCaptured or DateTime.TimeLimit == 0 then
		return
	end

	FirstAirfieldCaptured = true
	AirfieldObjective = AirfieldObjective or AddSecondaryObjective(USSR, "capture-airfield-before-cruisers")
	USSR.MarkCompletedObjective(AirfieldObjective)
	Trigger.AfterDelay(DateTime.Seconds(1), ReinforceCrateParatroopers)
end

--- The player has regained the Sub Pen, by approaching the
--- gate or otherwise discovering the production structures.
local function OnNavalBaseFound()
	if VictoryStarted or NavalBaseFound then
		return
	end

	NavalBaseFound = true
	USSR.MarkCompletedObjective(PenObjective)
	Media.PlaySpeechNotification(USSR, "NewOptions")
	local structures = { NavalPower1, NavalPower2, NavalFlame1, NavalFlame2, NavalConstructionYard, NavalPen }
	RegainBase(structures)
	SpawnRevealCamera(Waypoint52.Location)

	Trigger.AfterDelay(DateTime.Seconds(4), function()
		if not VictoryStarted then
			IntruderObjective = AddPrimaryObjective(USSR, "wipe-out-intruders-with-new-submarines")
		end
	end)
end

--- Prepare the chain of Soviet signal flares and their triggers.
--- Each trigger spawns the next flare and schedules the current one's removal.
local function PrepareSovietSignals()
	local signals =
	{
		{
			action = OnMineBaseReached,
			location = Waypoint0.Location,
			radius = WDist.FromCells(3)
		},
		{
			action = OnServiceBaseReached,
			location = Waypoint1.Location,
			radius = WDist.FromCells(11)
		},
		{
			action = OnAirbaseReached,
			location = Waypoint2.Location,
			radius = WDist.FromCells(6)
		},
		{
			location = Waypoint3.Location,
			radius = WDist.FromCells(3)
		}
	}

	for i = 1, #signals do
		local activated = false

		Trigger.OnEnteredProximityTrigger(Map.CenterOfCell(signals[i].location), signals[i].radius, function(actor, id)
			if activated or not IsMobileSoviet(actor) then
				return
			end

			activated = true
			Trigger.RemoveProximityTrigger(id)
			RemoveActor(signals[i].smoke, DateTime.Minutes(2))

			if signals[i].action then
				signals[i].action()
			end

			if signals[i + 1] and not NavalBaseFound then
				signals[i + 1].smoke = SpawnSignalFlare(signals[i + 1].location)
			end
		end)
	end

	signals[1].smoke = SpawnSignalFlare(Waypoint0.Location)
end

--- Send some engineers to capture the Tech Center if playing Hard.
--- This is a nod to the "end3" team unused in the RA1 mission.
---@return actor[]
local function SendSaboteurs()
	if Difficulty ~= "hard" then
		return { }
	end

	local cargoTypes = { "e6", "e6", "e1", "e3", "e3" }
	local entryPath = { Waypoint66.Location, CPos.New(56, 92), Waypoint87.Location }
	local apc = Reinforcements.ReinforceWithTransport(Greece, "apc", cargoTypes, entryPath)[1]
	local captureTypes = { "stek", "iron" }

	Utils.Do(apc.Passengers, function(passenger)
		Trigger.OnAddedToWorld(passenger, function()
			if not passenger.HasProperty("Capture") then
				IdleHunt(passenger)
				return
			end

			passenger.Move(Waypoint89.Location, 2)

			IdleHarass(passenger, captureTypes, SovietPlayers, nil, function(harasser, target)
				harasser.Capture(target)
			end)
		end)
	end)

	IdleHunt(apc)
	return apc.Passengers
end

local function OrderStartAttackers()
	local saboteurs = SendSaboteurs()
	local rockets = { StartAttacker1, StartAttacker2, StartAttacker3 }

	Utils.Do(rockets, function(a)
		-- Maintain their spread formation as they approach.
		local goal = a.Location + CVec.New(0, 6)
		a.AttackMove(goal, 2)
		IdleHunt(a)
	end)

	local attackers = Utils.Concat(saboteurs, rockets)
	Trigger.OnAllRemovedFromWorld(attackers, OnStartAttackersRemoved)
end

---@param actor actor Actor that must survive for the speech to play.
---@param sound string Sound notification to play.
---@param delay integer Ticks until the speech plays.
---@param camera? string Camera type to reveal Tanya as she speaks.
local function TauntWithTanya(actor, sound, delay, camera)
	Trigger.AfterDelay(delay, function()
		if actor.IsDead then
			return
		end

		if camera then
			SpawnRevealCamera(actor.Location, DateTime.Seconds(3), camera)
		end

		Media.PlaySpeechNotification(USSR, sound)
	end)
end

--- Arrange extraction for Tanya once her sabotage is complete.
---@param tanya actor
local function ExtractTanya(tanya)
	local path = { Waypoint93.Location, TanyaBackupUnload.Location }
	local boat = Reinforcements.Reinforce(Greece, { "lst" }, path)[1]
	tanya.Move(TanyaBackupUnload.Location)

	Trigger.OnIdle(boat, function()
		if tanya.IsDead or boat.HasPassengers then
			boat.Move(path[1])
			boat.Destroy()
			return
		end

		if tanya.IsIdle then
			tanya.EnterTransport(boat)
		end
	end)

	Trigger.OnPassengerEntered(boat, function()
		TauntWithTanya(boat, "TanyaLetsRock", 15, "camera.small")
	end)

	Trigger.OnIdle(tanya, function()
		if boat.IsDead then
			tanya.Hunt()
		end
	end)
end

local function ReinforceTanyaBackup()
	local path = { Waypoint68.Location, TanyaBackupUnload.Location }
	local exit = { Waypoint94.Location }
	local types = { "e3.vehiclehunter", "e3.vehiclehunter", "e3.vehiclehunter", "e1", "2tnk.widescan" }
	local boatTeam = Reinforcements.ReinforceWithTransport(Greece, "lst", types, path, exit)
	local boat, cargo = boatTeam[1], boatTeam[2]
	PrepareTransportReveal(boat, path[#path], DateTime.Seconds(1), "camera.small")

	return cargo
end

local function SendTanyaBackup()
	if Difficulty ~= "hard" then
		return
	end

	local units = ReinforceTanyaBackup()
	local attacking = false
	local guardGoal = Waypoint55.Location + CVec.New(0, 2)

	OnAnyDamaged(units, function()
		attacking = true
	end)

	Utils.Do(units, function(unit)
		Trigger.OnAddedToWorld(unit, function()
			-- Ignore structures for now and leave them to Tanya.
			unit.Stance = "Defend"
			unit.AttackMove(guardGoal, 2)
		end)

		Trigger.OnIdle(unit, function()
			if not attacking then
				return
			end

			if unit.Location ~= Waypoint0.Location then
				unit.AttackMove(Waypoint0.Location)
				return
			end

			unit.Stance = "AttackAnything"
			unit.Hunt()
		end)
	end)
end

--- Reinforce Tanya by boat, along with any backup she may have.
---@return actor
local function ReinforceTanya()
	local path = { Waypoint93.Location, Waypoint92.Location }
	local cargo = { "e7" }
	local boatTeam = Reinforcements.ReinforceWithTransport(Greece, "lst", cargo, path, { path[1] })
	local boat, tanya = boatTeam[1], boatTeam[2][1]
	PrepareTransportReveal(boat, path[#path], DateTime.Seconds(3), "camera", WDist.FromCells(4))
	Trigger.OnAddedToWorld(tanya, SendTanyaBackup)

	return tanya
end

--- Begin Tanya's demolition spree. She will attempt extraction when done.
local function SendTanya()
	if TanyaReinforced then
		return
	end

	TanyaReinforced = true
	local tanya = ReinforceTanya()
	local demolitionTypes = { "proc", "powr", "silo" }
	local lastTarget

	local onNewTarget = function(demolisher, target)
		-- Guard against a re-demolish, which may happen if the target
		-- list refreshes as a bomb timer is still ticking down.
		if target == lastTarget then
			return
		end

		demolisher.Demolish(target)
		lastTarget = target
	end

	Trigger.OnAddedToWorld(tanya, function()
		TauntWithTanya(tanya, "TanyaLaugh", 1)
		TauntWithTanya(tanya, "TanyaGiveItToMe", DateTime.Seconds(6))
		tanya.Move(Waypoint77.Location)
		tanya.Move(TanyaDemolishStart.Location)
		IdleHarass(tanya, demolitionTypes, SovietPlayers, IsEastOfCenterRidge, onNewTarget, ExtractTanya)
	end)

	-- Tanya's unload cell from the boat is randomized. Since that affects
	-- her travel time, this will be more consistent than a delay.
	Trigger.OnEnteredProximityTrigger(TanyaDemolishStart.CenterPosition, WDist.New(1536), function(actor, id)
		if actor ~= tanya then
			return
		end

		Trigger.RemoveProximityTrigger(id)
		TauntWithTanya(actor, "TanyaKissItByeBye", 1, "camera.small")
	end)
end

--- Airlift thieves to the mining base, based on RA1 trigger "ent3".
local function SendThieves()
	local thiefTypes = { "thf", "thf" }
	if Difficulty == "hard" then
		thiefTypes = { "thf", "thf", "thf", "thf" }
	end

	local path = { Waypoint68.Location, Waypoint55.Location }
	local thieves = Reinforcements.ReinforceWithTransport(Greece, "tran", thiefTypes, path, { path[1] })[2]
	local stealTypes = { "proc", "silo" }

	local onNewTarget = function(thief, target)
		thief.Infiltrate(target)
	end

	OnAllAddedToWorld(thieves, function()
		GroupHarass(thieves, stealTypes, SovietPlayers, IsEastOfCenterRidge, onNewTarget)
	end)
end

--- Send vehicles to help the beach runner, and prepare Tanya's arrival.
--- The original team was "sea4" from trigger "atk2".
local function SendBeachRescue()
	local path = { Waypoint94.Location, Waypoint95.Location }
	local cargoTypes = { "1tnk", "arty", "arty" }
	if Difficulty == "hard" then
		cargoTypes = { "2tnk", "2tnk", "e3", "e3", "arty" }
	end

	local boat, cargo = ReinforceBasicBoatTeam(cargoTypes, path)
	PrepareTransportReveal(boat, Waypoint74.Location, DateTime.Seconds(1), "camera.small", WDist.FromCells(15))

	Trigger.OnAllKilled(cargo, function()
		SendTanya()
		IdleHunt(BeachRunner)
	end)
end

--- Order a soldier to run for help, based on RA1 trigger "atk6".
local function OrderBeachRunner()
	if BeachRunner.IsDead then
		return
	end

	SpawnRevealCamera(BeachRunner.Location)
	BeachRunner.Stop()
	BeachRunner.Move(RidgeRunPoint1.Location)
	BeachRunner.Move(RidgeRunPoint2.Location)
	BeachRunner.Move(Waypoint74.Location)

	Trigger.OnIdle(BeachRunner, function()
		if BeachRunner.Location == Waypoint74.Location then
			Trigger.Clear(BeachRunner, "OnIdle")
			BeachRunner.Stance = "AttackAnything"
			return
		end

		BeachRunner.Move(Waypoint74.Location)
	end)
end

local function PrepareBeachRunner()
	local team = { BeachRunnerRocket1, BeachRunnerRocket2, BeachRunner }
	local alerted = false

	Trigger.OnEnteredFootprint(Footprints.atk6, function(actor, id)
		if alerted or not IsMobileSoviet(actor) then
			return
		end

		alerted = true
		OrderBeachRunner()
		Trigger.RemoveFootprintTrigger(id)
	end)

	OnAnyDamaged(team, function()
		if alerted then
			return
		end

		alerted = true
		OrderBeachRunner()
	end)

	Trigger.OnEnteredFootprint(Footprints.atk2, function(actor, id)
		if actor ~= BeachRunner then
			return
		end

		Trigger.RemoveFootprintTrigger(id)
		SendBeachRescue()
	end)
end

--- Send some APC troops for a flank attack at the north edge, based on "ent3".
local function SendLakeAmbushers()
	local path = { Waypoint57.Location, Waypoint56.Location }
	local cargoTypes = { "e3", "e3", "e3", "e3", "e3" }
	local apc = Reinforcements.ReinforceWithTransport(Greece, "apc", cargoTypes, path)[1]

	Trigger.OnPassengerExited(apc, function(_, passenger)
		IdleHunt(passenger)
	end)

	IdleHunt(apc)
end

--- Unload some mining base harassers, based on RA1 trigger "atk8".
--- Hard adds the intended but bugged "sea6" team, plus an Artillery unit.
local function SendEastEdgeRockets()
	local path = { Waypoint68.Location, Waypoint70.Location }
	local cargoTypes = { "e3.vehiclehunter", "e3.vehiclehunter", "e3.vehiclehunter", "e3.vehiclehunter", "e3.vehiclehunter" }
	local boat = ReinforceBasicBoatTeam(cargoTypes, path)
	PrepareTransportReveal(boat, Waypoint70.Location, DateTime.Seconds(1), "camera.small")

	if Difficulty ~= "hard" then
		return
	end

	local extras = { "e3.vehiclehunter", "e3.vehiclehunter", "e3.vehiclehunter", "arty" }
	local extraPath = { Waypoint68.Location, Waypoint69.Location }

	Trigger.AfterDelay(10, function()
		ReinforceBasicBoatTeam(extras, extraPath)
	end)
end

local function PrepareBasicFootprints()
	local triggers =
	{
		{
			cells = Footprints.atk7,
			actions = { SendEastEdgeRockets }
		},
		{
			cells = Footprints.des3,
			actions = { SendEastEdgeTanks }
		},
		{
			cells = Footprints.ent3,
			actions = { SendLakeAmbushers, SendThieves }
		},
		{
			cells = Footprints.tanya,
			actions = { SendTanya }
		}
	}

	Utils.Do(triggers, function(trigger)
		local activated = false

		Trigger.OnEnteredFootprint(trigger.cells, function(actor, id)
			if activated or not IsMobileSoviet(actor) then
				return
			end

			activated = true
			Trigger.RemoveFootprintTrigger(id)

			Utils.Do(trigger.actions, function(action)
				action()
			end)
		end)
	end)
end

local function PrepareCruiserReveals()
	local triggers =
	{
		{ cells = Footprints.rev4, reveal = Waypoint84.Location },
		{ cells = Footprints.rev3, reveal = Waypoint73.Location },
		{ cells = Footprints.ent4, reveal = Waypoint76.Location },
		{ cells = Footprints.ent5, reveal = Waypoint53.Location },
		{ cells = Footprints.ent6, reveal = Waypoint72.Location }
	}

	Utils.Do(triggers, function(trigger)
		Trigger.OnEnteredFootprint(trigger.cells, function(actor, id)
			if not IsCruiser(actor) then
				return
			end

			Trigger.RemoveFootprintTrigger(id)
			SpawnRevealCamera(trigger.reveal)
		end)
	end)
end

--- Easy will swap out the end teams' artillery. In RA1, Tesla Coils
--- outranged Allied artillery with ease, but the same does not apply here.
local function SwapEndArtillery()
	if Difficulty ~= "easy" then
		return
	end

	Utils.Do(EndTransportTeams, function(team)
		for i = 1, #team.types do
			if team.types[i] == "arty" then
				team.types[i] = "1tnk"
			end
		end
	end)
end

WorldLoaded = function()
	PrepareSovietSignals()
	PrepareCruiserReveals()
	PrepareBasicFootprints()
	PrepareBeachRunner()
	OrderStartAttackers()
	SwapEndArtillery()

	Camera.Position = TechCoil1.CenterPosition
	USSR.Cash = 500
	BadGuy.Cash = 5000

	InitObjectives(USSR)
	TechObjective = AddPrimaryObjective(USSR, "tech-center-survive")
	PenObjective = AddPrimaryObjective(USSR, "regain-control-of-our-naval-base")

	Trigger.OnKilledOrCaptured(TechCenter, OnTechCenterLost)
	Trigger.OnAllKilled({ NavalConstructionYard, NavalPen }, OnNavalBaseKilled)
	Trigger.OnDiscovered(NavalConstructionYard, OnNavalBaseFound)
	Trigger.OnDiscovered(NavalPen, OnNavalBaseFound)

	-- Fallback trigger that lets the player continue if using the
	-- visibility cheat; OnDiscovered events will be blocked.
	Trigger.OnEnteredProximityTrigger(NavalConstructionYard.CenterPosition, WDist.FromCells(4), function(actor, id)
		if not IsMobileSoviet(actor) then
			return
		end

		Trigger.RemoveProximityTrigger(id)
		OnNavalBaseFound()
	end)

	Trigger.AfterDelay(DateTime.Seconds(6), function()
		-- Ownership is delayed to help avoid the speech muddling others.
		RegainBase({ IronCurtain })
	end)

	Utils.Do(Greece.GetActorsByType("afld"), function(field)
		Trigger.OnCapture(field, OnAirfieldCaptured)
	end)
end

Tick = function()
	if CruisersArrived and TechCenter.IsInWorld and Greece.HasNoRequiredUnits() then
		AnnounceSovietVictory()
	end
end