local signposts = {}
local antigravdisabled = false
local checkedcezboss = false
local playimpossible = false

local function StandingOnSky(player)
	local thing = true

	--If your skies are intentionally not pits, then I guess you can mark that
	if mapheaderinfo[gamemap].antigravnoskypits != nil then
		thing = nil
	end
	--So I found out that ACZ3 is actually possible
	--Annoying, but possible
	if G_BuildMapName(gamemap) == "MAP15" and G_BuildMapTitle(gamemap) == "Arid Canyon" then
		//thing = nil
	end
	if thing != nil then
		if player.antigrav.wasflipped
			if player.mo.ceilingrover then
				if player.mo.ceilingrover.bottompic == "F_SKY1" or player.mo.ceilingrover.bottompic == "PIT" or player.mo.ceilingrover.bottompic == "~PIT" then
					P_KillMobj(player.mo)
				end
			else
				if player.mo.subsector.sector.ceilingpic == "F_SKY1" or player.mo.subsector.sector.ceilingpic == "PIT" or player.mo.subsector.sector.ceilingpic == "~PIT" then
					P_KillMobj(player.mo)
				end
			end
		else
			if player.mo.floorrover then
				if player.mo.floorrover.toppic == "F_SKY1" or player.mo.floorrover.toppic == "PIT" or player.mo.floorrover.toppic == "~PIT" then
					P_KillMobj(player.mo)
				end
			else
				if player.mo.subsector.sector.floorpic == "F_SKY1" or player.mo.subsector.sector.floorpic == "PIT" or player.mo.subsector.sector.floorpic == "~PIT" then
					P_KillMobj(player.mo)
				end
			end
		end
	end
end

local function LandOnFloor(player)
	--So we don't land on the same floor we jumped from
	if (player.pflags & PF_JUMPED) then return true end
	--If we were already on the floor, we don't have to land on it again
	//if P_IsObjectOnGround(player.mo) then return true end
	--Don't do this in a zoom tube
	if player.mo.tracer then
		if player.mo.tracer.valid then return true end
	end
	
	local height = player.mo.z
	local surface = P_FloorzAtPos(player.mo.x, player.mo.y, player.mo.z, player.mo.height)
	if player.antigrav.wasflipped
		height = player.mo.z + player.mo.height
		surface = P_CeilingzAtPos(player.mo.x, player.mo.y, player.mo.z, player.mo.height)
	end
	
	if abs(height - surface) >= FixedMul(player.mo.scale, 20*FRACUNIT) then return true end
	
	if not(player.antigrav.wasflipped and player.mo.momz >= -FRACUNIT or not player.antigrav.wasflipped and player.mo.momz <= FRACUNIT) then return true end

	StandingOnSky(player)
	return false
end

local function LandOnCeiling(player)
	//if (player.pflags & PF_JUMPED) then return true end
	if P_IsObjectOnGround(player.mo) then return true end
	--Don't do this in a zoom tube
	if player.mo.tracer then
		if player.mo.tracer.valid then return true end
	end
	
	local height = player.mo.z + player.mo.height
	local surface = P_CeilingzAtPos(player.mo.x, player.mo.y, player.mo.z, player.mo.height)
	if player.antigrav.wasflipped
		height = player.mo.z
		surface = P_FloorzAtPos(player.mo.x, player.mo.y, player.mo.z, player.mo.height)
	end
	
	if abs(height - surface) >= FixedMul(player.mo.scale, 20*FRACUNIT) then return true end
	
	if not(player.antigrav.wasflipped and player.mo.momz <= FRACUNIT or (not player.antigrav.wasflipped) and player.mo.momz >= -FRACUNIT) then return true end

	player.antigrav.wasflipped = not $
	if player.mo.eflags & MFE_VERTICALFLIP then
		player.mo.eflags = $ & ~MFE_VERTICALFLIP
	else
		player.mo.eflags = $ | MFE_VERTICALFLIP
	end
	
	if player.antigrav.wasflipped then
		player.mo.momz = 4*FRACUNIT
	else
		player.mo.momz = -4*FRACUNIT
	end

	StandingOnSky(player)
	return false
end

COM_AddCommand("antigravflip",function(player)
	if antigravdisabled == true or checkedcezboss == false then
		CONS_Printf(player, "Antigrav is currently disabled. Sorry.")
		return
	end

	if player.antigrav == nil then
		player.antigrav = {}	
	end
	
	player.antigrav.wasflipped = not $
	if player.mo.eflags & MFE_VERTICALFLIP then
		player.mo.eflags = $ & ~MFE_VERTICALFLIP
	else
		player.mo.eflags = $ | MFE_VERTICALFLIP
	end
end, 0)

COM_AddCommand("emergencygrav",function(player)
	if antigravdisabled == true or checkedcezboss == false then
		CONS_Printf(player, "Antigrav is currently disabled. Sorry.")
		return
	end
	
	player.mo.flags = $ & ~MF_NOGRAVITY
end, 0)

COM_AddCommand("antigravimpossible",function(player)
	playimpossible = not $

	if playimpossible == true then
		print("Impossible levels will be played with Antigrav enabled. They're probably impossible though.")
	else
		print("Impossible levels will be played normally.")
	end
	print("Reload the map to apply the change.")
end, 0)

addHook("MapLoad", function()
	checkedcezboss = false
	local foundcezboss = false
	antigravdisabled = false
	for mobj in mobjs.iterate() do
		if mobj.type == MT_SIGN then
			table.insert(signposts, mobj)
		end
		if playimpossible == false then
			if mobj.type == MT_EGGMOBILE4 and foundcezboss == false then
				foundcezboss = true
				print("An Egg Colosseum has been found, disabling Antigrav to make the level possible.")
			end
			--Fang is technically possible with a lot of hoping he bounces to your level, as well as waiting.
			if mobj.type == MT_FANG and foundcezboss == false then
				foundcezboss = true
				print("Fang has been found, disabling Antigrav to make the level not overly tedious.")
			end
			--Metal Sonic is possible as Fang, but Sonic is better.
			if mobj.type == MT_METALSONIC_BATTLE and foundcezboss == false then
				foundcezboss = true
				print("Metal Sonic has been found, disabling Antigrav to make the level possible.")
			end
		end
	end

	--It only breaks in ERZ, not the Metal Sonic race.
	if foundcezboss == false and playimpossible == false then
		for line in lines.iterate do
			--The sector-based gravity special
			if line.special == 1 then
				foundcezboss = true
				print("A reverse-gravity sector has been found, disabling Antigrav as to not break your vision.")
				break
			end
		end
	end

	checkedcezboss = true
	antigravdisabled = foundcezboss
	
	if antigravdisabled == false or playimpossible == true then
		for mobj in mobjs.iterate() do
			--To make THZ's boss actually able to hurt you for the first five hits
			if mobj.type == MT_GOOP then return end
			--To make ACZ1 possible
			if mobj.type == MT_PROXIMITYTNT then return end
			--To make ACZ2 possible
			if mobj.type == MT_MINECART then return end
		
			if mobj.type == MT_PLAYER then
				--The player thinker will set the NOGRAVITY flag
				mobj.player.jumpfactor = skins[mobj.player.skin].jumpfactor*2
			else
				--Here so that BC3 can actually start quickly
				mobj.flags = $ | MF_NOGRAVITY
			end
		end
	else
		for player in players.iterate() do
			player.mo.flags = $ & ~MF_NOGRAVITY
		end
	end
	
	--This makes FOF's not fall, making CEZ2 impossible, and fixes CEZ1's bridge (in a bad way).
	//gravity = 0
end)

addHook("NetVars", function(network)
	signposts = network($)
	antigravdisabled = network($)
end)

addHook("PlayerSpawn", function(player)
	player.jumpfactor = skins[player.skin].jumpfactor

	if antigravdisabled == true or checkedcezboss == false then
		CONS_Printf(player, "Antigrav is disabled. Check the console for more information.")
	end

	if player.mo then
		if player.mo.valid and player.mo.health then
			if player.antigrav == nil then
				player.antigrav = {}	
			end
			
			player.antigrav.wasflipped = ((player.mo.flags2 & MF2_OBJECTFLIP) > 0)
			player.mo.flags = $ | MF_NOGRAVITY
		end
	end
end)

addHook("PlayerThink", function(player)
	if antigravdisabled == true or checkedcezboss == false then return end
	
	if player.mo then
		if player.playerstate == PST_DEAD then
			player.antigrav.justspawned = true
		end
		
		if player.mo.valid and player.mo.health then
			if P_IsObjectOnGround(player.mo) then
				player.mo.flags = $ | MF_NOGRAVITY
			end
			
			if player.antigrav == nil then
				player.antigrav = {}	
			end
			
			if player.antigrav.justjumped == nil then
				player.antigrav.justjumped = 1
			end
			if player.antigrav.letgoofjump != true and player.antigrav.letgoofjump != false then
				player.antigrav.letgoofjump = true
			end
			if player.antigrav.jumped != true and player.antigrav.jumped != false then
				player.antigrav.jumped = false
			end
			if player.antigrav.wasflipped != true and player.antigrav.wasflipped != false then
				player.antigrav.wasflipped = ((player.mo.flags2 & MF2_OBJECTFLIP) > 0)
			end
			if player.antigrav.vertflipped != true and player.antigrav.vertflipped != false then
				//player.antigrav.vertflipped = ((player.mo.flags2 & MF2_OBJECTFLIP) > 0)
			end

			if (player.pflags & PF_JUMPED) and player.antigrav.letgoofjump == true and player.antigrav.jumped == false then
				player.antigrav.justjumped = 0
					player.antigrav.jumped = true
					player.antigrav.letgoofjump = false
			elseif (player.pflags & ~PF_JUMPED) then
				player.antigrav.justjumped = $+1
				player.antigrav.letgoofjump = true
			else
				player.antigrav.justjumped = $+1
			end

			if P_IsObjectOnGround(player.mo) then
				player.antigrav.jumped = false
			end
			
			--To make levels look cooler
			if player.antigrav.justjumped == 0 or player.mo.eflags & MFE_SPRUNG then
				if player.antigrav.justjumped == 0 then
					player.antigrav.wasflipped = not $
					if player.mo.eflags & MFE_VERTICALFLIP then
						player.mo.eflags = $ & ~MFE_VERTICALFLIP
					else
						player.mo.eflags = $ | MFE_VERTICALFLIP
					end
				elseif player.mo.momz > 0 then
					player.antigrav.wasflipped = true
					player.mo.eflags = $ | MFE_VERTICALFLIP
				elseif player.mo.momz > 0 then
					player.antigrav.wasflipped = false
					player.mo.eflags = $ & ~MFE_VERTICALFLIP
				end
			end
			
			if LandOnCeiling(player) then
				LandOnFloor(player)
			end

			--Remove other gravity changing effects, since, on their own, they don't actually work
			player.powers[pw_gravityboots] = 0

			if player.antigrav.wasflipped then
				player.mo.flags2 = $ | MF2_OBJECTFLIP
			else
				player.mo.flags2 = $ & ~MF2_OBJECTFLIP
			end
		end
	end
end)

addHook("MobjThinker", function(mo)
	if antigravdisabled == true or not checkedcezboss == false then return end

	if mo then
		if mo.valid and mo.health then
			--Flip the sign's gravity when it starts spinning
			if mo.antigravtriggered == nil then
				mo.antigravtriggered = true
				if mo.flags2 & MF2_OBJECTFLIP then
					mo.flags2 = $ & ~MF2_OBJECTFLIP
				else
					mo.flags2 = $|MF2_OBJECTFLIP
				end
			end
		end
	end
end, MT_SIGN)