// ##################################################
// Possession
// By RabidToaster
// ##################################################

local command = "!possess"

// #########################
// Don't change down here!
// #########################

if ( SERVER ) then
	AddCSLuaFile( "Possession.lua" )

	local function SetPossessing( pPlayer, pPossessed )
		// If we were possessing someone, tell them they're not being possessed any more.
		if ( pPlayer.Possessing && pPlayer.Possessing:IsValid() ) then	
			pPlayer.Possessing:SetNWBool( "Possessed", false )
			pPlayer.Possessing.Possessed = nil
		end
		
		// We're now possessing the other player.
		pPlayer.Possessing = pPossessed
		pPlayer:SetNetworkedEntity( "Possessing", pPossessed or GetWorldEntity() )
		pPlayer:SetViewEntity( pPossessed )
		
		// Tell the other player we're possessing them.
		if ( pPossessed ) then
			pPossessed.Possessed = true
			pPossessed:SetNWBool( "Possessed", true )
		end
	end	
	
	local tChat = {}
	local function PlayerSay( pPlayer, sText, bPublic )
		// Crappy command :D
		local tArgs = string.Explode( " ", sText )
		if ( pPlayer:IsAdmin() && string.lower( tArgs[ 1 ] or "" ) == command ) then
			if ( pPlayer.Possessed ) then
				pPlayer:ChatPrint( "You cannot possess while being possessed." )
				return ""
			end
			if ( pPlayer.Possessing == nil ) then
				table.remove( tArgs, 1 )
				local sName = string.lower( table.concat( tArgs, " " ) )
				if ( sName == "" ) then pPlayer:ChatPrint( "Usage: !possess <name>" ) return "" end
				for _, pOther in pairs( player.GetAll() ) do
					if ( !pOther.Possessed && pOther != pPlayer && string.find( string.lower( pOther:Name() ), sName ) ) then
						SetPossessing( pPlayer, pOther )
						pPlayer:ChatPrint( "You are possessing " .. pOther:Name() .. "." )
						pOther:ChatPrint( "You are being possessed!" )
						return ""
					end
				end
				pPlayer:ChatPrint( "No matches found for '" .. sName .. "'." )
			else
				pPlayer:ChatPrint( "You stopped possessing " .. pPlayer.Possessing:Name() .. "." )
				pPlayer.Possessing:ChatPrint( "You're no longer possessed." )
				SetPossessing( pPlayer, nil )
			end
			return ""
		end
		
		// If the player is possessing someone, make the possesed player say it.
		if ( bPublic && pPlayer.Possessing != nil && pPlayer.Possessing:IsValid() ) then
			tChat[ pPlayer.Possessing ] = tChat[ pPlayer.Possessing ] or {}
			table.insert( tChat[ pPlayer.Possessing ], sText )
			pPlayer.Possessing:ConCommand( "say " .. sText )
			return ""
		end
		
		// Don't let the possessed player say anything apart from what they're supposed to.
		if ( pPlayer.Possessed ) then
			for iA, sAllowed in pairs( tChat[ pPlayer ] or {} ) do
				if ( sText == sAllowed ) then table.remove( tChat, iA ) return end
			end
			return ""
		end
		
	end
	hook.Add( "PlayerSay", "Possession.PlayerSay", PlayerSay )
	
	// Forwards commands to the possessed player.
	local function ForwardBind( pPlayer, _, tArguments )
		if ( pPlayer.Possessing && pPlayer.Possessing:IsValid() ) then
			pPlayer.Possessing:ConCommand( table.concat( tArguments, " " ) )
		end
	end
	concommand.Add( "possession_forward", ForwardBind )
	
	// Keep eye angles synced.
	// TODO: Keep possessing players eyes the same.
	local function Think()	
		for _, pP in pairs( player.GetAll() ) do
			if ( pP.Possessing && pP.Possessing:IsValid() ) then
				pP.Possessing:SetEyeAngles( pP:EyeAngles() )
			end
		end
	end
	hook.Add( "Think", "Possession.Think", Think )
	
	// Stop the player running around when they're possessing someone.
	local function SetupMove( pPlayer, mdData )
		if ( pPlayer.Possessing && pPlayer.Possessing:IsValid() ) then
			mdData:SetForwardSpeed( 0 )
			mdData:SetSideSpeed( 0 )
			mdData:SetUpSpeed( 0 )
		end
	end
	hook.Add( "SetupMove", "Possession.SetupMove", SetupMove )
	
	// Horribly ineffiecient. D:
	// TODO: Find a better way!
	local function WeaponEquip()
		for _, pOwner in pairs( player.GetAll() ) do
			if ( pOwner.Possessing && pOwner.Possessing:IsValid() ) then
				local eOActive = pOwner:GetActiveWeapon()
				local ePActive = pOwner.Possessing:GetActiveWeapon()
				if ( eOActive:IsValid() && ePActive:IsValid() ) then
					if ( eOActive:GetClass() != ePActive:GetClass() ) then
						pOwner.Possessing:SelectWeapon( eOActive:GetClass() )
					end
				end
			end
		end
	end
	timer.Create( "WeaponTest", 0.5, 0, WeaponEquip )
	
	local tSpawn = {}
	local function PlayerSpawnSomething( pPlayer, sCommand, sType )
		if ( pPlayer.Possessing && pPlayer.Possessing:IsValid() ) then
			tSpawn[ pPlayer.Possessing ] = tSpawn[ pPlayer.Possessing ] or {}
			table.insert( tSpawn[ pPlayer.Possessing ], sType )
			pPlayer.Possessing:ConCommand( sCommand .. " " .. sType )
			return false
		end
		if ( pPlayer.Possessed ) then
			for _, sAllowed in pairs( tSpawn[ pPlayer ] or {} ) do
				if ( sType == sAllowed ) then table.remove( tSpawn[ pPlayer ], iA ) return end
			end
			return false
		end
	end
	
	hook.Add( "PlayerSpawnProp", "Possession.PlayerSpawnProp", function( p, m ) return PlayerSpawnSomething( p, "gm_spawn", m ) end )
	hook.Add( "PlayerSpawnVehicle", "Possession.PlayerSpawnVehicle", function( p ) if ( p.Possessed or p.Possessing ) then return false end end )
	hook.Add( "PlayerSpawnNPC", "Possession.PlayerSpawnNPC", function( p, c ) return PlayerSpawnSomething( p, "gmod_spawnnpc", c ) end )
	hook.Add( "PlayerSpawnSENT", "Possession.PlayerSpawnSENT", function( p, c ) return PlayerSpawnSomething( p, "gm_spawnsent", c ) end )
	
	
end

if ( CLIENT ) then
	local bFirstPerson = false	
	local iAttack = 0
	
	// Forwards binds up to the server, for bouncing down to the possessed player.
	local tDontBlock = { "messagemode", "messagemode2", "toggleconsole", "invnext", "invprev", "+menu", "-menu", "gm_giveswep" }
	local tLetThrough = { "messagemode", "messagemode2", "toggleconsole" } // Commands possessed players can do.
	local allowCommands = { "noclip", "gm_spawn", "gm_spawnsent", "gm_spawnvehicle", "gmod_spawnnpc", "gmod_setnpcweapon", "gm_giveswep", "undo" }
	local function PlayerBindPress( pPlayer, sBind, bPressed )
		local eP = pPlayer:GetNWEntity( "Possessing" )
		if ( eP && eP:IsValid() ) then
			if ( !bPressed && string.Left( sBind, 1 ) != "+" ) then return end
			if ( !bPressed ) then sBind = string.Replace( sBind, "+", "-" ) end
			
			local left = string.Left( sBind, 1 )
			if ( left == "+" || left == "-" || table.HasValue( allowCommands, sBind ) ) then
				RunConsoleCommand( "possession_forward", sBind )
			end
			
			if ( sBind == "invnext" || sBind == "invprev" ) then iAttack = CurTime() + 6 end
			if ( ( sBind == "+attack" && CurTime() < iAttack ) || sBind == "-attack" ) then iAttack = 0 return end
			
			if ( !table.HasValue( tDontBlock, sBind ) ) then return true end
		end
		
		if ( pPlayer:GetNWBool( "Possessed", false ) == true ) then
			if ( !table.HasValue( tLetThrough, sBind ) ) then return true end
		end
	end
	hook.Add( "PlayerBindPress", "Possession.PlayerBindPress", PlayerBindPress )
	
	// Move the players view to the possessed player.
	local function CalcView( pPlayer, vOrigin, aAngle, iFOV )
		local eP = pPlayer:GetNWEntity( "Possessing" )
		if ( eP && eP:IsValid() ) then
			if ( bFirstPerson ) then
				return { origin = eP:GetShootPos() + ( eP:GetAimVector() * 16 ) }
			else
				return { origin = ( eP:GetShootPos() - ( eP:GetAimVector() * 64 ) ) + Vector( 0, 0, 32 ) }
			end
		end
	end
	hook.Add( "CalcView", "Possession.CalcView", CalcView )
	
	// Draw the thirdperson crosshair.
	local function HUDPaint()
		if ( bFirstPerson ) then return end
		local eP = LocalPlayer():GetNWEntity( "Possessing" )
		if ( eP && eP:IsValid() ) then
			local vTarget = util.QuickTrace( eP:GetShootPos(), eP:GetAimVector() * 8192, eP ).HitPos
			local tTarget = vTarget:ToScreen()
			local iX, iY = tTarget.x, tTarget.y
			local iSize = 3
			
			// Black outline.
			surface.SetDrawColor( 0, 0, 0, 200 )
			surface.DrawRect( ( iX - 1 ) - iSize, iY - 1, ( iSize * 2 ) + 3, 3 )
			surface.DrawRect( iX - 1, ( iY - 1 ) - iSize, 3, ( iSize * 2 ) + 3 )
				
			// White inside.
			surface.SetDrawColor( 255, 255, 255, 200 )
			surface.DrawLine( iX - iSize, iY, iX + iSize, iY )
			surface.DrawLine( iX, iY - iSize, iX, iY + iSize )
		end
	end
	hook.Add( "HUDPaint", "Possession.HUDPaint", HUDPaint )
	
	// Allows us to change from view easily.
	concommand.Add( "possession_toggleview", function() bFirstPerson = !bFirstPerson end )
end