Autoshoot.

AutoAim by RabidToaster
if SERVER then return end

local AA = {}

local concommand = concommand
local cvars = cvars
local debug = debug
local ents = ents
local file = file
local hook = hook
local math = math
local spawnmenu = spawnmenu
local string = string
local surface = surface
local table = table
local timer = timer
local util = util
local vgui = vgui

local Angle = Angle
local CreateClientConVar = CreateClientConVar
local CurTime = CurTime
local ErrorNoHalt = ErrorNoHalt
local FrameTime = FrameTime
local GetConVarString = GetConVarString
local GetViewEntity = GetViewEntity
local include = include
local ipairs = ipairs
local LocalPlayer = LocalPlayer
local pairs = pairs
local pcall = pcall
local print = print
local RunConsoleCommand = RunConsoleCommand
local ScrH = ScrH
local ScrW = ScrW
local tonumber = tonumber
local type = type
local unpack = unpack
local ValidEntity = IsValid
local Vector = Vector

do
    local hooks = {}
    local created = {}
    local function CallHook(self, name, args)
        if !hooks[name] then return end
        for funcName, _ in pairs(hooks[name]) do
            local func = self[funcName]
            if func then
                local ok, err = pcall(func, self, unpack(args or {}))
                if !ok then
                    ErrorNoHalt(err .. "\n")
                elseif err then
                    return err
                end
            end
        end
    end
    local function RandomName()
        local random = ""
        for i = 1, math.random(4, 10) do
            local c = math.random(65, 116)
            if c >= 91 && c <= 96 then c = c + 6 end
            random = random .. string.char(c)
        end
        return random
    end
    local function AddHook(self, name, funcName)
        // If we haven't got a hook for this yet, make one with a random name and store it.
        // This is so anti-cheats can't detect by hook name, and so we can remove them later.
        if !created[name] then
            local random = RandomName()
            hook.Add(name, random, function(...) return CallHook(self, name, {...}) end)
            created[name] = random
        end
        
        hooks[name] = hooks[name] or {}
        hooks[name][funcName] = true
    end
    
    local cvarhooks = {}
    local function GetCallbackTable(convar)
        local callbacks = cvars.GetConVarCallbacks(convar)
        if !callbacks then
            cvars.AddChangeCallback(convar, function() end)
            callbacks = cvars.GetConVarCallbacks(convar)
        end
        return callbacks
    end
            
    local function AddCVarHook(self, convar, funcName, ...)
        local hookName = "CVar_" .. convar
        if !cvarhooks[convar] then
            local random = RandomName()
            
            local callbacks = GetCallbackTable(convar)
            callbacks[random] = function(...)
                CallHook(self, hookName, {...})
            end
            
            cvarhooks[convar] = random
        end
        AddHook(self, hookName, funcName)
    end
    
    // Don't let other scripts remove our hooks.
    local oldRemove = hook.Remove
    function hook.Remove(name, unique)
        if created[name] == unique then return end
        oldRemove(name, unique)
    end
    
    // Removes all hooks, useful if reloading the script.
    local function RemoveHooks()
        for hookName, unique in pairs(created) do
            oldRemove(hookName, unique)
        end
        for convar, unique in pairs(cvarhooks) do
            local callbacks = GetCallbackTable(convar)
            callbacks[unique] = nil
        end
    end
    
    // Add copies the script can access.
    AA.AddHook = AddHook
    AA.AddCVarHook = AddCVarHook
    AA.CallHook = CallHook
    AA.RemoveHooks = RemoveHooks
end

concommand.Add("aa_reload", function()
    AA:CallHook("Shutdown")
    print("Removing hooks...")
    AA:RemoveHooks()
    
    AA = nil
    local info = debug.getinfo(1, "S")
    if info && info.short_src then
        if string.Left(info.short_src, 3) == "lua" then
            info.short_src = string.sub(info.short_src, 5)
        end
        print("Reloading (" .. info.short_src .. ")...")
        include(info.short_src)
    else
        print("Cannot find AutoAim file, reload manually.")
    end
end)
print("AutoAim loaded.")

// ##################################################
// MetaTables
// ##################################################

local function GetMeta(name)
    return table.Copy(FindMetaTable(name) or {})
end

local AngM = GetMeta("Angle")
local CmdM = GetMeta("CUserCmd")
local EntM = GetMeta("Entity")
local PlyM = GetMeta("Player")
local VecM = GetMeta("Vector")

// ##################################################
// Settings
// ##################################################

do
    local settings = {}
    local function SettingVar(self, name)
        return (self.SettingPrefix or "") .. string.lower(name)
    end
    
    local function RandomName()
        local random = ""
        for i = 1, math.random(4, 10) do
            local c = math.random(65, 116)
            if c >= 91 && c <= 96 then c = c + 6 end
            random = random .. string.char(c)
        end
        return random
    end
    
    local function SetSetting(name, _, new)
        if !settings[name] then return end
        local info = settings[name]
        
        if info.Type == "number" then
            new = tonumber(new)
        elseif info.Type == "boolean" then
            new = (tonumber(new) or 0) > 0
        end
        
        info.Value = new
    end
    
    local function CreateSetting(self, name, desc, default, misc)
        local cvar = SettingVar(self, name)
        local info = {Name = name, Desc = desc, CVar = cvar, Type = type(default), Value = default}
        
        for k, v in pairs(misc or {}) do
            if !info[k] then info[k] = v end
        end
        
        // Convert default from boolean to number.
        if type(default) == "boolean" then
            default = default and 1 or 0
        end
        
        if !settings[cvar] then
            local tab = cvars.GetConVarCallbacks(cvar)
            if !tab then
                cvars.AddChangeCallback(cvar, function() end)
                tab = cvars.GetConVarCallbacks(cvar)
            end
            
            while true do
                local name = RandomName()
                if !tab[name] then
                    tab[name] = SetSetting
                    info.Callback = name
                    break
                end
            end
        end
        
        settings[cvar] = info
        settings[#settings + 1] = info
        
        // Create the convar.
        CreateClientConVar(cvar, default, (info.Save != false), false)
        SetSetting(cvar, _, GetConVarString(cvar))
    end
    local function GetSetting(self, name)
        local cvar = SettingVar(self, name)
        if !settings[cvar] then return end
        return settings[cvar].Value
    end
    local function Shutdown()
        print("Removing settings callbacks...")
        for _, info in ipairs(settings) do
            if info.CVar && info.Callback then
                local tab = cvars.GetConVarCallbacks(info.CVar)
                if tab then
                    tab[info.Callback] = nil
                end
            end
        end
    end
    local function SettingsList()
        return table.Copy(settings)
    end
    local function BuildMenu(self, panel)
        for _, info in ipairs(settings) do
            if info.Show != false then
                if info.MultiChoice then
                    local m = panel:MultiChoice(info.Desc or info.CVar, info.CVar)
                    for k, v in pairs(info.MultiChoice) do
                        m:AddChoice(k, v)
                    end
                elseif info.Type == "number" then
                    panel:NumSlider(info.Desc or info.CVar, info.CVar, info.Min or -1, info.Max or -1, info.Places or 0)
                elseif info.Type == "boolean" then
                    panel:CheckBox(info.Desc or info.CVar, info.CVar)
                elseif info.Type == "string" then
                    panel:TextEntry(info.Desc or info.CVar, info.CVar)
                end
            end
        end
    end
    
    AA.SettingPrefix = "aa_"
    AA.CreateSetting = CreateSetting
    AA.Setting = GetSetting
    AA.SettingsList = SettingsList
    AA.BuildMenu = BuildMenu
    
    AA.SettingsShutdown = Shutdown
    AA:AddHook("Shutdown", "SettingsShutdown")
end


// ##################################################
// Targetting - Positions
// ##################################################

AA.ModelTarget = {}
function AA:SetModelTarget(model, targ)
    self.ModelTarget[model] = targ
end
function AA:BaseTargetPosition(ent)
    // The eye attachment is a lot more stable than bones for players.
    if type(ent) == "Player" then
        local head = EntM["LookupAttachment"](ent, "eyes")
        if head then
            local pos = EntM["GetAttachment"](ent, head)
            if pos then
                return pos.Pos - (AngM["Forward"](pos.Ang) * 2)
            end
        end
    end
    
    // Check if the model has a special target assigned to it.
    local special = self.ModelTarget[string.lower(EntM["GetModel"](ent) or "")]
    if special then
        // It's a string - look for a bone.
        if type(special) == "string" then
            local bone = EntM["LookupBone"](ent, special)
            if bone then
                local pos = EntM["GetBonePosition"](ent, bone)
                if pos then
                    return pos
                end
            end
        // It's a Vector - return a relative position.
        elseif type(special) == "Vector" then
            return EntM["LocalToWorld"](ent, special)
        // It's a function - do something fancy!
        elseif type(special) == "function" then
            local pos = pcall(special, ent)
            if pos then return pos end
        end
    end

    // Try and use the head bone, found on all of the player + human models.
    local bone = "ValveBiped.Bip01_Head1"
    local head = EntM["LookupBone"](ent, bone)
    if head then
        local pos = EntM["GetBonePosition"](ent, head)
        if pos then
            return pos
        end
    end

    // Give up and return the center of the entity.
    return EntM["LocalToWorld"](ent, EntM["OBBCenter"](ent))
end
function AA:TargetPosition(ent)
    local targetPos = self:BaseTargetPosition(ent)
    
    local ply = LocalPlayer()
    if ValidEntity(ply) then
        targetPos = self:CallHook("TargetPrediction", {ply, ent, targetPos}) or targetPos
    end
    
    return targetPos
end

AA:SetModelTarget("models/crow.mdl", Vector(0, 0, 5))                        // Crow.
AA:SetModelTarget("models/pigeon.mdl", Vector(0, 0, 5))                     // Pigeon.
AA:SetModelTarget("models/seagull.mdl", Vector(0, 0, 6))                     // Seagull.
AA:SetModelTarget("models/combine_scanner.mdl", "Scanner.Body")                 // Scanner.
AA:SetModelTarget("models/hunter.mdl", "MiniStrider.body_joint")             // Hunter.
AA:SetModelTarget("models/combine_turrets/floor_turret.mdl", "Barrel")         // Turret.
AA:SetModelTarget("models/dog.mdl", "Dog_Model.Eye")                         // Dog.
AA:SetModelTarget("models/vortigaunt.mdl", "ValveBiped.Head")                 // Vortigaunt.
AA:SetModelTarget("models/antlion.mdl", "Antlion.Body_Bone")                     // Antlion.
AA:SetModelTarget("models/antlion_guard.mdl", "Antlion_Guard.Body")             // Antlion guard.
AA:SetModelTarget("models/antlion_worker.mdl", "Antlion.Head_Bone")             // Antlion worker.
AA:SetModelTarget("models/zombie/fast_torso.mdl", "ValveBiped.HC_BodyCube")     // Fast zombie torso.
AA:SetModelTarget("models/zombie/fast.mdl", "ValveBiped.HC_BodyCube")         // Fast zombie.
AA:SetModelTarget("models/headcrabclassic.mdl", "HeadcrabClassic.SpineControl") // Normal headcrab.
AA:SetModelTarget("models/headcrabblack.mdl", "HCBlack.body")                 // Poison headcrab.
AA:SetModelTarget("models/headcrab.mdl", "HCFast.body")                         // Fast headcrab.
AA:SetModelTarget("models/zombie/poison.mdl", "ValveBiped.Headcrab_Cube1")     // Poison zombie.
AA:SetModelTarget("models/zombie/classic.mdl", "ValveBiped.HC_Body_Bone")     // Zombie.
AA:SetModelTarget("models/zombie/classic_torso.mdl", "ValveBiped.HC_Body_Bone") // Zombie torso.
AA:SetModelTarget("models/zombie/zombie_soldier.mdl", "ValveBiped.HC_Body_Bone") // Zombine.
AA:SetModelTarget("models/combine_strider.mdl", "Combine_Strider.Body_Bone") // Strider.
AA:SetModelTarget("models/combine_dropship.mdl", "D_ship.Spine1")             // Combine dropship.
AA:SetModelTarget("models/combine_helicopter.mdl", "Chopper.Body")             // Combine helicopter.
AA:SetModelTarget("models/gunship.mdl", "Gunship.Body")                        // Combine gunship.
AA:SetModelTarget("models/lamarr.mdl", "HeadcrabClassic.SpineControl")        // Lamarr!
AA:SetModelTarget("models/mortarsynth.mdl", "Root Bone")                        // Mortar synth.
AA:SetModelTarget("models/synth.mdl", "Bip02 Spine1")                        // Synth.
AA:SetModelTarget("models/vortigaunt_slave.mdl", "ValveBiped.Head")            // Vortigaunt slave.


// ##################################################
// Targetting - General
// ##################################################

AA.NPCDeathSequences = {}
function AA:AddNPCDeathSequence(model, sequence)
    self.NPCDeathSequences = self.NPCDeathSequences or {}
    self.NPCDeathSequences[model] = self.NPCDeathSequences[model] or {}
    if !table.HasValue(self.NPCDeathSequences[model]) then
        table.insert(self.NPCDeathSequences[model], sequence)
    end
end

AA:AddNPCDeathSequence("models/barnacle.mdl", 4)
AA:AddNPCDeathSequence("models/barnacle.mdl", 15)
AA:AddNPCDeathSequence("models/antlion_guard.mdl", 44)
AA:AddNPCDeathSequence("models/hunter.mdl", 124)
AA:AddNPCDeathSequence("models/hunter.mdl", 125)
AA:AddNPCDeathSequence("models/hunter.mdl", 126)
AA:AddNPCDeathSequence("models/hunter.mdl", 127)
AA:AddNPCDeathSequence("models/hunter.mdl", 128)

AA:CreateSetting("friendlyfire", "Target teammates", false)
function AA:IsValidTarget(ent)
    // We only want players/NPCs.
    local typename = type(ent)
    if typename != "NPC" && typename != "Player" then return false end

    // No invalid entities.
    if !ValidEntity(ent) then return false end

    // Go shoot yourself, emo kid.
    local ply = LocalPlayer()
    if ent == ply then return false end

    if typename == "Player" then
        if !PlyM["Alive"](ent) then return false end // Dead players FTL.
        if !self:Setting("friendlyfire") && PlyM["Team"](ent) == PlyM["Team"](ply) then return false end
        if EntM["GetMoveType"](ent) == MOVETYPE_OBSERVER then return false end // No spectators.
        if EntM["GetMoveType"](ent) == MOVETYPE_NONE then return false end
        //if pl["Team"](ent) == 1001 then return false end
    end

    if typename == "NPC" then
        if EntM["GetMoveType"](ent) == MOVETYPE_NONE then return false end // No dead NPCs.

        // No dying NPCs.
        local model = string.lower(EntM["GetModel"](ent) or "")
        if table.HasValue(self.NPCDeathSequences[model] or {}, EntM["GetSequence"](ent)) then return false end
    end
end

AA:CreateSetting("predictblocked", "Predict blocked (time)", 0.4, {Min = 0, Max = 1})
function AA:BaseBlocked(target, offset)
    local ply = LocalPlayer()
    if !ValidEntity(ply) then return end
    
    // Trace from the players shootpos to the position.
    local shootPos = PlyM["GetShootPos"](ply)
    local targetPos = self:TargetPosition(target)
    
    if offset then targetPos = targetPos + offset end

    local trace = util.TraceLine({start = shootPos, endpos = targetPos, filter = {ply, target}, mask = MASK_SHOT})
    local wrongAim = self:AngleBetween(PlyM["GetAimVector"](ply), VecM["GetNormal"](targetPos - shootPos)) > 2

    // If we hit something, we're "blocked".
    if trace.Hit && trace.Entity != target then
        return true, wrongAim
    end

    // It is not blocked.
    return false, wrongAim
end
function AA:TargetBlocked(target)
    if !target then target = self:GetTarget() end
    if !target then return end
    
    local blocked, wrongAim = self:BaseBlocked(target)
    if self:Setting("predictblocked") > 0 && blocked then
        blocked = self:BaseBlocked(target, EntM["GetVelocity"](target) * self:Setting("predictblocked"))
    end
    return blocked, wrongAim
end
    

function AA:SetTarget(ent)
    if self.Target && !ent then
        self:CallHook("TargetLost")
    elseif !self.Target && ent then
        self:CallHook("TargetGained")
    elseif self.Target && ent && self.Target != ent then
        self:CallHook("TargetChanged")
    end

    self.Target = ent
end
function AA:GetTarget()
    if ValidEntity(self.Target) != false then
        return self.Target
    else
        return false
    end
end

AA:CreateSetting("maxangle", "Max angle", 30, {Min = 5, Max = 90})
AA:CreateSetting("targetblocked", "Don't check LOS", false)
AA:CreateSetting("holdtarget", "Hold targets", false)
function AA:FindTarget()
    if !self:Enabled() then return end

    local ply = LocalPlayer()
    if !ValidEntity(ply) then return end

    local maxAng = self:Setting("maxangle")
    local aimVec, shootPos = PlyM["GetAimVector"](ply), PlyM["GetShootPos"](ply)
    local targetBlocked = self:Setting("targetblocked")

    if self:Setting("holdtarget") then
        local target = self:GetTarget()
        if target then
            local targetPos = self:TargetPosition(target)
            local angle = self:AngleBetween(AngM["Forward"](self:GetView()), VecM["GetNormal"](targetPos - shootPos))
            local blocked = self:TargetBlocked(target)
            if angle <= maxAng && (!blocked || targetBlocked) then return end
        end
    end

    // Filter out targets.
    local targets = ents.GetAll()
    for i, ent in pairs(targets) do
        if self:IsValidTarget(ent) == false then
            targets[i] = nil
        end
    end

    local closestTarget, lowestAngle = _, maxAng
    for _, target in pairs(targets) do
        if targetBlocked || !self:TargetBlocked(target) then
            local targetPos = self:TargetPosition(target)
            local angle = self:AngleBetween(AngM["Forward"](self:GetView()), VecM["GetNormal"](targetPos - shootPos))

            if angle < lowestAngle then
                lowestAngle = angle
                closestTarget = target
            end
        end
    end

    self:SetTarget(closestTarget)
end
AA:AddHook("Think", "FindTarget")


// ##################################################
// Fake view
// ##################################################

AA.View = Angle(0, 0, 0)
function AA:GetView()
    return self.View * 1
end
function AA:KeepView()
    if !self:Enabled() then return end

    local ply = LocalPlayer()
    if !ValidEntity(ply) then return end

    self.View = EntM["EyeAngles"](ply)
end
AA:AddHook("OnToggled", "KeepView")

local sensitivity = 0.022
function AA:RotateView(cmd)
    self.View.p = math.Clamp(self.View.p + (CmdM["GetMouseY"](cmd) * sensitivity), -89, 89)
    self.View.y = math.NormalizeAngle(self.View.y + (CmdM["GetMouseX"](cmd) * sensitivity * -1))
end

AA:CreateSetting("debug", "Debug", false, {Show = false})
function AA:FakeView(ply, origin, angles, FOV)
    if !self:Enabled() && !self.SetAngleTo then return end
    if GetViewEntity() != LocalPlayer() then return end
    if self:Setting("debug") then return end
    
    local base = GAMEMODE:CalcView(ply, origin, self.SetAngleTo or self.View, FOV) or {}
            base.angles = base.angles or (self.AngleTo or self.View)
            base.angles.r = 0 // No crappy screen tilting in ZS.
    return base
end
AA:AddHook("CalcView", "FakeView")


function AA:TargetPrediction(ply, target, targetPos)
    local weap = PlyM["GetActiveWeapon"](ply)
    if ValidEntity(weap) then
        local class = EntM["GetClass"](weap)
        if class == "weapon_crossbow" then
            local dist = VecM["Length"](targetPos - PlyM["GetShootPos"](ply))
            local time = (dist / 3500) + 0.05 // About crossbow bolt speed.
            targetPos = targetPos + (EntM["GetVelocity"](target) * time)
        end
        
        local mul = 0.0075
        //targetPos = targetPos - (e["GetVelocity"](ply) * mul)
    end
    
    return targetPos
end
AA:AddHook("TargetPrediction", "TargetPrediction")

// ##################################################
// Aim
// ##################################################

function AA:SetAngle(ang)
    self.SetAngleTo = ang
end

AA:CreateSetting("smoothspeed", "Smooth aim speed (0 to disable)", 120, {Min = 0, Max = 360})
AA:CreateSetting("snaponfire", "Snap on fire", true)
AA:CreateSetting("snapgrace", "Snap on fire grace", 0.5, {Min = 0, Max = 3, Places = 1})
AA.LastAttack = 0
function AA:SetAimAngles(cmd)
    self:RotateView(cmd)

    if !self:Enabled() && !self.SetAngleTo then return end

    local ply = LocalPlayer()
    if !ValidEntity(ply) then return end

    // We're aiming with the view, normally.
    local targetAim = self:GetView()

    // If we have a target, aim at them!
    local target = self:GetTarget()
    if target then
        local targetPos = self:TargetPosition(target)
        targetAim = VecM["Angle"](targetPos - ply:GetShootPos())
    end

    // We're following the view, until we fire.
    if self:Setting("snaponfire") then
        local time = CurTime()
        if PlyM["KeyDown"](ply, IN_ATTACK) || PlyM["KeyDown"](ply, IN_ATTACK2) || self:Setting("autoshoot") != 0 then
            self.LastAttack = time
        end
        if CurTime() - self.LastAttack > self:Setting("snapgrace") then
            targetAim = self:GetView()
        end
    end

    // We want to change to whatever was SetAngle'd.
    if self.SetAngleTo then
        targetAim = self.SetAngleTo
    end

    // Smooth aiming.
    local smooth = self:Setting("smoothspeed")
    if smooth > 0 then
        local current = CmdM["GetViewAngles"](cmd)

        // Approach the target angle.
        current = self:ApproachAngle(current, targetAim, smooth * FrameTime())
        current.r = 0

        // If we're just following the view, we don't need to smooth it.
        if self.RevertingAim then
            local diff = self:NormalizeAngle(current - self:GetView())
            if math.abs(diff.p) < 1 && math.abs(diff.y) < 1 then self.RevertingAim = false end
        elseif targetAim == self:GetView() then
            current = targetAim
        end

        // Check if the angles are the same...
        if self.SetAngleTo then
            local diff = self:NormalizeAngle(current - self.SetAngleTo)
            if math.abs(diff.p) < 1 && math.abs(diff.y) < 1 then self.SetAngleTo = nil end
        end

        aim = current
    else
        aim = targetAim
        self.SetAngleTo = nil
    end

    // Set the angles.
    CmdM["SetViewAngles"](cmd, aim)
    local sensitivity = 0.22
    local diff = aim - CmdM["GetViewAngles"](cmd)
    CmdM["SetMouseX"](cmd, diff.y / sensitivity)
    CmdM["SetMouseY"](cmd, diff.p / sensitivity)
    

    // Change the players movement to be relative to their view instead of their aim.
    local move = Vector(CmdM["GetForwardMove"](cmd), CmdM["GetSideMove"](cmd), 0)
    local norm = VecM["GetNormal"](move)
    local set = AngM["Forward"](VecM["Angle"](norm) + (aim - self:GetView())) * VecM["Length"](move)
        CmdM["SetForwardMove"](cmd, set.x)
        CmdM["SetSideMove"](cmd, set.y)
end
AA:AddHook("CreateMove", "SetAimAngles")

function AA:RevertAim()
    self.RevertingAim = true
end
AA:AddHook("TargetLost", "RevertAim")
function AA:StopRevertAim()
    self.RevertingAim = false
end
AA:AddHook("TargetGained", "RevertAim")

// When we turn off the bot, we want our aim to go back to our view.
function AA:ViewToAim()
    if self:Enabled() then return end
    self:SetAngle(self:GetView())
end
AA:AddHook("OnToggled", "ViewToAim")


// ##################################################
// HUD
// ##################################################

AA:CreateSetting("crosshair", "Crosshair size (0 to disable)", 18, {Min = 0, Max = 20})
function AA:DrawTarget()
    if !self:Enabled() then return end

    local target = self:GetTarget()
    if !target then return end

    local size = self:Setting("crosshair")
    if size <= 0 then return end

    // Change colour on the block status.
    local blocked, aimOff = self:TargetBlocked()
    if blocked then
        surface.SetDrawColor(255, 0, 0, 255) // Red.
    elseif aimOff then
        surface.SetDrawColor(255, 255, 0, 255) // Yellow.
    else
        surface.SetDrawColor(0, 255, 0, 255) // Green.
    end

    // Get the onscreen coordinates for the target.
    local pos = self:TargetPosition(target)

    local screen = VecM["ToScreen"](pos)
    local x, y = screen.x, screen.y

    // Work out sizes.
    local a, b = size / 2, size / 6

    // Top left.
    surface.DrawLine(x - a, y - a, x - b, y - a)
    surface.DrawLine(x - a, y - a, x - a, y - b)

    // Bottom right.
    surface.DrawLine(x + a, y + a, x + b, y + a)
    surface.DrawLine(x + a, y + a, x + a, y + b)

    // Top right.
    surface.DrawLine(x + a, y - a, x + b, y - a)
    surface.DrawLine(x + a, y - a, x + a, y - b)

    // Bottom left.
    surface.DrawLine(x - a, y + a, x - b, y + a)
    surface.DrawLine(x - a, y + a, x - a, y + b)
end
AA:AddHook("HUDPaint", "DrawTarget")


AA.ScreenMaxAngle = {
    Length = 0,
    FOV = 0,
    MaxAngle = 0
}
AA:CreateSetting("draw_maxangle", "Draw Max Angle", true)
function AA:DrawMaxAngle()
    if !self:Enabled() then return end

    // Check that we want to be drawing this...
    local show = AA:Setting("draw_maxangle")
    if !show then return end

    // We need a player for this to work...
    local ply = LocalPlayer()
    if !ValidEntity(ply) then return end

    local info = self.ScreenMaxAngle
    local maxang = AA:Setting("maxangle")
    
    local fov = PlyM["GetFOV"](ply)
    if GetViewEntity() == ply && (maxang != info.MaxAngle || fov != info.FOV) then
        local view = self:GetView()
            view.p = view.p + maxang

        local screen = (PlyM["GetShootPos"](ply) + (AngM["Forward"](view) * 100))
        screen = VecM["ToScreen"](screen)

        info.Length = math.abs((ScrH() / 2) - screen.y)

        info.MaxAngle = maxang
        info.FOV = fov
    end

    local length = info.Length

    local cx, cy = ScrW() / 2, ScrH() / 2
    for x = -1, 1 do
        for y = -1, 1 do
            if x != 0 || y != 0 then
                local add = VecM["GetNormal"](Vector(x, y, 0)) * length
                surface.SetDrawColor(0, 0, 0, 255)
                surface.DrawRect((cx + add.x) - 2, (cy + add.y) - 2, 5, 5)
                surface.SetDrawColor(255, 255, 255, 255)
                surface.DrawRect((cx + add.x) - 1, (cy + add.y) - 1, 3, 3)
            end
        end
    end

end
AA:AddHook("HUDPaint", "DrawMaxAngle")

// ##################################################
// Auto-shoot
// ##################################################

AA.AttackDown = false
function AA:SetShooting(bool)
    if self.AttackDown == bool then return end
    self.AttackDown = bool

    local pre = {[true] = "+", [false] = "-"}
    RunConsoleCommand(pre[bool] .. "attack")
end

AA.NextShot = 0
AA:CreateSetting("autoshoot", "Max auto-shoot distance (0 to disable)", 0, {Min = 0, Max = 16384})
function AA:Shoot()
    if !self:Enabled() then
        self:SetShooting(false)
        return
    end

    // Get the maximum distance.
    local maxDist = self:Setting("autoshoot")
    if maxDist == 0 then return end

    // Check we've got something to shoot at...
    local target = self:GetTarget()
    if !target then return end
    
    // Don't shoot until we can hit, you idiot!
    local blocked, wrongAim = self:TargetBlocked(target)
    if blocked || wrongAim then return end

    // We're gonna need the player object in a second.
    local ply = LocalPlayer()
    if !ValidEntity(ply) then return end
    
    // Check we're within our maximum distance.
    local targetPos = self:TargetPosition(target)
    local distance = VecM["Length"](targetPos - ply:GetShootPos())
    if distance > maxDist && maxDist != -1 then return end

    // Check if it's time to shoot yet.
    if CurTime() < self.NextShot then return end

    // Check we got our weapon.
    local weap = PlyM["GetActiveWeapon"](ply)
    if !ValidEntity(weap) then return end

    // Shoot!
    self:SetShooting(true)
    // If we're semi-auto, we want to stop holding down fire.
    if self:IsSemiAuto(weap) then
        timer.Simple(0.05, function() self:SetShooting(false) end)
    end

    // Set the next time to shoot.
    self.NextShot = CurTime() + 0.1
end
AA:AddHook("Think", "Shoot")

// When we lose our target we stop shooting.
function AA:StopShooting()
    self:SetShooting(false)
end
AA:AddHook("TargetLost", "StopShooting")

// ##################################################
// Toggle
// ##################################################

AA.IsEnabled = false
function AA:Enabled() return self.IsEnabled end

function AA:SetEnabled(bool)
    if self.IsEnabled == bool then return end
    self.IsEnabled = bool

    local message = {[true] = "ON", [false] = "OFF"}
    print("AutoAim " .. message[self.IsEnabled])

    local e = {[true] = "1", [false] = "0"}
    RunConsoleCommand("aa_enabled", e[self.IsEnabled])

    self:CallHook("OnToggled")
end

function AA:Toggle()
    self:SetEnabled(!self:Enabled())
end
concommand.Add("aa_toggle", function() AA:Toggle() end)

AA:CreateSetting("enabled", "Enabled", false, {Save = false})
function AA:ConVarEnabled(_, old, val)
    if old == val then return end
    val = tonumber(val) or 0
    self:SetEnabled(val > 0)
end
AA:AddCVarHook("aa_enabled", "ConVarEnabled")

concommand.Add("+aa", function() AA:SetEnabled(true) end)
concommand.Add("-aa", function() AA:SetEnabled(false) end)

// ##################################################
// Menu
// ##################################################

function AA:OpenMenu()
    local w, h = ScrW() / 3, ScrH() / 2

    local menu = vgui.Create("DFrame")
    menu:SetTitle("KasHack v1.0")
    menu:SetSize(w, h)
    menu:Center()
    menu:MakePopup()

    local scroll = vgui.Create("DPanelList", menu)
    scroll:SetPos(5, 25)
    scroll:SetSize(w - 10, h - 30)
    scroll:EnableVerticalScrollbar()

    local form = vgui.Create("DForm", menu)
    form:SetName("")
    form.Paint = function() end
    scroll:AddItem(form)

    self:BuildMenu(form)

    if AA.Menu then AA.Menu:Remove() end
    AA.Menu = menu
end
concommand.Add("aa_menu", function() AA:OpenMenu() end)

function AA:RegisterMenu()
    spawnmenu.AddToolMenuOption("Options", "Hacks", "AutoAim", "AutoAim", "", "", function(p) self:BuildMenu(p) end)
end
AA:AddHook("PopulateToolMenu", "RegisterMenu")

// ##################################################
// Useful functions
// ##################################################

function AA:AngleBetween(a, b)
    return math.deg(math.acos(VecM["Dot"](a, b)))
end

function AA:NormalizeAngle(ang)
    return Angle(math.NormalizeAngle(ang.p), math.NormalizeAngle(ang.y), math.NormalizeAngle(ang.r))
end

function AA:ApproachAngle(start, target, add)
    local diff = self:NormalizeAngle(target - start)

    local vec = Vector(diff.p, diff.y, diff.r)
    local len = VecM["Length"](vec)
    vec = VecM["GetNormal"](vec) * math.min(add, len)

    return start + Angle(vec.x, vec.y, vec.z)
end

local notAuto = {"weapon_pistol", "weapon_rpg", "weapon_357", "weapon_crossbow"}
function AA:IsSemiAuto(weap)
    if !ValidEntity(weap) then return end
    return (weap.Primary && !weap.Primary.Automatic) || table.HasValue(notAuto, EntM["GetClass"](weap))
end