AddCSLuaFile()

ENT.Type = "ai"
ENT.Base = "base_ai"
ENT.AutomaticFrameAdvance = true 

local debug_show_ragdoll_targets        = CreateConVar("zcnpci_debug_show_ragdoll_targets", 0, bit.bor(FCVAR_ARCHIVE, FCVAR_REPLICATED))

local should_follow_head                = CreateConVar("zcnpci_target_should_follow_head", 0, bit.bor(FCVAR_ARCHIVE, FCVAR_REPLICATED))
local stop_targeting_when_unconscious   = CreateConVar("zcnpci_no_unconscious_targeting", 1, bit.bor(FCVAR_ARCHIVE, FCVAR_REPLICATED))

local vector_offset_to_shoot_at     = Vector(0, 0, 8)

local function UpdateRelationship(ent, me)
    if !IsValid(ent) or !ent:IsNPC() then return end

    if ent:Disposition(me.dummy_entity) == D_HT then
        ent:AddEntityRelationship(me, D_HT, -1)
    end
end

local function RemoveRelationship(ent, me)
    if !IsValid(ent) or !ent:IsNPC() then return end

    if ent:Disposition(me.dummy_entity) == D_HT then
        ent:AddEntityRelationship(me, D_NU, -1)
        ent:ClearEnemyMemory(me)

        if ent:GetEnemy() == me then
            ent:SetEnemy(nil)
            ent:ClearSchedule()
        end
    end
end

function ENT:Classify()
    return self.dummy_entity:Classify()
end

function ENT:Initialize()
    if SERVER then
        self:SetModel("models/maxofs2d/hover_basic.mdl")
        self:SetCollisionGroup(COLLISION_GROUP_NONE)
        self:SetHullType(HULL_TINY_CENTERED)
        self:SetNoDraw(!debug_show_ragdoll_targets:GetBool())
        
        self.dummy_entity = ents.Create(self.ragdoll_to_follow.class_in_previous_life)
        self.last_stop_targeting = nil

        -- Have to use this collision group otherwise ragdoll will obstruct visibility of target
        self.ragdoll_to_follow:SetCollisionGroup(COLLISION_GROUP_DEBRIS)

        hook.Add("OnEntityCreated", "zcnpci-"..self:GetCreationID(), function(new_entity)
            if !IsValid(new_entity) or !new_entity:IsNPC() then return end

            if !self.last_stop_targeting then
                UpdateRelationship(new_entity, self)
            end
        end)
    end
end

function ENT:Think()
    if SERVER then
        local ragdoll = self.ragdoll_to_follow
        if !IsValid(ragdoll) then return end

        if should_follow_head:GetBool() then
            local head = ragdoll:GetPhysicsObjectNum(ragdoll:TranslateBoneToPhysBone(ragdoll:LookupBone("ValveBiped.Bip01_Head1")))
            self:SetPos(head:GetPos() + vector_offset_to_shoot_at)
        else
            self:SetPos(ragdoll:GetPos())
        end

        self:SetNoDraw(!debug_show_ragdoll_targets:GetBool())

        if !ragdoll.organism then return true end

        local should_stop_targeting = !zcnpci_no_unconscious_targeting:GetBool() or (
            (ragdoll.organism.consciousness <= 0.4) or 
            (ragdoll.organism.critical)
        )

        if true or (should_stop_targeting != self.last_stop_targeting) then
            self.last_stop_targeting = should_stop_targeting

            if should_stop_targeting then 
                self:SetColor(Color(255, 0, 0))
                for i,ent in ipairs(ents.GetAll()) do
                    RemoveRelationship(ent, self)
                end
            else 
                self:SetColor(Color(0, 255, 0))
                for i,ent in ipairs(ents.GetAll()) do
                    UpdateRelationship(ent, self)
                end
            end
        end
        

        self:NextThink(CurTime())
    end

    return true
end

function ENT:OnRemove()
    if SERVER then
        for i,ent in ipairs(ents.GetAll()) do
            RemoveRelationship(ent, self)
        end

        self.dummy_entity:Remove()

        hook.Remove("OnEntityCreated", "zcnpci-"..self:GetCreationID())
    end
end