local _, Cell = ...
local L = Cell.L
local F = Cell.funcs
local B = Cell.bFuncs
local A = Cell.animations
local P = Cell.pixelPerfectFuncs

local npcFrame = CreateFrame("Frame", "CellNPCFrame", Cell.frames.mainFrame, "SecureHandlerStateTemplate")
Cell.frames.npcFrame = npcFrame
-- Cell:StylizeFrame(npcFrame, {1, 0.5, 0.5})

local anchors = {
    ["solo"] = CellSoloFramePlayer,
    ["party"] = CellPartyFrameHeaderUnitButton1Pet,
    ["raid"] = CellNPCFrameAnchor,
}

for k, v in pairs(anchors) do
    npcFrame:SetFrameRef(k, v)
end

-------------------------------------------------
-- separateAnchor
-------------------------------------------------
local tooltipPoint, tooltipRelativePoint, tooltipX, tooltipY

local separateAnchor = CreateFrame("Frame", "CellSeparateNPCFrameAnchor", Cell.frames.mainFrame, "BackdropTemplate")
Cell.frames.separateNpcFrameAnchor = separateAnchor
separateAnchor:SetMovable(true)
separateAnchor:SetClampedToScreen(true)
P:Size(separateAnchor, 20, 10)
PixelUtil.SetPoint(separateAnchor, "TOPLEFT", UIParent, "CENTER", 1, -1)
-- Cell:StylizeFrame(separateAnchor, {0, 1, 0, 0.4})

local hoverFrame = CreateFrame("Frame", nil, npcFrame)
hoverFrame:SetPoint("TOP", separateAnchor, 0, 1)
hoverFrame:SetPoint("BOTTOM", separateAnchor, 0, -1)
hoverFrame:SetPoint("LEFT", separateAnchor, -1, 0)
hoverFrame:SetPoint("RIGHT", separateAnchor, 1, 0)

A:ApplyFadeInOutToMenu(separateAnchor, hoverFrame)

local dumb = Cell:CreateButton(separateAnchor, nil, "accent", {20, 10}, false, true)
dumb:Hide()
dumb:SetFrameStrata("MEDIUM")
dumb:SetAllPoints(separateAnchor)
dumb:SetScript("OnDragStart", function()
    separateAnchor:StartMoving()
    separateAnchor:SetUserPlaced(false)
end)
dumb:SetScript("OnDragStop", function()
    separateAnchor:StopMovingOrSizing()
    P:SavePosition(separateAnchor, Cell.vars.currentLayoutTable["npc"]["position"])
end)
dumb:HookScript("OnEnter", function()
    hoverFrame:GetScript("OnEnter")(hoverFrame)
    CellTooltip:SetOwner(dumb, "ANCHOR_NONE")
    CellTooltip:SetPoint(tooltipPoint, dumb, tooltipRelativePoint, tooltipX, tooltipY)
    CellTooltip:AddLine(L["Friendly NPC Frame"])
    CellTooltip:Show()
end)
dumb:HookScript("OnLeave", function()
    hoverFrame:GetScript("OnLeave")(hoverFrame)
    CellTooltip:Hide()
end)

function npcFrame:UpdateSeparateAnchor()
    local show
    if Cell.vars.currentLayoutTable["npc"]["separate"] then
        for _, b in ipairs(Cell.unitButtons.npc) do
            show = b:IsShown()
            if show then break end
        end
    end
    
    hoverFrame:EnableMouse(show)
    if show then
        dumb:Show()
        if CellDB["general"]["fadeOut"] then
            if hoverFrame:IsMouseOver() then
                separateAnchor.fadeIn:Play()
            else
                separateAnchor.fadeOut:GetScript("OnFinished")(separateAnchor.fadeOut)
            end
        end
    else
        dumb:Hide()
    end
end

-------------------------------------------------
-- NOTE: update each npc unit button
-------------------------------------------------
local pointUpdater = [[
    local orientation, point, anchorPoint, unitSpacing = ...
    -- print(orientation, point, anchorPoint, unitSpacing)
    local last
    for i = 1, 8 do
        local button = self:GetFrameRef("button"..i)
        button:ClearAllPoints()
        if button:IsVisible() then
            if last then
                -- NOTE: anchor to last
                if orientation == "vertical" then
                    button:SetPoint(point, last, anchorPoint, 0, unitSpacing)
                else
                    button:SetPoint(point, last, anchorPoint, unitSpacing, 0)
                end
            else
                button:SetPoint("TOPLEFT", self)
            end
            last = button
        end
    end

    self:CallMethod("UpdateSeparateAnchor")
]]
npcFrame:SetAttribute("pointUpdater", pointUpdater)

-------------------------------------------------
-- create buttons
-------------------------------------------------
for i = 1, 8 do
    local button = CreateFrame("Button", npcFrame:GetName().."Button"..i, npcFrame, "CellUnitButtonTemplate")
    tinsert(Cell.unitButtons.npc, button)
    Cell.unitButtons.npc.units["boss"..i] = button
    -- button.type = "npc" -- layout setup

    button:SetAttribute("unit", "boss"..i)
    -- button:SetAttribute("unit", "player")
    -- for testing ------------------------------
    -- if i == 1 then
    --     button:SetAttribute("unit", "target")
    --     RegisterUnitWatch(button)
    -- end
    -- if i == 7 then
    --     button:SetAttribute("unit", "player")
    --     RegisterUnitWatch(button)
    -- elseif i == 2 then
    --     button:SetAttribute("unit", "target")
    --     RegisterAttributeDriver(button, "state-visibility", "[@target, exists] show; hide")
    -- elseif i == 4 then
    --     button:SetAttribute("unit", "target")
    --     RegisterAttributeDriver(button, "state-visibility", "[@target, help] show; hide")
    -- elseif i == 6 then
    --     button:SetAttribute("unit", "target")
    --     RegisterAttributeDriver(button, "state-visibility", "[@target, harm] show; hide")
    -- end

    -- if i >= 6 then
    --     UnregisterAttributeDriver(button, "state-visibility")
    --     button:SetAttribute("unit", "target")
    --     RegisterUnitWatch(button)

    --     local bar = Cell:CreateStatusBar(nil, button, 10, 5, 1, false, nil, nil, "Interface\\Buttons\\WHITE8x8", {1, 1, 1, 1})
    --     bar:SetFrameLevel(button.widget.healthBar:GetFrameLevel() + 1)
    --     bar.border:Hide()

    --     bar:SetPoint("BOTTOMLEFT", button.widget.healthBar)
    --     bar:SetPoint("BOTTOMRIGHT", button.widget.healthBar)
    --     bar:SetScript("OnUpdate", function()
    --         local health = UnitHealth("boss"..i)
    --         local healthMax = UnitHealthMax("boss"..i)
    --         bar:SetValue(health / healthMax)
    --     end)
    -- end
    ---------------------------------------------

    -- NOTE: save reference for re-point
    npcFrame:SetFrameRef("button"..i, button)

    -- NOTE: update each npc unitbutton's point on show/hide
    button.helper = CreateFrame("Frame", nil, button, "SecureHandlerShowHideTemplate")
    button.helper:SetFrameRef("npcFrame", npcFrame)
    button.helper:SetAttribute("pointUpdater", [[
        local orientation = self:GetAttribute("orientation")
        local point = self:GetAttribute("point")
        local anchorPoint = self:GetAttribute("anchorPoint")
        local unitSpacing = self:GetAttribute("unitSpacing")
        
        local npcFrame = self:GetFrameRef("npcFrame")
        self:RunFor(npcFrame, npcFrame:GetAttribute("pointUpdater"), orientation, point, anchorPoint, unitSpacing)
    ]])
    button.helper:SetAttribute("_onshow", [[ self:RunAttribute("pointUpdater") ]])
    button.helper:SetAttribute("_onhide", [[ self:RunAttribute("pointUpdater") ]])
end

-------------------------------------------------
-- FIXME: fix health updating boss678
-- ! BLIZZARD, FIX IT! 
-------------------------------------------------
local boss678_guidToButton = {}
local boss678_buttonToGuid = {}

local cleu = CreateFrame("Frame")
cleu:SetScript("OnEvent", function()
    local timestamp, subEvent, _, sourceGUID, sourceName, sourceFlags, sourceRaidFlags, destGUID, destName, destFlags, destRaidFlags = CombatLogGetCurrentEventInfo()
    if boss678_guidToButton[destGUID] then
        if subEvent == "SPELL_HEAL" or subEvent == "SPELL_PERIODIC_HEAL" or subEvent == "SPELL_DAMAGE" or subEvent == "SPELL_PERIODIC_DAMAGE" then
            -- print("UpdateHealth:", boss678_guidToButton[destGUID]:GetName())
            B.UpdateHealth(boss678_guidToButton[destGUID])
        elseif subEvent == "SPELL_AURA_REFRESH" or subEvent == "SPELL_AURA_APPLIED" or subEvent == "SPELL_AURA_REMOVED" or subEvent == "SPELL_AURA_APPLIED_DOSE" or subEvent == "SPELL_AURA_REMOVED_DOSE" then
            B.UpdateAuras(boss678_guidToButton[destGUID])
        end
    end
end)

for i = 6, 8 do
    local button = Cell.unitButtons.npc[i]
    button.helper:HookScript("OnShow", function()
        local guid = UnitGUID(button.state.unit)
        if not guid then return end

        boss678_buttonToGuid[i] = guid
        boss678_guidToButton[guid] = button
        
        -- update now
        B.UpdateAll(button)
    end)
    
    button.helper:HookScript("OnHide", function()
        boss678_guidToButton[boss678_buttonToGuid[i] or ""] = nil
        boss678_buttonToGuid[i] = nil

        button.helper.elapsed = nil
        button.helper.elapsed2 = nil
        button.helper.elapsed3 = nil

        if F:Getn(boss678_buttonToGuid) == 0 then
            cleu:UnregisterEvent("COMBAT_LOG_EVENT_UNFILTERED")
        end
    end)

    button.helper:HookScript("OnUpdate", function(self, elapsed)
        button.helper.elapsed = (button.helper.elapsed or 0) + elapsed
        button.helper.elapsed2 = (button.helper.elapsed2 or 0) + elapsed
        button.helper.elapsed3 = (button.helper.elapsed3 or 0) + elapsed

        if button.helper.elapsed >= 0.25 then
            local guid = UnitGUID(button.state.unit)
            -- check old guid
            if guid and boss678_buttonToGuid[i] ~= guid then --! unit changed
                -- remove old
                boss678_guidToButton[boss678_buttonToGuid[i] or ""] = nil
                -- add new
                boss678_buttonToGuid[i] = guid
                boss678_guidToButton[guid] = button
                -- update now
                B.UpdateAll(button)
            end
            button.helper.elapsed = 0
        end

        if button.helper.elapsed2 >= 1 then
            if not cleu:IsEventRegistered("COMBAT_LOG_EVENT_UNFILTERED") then
                cleu:RegisterEvent("COMBAT_LOG_EVENT_UNFILTERED")
            end
            button.helper.elapsed2 = 0
        end

        if button.helper.elapsed3 >= 5 then
            B.UpdateHealth(button)
            B.UpdateHealthMax(button)
            button.helper.elapsed3 = 0
        end
    end)
end

-------------------------------------------------
-- update point when group type changed
-------------------------------------------------
npcFrame:SetAttribute("_onstate-groupstate", [[
    -- print("groupstate", newstate)
    self:SetAttribute("group", newstate)
    
    local petstate = self:GetAttribute("pet")
    local anchor = self:GetFrameRef(newstate)
    local orientation = self:GetAttribute("orientation")
    local point = self:GetAttribute("point")
    local anchorPoint = self:GetAttribute("anchorPoint")
    local groupAnchorPoint = self:GetAttribute("groupAnchorPoint")
    local unitSpacing = self:GetAttribute("unitSpacing")
    local groupSpacing = self:GetAttribute("groupSpacing")

    self:ClearAllPoints()

    if orientation == "vertical" then
        if newstate == "raid" then
            self:SetPoint(point, anchor)
    
        elseif newstate == "party" then
            -- NOTE: at first time petstate == nil 
            if petstate == "nopet" then
                self:SetPoint(point, self:GetFrameRef("solo"), groupAnchorPoint, groupSpacing, 0)
            else
                self:SetPoint(point, self:GetFrameRef("party"), groupAnchorPoint, groupSpacing, 0)
            end
    
        else -- solo
            self:SetPoint(point, anchor, groupAnchorPoint, groupSpacing, 0)
        end
    else
        if newstate == "raid" then
            self:SetPoint(point, anchor)
    
        elseif newstate == "party" then
            -- NOTE: at first time petstate == nil 
            if petstate == "nopet" then
                self:SetPoint(point, self:GetFrameRef("solo"), groupAnchorPoint, 0, groupSpacing)
            else
                self:SetPoint(point, self:GetFrameRef("party"), groupAnchorPoint, 0, groupSpacing)
            end
    
        else -- solo
            self:SetPoint(point, anchor, groupAnchorPoint, 0, groupSpacing)
        end
    end

    -- NOTE: update each npc button
    self:RunAttribute("pointUpdater", orientation, point, anchorPoint, unitSpacing)
]])

-------------------------------------------------
-- update point when pet state changed
-------------------------------------------------
npcFrame:SetAttribute("_onstate-petstate", [[
    -- print("petstate", newstate)
    self:SetAttribute("pet", newstate)

    if self:GetAttribute("group") == "party" then
        local orientation = self:GetAttribute("orientation")
        local point = self:GetAttribute("point")
        local anchorPoint = self:GetAttribute("anchorPoint")
        local groupAnchorPoint = self:GetAttribute("groupAnchorPoint")
        local unitSpacing = self:GetAttribute("unitSpacing")
        local groupSpacing = self:GetAttribute("groupSpacing")

        self:ClearAllPoints()

        if orientation == "vertical" then
            if newstate == "nopet" then
                self:SetPoint(point, self:GetFrameRef("solo"), groupAnchorPoint, groupSpacing, 0)
            else
                self:SetPoint(point, self:GetFrameRef("party"), groupAnchorPoint, groupSpacing, 0)
            end
        else
            if newstate == "nopet" then
                self:SetPoint(point, self:GetFrameRef("solo"), groupAnchorPoint, 0, groupSpacing)
            else
                self:SetPoint(point, self:GetFrameRef("party"), groupAnchorPoint, 0, groupSpacing)
            end
        end
    end
]])
-- RegisterStateDriver(npcFrame, "petstate", "[@pet,exists] pet; [@partypet1,exists] pet1; [@partypet2,exists] pet2; [@partypet3,exists] pet3; [@partypet4,exists] pet4; nopet")

-------------------------------------------------
-- functions
-------------------------------------------------
local function UpdatePosition()
    local layout = Cell.vars.currentLayoutTable
    
    -- update npcFrame anchor if separate from main
    if layout["npc"]["separate"] then
        npcFrame:ClearAllPoints()
        P:LoadPosition(separateAnchor, layout["npc"]["position"])

        local anchor
        if layout["pet"]["sameArrangementAsMain"] then
            anchor = layout["main"]["anchor"]
        else
            anchor = layout["npc"]["anchor"]
        end

        if CellDB["general"]["menuPosition"] == "top_bottom" then
            P:Size(separateAnchor, 20, 10)
            if anchor == "BOTTOMLEFT" then
                npcFrame:SetPoint("BOTTOMLEFT", separateAnchor, "TOPLEFT", 0, 4)
                tooltipPoint, tooltipRelativePoint, tooltipX, tooltipY = "TOPLEFT", "BOTTOMLEFT", 0, -3
            elseif anchor == "BOTTOMRIGHT" then
                npcFrame:SetPoint("BOTTOMRIGHT", separateAnchor, "TOPRIGHT", 0, 4)
                tooltipPoint, tooltipRelativePoint, tooltipX, tooltipY = "TOPRIGHT", "BOTTOMRIGHT", 0, -3
            elseif anchor == "TOPLEFT" then
                npcFrame:SetPoint("TOPLEFT", separateAnchor, "BOTTOMLEFT", 0, -4)
                tooltipPoint, tooltipRelativePoint, tooltipX, tooltipY = "BOTTOMLEFT", "TOPLEFT", 0, 3
            elseif anchor == "TOPRIGHT" then
                npcFrame:SetPoint("TOPRIGHT", separateAnchor, "BOTTOMRIGHT", 0, -4)
                tooltipPoint, tooltipRelativePoint, tooltipX, tooltipY = "BOTTOMRIGHT", "TOPRIGHT", 0, 3
            end
        else
            P:Size(separateAnchor, 10, 20)
            if anchor == "BOTTOMLEFT" then
                npcFrame:SetPoint("BOTTOMLEFT", separateAnchor, "BOTTOMRIGHT", 4, 0)
                tooltipPoint, tooltipRelativePoint, tooltipX, tooltipY = "BOTTOMRIGHT", "BOTTOMLEFT", -3, 0
            elseif anchor == "BOTTOMRIGHT" then
                npcFrame:SetPoint("BOTTOMRIGHT", separateAnchor, "BOTTOMLEFT", -4, 0)
                tooltipPoint, tooltipRelativePoint, tooltipX, tooltipY = "BOTTOMLEFT", "BOTTOMRIGHT", 3, 0
            elseif anchor == "TOPLEFT" then
                npcFrame:SetPoint("TOPLEFT", separateAnchor, "TOPRIGHT", 4, 0)
                tooltipPoint, tooltipRelativePoint, tooltipX, tooltipY = "TOPRIGHT", "TOPLEFT", -3, 0
            elseif anchor == "TOPRIGHT" then
                npcFrame:SetPoint("TOPRIGHT", separateAnchor, "TOPLEFT", -4, 0)
                tooltipPoint, tooltipRelativePoint, tooltipX, tooltipY = "TOPLEFT", "TOPRIGHT", 3, 0
            end
        end
    end

    npcFrame:UpdateSeparateAnchor()
end

local function UpdateMenu(which)
    if not which or which == "lock" then
        if CellDB["general"]["locked"] then
            dumb:RegisterForDrag()
        else
            dumb:RegisterForDrag("LeftButton")
        end
    end

    if not which or which == "fadeOut" then
        if CellDB["general"]["fadeOut"] then
            separateAnchor.fadeOut:Play()
        else
            separateAnchor.fadeIn:Play()
        end
    end

    if which == "position" then
        UpdatePosition()
    end
end
Cell:RegisterCallback("UpdateMenu", "NPCFrame_UpdateMenu", UpdateMenu)

local previousLayout
local function NPCFrame_UpdateLayout(layout, which)
    -- if previousLayout == layout and not which then return end
    -- previousLayout = layout

    layout = Cell.vars.currentLayoutTable

    if not which or strfind(which, "size$") then
        local width, height
        if layout["npc"]["sameSizeAsMain"] then
            width, height = unpack(layout["main"]["size"])
        else
            width, height = unpack(layout["npc"]["size"])
        end

        P:Size(npcFrame, width, height)

        for _, b in ipairs(Cell.unitButtons.npc) do
            P:Size(b, width, height)
        end
    end

    -- NOTE: SetOrientation BEFORE SetPowerSize
    if not which or which == "barOrientation" then
        for _, b in ipairs(Cell.unitButtons.npc) do
            B:SetOrientation(b, layout["barOrientation"][1], layout["barOrientation"][2])
        end
    end
    
    if not which or strfind(which, "power$") or which == "barOrientation" or which == "powerFilter" then
        for _, b in ipairs(Cell.unitButtons.npc) do
            if layout["npc"]["sameSizeAsMain"] then
                B:SetPowerSize(b, layout["main"]["powerSize"])
            else
                B:SetPowerSize(b, layout["npc"]["powerSize"])
            end
        end
    end

    if not which or which == "pet" then
        if layout["pet"]["partyEnabled"] then
            npcFrame:SetFrameRef("party", CellPartyFrameHeaderUnitButton1Pet)
            anchors["party"] = CellPartyFrameHeaderUnitButton1Pet
        else
            npcFrame:SetFrameRef("party", CellPartyFrameHeaderUnitButton1)
            anchors["party"] = CellPartyFrameHeaderUnitButton1
        end
    end

    if not which or strfind(which, "arrangement$") or which == "npc" or which == "pet" then
        local groupType = F:GetGroupType()
        npcFrame:ClearAllPoints()

        local orientation, anchor, spacingX, spacingY
        if layout["npc"]["sameArrangementAsMain"] then
            orientation = layout["main"]["orientation"]
            anchor = layout["main"]["anchor"]
            spacingX = layout["main"]["spacingX"]
            spacingY = layout["main"]["spacingY"]
        else
            orientation = layout["npc"]["orientation"]
            anchor = layout["npc"]["anchor"]
            spacingX = layout["npc"]["spacingX"]
            spacingY = layout["npc"]["spacingY"]
        end

        local point, anchorPoint, groupAnchorPoint, unitSpacing, groupSpacing
        if orientation == "vertical" then
            if anchor == "BOTTOMLEFT" then
                point, anchorPoint, groupAnchorPoint = "BOTTOMLEFT", "TOPLEFT", "BOTTOMRIGHT"
                unitSpacing = spacingY
                groupSpacing = spacingX
            elseif anchor == "BOTTOMRIGHT" then
                point, anchorPoint, groupAnchorPoint = "BOTTOMRIGHT", "TOPRIGHT", "BOTTOMLEFT"
                unitSpacing = spacingY
                groupSpacing = -spacingX
            elseif anchor == "TOPLEFT" then
                point, anchorPoint, groupAnchorPoint = "TOPLEFT", "BOTTOMLEFT", "TOPRIGHT"
                unitSpacing = -spacingY
                groupSpacing = spacingX
            elseif anchor == "TOPRIGHT" then
                point, anchorPoint, groupAnchorPoint = "TOPRIGHT", "BOTTOMRIGHT", "TOPLEFT"
                unitSpacing = -spacingY
                groupSpacing = -spacingX
            end

            if not layout["npc"]["separate"] then
                -- update whole NPCFrame point
                if groupType == "raid" then
                    npcFrame:SetPoint(point, anchors["raid"])
    
                elseif groupType == "party" then
                    if npcFrame:GetAttribute("pet") == "nopet" then
                        npcFrame:SetPoint(point, anchors["solo"], groupAnchorPoint, groupSpacing, 0)
                    else
                        npcFrame:SetPoint(point, anchors["party"], groupAnchorPoint, groupSpacing, 0)
                    end
            
                else -- solo
                    npcFrame:SetPoint(point, anchors["solo"], groupAnchorPoint, groupSpacing, 0)
                end
            end
        else
            if anchor == "BOTTOMLEFT" then
                point, anchorPoint, groupAnchorPoint = "BOTTOMLEFT", "BOTTOMRIGHT", "TOPLEFT"
                unitSpacing = spacingX
                groupSpacing = spacingY
            elseif anchor == "BOTTOMRIGHT" then
                point, anchorPoint, groupAnchorPoint = "BOTTOMRIGHT", "BOTTOMLEFT", "TOPRIGHT"
                unitSpacing = -spacingX
                groupSpacing = spacingY
            elseif anchor == "TOPLEFT" then
                point, anchorPoint, groupAnchorPoint = "TOPLEFT", "TOPRIGHT", "BOTTOMLEFT"
                unitSpacing = spacingX
                groupSpacing = -spacingY
            elseif anchor == "TOPRIGHT" then
                point, anchorPoint, groupAnchorPoint = "TOPRIGHT", "TOPLEFT", "BOTTOMRIGHT"
                unitSpacing = -spacingX
                groupSpacing = -spacingY
            end

            if not layout["npc"]["separate"] then
                -- update whole NPCFrame point
                if groupType == "raid" then
                    npcFrame:SetPoint(point, anchors["raid"])
    
                elseif groupType == "party" then
                    if npcFrame:GetAttribute("pet") == "nopet" then
                        npcFrame:SetPoint(point, anchors["solo"], groupAnchorPoint, 0, groupSpacing)
                    else
                        npcFrame:SetPoint(point, anchors["party"], groupAnchorPoint, 0, groupSpacing)
                    end
            
                else -- solo
                    npcFrame:SetPoint(point, anchors["solo"], groupAnchorPoint, 0, groupSpacing)
                end
            end
        end

        -- save point data
        npcFrame:SetAttribute("orientation", orientation)
        npcFrame:SetAttribute("point", point)
        npcFrame:SetAttribute("anchorPoint", anchorPoint)
        npcFrame:SetAttribute("groupAnchorPoint", groupAnchorPoint)
        npcFrame:SetAttribute("unitSpacing", unitSpacing)
        npcFrame:SetAttribute("groupSpacing", groupSpacing)
    
        local last
        for i = 1, 8 do
            local button = Cell.unitButtons.npc[i]
            button.helper:SetAttribute("orientation", orientation)
            button.helper:SetAttribute("point", point)
            button.helper:SetAttribute("anchorPoint", anchorPoint)
            button.helper:SetAttribute("unitSpacing", unitSpacing)
            
            -- update each npc button now
            if button:IsVisible() then
                button:ClearAllPoints()
                if last then
                    if orientation == "vertical" then
                        button:SetPoint(point, last, anchorPoint, 0, unitSpacing)
                    else
                        button:SetPoint(point, last, anchorPoint, unitSpacing, 0)
                    end
                else
                    button:SetPoint("TOPLEFT", npcFrame)
                end
                last = button
            end
        end
    end

    if not which or strfind(which, "arrangement$") or which == "npc" then
        UpdatePosition()
    end

    if not which or which == "npc" then
        if layout["npc"]["enabled"] then
            -- NOTE: RegisterAttributeDriver
            for i, b in ipairs(Cell.unitButtons.npc) do
                RegisterAttributeDriver(b, "state-visibility", "[@boss"..i..", help] show; hide")
                -- RegisterAttributeDriver(b, "state-visibility", "[@player, help] show; hide")
            end
            if layout["npc"]["separate"] then
                UnregisterStateDriver(npcFrame, "groupstate")
                UnregisterStateDriver(npcFrame, "petstate")
                -- load separate npc frame position
                P:LoadPosition(separateAnchor, layout["npc"]["position"])
            else
                -- RegisterStateDriver(npcFrame, "groupstate", "[group:raid] raid;[group:party] party;solo")
                RegisterStateDriver(npcFrame, "groupstate", "[@raid1,exists] raid;[@party1,exists] party;solo")
                RegisterStateDriver(npcFrame, "petstate", "[@pet,exists] pet; [@partypet1,exists] pet1; [@partypet2,exists] pet2; [@partypet3,exists] pet3; [@partypet4,exists] pet4; nopet")
            end
        else
            -- NOTE: RegisterAttributeDriver
            for _, b in ipairs(Cell.unitButtons.npc) do
                UnregisterAttributeDriver(b, "state-visibility")
                b:Hide()
            end
        end
    end
end
Cell:RegisterCallback("UpdateLayout", "NPCFrame_UpdateLayout", NPCFrame_UpdateLayout)

local function NPCFrame_UpdateVisibility(which)
    if not which or which == "solo" or which == "party" then
        local showSolo = CellDB["general"]["showSolo"] and "show" or "hide"
        local showParty = CellDB["general"]["showParty"] and "show" or "hide"
        -- RegisterAttributeDriver(npcFrame, "state-visibility", "[group:raid] show; [group:party] "..showParty.."; "..showSolo)
        RegisterAttributeDriver(npcFrame, "state-visibility", "[@raid1,exists] show;[@party1,exists] "..showParty..";"..showSolo)
    end
end
Cell:RegisterCallback("UpdateVisibility", "NPCFrame_UpdateVisibility", NPCFrame_UpdateVisibility)