--- UnitFrames/Engine/MSUF_UF_Layers.lua
--- Shared frame-level contract for live unit frames and menu previews.

local _, MSUF = ...
MSUF = MSUF or _G.MSUF_NS or {}
local UF = MSUF.UF or {}
MSUF.UF = UF

local Layers = UF.Layers or {}
UF.Layers = Layers

Layers.TEXT_BASE_OFFSET = 10
Layers.STATUS_BASE_OFFSET = 10
Layers.PORTRAIT_OFFSET = 6
Layers.PORTRAIT_BORDER_OFFSET = 7
Layers.POWER_INLINE_OFFSET = 1
Layers.POWER_DETACHED_DEFAULT = 6
Layers.TARGETED_SPELLS_BASE_OFFSET = 40
Layers.PREVIEW_FRAME_BORDER_OFFSET = 40
Layers.PREVIEW_BOUNDS_OFFSET = 48

local floor = math.floor
local tonumber = tonumber

function Layers.ClampLayer(layer, fallback)
  layer = floor((tonumber(layer) or fallback or 0) + 0.5)
  if layer < 0 then
    return 0
  elseif layer > 30 then
    return 30
  end
  return layer
end

function Layers.BaseFrameLevel(frame)
  local base = frame and (frame.Health or frame.hpBar or frame)
  return base and base.GetFrameLevel and (base:GetFrameLevel() or 0) or 0
end

function Layers.TextLevel(frameOrLevel, layer, fallback)
  local base = type(frameOrLevel) == "number" and frameOrLevel or Layers.BaseFrameLevel(frameOrLevel)
  return base + Layers.TEXT_BASE_OFFSET + Layers.ClampLayer(layer, fallback)
end

function Layers.StatusLevel(frameOrLevel, layer, fallback)
  local base = type(frameOrLevel) == "number" and frameOrLevel or Layers.BaseFrameLevel(frameOrLevel)
  return base + Layers.STATUS_BASE_OFFSET + Layers.ClampLayer(layer, fallback or 7)
end

function Layers.PreviewBoundsLevel(frameOrLevel)
  local base = type(frameOrLevel) == "number" and frameOrLevel or Layers.BaseFrameLevel(frameOrLevel)
  return base + Layers.PREVIEW_BOUNDS_OFFSET
end
