local _G = ShaguTweaks.GetGlobalEnv()
local T = ShaguTweaks.T
local GetUnitData = ShaguTweaks.GetUnitData
local API = ShaguTweaks.API

local module = ShaguTweaks:register({
  title = T["Nameplate Class Colors"],
  description = T["Changes the nameplate health bar color to the class color."],
  expansions = { ["vanilla"] = true },
  category = T["Nameplates"],
  enabled = true,
})

module.enable = function(self)
  if ShaguPlates then return end

  local colorsByName = {}
  local useClassicTokens = API and API.eventutils and API.GetNamePlateForUnit
    and _G.C_EventUtils
    and _G.C_EventUtils.IsEventValid("NAME_PLATE_UNIT_ADDED")
    and _G.C_EventUtils.IsEventValid("NAME_PLATE_UNIT_REMOVED")

  if useClassicTokens then
    local listener = CreateFrame("Frame")
    listener:RegisterEvent("NAME_PLATE_UNIT_ADDED")
    listener:RegisterEvent("NAME_PLATE_UNIT_REMOVED")
    listener:SetScript("OnEvent", function()
      local unit = arg1
      if not unit then return end

      local plate = API.GetNamePlateForUnit(unit)
      if event == "NAME_PLATE_UNIT_ADDED" then
        if not plate then return end

        local color
        if UnitIsPlayer(unit) then
          local _, class = UnitClass(unit)
          color = class and RAID_CLASS_COLORS[class] or nil
        end

        -- Cache the exact unit result once. The native nameplate may repaint
        -- its reaction color later, so the lightweight OnUpdate below only
        -- reapplies this cached color and performs no unit/name scan.
        plate.stClassColor = color or false
        plate.stClassUnit = unit

        local name = UnitName(unit)
        if name then colorsByName[name] = color or false end
      elseif event == "NAME_PLATE_UNIT_REMOVED" then
        -- ClassicAPI keeps the token resolvable during REMOVED. Clear fields
        -- before the native frame can be recycled for another unit.
        if plate and plate.stClassUnit == unit then
          plate.stClassColor = nil
          plate.stClassUnit = nil
        end
      end
    end)
  end

  table.insert(ShaguTweaks.libnameplate.OnUpdate, function()
    if useClassicTokens then
      local color = this.stClassColor

      -- The ClassicAPI wrapper returned by GetNamePlateForUnit normally is
      -- the same Lua frame. Keep a name-keyed cache as a harmless fallback
      -- for wrapper recreation without falling back to active unit scanning.
      if color == nil and this.name then
        color = colorsByName[this.name:GetText()]
      end

      if color then
        this.healthbar:SetStatusBarColor(color.r, color.g, color.b, 1)
      end
      return
    end

    -- Plain Vanilla / old ClassicAPI compatibility path.
    local name = this.name:GetText()
    local class, _, _, player = GetUnitData(name, true)
    if class and player then
      local color = RAID_CLASS_COLORS[class] or { r = .5, g = .5, b = .5, a = 1 }
      this.healthbar:SetStatusBarColor(color.r, color.g, color.b, 1)
    end
  end)
end