local _G = ShaguTweaks.GetGlobalEnv()
local T = ShaguTweaks.T
local GetExpansion = ShaguTweaks.GetExpansion
local API = ShaguTweaks.API
local LegacyCastingInfo = ShaguTweaks.UnitCastingInfo
local LegacyChannelInfo = ShaguTweaks.UnitChannelInfo

local module = ShaguTweaks:register({
  title = T["Enemy Castbars"],
  description = T["Shows an enemy castbar on target unit frame."],
  expansions = { ["vanilla"] = true },
  category = T["Unit Frames"],
  enabled = true,
})

local castbar = CreateFrame("StatusBar", "ShaguTargetCastbar", TargetFrame)
castbar:SetPoint("BOTTOM", TargetFrame, "BOTTOM", -12, -4)
castbar:SetStatusBarTexture("Interface\\TargetingFrame\\UI-StatusBar")
castbar:SetStatusBarColor(1, .8, 0, 1)
castbar:SetWidth(140)
castbar:SetHeight(10)
castbar:Hide()

castbar.texture = CreateFrame("Frame", nil, castbar)
castbar.texture:SetPoint("RIGHT", castbar, "LEFT", -2, 0)
castbar.texture:SetHeight(20)
castbar.texture:SetWidth(20)

castbar.texture.icon = castbar.texture:CreateTexture(nil, "BACKGROUND")
castbar.texture.icon:SetPoint("CENTER", 0, 0)
castbar.texture.icon:SetWidth(16)
castbar.texture.icon:SetHeight(16)
castbar.texture:SetBackdrop({
  edgeFile = "Interface\\Tooltips\\UI-Tooltip-Border",
  tile = true, tileSize = 8, edgeSize = 12,
  insets = { left = 3, right = 3, top = 3, bottom = 3 }
})

castbar.bg = castbar:CreateTexture(nil, "BACKGROUND")
castbar.bg:SetTexture("Interface\\TARGETINGFRAME\\UI-StatusBar")
castbar.bg:SetVertexColor(.1, .1, 0, .8)
castbar.bg:SetAllPoints(true)

castbar.spark = castbar:CreateTexture(nil, "OVERLAY")
castbar.spark:SetTexture("Interface\\CastingBar\\UI-CastingBar-Spark")
castbar.spark:SetWidth(20)
castbar.spark:SetHeight(20)
castbar.spark:SetBlendMode("ADD")

castbar.backdrop = CreateFrame("Frame", nil, castbar)
castbar.backdrop:SetFrameStrata("BACKGROUND")
castbar.backdrop:SetPoint("TOPLEFT", castbar, "TOPLEFT", -3, 3)
castbar.backdrop:SetPoint("BOTTOMRIGHT", castbar, "BOTTOMRIGHT", 3, -3)
castbar.backdrop:SetBackdrop({
  edgeFile = "Interface\\Tooltips\\UI-Tooltip-Border",
  tile = true, tileSize = 8, edgeSize = 12,
  insets = { left = 3, right = 3, top = 3, bottom = 3 }
})

castbar.text = castbar:CreateFontString(nil, "HIGH", "GameFontWhite")
castbar.text:SetPoint("CENTER", castbar, "CENTER", 0, 0)
local font, size, opts = castbar.text:GetFont()
castbar.text:SetFont(font, size - 2, "THINOUTLINE")

local function QueryLegacy(query)
  if not query then return end

  local cast, nameSubtext, text, texture, startTime, endTime, isTradeSkill = LegacyCastingInfo(query)
  if cast then
    return cast, nameSubtext, text, texture, startTime, endTime, isTradeSkill, false
  end

  local channel
  channel, nameSubtext, text, texture, startTime, endTime, isTradeSkill = LegacyChannelInfo(query)
  if channel then
    return channel, nameSubtext, text, texture, startTime, endTime, isTradeSkill, true
  end
end

local function QueryCast(unit)
  if not unit then return end

  -- ClassicAPI is authoritative for real unit tokens and provides exact
  -- engine/server timing. Keep the old parser only as a compatibility layer.
  local cast, nameSubtext, text, texture, startTime, endTime, isTradeSkill = API.GetCastInfo(unit)
  if cast then
    return cast, nameSubtext, text, texture, startTime, endTime, isTradeSkill, false
  end

  local channel
  channel, nameSubtext, text, texture, startTime, endTime, isTradeSkill = API.GetChannelInfo(unit)
  if channel then
    return channel, nameSubtext, text, texture, startTime, endTime, isTradeSkill, true
  end

  -- SuperWoW remains a second source for GUID-keyed casts when available.
  if ShaguTweaks.superwow_active and not UnitIsUnit(unit, "player") then
    local _, guid = UnitExists(unit)
    if guid then
      local a, b, c, d, e, f, g, h = QueryLegacy(guid)
      if a then return a, b, c, d, e, f, g, h end
    end
  end

  return QueryLegacy(unit)
end

module.enable = function(self)
  local oldUpdate = TargetFrame:GetScript("OnUpdate")
  TargetFrame:SetScript("OnUpdate", function(arg)
    if oldUpdate then oldUpdate(arg) end

    local unit = this.unit or "target"
    local cast, nameSubtext, text, texture, startTime, endTime, isTradeSkill, isChannel = QueryCast(unit)

    if cast and startTime and endTime and endTime > startTime then
      local duration = endTime - startTime
      local max = duration / 1000
      local cur = GetTime() - startTime / 1000

      if isChannel then
        cur = max + startTime/1000 - GetTime()
      end

      cur = cur > max and max or cur
      cur = cur < 0 and 0 or cur

      castbar:Show()
      castbar:SetMinMaxValues(0, max)
      castbar:SetValue(cur)

      local percent = cur / max
      local x = castbar:GetWidth()*percent
      castbar.spark:SetPoint("CENTER", castbar, "LEFT", x, 0)

      castbar.text:SetText(cast)

      if texture then
        castbar.texture.icon:SetTexture(texture)
        castbar.texture.icon:Show()
      else
        castbar.texture.icon:Hide()
      end

      castbar:ClearAllPoints()
      castbar:SetPoint("BOTTOM", TargetFrame, "BOTTOM", -12, -4)

      local targetOfTarget = TargetofTargetFrame and TargetofTargetFrame:IsShown()
      local debuff11 = TargetFrameDebuff11 and TargetFrameDebuff11:IsShown()
      local debuff7 = TargetFrameDebuff7 and TargetFrameDebuff7:IsShown()
      local buff1 = TargetFrameBuff1 and TargetFrameBuff1:IsShown()

      if targetOfTarget then
        castbar:ClearAllPoints()
        castbar:SetPoint("BOTTOM", TargetFrame, "BOTTOM", -12, -24)
        if debuff11 then
          castbar:ClearAllPoints()
          castbar:SetPoint("BOTTOM", TargetFrame, "BOTTOM", -12, -45)
          if buff1 then
              castbar:ClearAllPoints()
              castbar:SetPoint("BOTTOM", TargetFrame, "BOTTOM", -12, -65)
          end
        end
      else
        if debuff7 then
          castbar:ClearAllPoints()
          castbar:SetPoint("BOTTOM", TargetFrame, "BOTTOM", -12, -24)
        end
      end
    else
      castbar:Hide()
    end
  end)
end