pfUI:RegisterModule("castbar", "vanilla", function ()

  local font = C.castbar.use_unitfonts == "1" and pfUI.font_unit or pfUI.font_default
  local font_size = C.castbar.use_unitfonts == "1" and C.global.font_unit_size or C.global.font_size
  local rawborder, default_border = GetBorderSize("unitframes")
  local cbtexture = pfUI.media[C.appearance.castbar.texture]

  -- Helper function for castbar timer formatting
  local function FormatCastbarTime(value)
    if C.unitframes.castbardecimals == "1" then
      -- 1 decimal, round half up (matches Blizzard spellbook display)
      return string.format("%.1f", floor(value * 10 + 0.5) / 10)
    else
      -- 2 decimals (default)
      return string.format("%.2f", value)
    end
  end

  local function CreateCastbar(name, parent, unitstr, unitname)
    local cb = CreateFrame("Frame", name, parent or UIParent)

    cb:SetHeight(C.global.font_size * 1.5)
    cb:SetFrameStrata("MEDIUM")
    cb:SetFrameLevel(8)

    cb.unitstr = unitstr
    cb.unitname = unitname

    -- icon
    cb.icon = CreateFrame("Frame", nil, cb)
    cb.icon:SetPoint("TOPLEFT", 0, 0)
    cb.icon:SetHeight(16)
    cb.icon:SetWidth(16)

    cb.icon.texture = cb.icon:CreateTexture(nil, "OVERLAY")
    cb.icon.texture:SetAllPoints()
    cb.icon.texture:SetTexCoord(.08, .92, .08, .92)
    CreateBackdrop(cb.icon, default_border)

    -- statusbar
    cb.bar = CreateFrame("StatusBar", nil, cb)
    cb.bar:SetStatusBarTexture(cbtexture)
    cb.bar:ClearAllPoints()
    cb.bar:SetAllPoints(cb)
    cb.bar:SetMinMaxValues(0, 100)
    cb.bar:SetValue(20)
    local r,g,b,a = strsplit(",", C.appearance.castbar.castbarcolor)
    cb.bar:SetStatusBarColor(r,g,b,a)
    CreateBackdrop(cb.bar, default_border)
    CreateBackdropShadow(cb.bar)

    -- text left
    cb.bar.left = cb.bar:CreateFontString("Status", "DIALOG", "GameFontNormal")
    cb.bar.left:ClearAllPoints()
    cb.bar.left:SetPoint("TOPLEFT", cb.bar, "TOPLEFT", 3 + C.castbar[unitstr].txtleftoffx, C.castbar[unitstr].txtleftoffy)
    cb.bar.left:SetPoint("BOTTOMRIGHT", cb.bar, "BOTTOMRIGHT", -3 + C.castbar[unitstr].txtleftoffx, C.castbar[unitstr].txtleftoffy)
    cb.bar.left:SetNonSpaceWrap(false)
    cb.bar.left:SetFontObject(GameFontWhite)
    cb.bar.left:SetTextColor(1,1,1,1)
    cb.bar.left:SetFont(font, font_size, "OUTLINE")
    cb.bar.left:SetJustifyH("left")

    -- text right
    cb.bar.right = cb.bar:CreateFontString("Status", "DIALOG", "GameFontNormal")
    cb.bar.right:ClearAllPoints()
    cb.bar.right:SetPoint("TOPLEFT", cb.bar, "TOPLEFT", 3 + C.castbar[unitstr].txtrightoffx, C.castbar[unitstr].txtrightoffy)
    cb.bar.right:SetPoint("BOTTOMRIGHT", cb.bar, "BOTTOMRIGHT", -3 + C.castbar[unitstr].txtrightoffx, C.castbar[unitstr].txtrightoffy)
    cb.bar.right:SetNonSpaceWrap(false)
    cb.bar.right:SetFontObject(GameFontWhite)
    cb.bar.right:SetTextColor(1,1,1,1)
    cb.bar.right:SetFont(font, font_size, "OUTLINE")
    cb.bar.right:SetJustifyH("right")

    cb.bar.lag = cb.bar:CreateTexture(nil, "OVERLAY")
    cb.bar.lag:SetPoint("TOPRIGHT", cb.bar, "TOPRIGHT", 0, 0)
    cb.bar.lag:SetPoint("BOTTOMRIGHT", cb.bar, "BOTTOMRIGHT", 0, 0)
    cb.bar.lag:SetTexture(1,.2,.2,.2)

    -- OnUpdate script with throttle for performance optimization
    cb:SetScript("OnUpdate", function()
      -- Throttle for performance
      if (this.tick or 0) > GetTime() then return end
      this.tick = GetTime() + 0.020 -- ~50 FPS for smooth castbar

      if this.drag and this.drag:IsShown() then
        this:SetAlpha(1)
        return
      end

      if not UnitExists(this.unitstr) then
        this:SetAlpha(0)
      end

      if this.fadeout and this:GetAlpha() > 0 then
        if this:GetAlpha() == 0 then
          this.fadeout = nil
        end

        this:SetAlpha(this:GetAlpha()-0.05)
      end

      local channel = nil
      local query = this.unitstr ~= "" and this.unitstr or this.unitname
      if not query then return end

      -- Check if we have a GUID-based focus (Turtle WoW native GUID)
      local focusGuid = nil
      if this.unitstr and string.find(this.unitstr, "^0x") then
        focusGuid = this.unitstr
      elseif this.unitstr and this.unitstr == "player" and GetUnitGUID then
        focusGuid = GetUnitGUID("player")
      elseif this.unitstr and this.unitstr ~= "player" then
        local guid = GetUnitGUID(this.unitstr)
        if guid then focusGuid = guid end
      end
      this.focusGuid = focusGuid

      -- Try libdebuff_casts first for GUID-based units (works with Turtle GUID + Nampower events)
      local cast, nameSubtext, text, texture, startTime, endTime
      local castBlocked = false
      if focusGuid and pfUI.libdebuff_casts and pfUI.libdebuff_casts[focusGuid] then
        local castData = pfUI.libdebuff_casts[focusGuid]
        if castData.event == "CAST" or castData.event == "FAIL" then
          castBlocked = true
          pfUI.libdebuff_casts[focusGuid] = nil
        elseif (castData.event == "START" or castData.event == "CHANNEL") and castData.endTime and castData.endTime > GetTime() then
          cast = castData.spellName
          texture = castData.icon
          startTime = castData.startTime * 1000
          endTime = castData.endTime * 1000
          -- Try to get rank from spell DB via spellID (nameSubtext is not stored in libdebuff_casts)
          if castData.spellID and GetSpellRecField then
            nameSubtext = GetSpellRecField(castData.spellID, "rank") or ""
          else
            nameSubtext = ""
          end
          if castData.event == "CHANNEL" then
            channel = cast
          end
        end
      end

      local useLibcastForPlayer = this.unitstr == "player"

      -- For player: use player name to query libcast.db directly
      if not cast and useLibcastForPlayer then
        query = UnitName("player")
      end

      -- Fallback: pfGetCastInfo only when no focusGuid (Nampower not available for this unit).
      -- If we have a focusGuid, libdebuff is authoritative - don't fall back to libcast
      -- even if no cast is active (prevents false positives e.g. spellbook clicks on CD spells).
      if not cast and not castBlocked and not focusGuid and pfGetCastInfo then
        cast, nameSubtext, text, texture, startTime, endTime, isTradeSkill = pfGetCastInfo(query)
      end

      if not cast and not castBlocked and not focusGuid and pfGetChannelInfo then
        channel, nameSubtext, text, texture, startTime, endTime, isTradeSkill = pfGetChannelInfo(this.unitstr or this.unitname)
        cast = channel
      end

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

        this:SetAlpha(1)

        local spellname = this.showname and cast and cast .. " " or ""
        local rank = this.showrank and nameSubtext and nameSubtext ~= "" and string.format("|cffaaffcc[%s]|r", nameSubtext) or ""

        if this.endTime ~= endTime then
          this.bar:SetStatusBarColor(strsplit(",", C.appearance.castbar[(channel and "channelcolor" or "castbarcolor")]))
          this.bar.left:SetText(spellname .. rank)
          this.fadeout = nil
          this.endTime = endTime

          -- set texture
          if texture and this.showicon then
            local size = this:GetHeight()
            this.icon:Show()
            this.icon:SetHeight(size)
            this.icon:SetWidth(size)
            
            -- Override with item icon from libdebuff_casts or persistent item icon cache
            local useTexture = texture
            local useItemName = nil
            if pfUI.libdebuff_casts or pfUI.libdebuff_item_icons then
              local castGuid = nil
              if this.unitstr and UnitExists then
                local guid = GetUnitGUID(this.unitstr)
                castGuid = guid
              end
              if castGuid then
                -- First check active cast data
                if pfUI.libdebuff_casts and pfUI.libdebuff_casts[castGuid] and pfUI.libdebuff_casts[castGuid].itemID then
                  useTexture = pfUI.libdebuff_casts[castGuid].icon or texture
                -- Fallback to persistent item icon cache
                elseif pfUI.libdebuff_item_icons and pfUI.libdebuff_item_icons[castGuid] then
                  useTexture = pfUI.libdebuff_item_icons[castGuid].icon or texture
                  useItemName = pfUI.libdebuff_item_icons[castGuid].name
                end
              end
            end
            
            this.icon.texture:SetTexture(useTexture)
            this.bar:SetPoint("TOPLEFT", this.icon, "TOPRIGHT", this.spacing, 0)
            
            -- Override spell name with item name for item-triggered casts
            if useItemName and this.showname then
              this.bar.left:SetText(useItemName .. " " .. rank)
            end
          else
            this.bar:SetPoint("TOPLEFT", this, 0, 0)
            this.icon:Hide()
          end

          if this.showlag then
            local _, _, lag = GetNetStats()
            local width = this:GetWidth() / (duration/1000) * (lag/1000)
            this.bar.lag:SetWidth(math.min(this:GetWidth(), width))
          else
            this.bar.lag:Hide()
          end
        end

        local newMax = duration / 1000
        if this.lastMax ~= newMax then
          this.bar:SetMinMaxValues(0, newMax)
          this.lastMax = newMax
        end

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

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

        this.bar:SetValue(cur)

        if this.showtimer then
          if this.delay and this.delay > 0 then
            local delay = "|cffffaaaa" .. (channel and "-" or "+") .. FormatCastbarTime(this.delay) .. " |r "
            this.bar.right:SetText(delay .. FormatCastbarTime(cur) .. " / " .. FormatCastbarTime(max))
          else
            this.bar.right:SetText(FormatCastbarTime(cur) .. " / " .. FormatCastbarTime(max))
          end
        end

        this.fadeout = nil
      else
        this.bar:SetMinMaxValues(1,100)
        this.bar:SetValue(100)
        this.lastMax = nil
        this.fadeout = 1
        this.delay = 0
        this.itemIconApplied = nil
      end
    end)

    -- register for spell delay
    -- Prefer Nampower's SPELL_DELAYED_SELF (gives casterGuid + delayMs directly).
    -- Fall back to vanilla SPELLCAST_DELAYED if Nampower is not available.
    local playerarg = nil
    local function ApplyPushback(delayMs)
      if not delayMs or delayMs <= 0 or not this.endTime then return end
      this.delay = (this.delay or 0) + delayMs / 1000
      this.endTime = this.endTime + delayMs
      local focusGuid = this.focusGuid
      if focusGuid and pfUI.libdebuff_casts and pfUI.libdebuff_casts[focusGuid] then
        pfUI.libdebuff_casts[focusGuid].endTime = this.endTime / 1000
      end
    end

    cb:RegisterEvent("SPELL_DELAYED_SELF")
    cb:RegisterEvent(CASTBAR_EVENT_CAST_DELAY)
    cb:RegisterEvent(CASTBAR_EVENT_CHANNEL_DELAY)
    cb:RegisterEvent(CASTBAR_EVENT_CAST_START)
    cb:RegisterEvent(CASTBAR_EVENT_CHANNEL_START)
    cb:SetScript("OnEvent", function()
      if this.unitstr and not UnitIsUnit(this.unitstr, "player") then return end

      if event == "SPELL_DELAYED_SELF" then
        -- arg1=casterGuid, arg2=delayMs (Nampower, most accurate)
        ApplyPushback(arg2)

      elseif event == CASTBAR_EVENT_CAST_DELAY then
        -- SPELLCAST_DELAYED fallback intentionally removed - addon requires Nampower.
        -- Cast pushback is handled by SPELL_DELAYED_SELF above.
        return

      elseif event == CASTBAR_EVENT_CHANNEL_DELAY then
        -- SPELLCAST_CHANNEL_UPDATE fires when a channel is pushed back by damage.
        -- arg1 = new remaining time in ms. Channel ends sooner = newEndTime < this.endTime.
        if not this.endTime or not arg1 then return end
        local newEndTime = GetTime() * 1000 + arg1
        local diff = this.endTime - newEndTime  -- positive = time lost to pushback
        if diff > 50 then
          this.delay = (this.delay or 0) + diff / 1000
          this.endTime = newEndTime
          local focusGuid = this.focusGuid
          if focusGuid and pfUI.libdebuff_casts and pfUI.libdebuff_casts[focusGuid] then
            pfUI.libdebuff_casts[focusGuid].endTime = newEndTime / 1000
          end
        end

      elseif event == CASTBAR_EVENT_CAST_START or event == CASTBAR_EVENT_CHANNEL_START then
        playerarg = pfUI.client <= 11200 or arg1 == "player" and true or nil
        if playerarg then this.delay = 0 end
      end
    end)

    cb:SetAlpha(0)
    return cb
  end

  pfUI.castbar = CreateFrame("Frame", "pfCastBar", UIParent)

  -- hide blizzard
  if C.castbar.player.hide_blizz == "1" then
    CastingBarFrame:SetScript("OnShow", function() CastingBarFrame:Hide() end)
    CastingBarFrame:UnregisterAllEvents()
    CastingBarFrame:Hide()
  end

  -- [[ pfPlayerCastbar ]] --
  if C.castbar.player.hide_pfui == "0" then
    pfUI.castbar.player = CreateCastbar("pfPlayerCastbar", UIParent, "player")
    pfUI.castbar.player.showicon = C.castbar.player.showicon == "1" and true or nil
    pfUI.castbar.player.showname = C.castbar.player.showname == "1" and true or nil
    pfUI.castbar.player.showtimer = C.castbar.player.showtimer == "1" and true or nil
    pfUI.castbar.player.showlag = C.castbar.player.showlag == "1" and true or nil
    pfUI.castbar.player.showrank = C.castbar.player.showrank == "1" and true or nil
    pfUI.castbar.player.spacing = default_border * 2 + tonumber(C.unitframes.player.pspace) * GetPerfectPixel()

    if pfUI.uf.player then
      local anchor = pfUI.uf.player.portrait:GetHeight() > pfUI.uf.player:GetHeight() and pfUI.uf.player.power or pfUI.uf.player
      local width = C.castbar.player.width ~= "-1" and C.castbar.player.width or anchor:GetWidth()
      pfUI.castbar.player:SetPoint("TOPLEFT", anchor, "BOTTOMLEFT", 0, -pfUI.castbar.player.spacing)
      pfUI.castbar.player:SetWidth(width)
    else
      local width = C.castbar.player.width ~= "-1" and C.castbar.player.width or 200
      pfUI.castbar.player:SetPoint("CENTER", 0, -200)
      pfUI.castbar.player:SetWidth(width)
    end

    if C.castbar.player.height ~= "-1" then
      pfUI.castbar.player:SetHeight(C.castbar.player.height)
    end

    UpdateMovable(pfUI.castbar.player)
  end

  -- [[ pfTargetCastbar ]] --
  if C.castbar.target.hide_pfui == "0" then
    pfUI.castbar.target = CreateCastbar("pfTargetCastbar", UIParent, "target")
    pfUI.castbar.target.showicon = C.castbar.target.showicon == "1" and true or nil
    pfUI.castbar.target.showname = C.castbar.target.showname == "1" and true or nil
    pfUI.castbar.target.showtimer = C.castbar.target.showtimer == "1" and true or nil
    pfUI.castbar.target.showlag = C.castbar.target.showlag == "1" and true or nil
    pfUI.castbar.target.showrank = C.castbar.target.showrank == "1" and true or nil
    pfUI.castbar.target.spacing = default_border * 2 + tonumber(C.unitframes.target.pspace) * GetPerfectPixel()

    if pfUI.uf.target then
      local anchor = pfUI.uf.target.portrait:GetHeight() > pfUI.uf.target:GetHeight() and pfUI.uf.target.power or pfUI.uf.target
      local width = C.castbar.target.width ~= "-1" and C.castbar.target.width or anchor:GetWidth()
      pfUI.castbar.target:SetPoint("TOPLEFT", anchor, "BOTTOMLEFT", 0, -pfUI.castbar.target.spacing)
      pfUI.castbar.target:SetWidth(width)
    else
      local width = C.castbar.target.width ~= "-1" and C.castbar.target.width or 200
      pfUI.castbar.target:SetPoint("CENTER", 0, -225)
      pfUI.castbar.target:SetWidth(width)
    end

    if C.castbar.target.height ~= "-1" then
      pfUI.castbar.target:SetHeight(C.castbar.target.height)
    end

    UpdateMovable(pfUI.castbar.target)
  end

  -- [[ pfFocusCastbar ]] --
  if C.castbar.focus.hide_pfui == "0" and pfUI.uf.focus then
    pfUI.castbar.focus = CreateCastbar("pfFocusCastbar", UIParent, "focus")
    pfUI.castbar.focus.showicon = C.castbar.focus.showicon == "1" and true or nil
    pfUI.castbar.focus.showname = C.castbar.focus.showname == "1" and true or nil
    pfUI.castbar.focus.showtimer = C.castbar.focus.showtimer == "1" and true or nil
    pfUI.castbar.focus.showlag = C.castbar.focus.showlag == "1" and true or nil
    pfUI.castbar.focus.showrank = C.castbar.focus.showrank == "1" and true or nil
    pfUI.castbar.focus.spacing = default_border * 2 + tonumber(C.unitframes.focus.pspace) * GetPerfectPixel()

    -- reset unitstr for vanilla focus frame emulation
    if pfUI.client <= 11200 then
      pfUI.castbar.focus.unitstr = nil
    end

    local anchor = pfUI.uf.focus.portrait:GetHeight() > pfUI.uf.focus:GetHeight() and pfUI.uf.focus.power or pfUI.uf.focus
    local width = C.castbar.focus.width ~= "-1" and C.castbar.focus.width or anchor:GetWidth()
    pfUI.castbar.focus:SetPoint("TOPLEFT", anchor, "BOTTOMLEFT", 0, -pfUI.castbar.focus.spacing)
    pfUI.castbar.focus:SetWidth(width)

    if C.castbar.focus.height ~= "-1" then
      pfUI.castbar.focus:SetHeight(C.castbar.focus.height)
    end

    -- keep unit values in sync with focus unitframe
    HookScript(pfUI.castbar.focus, "OnUpdate", function()
      -- clear on empty focus frames
      if pfUI.uf.focus.unitname == nil and pfUI.uf.focus.label == nil then
        pfUI.castbar.focus.unitstr = nil
        pfUI.castbar.focus.unitname = nil
        return
      end

      -- skip on initial values
      if pfUI.uf.focus.unitname == "focus" then return end
      if pfUI.uf.focus.unitname == "" then return end

      -- try to obtain a unitstr
      pfUI.castbar.focus.unitstr = string.format("%s%s", (pfUI.uf.focus.label or ""), (pfUI.uf.focus.id or ""))
      pfUI.castbar.focus.unitstr = pfUI.castbar.focus.unitstr == "" and nil or pfUI.castbar.focus.unitstr

      if pfUI.castbar.focus.unitstr then
        -- read non-lowercase unitname when possible
        pfUI.castbar.focus.unitname = UnitName(pfUI.castbar.focus.unitstr) or pfUI.castbar.focus.unitname
      elseif strlower(pfUI.castbar.focus.unitname) ~= strlower(pfUI.uf.focus.unitname) then
        -- sync unitname with focus frame's lowercase value
        pfUI.castbar.focus.unitname = pfUI.uf.focus.unitname
      end
    end)

    UpdateMovable(pfUI.castbar.focus)
  end
end)