--[[--------------------------------------------------------------------------
  ManiaxSocial - the Account tab.

  WHAT THIS CLIENT'S FRIENDS LIST ACTUALLY IS, AND WHY THAT MATTERS

  It is NOT stock 3.3.5a FrameXML. `Interface\FrameXML\FriendsFrame.xml` and
  `.lua` are replaced out of `patch-enUS-3.MPQ` (204 KB against the stock
  153 KB), by a Battle.net-era backport: the frame carries a
  `FriendsTabHeader` with THREE tabs - Friends, Ignore and Pending - a
  `FRIENDSFRAME_SUBFRAMES` list, `FriendsFrame_ShowSubFrame`, and a
  DynamicScrollFrame friends list. Read that file, not a 3.3.5 wiki page, and
  not the UI simulator: the simulator ships a modern FrameXML, and the stock
  WotLK FriendsFrame has no tab header at all.

  The dark "skin" is not an add-on either. Nothing in the pack restyles the
  Friends List; the art is replaced at the client level - the frame textures
  by the same `patch-enUS-3.MPQ`, the blue buttons by `patch-9.MPQ`
  (`Interface\Buttons\UI-Panel-Button-Up` and friends). That is the whole
  reason this file draws NOTHING of its own: every widget here is built from
  the client's own templates - TabButtonTemplate, UIPanelButtonTemplate2,
  UIPanelScrollFrameTemplate, UIPanelDialogTemplate - and from the client's
  own textures, so the reskin reaches it automatically. Hand-painting the
  mockup's sampled colours would have produced a tab that looked right today
  and wrong the next time the art changed.

  HOW THE TAB IS INJECTED

  `FriendsTabHeader` is an ordinary PanelTemplates tab group: tabs are
  `FriendsTabHeaderTab<N>`, `PanelTemplates_UpdateTabs` walks 1..numTabs by
  global name. So a fourth tab is a Button named `FriendsTabHeaderTab4` with
  id 4, plus `PanelTemplates_SetNumTabs(FriendsTabHeader, 4)`. Selecting it
  leaves the stock `FriendsFrame_Update` in its "else" branch (the ignore
  list), so a post-hook takes over from there and shows our sub-frame instead.
  Our frame name is appended to `FRIENDSFRAME_SUBFRAMES`, which is what makes
  the client hide it again when any other tab is picked - no bookkeeping of
  our own, and nothing to forget.

  Tab 3 is hidden when `BNFeaturesEnabled()` is false, which it is here, so
  the Account tab anchors to whichever header tab is actually visible.

  If any of that is missing - a different FrameXML, another add-on that owns
  the header - the injection is refused as a whole and the same panel opens as
  a standalone window instead (mockup figure 7, pre-approved as the fallback).
  Every widget is anchored to `panel`, never to FriendsFrame, so the fallback
  is a re-parent and not a second layout.

  GEOMETRY comes from the client, not from the mockup image: the list sits
  where `FriendsFrameFriendsScrollFrame` sits (21, -100, 302 x 307) and the two
  bottom buttons are the 131 x 21 pair at the client's own offsets. The
  mockup's pixels are that same frame photographed at 1.151x.
----------------------------------------------------------------------------]]

local NS = ManiaxSocial
if not NS then return end

local LIST_X, LIST_Y = 21, -100
local LIST_W, LIST_H = 302, 307
local ROW_H = 37
local ROW_SELECTED_H = 61
local CARD_H = 76
local HEADER_H = 17

local TEXTURE_ONLINE = "Interface\\FriendsFrame\\StatusIcon-Online"
local TEXTURE_OFFLINE = "Interface\\FriendsFrame\\StatusIcon-Offline"
local TEXTURE_HIGHLIGHT = "Interface\\FriendsFrame\\UI-FriendsFrame-HighlightBar"
local TEXTURE_DIVIDER = "Interface\\FriendsFrame\\UI-FriendsFrame-OnlineDivider"

-- Sampled from the client screenshot the mockup was measured against; the
-- states the screenshot does not contain are the mockup's derived values.
local COLOR_NAME = { 0.984, 0.910, 0.478 }
local COLOR_INFO = { 0.592, 0.702, 0.839 }
local COLOR_NAME_OFF = { 0.494, 0.478, 0.447 }
local COLOR_INFO_OFF = { 0.373, 0.420, 0.463 }
local COLOR_NOTE = { 0.714, 0.678, 0.612 }
local COLOR_MUTED = { 0.427, 0.416, 0.388 }

local TOOLTIP_OFFLINE = "Friend is offline."
local TOOLTIP_HIDDEN = "This friend has chosen not to show their character."
local TOOLTIP_NO_SELECTION = "Select a friend."
local TOOLTIP_UNAVAILABLE = "Awaiting realm support."
local TEXT_UNAVAILABLE = "Account service unavailable"

NS.selected = nil     -- {kind = "friend"|"request", handle = ...}
NS.injected = false

--[[ tooltips ------------------------------------------------------------- ]]

-- A disabled control carries its reason. Nothing is greyed here without one.
local function tip(widget, title, reason)
  widget.tipTitle, widget.tipReason = title, reason
  widget:SetScript("OnEnter", function(self)
    if not self.tipTitle and not self.tipReason then
      return
    end
    GameTooltip:SetOwner(self, "ANCHOR_RIGHT")
    if self.tipTitle then
      GameTooltip:SetText(self.tipTitle, 1, 1, 1)
    end
    if self.tipReason then
      GameTooltip:AddLine(self.tipReason, nil, nil, nil, true)
    end
    GameTooltip:Show()
  end)
  widget:SetScript("OnLeave", GameTooltip_Hide)
end

--[[ the panel ------------------------------------------------------------ ]]

local panel = CreateFrame("Frame", "ManiaxSocialListFrame", UIParent)
panel:Hide()
NS.panel = panel

local handleLabel = panel:CreateFontString(nil, "OVERLAY", "GameFontHighlightSmall")
handleLabel:SetPoint("TOPLEFT", panel, "TOPLEFT", 140, -46)
handleLabel:SetText("Handle:")
handleLabel:SetTextColor(0.561, 0.533, 0.486)

local handleText = panel:CreateFontString(nil, "OVERLAY", "GameFontNormal")
handleText:SetPoint("LEFT", handleLabel, "RIGHT", 5, 0)

local privacyText = panel:CreateFontString(nil, "OVERLAY", "GameFontHighlightSmall")
privacyText:SetPoint("TOPRIGHT", panel, "TOPRIGHT", -42, -46)
privacyText:SetTextColor(COLOR_INFO[1], COLOR_INFO[2], COLOR_INFO[3])

local settingsButton = CreateFrame("Button", "ManiaxSocialSettingsButton", panel,
  "UIPanelButtonTemplate2")
settingsButton:SetWidth(70)
settingsButton:SetHeight(20)
settingsButton:SetPoint("TOPRIGHT", panel, "TOPRIGHT", -42, -68)
settingsButton:SetText("Settings")
settingsButton:SetScript("OnClick", function()
  NS.ToggleSettings()
end)

local scroll = CreateFrame("ScrollFrame", "ManiaxSocialScrollFrame", panel,
  "UIPanelScrollFrameTemplate")
scroll:SetPoint("TOPLEFT", panel, "TOPLEFT", LIST_X, LIST_Y)
scroll:SetWidth(LIST_W)
scroll:SetHeight(LIST_H)

local content = CreateFrame("Frame", "ManiaxSocialScrollChild", scroll)
content:SetWidth(LIST_W)
content:SetHeight(LIST_H)
scroll:SetScrollChild(content)

local emptyText = panel:CreateFontString(nil, "OVERLAY", "GameFontHighlightSmall")
emptyText:SetPoint("TOP", scroll, "TOP", 0, -24)
emptyText:SetWidth(LIST_W - 40)
emptyText:SetJustifyH("CENTER")
emptyText:Hide()

-- The empty line is a FontString, which cannot own a tooltip, so an invisible
-- button sits over it to carry the reason.
local emptyHover = CreateFrame("Button", nil, panel)
emptyHover:SetPoint("TOPLEFT", emptyText, "TOPLEFT", 0, 0)
emptyHover:SetPoint("BOTTOMRIGHT", emptyText, "BOTTOMRIGHT", 0, 0)
emptyHover:Hide()

local addButton = CreateFrame("Button", "ManiaxSocialAddFriendButton", panel,
  "UIPanelButtonTemplate2")
addButton:SetWidth(131)
addButton:SetHeight(21)
addButton:SetPoint("BOTTOMLEFT", panel, "BOTTOMLEFT", 15, 81)
addButton:SetText(ADD_FRIEND)
addButton:SetScript("OnClick", function()
  NS.ShowAddFriend()
end)

local actionButton = CreateFrame("Button", "ManiaxSocialActionButton", panel,
  "UIPanelButtonTemplate2")
actionButton:SetWidth(131)
actionButton:SetHeight(21)
actionButton:SetPoint("BOTTOMRIGHT", panel, "BOTTOMRIGHT", -41, 81)
actionButton:SetText(SEND_MESSAGE)

--[[ widget pools --------------------------------------------------------- ]]

local headers, rows, cards = {}, {}, {}

local function acquireHeader(index)
  local header = headers[index]
  if not header then
    header = CreateFrame("Frame", nil, content)
    header:SetWidth(LIST_W)
    header:SetHeight(HEADER_H)
    header.text = header:CreateFontString(nil, "ARTWORK", "GameFontHighlightSmall")
    header.text:SetPoint("LEFT", header, "LEFT", 8, 0)
    header.text:SetTextColor(COLOR_MUTED[1], COLOR_MUTED[2], COLOR_MUTED[3])
    header.line = header:CreateTexture(nil, "ARTWORK")
    header.line:SetTexture(TEXTURE_DIVIDER)
    header.line:SetHeight(8)
    header.line:SetPoint("RIGHT", header, "RIGHT", -6, 0)
    headers[index] = header
  end
  header:Show()
  return header
end

local function selectEntry(kind, handle)
  if NS.selected and NS.selected.kind == kind and NS.selected.handle == handle then
    NS.selected = nil
  else
    NS.selected = { kind = kind, handle = handle }
  end
  PlaySound("igMainMenuOptionCheckBoxOn")
  NS.Refresh()
end

local function acquireRow(index)
  local row = rows[index]
  if not row then
    local name = "ManiaxSocialRow" .. index
    row = CreateFrame("Button", name, content)
    row:SetWidth(LIST_W)
    row:SetHeight(ROW_H)
    row:SetHighlightTexture(TEXTURE_HIGHLIGHT)

    row.selection = row:CreateTexture(nil, "BACKGROUND")
    row.selection:SetTexture(TEXTURE_HIGHLIGHT)
    row.selection:SetPoint("TOPLEFT", row, "TOPLEFT", 0, 0)
    row.selection:SetPoint("BOTTOMRIGHT", row, "BOTTOMRIGHT", 0, 0)
    row.selection:Hide()

    row.icon = row:CreateTexture(nil, "ARTWORK")
    row.icon:SetWidth(16)
    row.icon:SetHeight(16)
    row.icon:SetPoint("TOPLEFT", row, "TOPLEFT", 6, -6)

    row.name = row:CreateFontString(nil, "ARTWORK", "GameFontNormal")
    row.name:SetPoint("TOPLEFT", row, "TOPLEFT", 27, -4)
    row.name:SetJustifyH("LEFT")

    row.info = row:CreateFontString(nil, "ARTWORK", "GameFontHighlightSmall")
    row.info:SetPoint("TOPLEFT", row, "TOPLEFT", 27, -20)
    row.info:SetWidth(LIST_W - 40)
    row.info:SetJustifyH("LEFT")

    row.note = row:CreateFontString(nil, "ARTWORK", "GameFontHighlightSmall")
    row.note:SetPoint("TOPLEFT", row, "TOPLEFT", 27, -36)
    row.note:SetWidth(LIST_W - 40)
    row.note:SetJustifyH("LEFT")
    row.note:SetTextColor(COLOR_NOTE[1], COLOR_NOTE[2], COLOR_NOTE[3])

    row.editNote = CreateFrame("Button", name .. "EditNote", row, "UIPanelButtonTemplate2")
    row.editNote:SetWidth(78)
    row.editNote:SetHeight(19)
    row.editNote:SetPoint("BOTTOMRIGHT", row, "BOTTOMRIGHT", -92, 5)
    row.editNote:SetText("Edit Note")

    row.remove = CreateFrame("Button", name .. "Remove", row, "UIPanelButtonTemplate2")
    row.remove:SetWidth(78)
    row.remove:SetHeight(19)
    row.remove:SetPoint("BOTTOMRIGHT", row, "BOTTOMRIGHT", -10, 5)
    row.remove:SetText("Remove")

    row:SetScript("OnClick", function(self)
      selectEntry("friend", self.handle)
    end)
    rows[index] = row
  end
  row:Show()
  return row
end

local function acquireCard(index)
  local card = cards[index]
  if not card then
    local name = "ManiaxSocialRequest" .. index
    card = CreateFrame("Button", name, content)
    card:SetWidth(LIST_W - 12)
    card:SetHeight(CARD_H - 6)
    card:SetBackdrop({
      bgFile = "Interface\\Tooltips\\UI-Tooltip-Background",
      edgeFile = "Interface\\Tooltips\\UI-Tooltip-Border",
      tile = true, tileSize = 16, edgeSize = 16,
      insets = { left = 4, right = 4, top = 4, bottom = 4 },
    })
    card:SetBackdropColor(0.04, 0.04, 0.04, 0.9)

    card.name = card:CreateFontString(nil, "ARTWORK", "GameFontNormal")
    card.name:SetPoint("TOPLEFT", card, "TOPLEFT", 12, -10)
    card.name:SetTextColor(COLOR_NAME[1], COLOR_NAME[2], COLOR_NAME[3])

    card.info = card:CreateFontString(nil, "ARTWORK", "GameFontHighlightSmall")
    card.info:SetPoint("TOPLEFT", card, "TOPLEFT", 12, -27)
    card.info:SetWidth(LIST_W - 40)
    card.info:SetJustifyH("LEFT")
    card.info:SetTextColor(COLOR_INFO[1], COLOR_INFO[2], COLOR_INFO[3])
    card.info:SetText("Requested to add you as a friend.")

    card.accept = CreateFrame("Button", name .. "Accept", card, "UIPanelButtonTemplate2")
    card.accept:SetWidth(90)
    card.accept:SetHeight(20)
    card.accept:SetPoint("BOTTOMLEFT", card, "BOTTOMLEFT", 12, 9)
    card.accept:SetText(ACCEPT)

    card.decline = CreateFrame("Button", name .. "Decline", card, "UIPanelButtonTemplate2")
    card.decline:SetWidth(90)
    card.decline:SetHeight(20)
    card.decline:SetPoint("LEFT", card.accept, "RIGHT", 10, 0)
    card.decline:SetText(DECLINE)

    card:SetScript("OnClick", function(self)
      selectEntry("request", self.handle)
    end)
    cards[index] = card
  end
  card:Show()
  return card
end

local function hideFrom(pool, index)
  for i = index, #pool do
    pool[i]:Hide()
  end
end

--[[ row text ------------------------------------------------------------- ]]

local function className(class)
  if not class or class == "" then
    return nil
  end
  local localised = LOCALIZED_CLASS_NAMES_MALE and LOCALIZED_CLASS_NAMES_MALE[class]
  return localised or class
end

-- The second line of a friend row, plus the reason it says what it says.
function NS.FriendLine(friend)
  if friend.status == NS.STATUS_PENDING_OUT then
    return "Request sent", "Waiting for this friend to answer."
  end
  if not friend.online then
    return FRIENDS_LIST_OFFLINE, nil
  end
  if not friend.char or friend.char == "" then
    return "Online — another character", TOOLTIP_HIDDEN
  end
  local line = friend.char
  local class = className(friend.class)
  if friend.level and class then
    line = line .. ", " .. string.format(FRIENDS_LEVEL_TEMPLATE, friend.level, class)
  elseif friend.level then
    line = line .. ", Level " .. friend.level
  elseif class then
    line = line .. ", " .. class
  end
  local zone = NS.ZoneName and NS.ZoneName(friend.zone)
  if zone then
    line = line .. " — " .. zone
  end
  return line, nil
end

--[[ the contextual bottom-right button ----------------------------------- ]]

local function updateActionButton()
  local selected = NS.selected
  if selected and selected.kind == "request" then
    actionButton:SetText("Accept Request")
    actionButton:Enable()
    actionButton:SetScript("OnClick", function()
      NS.Accept(selected.handle)
      NS.DropRequest(selected.handle)
      NS.selected = nil
      PlaySound("igMainMenuOptionCheckBoxOn")
      NS.Refresh()
    end)
    tip(actionButton, nil, "Accept " .. selected.handle .. "'s friend request.")
    return
  end

  actionButton:SetText(SEND_MESSAGE)
  local friend = selected and selected.kind == "friend" and NS.Friend(selected.handle)
  if friend and friend.online and friend.char and friend.char ~= "" then
    actionButton:Enable()
    actionButton:SetScript("OnClick", function()
      PlaySound("igMainMenuOptionCheckBoxOn")
      ChatFrame_SendTell(friend.char)
    end)
    tip(actionButton, nil, nil)
    return
  end

  actionButton:Disable()
  actionButton:SetScript("OnClick", nil)
  if not friend then
    tip(actionButton, SEND_MESSAGE, TOOLTIP_NO_SELECTION)
  elseif friend.online then
    tip(actionButton, SEND_MESSAGE, TOOLTIP_HIDDEN)
  else
    tip(actionButton, SEND_MESSAGE, TOOLTIP_OFFLINE)
  end
end

--[[ refresh -------------------------------------------------------------- ]]

local function setEmpty(text, reason)
  if not text then
    emptyText:Hide()
    emptyHover:Hide()
    return
  end
  emptyText:SetText(text)
  emptyText:SetTextColor(COLOR_MUTED[1], COLOR_MUTED[2], COLOR_MUTED[3])
  emptyText:Show()
  if reason then
    tip(emptyHover, text, reason)
    emptyHover:Show()
  else
    emptyHover:Hide()
  end
end

function NS.Refresh()
  if not panel:IsShown() then
    return
  end

  local state = NS.state
  handleText:SetText(state.handle or "—")
  if state.showCharacter == false then
    privacyText:SetText("Character hidden")
  else
    privacyText:SetText("Character shown")
  end

  local y = 0
  local headerIndex, rowIndex, cardIndex = 1, 1, 1

  local requests = state.requests
  if #requests > 0 then
    local header = acquireHeader(headerIndex)
    header:SetPoint("TOPLEFT", content, "TOPLEFT", 0, -y)
    header.text:SetText(string.format("Requests  %d of %d", #requests, NS.MaxRequests()))
    header.line:SetPoint("LEFT", header.text, "RIGHT", 8, 0)
    headerIndex = headerIndex + 1
    y = y + HEADER_H

    for i = 1, #requests do
      local card = acquireCard(cardIndex)
      local handle = requests[i].handle
      card.handle = handle
      card.name:SetText(handle)
      card:SetPoint("TOPLEFT", content, "TOPLEFT", 6, -y)
      card.accept:SetScript("OnClick", function()
        NS.Accept(handle)
        NS.DropRequest(handle)
        NS.selected = nil
        PlaySound("igMainMenuOptionCheckBoxOn")
        NS.Refresh()
      end)
      card.decline:SetScript("OnClick", function()
        NS.Decline(handle)
        NS.DropRequest(handle)
        NS.selected = nil
        PlaySound("igMainMenuOptionCheckBoxOn")
        NS.Refresh()
      end)
      if NS.selected and NS.selected.kind == "request" and NS.selected.handle == handle then
        card:SetBackdropBorderColor(0.24, 0.45, 0.75)
      else
        card:SetBackdropBorderColor(1, 1, 1)
      end
      cardIndex = cardIndex + 1
      y = y + CARD_H
    end
  end

  local friends = state.friends
  local header = acquireHeader(headerIndex)
  header:SetPoint("TOPLEFT", content, "TOPLEFT", 0, -y)
  header.text:SetText(string.format("Friends  %d of %d", #friends, NS.MaxFriends()))
  header.line:SetPoint("LEFT", header.text, "RIGHT", 8, 0)
  headerIndex = headerIndex + 1
  y = y + HEADER_H

  for i = 1, #friends do
    local friend = friends[i]
    local row = acquireRow(rowIndex)
    local selected = NS.selected and NS.selected.kind == "friend"
      and NS.selected.handle == friend.handle
    row.handle = friend.handle
    row:SetPoint("TOPLEFT", content, "TOPLEFT", 0, -y)
    row:SetHeight(selected and ROW_SELECTED_H or ROW_H)
    row.icon:SetTexture(friend.online and TEXTURE_ONLINE or TEXTURE_OFFLINE)
    row.name:SetText(friend.handle)

    local line, reason = NS.FriendLine(friend)
    row.info:SetText(line)
    tip(row, friend.handle, reason)

    if friend.online then
      row.name:SetTextColor(COLOR_NAME[1], COLOR_NAME[2], COLOR_NAME[3])
      row.info:SetTextColor(COLOR_INFO[1], COLOR_INFO[2], COLOR_INFO[3])
    else
      row.name:SetTextColor(COLOR_NAME_OFF[1], COLOR_NAME_OFF[2], COLOR_NAME_OFF[3])
      row.info:SetTextColor(COLOR_INFO_OFF[1], COLOR_INFO_OFF[2], COLOR_INFO_OFF[3])
    end

    if selected then
      row.selection:Show()
      if friend.note and friend.note ~= "" then
        row.note:SetText("Note: " .. friend.note)
      else
        row.note:SetText("No note.")
      end
      row.note:Show()
      row.editNote:Show()
      row.remove:Show()
      row.editNote:SetScript("OnClick", function()
        NS.ShowNoteEditor(friend.handle, friend.note)
      end)
      row.remove:SetScript("OnClick", function()
        NS.ConfirmRemove(friend.handle)
      end)
    else
      row.selection:Hide()
      row.note:Hide()
      row.editNote:Hide()
      row.remove:Hide()
    end

    rowIndex = rowIndex + 1
    y = y + (selected and ROW_SELECTED_H or ROW_H)
  end

  hideFrom(headers, headerIndex)
  hideFrom(rows, rowIndex)
  hideFrom(cards, cardIndex)

  content:SetHeight(y > 0 and y or 1)

  if not state.available then
    setEmpty(TEXT_UNAVAILABLE, TOOLTIP_UNAVAILABLE)
  elseif #friends == 0 and #requests == 0 then
    setEmpty("No friends yet.", nil)
  else
    setEmpty(nil)
  end

  updateActionButton()
end

-- Opening the tab is a good moment to re-ask for the roster, but
-- FriendsFrame_Update fires on a dozen unrelated events, so this is metered:
-- one LIST every ROSTER_REFRESH seconds, never one per event.
local ROSTER_REFRESH = 15
local lastRosterRequest = 0

function NS.RequestRoster()
  local now = GetTime()
  if now - lastRosterRequest < ROSTER_REFRESH then
    return false
  end
  lastRosterRequest = now
  return NS.List()
end

--[[ tab injection -------------------------------------------------------- ]]

local ACCOUNT_TAB_ID = 4

local function tabInjectable()
  return FriendsFrame and FriendsTabHeader and FriendsTabHeader.GetName
    and FriendsTabHeaderTab1 and FriendsTabHeaderTab2
    and type(PanelTemplates_SetNumTabs) == "function"
    and type(FriendsFrame_ShowSubFrame) == "function"
    and type(FRIENDSFRAME_SUBFRAMES) == "table"
    and not _G["FriendsTabHeaderTab" .. ACCOUNT_TAB_ID]
end

local function injectTab()
  if not tabInjectable() then
    return false
  end

  local tab = CreateFrame("Button", "FriendsTabHeaderTab" .. ACCOUNT_TAB_ID,
    FriendsTabHeader, "TabButtonTemplate")
  tab:SetID(ACCOUNT_TAB_ID)
  tab:SetText("Account")
  PanelTemplates_TabResize(tab, 0)
  local highlight = _G[tab:GetName() .. "HighlightTexture"]
  if highlight then
    highlight:SetWidth(tab:GetTextWidth() + 31)
  end

  -- Tab 3 (Pending) is hidden when Battle.net features are off, which they
  -- are on this realm. Anchoring to a hidden tab would leave a hole.
  local anchor = FriendsTabHeaderTab2
  if FriendsTabHeaderTab3 and FriendsTabHeaderTab3:IsShown() then
    anchor = FriendsTabHeaderTab3
  end
  tab:SetPoint("LEFT", anchor, "RIGHT", 0, 0)

  tab:SetScript("OnClick", function(self)
    PanelTemplates_Tab_OnClick(self, FriendsTabHeader)
    FriendsFrame_Update()
    PlaySound("igMainMenuOptionCheckBoxOn")
  end)

  PanelTemplates_SetNumTabs(FriendsTabHeader, ACCOUNT_TAB_ID)
  PanelTemplates_UpdateTabs(FriendsTabHeader)

  panel:SetParent(FriendsFrame)
  panel:ClearAllPoints()
  panel:SetAllPoints(FriendsFrame)
  FRIENDSFRAME_SUBFRAMES[#FRIENDSFRAME_SUBFRAMES + 1] = "ManiaxSocialListFrame"

  hooksecurefunc("FriendsFrame_Update", function()
    if FriendsFrame.selectedTab ~= 1 or FriendsTabHeader.selectedTab ~= ACCOUNT_TAB_ID then
      return
    end
    -- The stock function has already run its "ignore list" branch by now, so
    -- this puts the frame back the way the Friends tab leaves it: same four
    -- art pieces, same title, our sub-frame instead of theirs.
    FriendsFrameTopLeft:SetTexture("Interface\\FriendsFrame\\UI-FriendsFrame-TopLeft-bnet")
    FriendsFrameTopRight:SetTexture("Interface\\FriendsFrame\\UI-FriendsFrame-TopRight-bnet")
    FriendsFrameBottomLeft:SetTexture("Interface\\FriendsFrame\\UI-FriendsFrameMute-BotLeft-bnet")
    FriendsFrameBottomRight:SetTexture("Interface\\FriendsFrame\\UI-FriendsFrameMute-BotRight-bnet")
    FriendsFrameTitleText:SetText(FRIENDS_LIST)
    FriendsFrame_ShowSubFrame("ManiaxSocialListFrame")
    NS.Refresh()
    NS.RequestRoster()
  end)

  NS.injected = true
  return true
end

--[[ the standalone fallback ---------------------------------------------- ]]

local function buildStandalone()
  local window = CreateFrame("Frame", "ManiaxSocialFrame", UIParent, "UIPanelDialogTemplate")
  window:SetWidth(384)
  window:SetHeight(460)
  window:SetPoint("CENTER", UIParent, "CENTER", 0, 0)
  window:SetMovable(true)
  window:EnableMouse(true)
  window:RegisterForDrag("LeftButton")
  window:SetScript("OnDragStart", window.StartMoving)
  window:SetScript("OnDragStop", window.StopMovingOrSizing)
  window:SetToplevel(true)
  window:Hide()
  if window.title then
    window.title:SetText("ManiaxSocial")
  end
  tinsert(UISpecialFrames, "ManiaxSocialFrame")

  panel:SetParent(window)
  panel:ClearAllPoints()
  panel:SetAllPoints(window)
  panel:Show()

  -- The window has no portrait band, so the list starts higher and the
  -- buttons sit on its own floor.
  scroll:ClearAllPoints()
  scroll:SetPoint("TOPLEFT", panel, "TOPLEFT", 21, -74)
  scroll:SetHeight(300)
  handleLabel:ClearAllPoints()
  handleLabel:SetPoint("TOPLEFT", panel, "TOPLEFT", 16, -30)
  settingsButton:ClearAllPoints()
  settingsButton:SetPoint("TOPRIGHT", panel, "TOPRIGHT", -16, -28)
  addButton:ClearAllPoints()
  addButton:SetPoint("BOTTOMLEFT", panel, "BOTTOMLEFT", 15, 16)
  actionButton:ClearAllPoints()
  actionButton:SetPoint("BOTTOMRIGHT", panel, "BOTTOMRIGHT", -15, 16)

  window:SetScript("OnShow", function()
    NS.Refresh()
    NS.RequestRoster()
  end)
  NS.window = window
end

function NS.OpenAccountTab()
  if NS.injected then
    if not FriendsFrame:IsShown() then
      ToggleFriendsFrame(1)
    else
      PanelTemplates_SetTab(FriendsFrame, 1)
    end
    PanelTemplates_SetTab(FriendsTabHeader, ACCOUNT_TAB_ID)
    FriendsFrame_Update()
    return
  end
  if NS.window then
    if NS.window:IsShown() then
      NS.window:Hide()
    else
      NS.window:Show()
    end
  end
end

--[[ startup -------------------------------------------------------------- ]]

local loader = CreateFrame("Frame")
loader:RegisterEvent("PLAYER_LOGIN")
loader:SetScript("OnEvent", function()
  if not injectTab() then
    buildStandalone()
    NS.Print("the Friends List tab header could not be extended; " ..
      "ManiaxSocial opens as its own window (/msoc).")
  end
  NS.Subscribe(function(event, detail)
    NS.Refresh()
    if event == "REQ" and NS.OnRequestArrived then
      NS.OnRequestArrived(detail)
    end
    if event == "ERR" and NS.state.lastError then
      NS.Print(NS.state.lastError.text ~= "" and NS.state.lastError.text
        or ("error " .. tostring(NS.state.lastError.code)))
    end
  end)
end)