backends.lua

--[[ Stash / backends ----------------------------------------------------------

  Which window the cached bank is poured into.

  Showing Blizzard's BankFrame is only the right answer when that is what you
  see at a real bank. A backend is a small description of somebody else's bank
  window, and the highest priority one that is actually loaded wins.

  A backend that sets ownscache means the addon behind it already keeps its own
  copy of the bank and will show that. In those cases the API diversion in
  shim.lua stays switched off so there is only ever one source of truth on
  screen; Stash just opens the window.

  Adding one for another bag addon is a few lines:

    Stash:RegisterBackend({
      name     = "mybags",
      priority = 10,
      detect   = function() return MyBags_OpenBank and true or nil end,
      isopen   = function() return MyBankFrame:IsVisible() end,
      open     = function() MyBags_OpenBank() end,
      close    = function() MyBankFrame:Hide() end,
      install  = function() Stash:HookClose(MyBankFrame) end,
    })

-----------------------------------------------------------------------------]]

local pairs, ipairs = pairs, ipairs
local getn, sort = table.getn, table.sort

Stash.modules.backends = true
Stash.backends = {}

function Stash:RegisterBackend(def)
  if not def or not def.name or not def.detect then
    return
  end
  Stash.backends[def.name] = def
end

-- The backend in use: whatever was pinned with /stash ui, else the best one
-- present.
function Stash:GetBackend()
  local pinned = StashDB and StashDB.ui
  if pinned and Stash.backends[pinned] and Stash.backends[pinned].detect() then
    return Stash.backends[pinned]
  end

  local best
  for _, backend in pairs(Stash.backends) do
    if backend.detect() and (not best or (backend.priority or 0) > (best.priority or 0)) then
      best = backend
    end
  end

  return best
end

function Stash:ListBackends()
  local names = {}
  for name in pairs(Stash.backends) do
    names[getn(names) + 1] = name
  end
  sort(names)
  return names
end

-- --------------------------------------------------------------------------
-- Bagnon
--
-- Banknon is Bagnon's bank window. Bagnon keeps its own cache in BagnonDB and
-- switches Banknon over to it whenever the player is away from the bank, so
-- there is nothing for the shim to do here beyond opening the frame.
-- --------------------------------------------------------------------------

Stash:RegisterBackend({
  name = "bagnon",
  priority = 20,
  ownscache = true,
  label = "Bagnon (Banknon)",

  detect = function()
    return BagnonFrame_Open and Banknon and BagnonDB and true or nil
  end,

  isopen = function()
    return Banknon and Banknon:IsVisible() and true or nil
  end,

  open = function()
    BagnonFrame_Open("Banknon")
  end,

  close = function()
    BagnonFrame_Close("Banknon")
  end,

  install = function()
    Stash:HookClose(Banknon)
  end,
})

-- --------------------------------------------------------------------------
-- Blizzard
--
-- Always available, and the right answer for bag addons that replace the bags
-- but leave the bank alone - EngInventory, for one, has no bank window at all,
-- so this is what its users see at a real bank too.
-- --------------------------------------------------------------------------

Stash:RegisterBackend({
  name = "blizzard",
  priority = 0,
  label = "Blizzard BankFrame",

  detect = function()
    return BankFrame and true or nil
  end,

  isopen = function()
    return BankFrame and BankFrame:IsShown() and true or nil
  end,

  open = function()
    if ShowUIPanel then
      ShowUIPanel(BankFrame)
    else
      BankFrame:Show()
    end
  end,

  close = function()
    if HideUIPanel then
      HideUIPanel(BankFrame)
    else
      BankFrame:Hide()
    end
  end,

  refresh = function()
    Stash:RefreshBankFrame()
  end,

  install = function()
    Stash:HookClose(BankFrame)
  end,
})

-- --------------------------------------------------------------------------
-- init
--
-- Installing waits for PLAYER_LOGIN: the frames belonging to other addons do
-- not necessarily exist while this file is being read.
-- --------------------------------------------------------------------------

local init = CreateFrame("Frame")
init:RegisterEvent("PLAYER_LOGIN")
init:SetScript("OnEvent", function()
  for _, backend in pairs(Stash.backends) do
    if backend.detect() and backend.install then
      backend.install()
    end
  end
end)