-- Copyright (C) 2018-2021 by KittenOS NEO contributors
--
-- Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted.
--
-- THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
-- THIS SOFTWARE.

-- just don't bother with proper indent here
return function (event, nexus, retFunc, fs, pkg, mode, defName)

local fmt = require("fmttext")
local class = "manage"
if mode ~= nil then
 if mode then
  class = "save"
 else
  class = "load"
 end
end

-- State
local w, h, ctrl = 30, 8, false
local l, selection, unknownTx
local node, wnd

local function prepareNode(n)
 node = n
 l = node.list()
 selection, unknownTx = 1, ""
 wnd.setSize(w, h)
end

local function format(a)
 if a <= 1 then
  return false, fmt.pad(unicode.safeTextFormat(node.name), w, true, true)
 end
 local camY = math.max(1, selection - 3)
 local idx = a + camY - 2
 local utx = (" "):rep(w)
 if node.unknownAvailable and idx == #l + 1 then
  utx = "<OK>[" .. fmt.pad(unicode.safeTextFormat(unknownTx), w - 6, false, true, true) .. "]"
 end
 if l[idx] then
  utx = "<" .. fmt.pad(unicode.safeTextFormat(l[idx][1]), w - 2, false, true) .. ">"
 end
 return selection == idx, utx
end

local function updateLine(a)
 local colA, colB = 0xFFFFFF, 0
 local sel, text = format(a)
 if sel then
  colB, colA = 0xFFFFFF, 0
 end
 wnd.span(1, a, text, colA, colB)
end

local function flush()
 for i = 1, h do
  updateLine(i)
 end
end

local function key(ka, kc, down)
 if kc == 29 then
  ctrl = down
 end
 if not down then return end
 if ctrl then
  if kc == 200 then
   h = math.max(2, h - 1)
  elseif kc == 208 then
   h = h + 1
  elseif kc == 203 then
   w = math.max(6, w - 1)
  elseif kc == 205 then
   w = w + 1
  else
   return
  end
  wnd.setSize(w, h)
  return
 elseif (ka == 9) or (kc == 208) then
  local lo = selection
  selection = selection + 1
  local max = #l
  if node.unknownAvailable then
   max = max + 1
  end
  if selection > max then
   selection = 1
  end
 elseif kc == 200 then
  local lo = selection
  selection = selection - 1
  local max = #l
  if node.unknownAvailable then
   max = max + 1
  end
  if selection == 0 then
   selection = max
  end
 elseif ka == 13 then
  local aResult, res
  if selection ~= #l + 1 then
   aResult, res = l[selection][2]()
  else
   aResult, res = node.selectUnknown(unknownTx)
  end
  if aResult then
   retFunc(res)
   nexus.windows[wnd.id] = nil
   wnd.close()
  else
   prepareNode(res)
  end
 elseif selection == #l + 1 then
  if ka == 8 or kc == 211 then
   unknownTx = unicode.sub(unknownTx, 1, unicode.len(unknownTx) - 1)
  elseif ka ~= 0 then
   unknownTx = unknownTx .. unicode.char(ka)
  end
 end
 flush()
end

local function key2(...)
 local res, e = pcall(key, ...)
 if not res then
  prepareNode({
   name = "F.M. Error",
   list = function ()
    local l = {}
    for k, v in ipairs(fmt.fmtText(unicode.safeTextFormat(e), w)) do
     l[k] = {v, function () return true end}
    end
    return l
   end,
   unknownAvailable = false,
   selectUnknown = function (text) end
  })
 end
end

nexus.create(w, h, class .. " " .. pkg, function (w, ev, a, b, c)
 if not wnd then
  wnd = w
  prepareNode(require("sys-filevfs")(fs, mode, defName))
 end
 if ev == "key" then
  key2(a, b, c)
 end
 if ev == "touch" then
  local ns = b + math.max(1, selection - 3) - 2
  local max = #l
  if node.unknownAvailable then
   max = max + 1
  end
  if ns == selection and ((selection ~= #l + 1) or (a <= 4)) then
   key2(13, 0, true)
  else
   selection = math.min(math.max(1, ns), max)
   flush()
  end
 end
 if ev == "line" then
  updateLine(a)
 end
 if ev == "close" then
  retFunc(nil)
  nexus.windows[wnd.id] = nil
  wnd.close()
 end
end)

return function ()
 retFunc()
 closer()
 if wnd then
  nexus.windows[wnd.id] = nil
  wnd.close()
  wnd = nil
 end
end

-- end bad indent
end