-- 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.

-- s-everest

-- Terminology:
-- "monitor": Either the Null Virtual Monitor[0] (a safetynet),
--             or an actual GPU/Screen pair managed by Glacier.
-- "surface": Everest system-level drawing primitive
-- "window" : Everest user-level wrapper around a surface providing a reliable window frame, movement, etc.
-- "line"   : A Wx1 area across a surface.
-- "span"   : A ?x1 area across a surface with text and a single fg/bg colour.
-- This has less user calls as opposed to the old KittenOS system, which had a high CPU usage.
-- Another thing to note is that Everest still uses callbacks, both for efficiency and library convenience,
--  though with automatically closing windows on process death.

-- How Bristol talks to this is:
-- 1. The user logs in
-- 2. Bristol starts up Everest, and frees the primary monitor
-- 3. The primary monitor is claimed by Everest and becomes monitor 1
-- 4. After a small time, Bristol dies, unclaiming all monitors
-- 5. Everest claims the new monitors, and the desktop session begins
-- 6. Everest shuts down for some reason,
--     sys-init gets started UNLESS endSession(false) was used

local everestProvider = neo.requireAccess("r.neo.pub.window", "registering npw")
local everestSessionProvider = neo.requireAccess("r.neo.sys.session", "registering nsse")

-- Got mutexes. Now setup saving throw and shutdown callback
-- Something to note is that Donkonit is the safety net on this,
--  as it auto-releases the monitors.
local screens = neo.requireAccess("x.neo.sys.screens", "access to screens")

neo.requestAccess("s.h.clipboard")
neo.requestAccess("s.h.touch")
neo.requestAccess("s.h.drag")
neo.requestAccess("s.h.drop")
neo.requestAccess("s.h.scroll")
neo.requestAccess("s.h.key_up")
neo.requestAccess("s.h.key_down")

-- {gpu, screenAddr, w, h, bg, fg}
local monitors = {}

-- NULL VIRTUAL MONITOR!
-- This is where we stuff processes until monitors show up
monitors[0] = {nil, nil, 160, 50}

-- {monitor, x, y, w, h, callback, title}
-- callback events are:
-- key ka kc down
-- line y
local surfaces = {}

-- Last Interact Monitor
local lIM = 1

-- Stops the main loop
local shuttingDown = false

-- Also used for settings.
local savingThrow = neo.requestAccess("x.neo.sys.manage")

local draggingWindowX, draggingWindowY

local function suggestAppsStop()
 for k, v in ipairs(surfaces) do
  for i = 1, 4 do
   v[6](v[8], "close")
  end
 end
end

local function dying()
 local primary = (monitors[1] or {})[2] or ""
 for _, v in ipairs(monitors) do
  pcall(screens.disclaim, v[2])
 end
 monitors = {}
 neo.executeAsync("sys-init", primary)
 -- In this case the surfaces are leaked and hold references here. They have to be removed manually.
 -- Do this via a "primary event" (k.deregistration) and "deathtrap events"
 -- If a process evades the deathtrap then it clearly has reason to stay alive regardless of Everest status.
 -- Also note, should savingThrow fail, neo.dead is now a thing.
 for _, v in ipairs(surfaces) do
  pcall(v[6], v[8], "line", 1)
  pcall(v[6], v[8], "line", 2)
 end
 surfaces = {}
end
if savingThrow then
 savingThrow.registerForShutdownEvent()
 savingThrow.registerSavingThrow(dying)
end

local function renderingAllowed()
 -- This is a safety feature to prevent implosion due to missing monitors.
 return #monitors > 0
end

local function surfaceAt(monitor, x, y)
 for k, v in ipairs(surfaces) do
  if v[1] == monitor then
   if x >= v[2] then
    if y >= v[3] then
     if x < (v[2] + v[4]) then
      if y < (v[3] + v[5]) then
       return k, (x - v[2]) + 1, (y - v[3]) + 1
      end
     end
    end
   end
  end
 end
end

-- Always use the first if the GPU has been rebound
local function monitorResetBF(m)
 m[5] = -1
 m[6] = -1
end
local function monitorGPUColours(m, cb, bg, fg)
 local nbg = m[5]
 local nfg = m[6]
 if nbg ~= bg then
  pcall(cb.setBackground, bg)
  m[5] = bg
 end
 if nfg ~= fg then
  pcall(cb.setForeground, fg)
  m[6] = fg
 end
end

-- Status line at top of screen
local statusLine = nil

local function doBackgroundLine(m, mg, bdx, bdy, bdl)
 if statusLine and (bdy == 1) then
  -- Status bar
  monitorGPUColours(m, mg, 0x000000, 0xFFFFFF)
  local str = unicode.sub(statusLine, bdx, bdx + bdl - 1)
  local strl = unicode.len(str)
  pcall(mg.set, bdx, bdy, unicode.undoSafeTextFormat(str))
  pcall(mg.set, bdx + strl, bdy, (" "):rep(bdl - strl))
 else
  monitorGPUColours(m, mg, 0x000040, 0)
  pcall(mg.set, bdx, bdy, (" "):rep(bdl))
 end
end

local function handleSpan(target, x, y, text, bg, fg)
 if not renderingAllowed() then return end
 local m = monitors[target[1]]
 local cb, rb = m[1]()
 if not cb then return end
 if rb then
  monitorResetBF(m)
 end
 -- It is assumed basic type checks were handled earlier.
 if y < 1 then return end
 if y > target[5] then return end
 if x < 1 then return end
 -- Note the use of unicode.len here.
 -- It's assumed that if the app is using Unicode text, then it used safeTextFormat earlier.
 -- This works for a consistent safety check.
 local w = unicode.len(text)
 if ((x + w) - 1) > target[4] then return end
 -- Checks complete, now commence screen cropping...
 local worldY = ((y + target[3]) - 1)
 if worldY < 1 then return end
 if worldY > monitors[target[1]][4] then return end
 -- The actual draw loop
 local buildingSegmentWX = nil
 local buildingSegmentWY = nil
 local buildingSegment = nil
 local buildingSegmentE = nil
 local function submitSegment()
  if buildingSegment then
   base = unicode.sub(text, buildingSegment, buildingSegmentE)
   -- rely on undoSafeTextFormat for this transform now
   monitorGPUColours(m, cb, bg, fg)
   pcall(cb.set, buildingSegmentWX, buildingSegmentWY, unicode.undoSafeTextFormat(base))
   buildingSegment = nil
  end
 end
 for i = 1, w do
  local rWX = (i - 1) + (x - 1) + target[2]
  local rWY = (y - 1) + target[3]
  local s = surfaceAt(target[1], rWX, rWY)
  local ok = false
  if s then
   ok = surfaces[s] == target
  end
  if ok then
   if not buildingSegment then
    buildingSegmentWX = rWX
    buildingSegmentWY = rWY
    buildingSegment = i
   end
   buildingSegmentE = i
  else
   submitSegment()
  end
 end
 submitSegment()
end

local function updateRegion(monitorId, x, y, w, h, surfaceSpanCache)
 if not renderingAllowed() then return end
 local m = monitors[monitorId]
 local mg, rb = m[1]()
 if not mg then return end
 if rb then
  monitorResetBF(m)
 end
 -- The input region is the one that makes SENSE.
 -- Considering WC handling, that's not an option.
 -- WCHAX: start
 if x > 1 then
  x = x - 1
  w = w + 1
 end
 -- this, in combination with 'forcefully blank out last column of window during render',
 -- cleans up littering
 w = w + 1
 -- WCHAX: end

 for span = 1, h do
  local backgroundMarkStart = nil
  for sx = 1, w do
   local t, tx, ty = surfaceAt(monitorId, sx + x - 1, span + y - 1)
   if t then
    -- Background must occur first due to wide char weirdness
    if backgroundMarkStart then
     local bdx, bdy, bdl = backgroundMarkStart + x - 1, span + y - 1, sx - backgroundMarkStart
     doBackgroundLine(m, mg, bdx, bdy, bdl)
     backgroundMarkStart = nil
    end
    if not surfaceSpanCache[monitorId .. "_" .. t .. "_" .. ty] then
     surfaceSpanCache[monitorId .. "_" .. t .. "_" .. ty] = true
     if ty == 1 then
      local lw = surfaces[t][4]
      local bg = 0x0080FF
      local fg = 0x000000
      local tx = "-"
      if t == 1 then
       bg = 0x000000
       fg = 0x0080FF
       tx = "+"
      end
      local vtitle = surfaces[t][7]
      local vto = unicode.len(vtitle)
      if vto < lw then
       vtitle = vtitle .. (tx):rep(lw - vto)
      else
       vtitle = unicode.sub(vtitle, 1, lw)
      end
      handleSpan(surfaces[t], 1, 1, vtitle, bg, fg)
     else
      surfaces[t][6](surfaces[t][8], "line", ty - 1)
     end
    end
   elseif not backgroundMarkStart then
    backgroundMarkStart = sx
   end
  end
  if backgroundMarkStart then
   doBackgroundLine(monitors[monitorId], mg, backgroundMarkStart + x - 1, span + y - 1, (w - backgroundMarkStart) + 1)
  end
 end
end

local function updateStatus()
 statusLine = "Λ-¶: menu (launch 'control' to logout)"
 if surfaces[1] then
  if #monitors > 1 then
   --            123456789X123456789X123456789X123456789X123456789X
   statusLine = "Λ-+: move, Λ-Z: switch, Λ-X: swMonitor, Λ-C: close"
  else
   statusLine = "Λ-+: move, Λ-Z: switch, Λ-C: close"
  end
 end
 statusLine = unicode.safeTextFormat(statusLine)
 for k, v in ipairs(monitors) do
  updateRegion(k, 1, 1, v[3], 1, {})
 end
end

local function ensureOnscreen(monitor, x, y, w, h)
 if monitor <= 0 then monitor = #monitors end
 if monitor >= (#monitors + 1) then monitor = 1 end
 -- Failing anything else, revert to monitor 0
 if #monitors == 0 then monitor = 0 end
 x = math.min(math.max(x, 1), monitors[monitor][3] - (w - 1))
 y = math.max(2 - h, math.min(monitors[monitor][4], y))
 return monitor, x, y
end

-- This is the "a state change occurred" function, only for use when needed
local function reconcileAll()
 for k, v in ipairs(surfaces) do
  -- About to update whole screen anyway so avoid the wait.
  v[1], v[2], v[3] = ensureOnscreen(v[1], v[2], v[3], v[4], v[5])
 end
 local k = 1
 while k <= #monitors do
  local v = monitors[k]
  local mon, rb = v[1]()
  if rb then
   monitorResetBF(v)
  end
  if mon then
   -- This *can* return null if something went wonky. Let's detect that
   v[3], v[4] = mon.getResolution()
   if not v[3] then
    neo.emergency("everest: monitor went AWOL and nobody told me u.u")
    table.remove(monitors, k)
    v = nil
   end
  end
  if v then
   updateRegion(k, 1, 1, v[3], v[4], {})
   k = k + 1
  end
 end
 updateStatus()
end

-- NOTE: If the M, X, Y, W and H are the same, this function ignores you, unless you put , true on the end.
local function moveSurface(surface, m, x, y, w, h, force)
 local om, ox, oy, ow, oh = table.unpack(surface, 1, 5)
 m = m or om
 x = x or ox
 y = y or oy
 w = w or ow
 h = h or oh
 surface[1], surface[2], surface[3], surface[4], surface[5] = m, x, y, w, h
 local cache = {}
 if om == m and ow == w and oh == h then
  if ox == x and oy == y and not force then
   return
  end
  -- note: this doesn't always work due to WC support, and due to resize-to-repaint
  if renderingAllowed() and not force then
   local cb, b = monitors[m][1]()
   if b then
    monitorResetBF(monitors[m])
   end
   if cb then
    local monH = monitors[m][4]
    local cutTop = math.max(0, 1 - math.min(oy, y))
    local cutBottom = math.max(0, (math.max(oy + oh, y + h) - 1) - monH)
    pcall(cb.copy, ox, oy + cutTop, w, h - (cutTop + cutBottom), x - ox, y - oy)
    if surface == surfaces[1] then
     local cacheControl = {}
     for i = 1 + cutTop, h - cutBottom do
      cacheControl[om .. "_1_" .. i] = true
     end
     updateRegion(om, ox, oy, ow, oh, cacheControl)
     return
    end
   end
  end
 end
 updateRegion(om, ox, oy, ow, oh, cache)
 updateRegion(m, x, y, w, h, cache)
end
-- Returns offset from where we expected to be to where we are.
local function ofsSurface(focus, dx, dy)
 local exX, exY = focus[2] + dx, focus[3] + dy
 local m, x, y = ensureOnscreen(focus[1], exX, exY, focus[4], focus[5])
 moveSurface(focus, nil, x, y)
 return focus[2] - exX, focus[3] - exY
end
local function ofsMSurface(focus, dm)
 local m, x, y = ensureOnscreen(focus[1] + dm, focus[2], focus[3], focus[4], focus[5])
 moveSurface(focus, m, x, y)
end

local basePalT2 = {
 -- on T2 we provide 'system colours' by default
 0x000000, 0x0080FF, 0x000040, 0xFFFFFF,
 -- stuff above cannot be altered by user applications, to prevent graphical glitches.
 -- Provide some shades of grey to try and prevent accidental chroma.
 0x182828, 0x404040, 0x686868, 0x909090,
 0xB8B8B8, 0xE0E0E0, 0x800080, 0xFF0000,
 0x808000, 0x00FF00, 0x008080, 0x0000FF
}
local basePalT3 = {
 -- on T3 we provide the Tier 3 pal.
 0x0F0F0F, 0x1E1E1E, 0x2D2D2D, 0x3C3C3C,
 0x4B4B4B, 0x5A5A5A, 0x696969, 0x787878,
 0x878787, 0x969696, 0xA5A5A5, 0xB4B4B4,
 0xC3C3C3, 0xD2D2D2, 0xE1E1E1, 0xF0F0F0
}

local function setSurfacePalette(surf, pal)
 if neo.dead then return 0 end
 local m = monitors[surf[1]]
 if not m then return 0 end
 local cb, rb = m[1]()
 if not cb then return 0 end
 local dok, depth = pcall(cb.getDepth)
 if not dok then depth = 4 end
 if rb then
  monitorResetBF(m)
 end
 local ko = -1
 local unlocked = false
 if not rawequal(pal, nil) then
  neo.ensureType(pal, "table")
  if depth < 8 then
   ko = 3 -- start overriding at indexes 4+
  end
 elseif depth < 8 then
  pal = basePalT2
  unlocked = true
 else
  pal = basePalT3
  unlocked = true
 end
 for k, v in ipairs(pal) do
  -- prevent graphical glitches for
  -- critical system colours on T3
  local av = v % 0x1000000
  if unlocked or (av ~= 0xFFFFFF and
     av ~= 0x000000 and
     av ~= 0x0080FF and
     av ~= 0x000040) then
   local ok = pcall(cb.setPaletteColor, k + ko, v)
   if not ok then return k - 1 end
  end
 end
 return #pal
end

local function changeFocus(oldSurface, optcache)
 local ns1 = surfaces[1]
 optcache = optcache or {}
 if ns1 ~= oldSurface then
  if oldSurface then
   setSurfacePalette(oldSurface, nil)
   oldSurface[6](oldSurface[8], "focus", false)
  end
  if ns1 then
   setSurfacePalette(ns1, nil)
   ns1[6](ns1[8], "focus", true)
  end
  updateStatus()
  if oldSurface then
   updateRegion(oldSurface[1], oldSurface[2], oldSurface[3], oldSurface[4], oldSurface[5], optcache)
  end
  if ns1 then
   updateRegion(ns1[1], ns1[2], ns1[3], ns1[4], ns1[5], optcache)
  end
 end
end

-- THE EVEREST USER API BEGINS
local surfaceOwners = {}

-- Not relevant here really, but has to be up here because it closes the window
local waitingShutdownCallback = nil
local function checkWSC()
 if waitingShutdownCallback then
  if #surfaces == 0 then
   waitingShutdownCallback()
   waitingShutdownCallback = nil
  end
 end
end

everestProvider(function (pkg, pid, sendSig)
 local base = pkg .. "/" .. pid
 local lid = 0
 return function (w, h, title)
  if neo.dead then error("everest died") end
  if shuttingDown or waitingShutdownCallback then error("system shutting down") end
  w = math.floor(math.max(w, 8))
  h = math.floor(math.max(h, 1)) + 1
  if type(title) ~= "string" then
   title = base
  else
   title = base .. ":" .. title
  end
  local llid = lid
  lid = lid + 1
  local surf = {math.min(#monitors, math.max(1, lIM)), 1, 2, w, h, sendSig, title, llid}
  if h >= monitors[surf[1]][4] then
   surf[3] = 1
  end
  local osrf = surfaces[1]
  table.insert(surfaces, 1, surf)
  surfaceOwners[surf] = pid
  changeFocus(osrf)
  return {
   id = llid,
   setSize = function (w, h)
    if neo.dead then return end
    w = math.floor(math.max(w, 8))
    h = math.floor(math.max(h, 1)) + 1
    local _, x, y = ensureOnscreen(surf[1], surf[2], surf[3], w, h)
    moveSurface(surf, nil, x, y, w, h, true)
    return w, (h - 1)
   end,
   getDepth = function ()
    if neo.dead then return 1 end
    local m = monitors[surf[1]]
    if not m then return 1 end
    local cb, rb = m[1]()
    if not cb then return 1 end
    if rb then
     monitorResetBF(m)
    end
    return cb.getDepth()
   end,
   span = function (x, y, text, bg, fg)
    if neo.dead then error("everest died") end
    checkArg(3, text, "string")
    x, y, bg, fg = math.floor(x), math.floor(y), math.floor(bg), math.floor(fg)
    if y == 0 then return end
    handleSpan(surf, x, y + 1, text, bg, fg)
   end,
   recommendPalette = function (pal)
    if surfaces[1] ~= surf then return 0 end
    return setSurfacePalette(surf, pal)
   end,
   close = function ()
    if neo.dead then return end
    local os1 = surfaces[1]
    surfaceOwners[surf] = nil
    for k, v in ipairs(surfaces) do
     if v == surf then
      table.remove(surfaces, k)
      local cache = {}
      checkWSC()
      changeFocus(os1, cache)
      -- focus up to date, deal with any remains
      updateRegion(surf[1], surf[2], surf[3], surf[4], surf[5], cache)
      return
     end
    end
   end
  }
 end
end)
-- THE EVEREST USER API ENDS (now for the session API, which just does boring stuff)
-- used later on for lost monitor, too
local function disclaimMonitor(mon)
 checkArg(1, mon, "string")
 screens.disclaim(mon)
 for k, v in ipairs(monitors) do
  if v[2] == mon then
   table.remove(monitors, k)
   reconcileAll()
   return true
  end
 end
 return false
end
everestSessionProvider(function (pkg, pid, sendSig)
 return {
  endSession = function (gotoBristol)
   checkArg(1, gotoBristol, "boolean")
   shuttingDown = true
   if gotoBristol then
    suggestAppsStop()
    dying()
   end
  end,
  getMonitors = function ()
   local details = {}
   for k, v in ipairs(monitors) do
    details[k] = v[2]
   end
   return details
  end,
  disclaimMonitor = disclaimMonitor
 }
end)
-- THE EVEREST SESSION API ENDS

local function startLauncher()
 if not waitingShutdownCallback then
  local lApp = "app-launcher"
  if savingThrow then
   lApp = savingThrow.getSetting("sys-everest.launcher") or lApp
  end
  if lApp then
   neo.executeAsync(lApp)
  end
 end
end

-- WM shortcuts are:
-- Alt-Z: Switch surface
-- Alt-Enter: Launcher
-- Alt-Up/Down/Left/Right: Move surface
local isAltDown = false
local isCtrDown = false
local function key(ku, ka, kc, down)
 local ku, lin = screens.getMonitorByKeyboard(ku)
 for k, v in ipairs(monitors) do
  if ku and v[2] == ku then
   lin = k
   break
  end
 end
 if not lin then return end
 lIM = lin

 local focus = surfaces[1]
 if kc == 29 then
  isCtrDown = down
 elseif kc == 56 then
  isAltDown = down
 end
 if isAltDown and ka == 122 then
  if focus and down then
   local n = table.remove(surfaces, 1)
   table.insert(surfaces, n)
   changeFocus(n)
  end
 elseif isAltDown and kc == 200 then
  if focus and down then ofsSurface(focus, 0, -1) end
 elseif isAltDown and kc == 208 then
  if focus and down then ofsSurface(focus, 0, 1) end
 elseif isAltDown and kc == 203 then
  if focus and down then ofsSurface(focus, -1, 0) end
 elseif isAltDown and kc == 205 then
  if focus and down then ofsSurface(focus, 1, 0) end
 elseif isAltDown and ka == 120 then
  if focus and down then ofsMSurface(focus, 1) end
 elseif isAltDown and ka == 97 then
  if not down then
   isAltDown = false
  end
 elseif isAltDown and (ka == 3 or ka == 99) then
  if down then
   if isCtrDown then
    error("User-authorized Everest crash.")
   elseif focus then
    focus[6](focus[8], "close")
   end
  end
 elseif isAltDown and ka == 13 then
  if down then
   startLauncher()
  end
 elseif focus then
  if kc ~= 56 then
   lIM = focus[1]
  end
  focus[6](focus[8], "key", ka, kc, down)
 end
end

-- take all displays!
local function performClaim(s3)
 local gpu, _ = screens.claim(s3)
 local gpucb = gpu and (gpu())
 if gpucb then
  local w, h = gpucb.getResolution()
  table.insert(monitors, {gpu, s3, w, h, -1, -1})
  setSurfacePalette({#monitors}, nil)
  -- This is required to ensure windows are moved off of the null monitor.
  -- Luckily, there's an obvious sign if they aren't - everest will promptly crash.
  reconcileAll()
 end
end

for _, v in ipairs(screens.getClaimable()) do
 performClaim(v)
end

while not shuttingDown do
 local s = {coroutine.yield()}
 if renderingAllowed() then
  if s[1] == "h.key_down" then
   key(s[2], s[3], s[4], true)
  end
  if s[1] == "h.key_up" then
   key(s[2], s[3], s[4], false)
  end
  if s[1] == "h.clipboard" then
   if surfaces[1] then
    surfaces[1][6](surfaces[1][8], "clipboard", s[3])
   end
  end
  -- next on my list: high-res coordinates
  if s[1] == "h.touch" then
   for k, v in ipairs(monitors) do
    if v[2] == s[2] then
     lIM = k
     local x, y = math.ceil(s[3]), math.ceil(s[4])
     local ix, iy = s[3] - math.floor(x), s[4] - math.floor(y)
     local sid, lx, ly = surfaceAt(k, x, y)
     if sid then
      local os = surfaces[1]
      local ns = table.remove(surfaces, sid)
      table.insert(surfaces, 1, ns)
      changeFocus(os)
      draggingWindowX, draggingWindowY = nil
      if ly == 1 then
       if s[5] == 1 then
        ns[6](ns[8], "close")
       else
        draggingWindowX, draggingWindowY = lx, ly
       end
      else
       ns[6](ns[8], "touch", lx, ly - 1, ix, iy, s[5])
      end
     else
      if s[5] == 1 then startLauncher() end
     end
     break
    end
   end
  end
  if s[1] == "h.drag" or s[1] == "h.drop" or s[1] == "h.scroll" then
   -- Pass to focus surface, even if out of bounds
   local focus = surfaces[1]
   if focus then
    for k, v in ipairs(monitors) do
     if v[2] == s[2] then
      if k == focus[1] then
       local x, y = (math.ceil(s[3]) - focus[2]) + 1, (math.ceil(s[4]) - focus[3]) + 1
       local ix, iy = s[3] - math.floor(s[3]), s[4] - math.floor(s[4])
       if s[1] == "h.drag" and draggingWindowX then
        local ofsX, ofsY = x - draggingWindowX, y - draggingWindowY
        if ofsX ~= 0 or ofsY ~= 0 then
         ofsSurface(focus, ofsX, ofsY)
        end
       else
        draggingWindowX, draggingWindowY = nil
        -- Ok, so let's see...
        focus[6](focus[8], s[1]:sub(3), x, y - 1, ix, iy, s[5])
       end
      end
      break
     end
    end
   end
  end
 else
  isCtrDown = false
  isAltDown = false
 end
 if s[1] == "k.procdie" then
  local os1 = surfaces[1]
  -- Note this is in order (that's important)
  local tags = {}
  for k, v in ipairs(surfaces) do
   if surfaceOwners[v] == s[3] then
    table.insert(tags, k)
    surfaceOwners[v] = nil
   end
  end
  for k, v in ipairs(tags) do
   local surf = table.remove(surfaces, v - (k - 1))
   if os1 == surf then
    os1 = nil
   end
   updateRegion(surf[1], surf[2], surf[3], surf[4], surf[5], {})
  end
  checkWSC()
  if os1 then
   changeFocus(os1)
  else
   changeFocus()
  end
 end
 if s[1] == "x.neo.sys.screens" then
  if s[2] == "available" then
   performClaim(s[3])
  end
  if s[2] == "lost" then
   disclaimMonitor(s[3])
  end
 end
 if s[1] == "x.neo.sys.manage" then
  if s[2] == "shutdown" then
   waitingShutdownCallback = s[4]
   suggestAppsStop()
   checkWSC()
  end
 end
end