-- This is released into the public domain.
-- No warranty is provided, implied or otherwise.

-- s-bristol splash screen, login agent
-- Named to allude to Plymouth (splash screen used in some linux distros)

local callerPkg, callerPid, callerScr = ...

local shutdownEmergency = neo.requestAccess("k.computer").shutdown
neo.requestAccess("s.h.key_down")
neo.requestAccess("s.h._kosneo_syslog")

-- gpuG/performDisclaim are GPU management, while screen is used for prioritization
local gpuG, performDisclaim, screen = nil
local scrW, scrH
local nssInst

local console = {}
local helpActive = false
local buttonsActive = false

-- Attempts to call upon nsm for a safe shutdown
local function shutdown(reboot)
 local nsm = neo.requestAccess("x.neo.sys.manage")
 if nsm then
  nsm.shutdown(reboot)
  while true do
   coroutine.yield()
  end
 else
  shutdownEmergency(reboot)
 end
end

local function basicDraw(bg)
 local gpu = gpuG()
 pcall(gpu.setBackground, bg or 0xFFFFFF)
 pcall(gpu.setForeground, 0x000000)
 local ok, sw, sh = pcall(gpu.getResolution)
 if not ok then return end
 scrW, scrH = sw, sh
 pcall(gpu.fill, 1, 1, scrW, scrH, " ")
 pcall(gpu.set, 2, 2, "KittenOS NEO")
 local usage = math.floor((os.totalMemory() - os.freeMemory()) / 1024)
 pcall(gpu.set, 2, 3, "RAM Usage: " .. usage .. "K / " .. math.floor(os.totalMemory() / 1024) .. "K")
 local cut = 7
 if buttonsActive then cut = 9 end
 local areaSize = scrH - cut
 local n2 = 0
 if helpActive then
  if _VERSION == "Lua 5.2" then
   table.insert(console, "WARNING: Lua 5.2 memory usage issue!")
   table.insert(console, "Shift-right-click while holding the CPU/APU.")
   n2 = 2
  end
  table.insert(console, "TAB to change option, ENTER to select.")
  n2 = n2 + 1
 end
 for i = 1, areaSize do
  pcall(gpu.set, 2, 6 + i, console[#console + i - areaSize] or "")
 end
 for i = 1, n2 do
  table.remove(console, #console)
 end
 return gpu
end

local function consoleEventHandler(ev)
 if ev[1] == "h._kosneo_syslog" then
  local text = ""
  for i = 3, #ev do
   if i ~= 3 then text = text .. " " end
   text = text .. tostring(ev[i])
  end
  table.insert(console, text)
 end
end

-- Attempts to get an NSS monitor with a priority list of screens
local function retrieveNssMonitor(...)
 local spc = {...}
 gpuG = nil
 local subpool = {}
 while not gpuG do
  if performDisclaim then
   performDisclaim(true)
   performDisclaim = nil
  end
  -- nss available - this means the monitor pool is now ready.
  -- If no monitors are available, shut down now.
  -- NSS monitor pool output is smaller than, but similar to, Everest monitor data:
  -- {gpu, screenAddr}
  local pool = nssInst.getClaimable()
  while not pool[1] do
   -- wait for presumably a NSS notification
   consoleEventHandler({coroutine.yield()})
   pool = nssInst.getClaimable()
  end
  subpool = {}
  -- Specifies which element to elevate to top priority
  local optimalSwap = nil
  local optimal = #spc + 1
  if screen then
   for k, v in ipairs(pool) do
    for k2, v2 in ipairs(spc) do
     if v == v2 and optimal > k2 then
      optimalSwap, optimal = k, k2
      break
     end
    end
   end
  end
  if optimalSwap then
   local swapA = pool[optimalSwap]
   pool[optimalSwap] = pool[1]
   pool[1] = swapA
  end
  for _, v in ipairs(pool) do
   local gpu = nssInst.claim(v)
   if gpu then
    local gcb = gpu()
    if gcb then
     pcall(function ()
      gcb.setBackground(0x000020)
      local w, h = gcb.getResolution()
      gcb.fill(1, 1, w, h, " ")
      table.insert(subpool, {gpu, v})
     end)
    end
   end
  end
  if subpool[1] then
   gpuG, screen = table.unpack(subpool[1])
  end
 end
 -- done with search
 performDisclaim = function (full)
  nssInst.disclaim(subpool[1][2])
  if full then
   for _, v in ipairs(subpool) do
    nssInst.disclaim(v[2])
   end
  end
 end
end

local function sleep(t)
 neo.scheduleTimer(os.uptime() + t)
 while true do
  local ev = {coroutine.yield()}
  consoleEventHandler(ev)
  if ev[1] == "k.timer" then
   break
  end
  if ev[1] == "x.neo.sys.screens" then
   retrieveNssMonitor(screen)
   basicDraw()
  end
 end
end

local function alert(s)
 console = {s}
 helpActive, buttonsActive = false, false
 basicDraw()
 sleep(1)
 buttonsActive = true
end

local function finalPrompt()
 nssInst = neo.requestAccess("x.neo.sys.screens")
 if not nssInst then
  console = {"sys-glacier not available"}
  basicDraw()
  error("no nssInst")
 end
 retrieveNssMonitor()
 helpActive, buttonsActive = true, true
 -- This is nsm's final chance to make itself available and thus allow the password to be set
 local nsm = neo.requestAccess("x.neo.sys.manage")
 local waiting = true
 local safeModeActive = false
 local password = ""
 if nsm then
  password = nsm.getSetting("password")
  if nsm.getSetting("sys-init.nologin") == "yes" then
   return false
  end
 end
 -- The actual main prompt loop
 while waiting do
  local entry = ""
  local entry2 = ""
  local active = true
  local pw = {function ()
     return "Password: " .. entry2
    end, function (key)
     if key >= 32 then
      entry = entry .. unicode.char(key)
      entry2 = entry2 .. "*"
     end
     if key == 13 then
      if entry == password then
       waiting = false
      else
       alert("Incorrect password")
      end
      active = false
     end
    end, 2, 5, scrW - 2}
  if password == "" then
   pw = {function ()
     return "Log in..."
    end, function (key)
     if key == 13 then
      waiting = false
      active = false
     end
    end, 2, 5, scrW - 2}
  end
  local controls = {
   {function ()
     return "<Shutdown>"
    end, function (key)
     if key == 13 then
      alert("Shutting down...")
      shutdown(false)
     end
    end, 2, scrH - 1, 10},
   {function ()
     return "<Reboot>"
    end, function (key)
     if key == 13 then
      alert("Rebooting...")
      shutdown(true)
     end
    end, 13, scrH - 1, 8},
   {function ()
     return "<Safe Mode>"
    end, function (key)
     if key == 13 then
      safeModeActive = true
      alert("Login to activate Safe Mode.")
     end
    end, 22, scrH - 1, 11},
   pw,
  }
  local control = #controls
  local lastKeyboard
  while active do
   local gpu = basicDraw()
   if gpu then
    for k, v in ipairs(controls) do
     if k == control then
      pcall(gpu.setBackground, 0x000000)
      pcall(gpu.setForeground, 0xFFFFFF)
     else
      pcall(gpu.setBackground, 0xFFFFFF)
      pcall(gpu.setForeground, 0x000000)
     end
     pcall(gpu.fill, v[3], v[4], v[5], 1, " ")
     pcall(gpu.set, v[3], v[4], v[1]())
    end
   end
   -- event handling...
   local sig = {coroutine.yield()}
   consoleEventHandler(sig)
   if sig[1] == "x.neo.sys.screens" then
    -- We need to reinit screens no matter what.
    retrieveNssMonitor(screen)
   end
   if sig[1] == "h.key_down" then
    if sig[2] ~= lastKeyboard then
     lastKeyboard = sig[2]
     local nScreen = nssInst.getMonitorByKeyboard(lastKeyboard)
     if nScreen and nScreen ~= screen then
      neo.emergency("new primary:", nScreen)
      retrieveNssMonitor(nScreen, screen)
      basicDraw()
     end
    end
    if sig[4] == 15 then
     -- this makes sense in context
     control = control % #controls
     control = control + 1
    else
     controls[control][2](sig[3])
    end
   end
  end
 end
 helpActive, buttonsActive = false, false
 return safeModeActive
end
local function postPrompt()
 local nsm = neo.requestAccess("x.neo.sys.manage")
 local sh = "sys-everest"
 console = {"Unable to get shell (no sys-glacier)"}
 if nsm then
  sh = nsm.getSetting("sys-init.shell") or sh
  console = {"Starting "  .. sh}
 end
 basicDraw()
 performDisclaim()
 neo.executeAsync(sh)
 -- There's a delay here to allow taking the monitor.
 sleep(0.5)
 for i = 1, 9 do
  local v = neo.requestAccess("x.neo.sys.session")
  sleep(0.5) -- Important timing - allows it to take the monitor
  if v then
   return
  end
 end
 -- ...oh. hope this works then?
 console = {"x.neo.sys.session not found, try Safe Mode."}
 retrieveNssMonitor(screen)
 basicDraw()
 sleep(1)
 shutdown(true)
end

local function initializeSystem()
 -- System has just booted, bristol is in charge
 -- No screen configuration, so just guess.
 -- Note that we should try to keep going with this if there's no reason to do otherwise.
 local gpuAc = neo.requestAccess("c.gpu")
 local screenAc = neo.requestAccess("c.screen")
 local gpu
 -- time to setup gpu/screen variables!
 if gpuAc and screenAc then
  local scrBestWHD = 0
  for s in screenAc.list() do
   for g in gpuAc.list() do
    g.bind(s.address, false)
    local whd = g.maxDepth()
    if whd > scrBestWHD then
     screen = s
     gpu = g
     scrBestWHD = whd
    end
   end
  end
 end
 if gpu then
  screen = screen.address
  gpu.bind(screen, true)
  local gW, gH = gpu.maxResolution()
  gW, gH = math.min(80, gW), math.min(25, gH)
  pcall(gpu.setResolution, gW, gH)
  pcall(gpu.setDepth, gpu.maxDepth()) -- can crash on OCEmu if done at the "wrong time"
 end
 -- Setup the new GPU provider
 gpuG = function () return gpu end
 -- 
 local w = 1
 local steps = {"sys-glacier"}
 for i = 1, 4 do table.insert(steps, "WAIT") end
 table.insert(steps, "INJECT")
 for i = 1, 8 do table.insert(steps, "WAIT") end

 local stepCount = #steps

 neo.scheduleTimer(os.uptime())
 while true do
  local ev = {coroutine.yield()}
  consoleEventHandler(ev)
  if ev[1] == "k.timer" then
   if gpu then
    local bg = 0xFFFFFF
    if w < stepCount then
     local n = math.floor((w / stepCount) * 255)
     bg = (n * 0x10000) + (n * 0x100) + n
    end
    basicDraw(bg)
   end
   if steps[w] then
    if steps[w] == "INJECT" then
     local nsm = neo.requestAccess("x.neo.sys.manage")
     if not nsm then
      table.insert(console, "Settings not available for INJECT.")
     else
      local nextstepsA = {}
      local nextstepsB = {}
      for _, v in ipairs(neo.listApps()) do
       if nsm.getSetting("run." .. v) == "yes" then
        if v:sub(1, 4) == "sys-" then
         table.insert(nextstepsA, v)
        else
         table.insert(nextstepsB, v)
        end
       end
      end
      for _, v in ipairs(nextstepsB) do
       table.insert(steps, w + 1, v)
      end
      for _, v in ipairs(nextstepsA) do
       table.insert(steps, w + 1, v)
      end
     end
    elseif steps[w] == "WAIT" then
    else
     local v, err = neo.executeAsync(steps[w])
     if not v then
      neo.emergency("failed start:", steps[w])
      neo.emergency(err)
     end
    end
   else
    break
   end
   w = w + 1
   neo.scheduleTimer(os.uptime() + 0.049)
  end
 end
end
-- Actual sequence

if callerPkg ~= nil then
 screen = callerScr
 -- Skip to "System initialized" (Everest either logged off, or died & used a Saving Throw to restart)
else
 initializeSystem()
end
-- System initialized
if finalPrompt() then
 -- Safe Mode
 local nsm = neo.requestAccess("x.neo.sys.manage")
 if nsm then
  console = {"Rebooting for Safe Mode..."}
  basicDraw()
  for _, v in ipairs(nsm.listSettings()) do
   if v ~= "password" then
    nsm.delSetting(v)
   end
  end
 else
  -- assume sysconf.lua did something very bad
  console = {"No NSM. Wiping configuration completely."}
  local fs = neo.requestAccess("c.filesystem")
  if not fs then
   table.insert(console, "Failed to get permission, you're doomed.")
  else
   fs.primary.remove("/data/sys-glacier/sysconf.lua")
  end
  basicDraw()
 end
 -- Do not give anything a chance to alter the new configuration
 shutdownEmergency(true)
 return
end
postPrompt()