-- 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 gpu, screen = nil, nil
local shutdownEmergency = neo.requestAccess("k.computer").shutdown
neo.requestAccess("s.h.key_down")

local scrW, scrH
local warnings = {
 "",
 "",
 ""
}

-- 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()
 scrW, scrH = gpu.getResolution()
 gpu.fill(1, 1, scrW, scrH, " ")
 gpu.set(2, 2, "KittenOS NEO")
end

local function advDraw()
 basicDraw()
 local usage = math.floor((os.totalMemory() - os.freeMemory()) / 1024)
 gpu.set(2, 3, "RAM Usage: " .. usage .. "K / " .. math.floor(os.totalMemory() / 1024) .. "K")
 for i = 1, #warnings do
  gpu.set(2, 6 + i, warnings[i])
 end
end

-- Callback setup by finalPrompt to disclaim the main monitor first
local performDisclaim = nil

local function retrieveNssMonitor(nss)
 gpu = nil
 local subpool = {}
 while not gpu do
  if performDisclaim then
   performDisclaim()
  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 = nss.getClaimable()
  while not pool[1] do
   coroutine.yield() -- wait for presumably a NSS notification
   pool = nss.getClaimable()
  end
  subpool = {}
  -- Specifies which element to elevate to top priority
  local optimalSwap = nil
  if screen then
   for k, v in ipairs(pool) do
    if v == screen then
     optimalSwap = k
     break
    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 = nss.claim(v)
   if gpu then
    local gcb = gpu()
    if gcb then
     table.insert(subpool, {gpu, v})
     gcb.setBackground(0x000020)
     local w, h = gcb.getResolution()
     gcb.fill(1, 1, w, h, " ")
    end
   end
  end
 
  if not subpool[1] then error("Unable to claim any monitor.") end
  gpu = subpool[1][1]() -- BAD
  screen = subpool[1][2]
 end
 -- done with search
 scrW, scrH = gpu.getResolution()
 gpu.setBackground(0xFFFFFF)
 gpu.setForeground(0x000000)
 gpu.fill(1, 1, scrW, scrH, " ")
 performDisclaim = function ()
  for _, v in ipairs(subpool) do
   nss.disclaim(v[2])
  end
 end
end

local function sleep(t)
 neo.scheduleTimer(os.uptime() + t)
 while true do
  local ev = {coroutine.yield()}
  if ev[1] == "k.timer" then
   break
  end
  if ev[1] == "x.neo.sys.screens" then
   -- This implies we have and can use nss, but check anyway
   local nss = neo.requestAccess("x.neo.sys.screens")
   if nss then
    retrieveNssMonitor(nss)
    gpu.setBackground(0xFFFFFF)
    gpu.setForeground(0x000000)
    basicDraw()
   end
  end
 end
end

local function finalPrompt()
 local nss = neo.requestAccess("x.neo.sys.screens")
 if nss then
  retrieveNssMonitor(nss)
 end
 -- 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")
 end
 warnings[1] = "TAB to change option,"
 warnings[2] = "ENTER to select..."
 -- The actual main prompt loop
 while waiting do
  advDraw()
  local entry = ""
  local entry2 = ""
  local active = true
  local shButton = "<Shutdown>"
  local rbButton = "<Reboot>"
  local smButton = "<Safe Mode>"
  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
       advDraw()
       sleep(1)
      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 shButton
    end, function (key)
     if key == 13 then
      basicDraw()
      gpu.set(2, 4, "Shutting down...")
      shutdown(false)
     end
    end, 2, scrH - 1, unicode.len(shButton)},
   {function ()
     return rbButton
    end, function (key)
     if key == 13 then
      basicDraw()
      gpu.set(2, 4, "Rebooting...")
      shutdown(true)
     end
    end, 3 + unicode.len(shButton), scrH - 1, unicode.len(rbButton)},
   {function ()
     return smButton
    end, function (key)
     if key == 13 then
      basicDraw()
      gpu.set(2, 4, "Login to activate Safe Mode.")
      sleep(1)
      safeModeActive = true
      advDraw()
     end
    end, 4 + unicode.len(shButton) + unicode.len(rbButton), scrH - 1, unicode.len(smButton)},
   pw,
  }
  local control = #controls
  while active do
   for k, v in ipairs(controls) do
    if k == control then
     gpu.setBackground(0x000000)
     gpu.setForeground(0xFFFFFF)
    else
     gpu.setBackground(0xFFFFFF)
     gpu.setForeground(0x000000)
    end
    gpu.fill(v[3], v[4], v[5], 1, " ")
    gpu.set(v[3], v[4], v[1]())
   end
   -- Reset to normal
   gpu.setBackground(0xFFFFFF)
   gpu.setForeground(0x000000)
   -- event handling...
   local sig = {coroutine.yield()}
   if sig[1] == "x.neo.sys.screens" then
    -- We need to reinit screens no matter what.
    retrieveNssMonitor(nss)
   end
   if sig[1] == "h.key_down" then
    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
 advDraw()
 return safeModeActive
end
local function postPrompt()
 -- Begin to finish login, or fail
 local everests = neo.requestAccess("x.neo.sys.session")
 if everests then
  local s, e = pcall(everests.startSession)
  if not s then
   table.insert(warnings, "Everest failed to create a session")
   table.insert(warnings, tostring(e))
  else
   warnings = {"Transferring to Everest..."}
   advDraw()
   if performDisclaim then
    performDisclaim()
    -- Give Everest time (this isn't perceptible, and is really just a safety measure)
    sleep(1)
   end
   return
  end
 else
  table.insert(warnings, "Couldn't communicate with Everest...")
 end
 advDraw()
 sleep(1)
 shutdown(true)
end

local function initializeSystem()
 -- System has just booted, bristol is in charge
 -- Firstly, initialize hardware to something sensible since we don't know scrcfg
 gpu = neo.requestAccess("c.gpu").list()()
 if gpu then
  screen = neo.requestAccess("c.screen").list()()
  if not screen then gpu = nil end
 end
 if gpu then
  screen = screen.address
  gpu.bind(screen, true)
  gpu.setDepth(gpu.maxDepth())
  local gW, gH = gpu.maxResolution()
  gW, gH = math.min(80, gW), math.min(25, gH)
  gpu.setResolution(gW, gH)
  gpu.setForeground(0x000000)
 end
 local w = 1
 local steps = {
  "sys-glacier", -- (Glacier : Config, Screen, Power)
  -- Let that start, and system GC
  "WAIT",
  "WAIT",
  "WAIT",
  "WAIT",
  -- Start services
  "INJECT",
  -- extra GC time
  "WAIT",
  "WAIT",
  "WAIT",
  "WAIT",
  "WAIT",
  "WAIT",
  "WAIT"
 }
 local stepCount = #steps

 neo.scheduleTimer(os.uptime())
 while true do
  local ev = {coroutine.yield()}
  if ev[1] == "k.procnew" then
   table.insert(warnings, ev[2] .. "/" .. ev[3] .. " UP")
  end
  if ev[1] == "k.procdie" then
   table.insert(warnings, ev[2] .. "/" .. ev[3] .. " DOWN")
   table.insert(warnings, tostring(ev[4]))
  end
  if ev[1] == "k.timer" then
   if gpu then
    gpu.setForeground(0x000000)
    if w < stepCount then
     local n = math.floor((w / stepCount) * 255)
     gpu.setBackground((n * 0x10000) + (n * 0x100) + n)
    else
     gpu.setBackground(0xFFFFFF)
    end
    basicDraw()
   end
   if steps[w] then
    if steps[w] == "INJECT" then
     local nsm = neo.requestAccess("x.neo.sys.manage")
     if not nsm then
      table.insert(warnings, "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
      table.insert(warnings, steps[w] .. " STF")
      table.insert(warnings, err)
     end
    end
   else
    break
   end
   w = w + 1
   neo.scheduleTimer(os.uptime() + 0.049)
  end
 end
end
-- Actual sequence

if callerPkg ~= nil then
 -- Everest can call into this to force a login screen
 -- In this case it locks Everest, then starts Bristol.
 -- 
 if callerPkg ~= "sys-everest" then
  return
 end
 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
 basicDraw()
 local nsm = neo.requestAccess("x.neo.sys.manage")
 if nsm then
  gpu.set(2, 4, "Rebooting for Safe Mode...")
  for _, v in ipairs(nsm.listSettings()) do
   if v ~= "password" then
    nsm.delSetting(v)
   end
  end
 else
  -- assume sysconf.lua did something very bad
  gpu.set(2, 4, "No NSM. Wiping configuration completely.")
  local fs = neo.requestAccess("c.filesystem")
  fs.primary.remove("/data/sys-glacier/sysconf.lua")
 end
 -- Do not give anything a chance to alter the new configuration
 shutdownEmergency(true)
 return
end
postPrompt()