local gpu = component.proxy(component.list("gpu")())
local resX, resY = gpu.getResolution()

local function loadfile(file)
  checkArg(1, file, "string")
  local handle = component.invoke(computer.getBootAddress(), "open", file, "r")
  local data = ""
  repeat
    local tmpdata = component.invoke(computer.getBootAddress(), "read", handle, math.huge or math.maxinteger)
    data = data .. (tmpdata or "")
  until not tmpdata
  component.invoke(computer.getBootAddress(), "close", handle)
  return assert(load(data, "=" .. file))
end

local function handleError(errorMessage)
  return (errorMessage .. "\n \n" .. debug.traceback())
end

function loadthething()
  local foundArchitecture = false
  for _, arch in pairs(computer.getArchitectures()) do
    if arch == "Lua 5.3" then
      foundArchitecture = true
      break
    end
  end

  if foundArchitecture then
    local _, errorMesage = computer.setArchitecture("Lua 5.3")
    if errorMessage then
      error(errorMessage)
    end
  else
    gpu.set(1, 1, "Required architecture (Lua 5.3) is not supported.")
    gpu.set(1, 2, "Halting.")
    while true do
      computer.pullSignal()
    end
  end
  loadfile("/halyde/kernel/boot.lua")(loadfile)
end

gpu.setBackground(0x000000)
gpu.fill(1, 1, resX, resY, " ")

-- Copying low-level functions in case of post-preload failure
local pullSignal = computer.pullSignal
local beep = computer.beep
local shutdown = computer.shutdown
local unicode = unicode

local result, reason = xpcall(loadthething, handleError)
local lines = {}
if not result then
  resX, resY = gpu.getResolution() -- doing it again because boot.lua changes the resolution
  local log
  local logSuccess, logError = false, nil
  if _G.require then
    logSuccess, logError = pcall(function()
      log = _G.require("log")
      log.kernel.error("Halyde has crashed!\n" .. tostring(reason or "unknown error"))
    end)
  end
  reason = "A fatal error has occurred.\nHalyde cannot continue.\n \n"
    .. tostring(reason or "unknown error"):gsub("\t", "  ")
  if not log then
    reason = "WARNING: This error has occured early enough in the boot process that no log entry could be made.\n\n"
      .. reason
  elseif not logSuccess then
    if type(logError) == "nil" then
      logError = ""
    else
      logError = "\n │ " .. tostring(logError)
    end
    reason = "WARNING: An error has occured when making a log entry for this crash." .. logError .. "\n\n" .. reason
  end
  local bgColor
  if gpu.getDepth() == 1 then
    bgColor = 0x000000
  else
    bgColor = 0x000080
  end
  gpu.setBackground(bgColor)
  gpu.fill(1, 1, resX, resY, " ")
  for line in string.gmatch(reason, "([^\n]*)\n?") do
    table.insert(lines, line)
  end
  local function render()
    gpu.setForeground(0xFFFFFF)
    for i = 1, #lines do
      gpu.set(2, i + 1, lines[i])
    end
    gpu.fill(1, resY - 1, resX, 1, "─")
    gpu.fill(1, resY, resX, 1, " ")
    gpu.setForeground(bgColor)
    gpu.setBackground(0xFFFFFF)
    gpu.set(2, resY, "🠅   🠄   🠇   🠆        ⏎")
    gpu.setForeground(0xFFFFFF)
    gpu.setBackground(bgColor)
    gpu.set(4, resY, " / ")
    gpu.set(9, resY, " / ")
    gpu.set(14, resY, " / ")
    gpu.set(19, resY, " Scroll ")
    gpu.set(29, resY, " Reboot")
  end
  local function cropset(x, y, txt)
    gpu.set(math.max(x, 1), y, unicode.sub(txt, math.max(2 - x, 1)))
  end
  local scrollX = 0
  local scrollY = 0
  local function scrollDown()
    if scrollY >= #lines - resY + 2 then
      return
    end
    gpu.copy(1, 2, resX, resY - 3, 0, -1)
    gpu.fill(1, resY - 2, resX, 1, " ")
    local line = lines[scrollY + resY - 2]
    if type(line) == "string" then
      cropset(2 - scrollX, resY - 2, line)
    end
    scrollY = scrollY + 1
  end
  local function scrollUp()
    if scrollY <= 0 then
      return
    end
    gpu.copy(1, 1, resX, resY - 3, 0, 1)
    gpu.fill(1, 1, resX, 1, " ")
    local line = lines[scrollY - 1]
    if type(line) == "string" then
      cropset(2 - scrollX, 1, line)
    end
    scrollY = scrollY - 1
  end
  local width = 0
  for i = 1, #lines do
    width = math.max(width, unicode.len(lines[i]))
  end
  local function rerender()
    for i = 1, #lines do
      local y = i - scrollY + 1
      if y > 0 and y <= resY - 2 then
        gpu.fill(1, y, resX, 1, " ")
        cropset(2 - scrollX, y, lines[i])
      end
    end
  end
  local function scrollRight()
    if scrollX >= width - resX + 2 then
      return
    end
    scrollX = scrollX + 1
    rerender()
  end
  local function scrollLeft()
    if scrollX <= 0 then
      return
    end
    scrollX = scrollX - 1
    rerender()
  end
  render()
  beep(440, 0.2)
  beep(465, 0.2)
  beep(440, 0.2)
  beep(370, 0.5)
  while true do
    local ev = { pullSignal() }
    if ev[1] == "key_down" then
      if ev[4] == 200 then
        scrollUp()
      end
      if ev[4] == 208 then
        scrollDown()
      end
      if ev[4] == 203 then
        scrollLeft()
      end
      if ev[4] == 205 then
        scrollRight()
      end
      if ev[4] == 28 then
        -- Next time copy this function too doofus
        -- computer.shutdown(true)
        shutdown(true)
      end
    end
    if ev[1] == "scroll" then
      if ev[5] > 0 then
        scrollUp()
      else
        scrollDown()
      end
    end
  end
end