DOGGY CORP single boot BIOS for Opencomputers

local init
do
  local component_invoke = component.invoke
  local function boot_invoke(address, method, ...)
    local result = table.pack(pcall(component_invoke, address, method, ...))
    if not result[1] then
      return nil, result[2]
    else
      return table.unpack(result, 2, result.n)
    end
  end

  local function drawCenteredText(text)
    local gpu = component.list("gpu")()
    local w, h = component.invoke(gpu, "getResolution")
    local x = math.floor((w - #text) / 2)
    local y = math.floor(h / 2)
    component.invoke(gpu, "set", x, y, text)
  end

  local function setResolution(width, height)
    local gpu = component.list("gpu")()
    component.invoke(gpu, "setResolution", width, height)
  end

  local function delay(seconds)
    local deadline = computer.uptime() + seconds
    repeat until computer.uptime() >= deadline
  end

  -- backwards compatibility, may remove later
  local eeprom = component.list("eeprom")()
  computer.getBootAddress = function()
    return boot_invoke(eeprom, "getData")
  end
  computer.setBootAddress = function(address)
    return boot_invoke(eeprom, "setData", address)
  end

  do
    local screen = component.list("screen")()
    local gpu = component.list("gpu")()
    if gpu and screen then
      boot_invoke(gpu, "bind", screen)
      setResolution(80, 25)  -- Adjust resolution for larger text
    end
  end

  local function tryLoadFrom(address)
    local handle, reason = boot_invoke(address, "open", "/init.lua")
    if not handle then
      return nil, reason
    end
    local buffer = ""
    repeat
      local data, reason = boot_invoke(address, "read", handle, math.maxinteger or math.huge)
      if not data and reason then
        return nil, reason
      end
      buffer = buffer .. (data or "")
    until not data
    boot_invoke(address, "close", handle)
    return load(buffer, "=init")
  end

  local function drawBootMessage()
    local gpu = component.list("gpu")()
    local w, h = component.invoke(gpu, "getResolution")
    component.invoke(gpu, "fill", 1, 1, w, h, " ") -- Clear the screen
    component.invoke(gpu, "setBackground", 0x000000) -- Set background to black
    drawCenteredText("DOGGY CORP")
  end

  local function drawErrorMessage()
    local gpu = component.list("gpu")()
    local w, h = component.invoke(gpu, "getResolution")
    component.invoke(gpu, "fill", 1, 1, w, h, " ") -- Clear the screen
    component.invoke(gpu, "setBackground", 0x000000) -- Set background to black
    drawCenteredText("BIOS failed to locate boot drive!")
  end

  local function runWithoutHalting()
    drawErrorMessage()
    computer.beep(1500, 0.5)  -- Longer beep
    delay(0.5)  -- Delay after the beep
    for _ = 1, 2 do
      computer.beep(1500, 0.10)  -- Beep 2 times quickly
      delay(0.2)  -- Delay between beeps
    end
    while true do
      computer.pullSignal(0.5)  -- Adjust the delay time as needed
      drawErrorMessage()
    end
  end

  local reason
  drawBootMessage()
  delay(2) -- Wait 2 seconds
  if computer.getBootAddress() then
    init, reason = tryLoadFrom(computer.getBootAddress())
  end
  if not init then
    computer.setBootAddress()
    for address in component.list("filesystem") do
      init, reason = tryLoadFrom(address)
      if init then
        computer.setBootAddress(address)
        break
      end
    end
  end
  if not init then
    runWithoutHalting()  -- Run the error message without halting the computer
    return
  end
  computer.beep(1000, 0.10)
end
return init()