[LUA][OC] RogueBIOS

local searchPaths = {
    '/boot/boot.lua',
    '/boot.lua',
    '/init.lua',
}
local sf = string.format
-- Boot device
local bdev = {
    comp = computer,
    ls = component.list,
    disp = false,
    rom = component.list('eeprom', true)(),
    sl = { version = '1.0' }
}
setmetatable(bdev, {__index = component})

function bdev:panic(msg, data)
    self.comp.beep(2000, 0.2)
    return error(msg .. (data and ': ' .. data or ''), 0)
end

function bdev:pullsig(timeout)
    return self.comp.pullSignal(timeout)
end

function bdev:print(msg)
    if self.disp then
        self.gpu.set(1, self.gpu.cur_y, msg)
        if self.gpu.cur_y == self.gpu.scr_h then
            self.gpu.copy(1, 2, self.gpu.scr_w, self.gpu.scr_h - 1, 0, -1)
            self.gpu.fill(1, self.gpu.scr_h, self.gpu.scr_w, 1, ' ')
        else self.gpu.cur_y = self.gpu.cur_y + 1 end
    end
end

function bdev:clear()
    if self.disp then
        self.gpu.cur_y = 1
        self.gpu.fill(1, 1, self.gpu.scr_w, self.gpu.scr_h, ' ')
    end
end

function bdev:sleep(timeout)
    local deadline = self.comp.uptime() + (timeout or 0)
    repeat self.pullsig(deadline - self.comp.uptime())
    until self.comp.uptime() >= deadline
end

function computer.getBootAddress()
  return bdev.invoke(bdev.rom, 'getData')
end
function computer.setBootAddress(address)
  return bdev.invoke(bdev.rom, 'setData', address)
end

do
    local gpu = bdev.ls('gpu', true)()
    local screen = bdev.ls('screen', true)()
    if gpu and screen then
        bdev.disp = true
        bdev.gpu = bdev.proxy(gpu)
        bdev.screen = bdev.proxy(screen)
        bdev.gpu.bind(screen)
        bdev.screen.turnOn()
        bdev.gpu.setBackground(0)
        bdev.gpu.setForeground(0xFFFFFF)
        bdev.gpu.scr_w, bdev.gpu.scr_h = bdev.gpu.getResolution()
        bdev:clear()
    end
end

bdev:print(sf('RogueBIOS v%s --- by RogueNet', bdev.sl.version))
bdev:print''

bdev:print'Searching for boot files ...'
local bFSs = {}
for address in bdev.ls('filesystem', true) do
    for _,path in ipairs(searchPaths) do
        if bdev.invoke(address, 'exists', path) then
            table.insert(bFSs, {address, path})
            break
        end
    end

    if #bFSs == 9 then break end
end
local nbFSs = #bFSs

local sFS = 0
if nbFSs == 1 or not bdev.disp then sFS = 1
elseif nbFSs > 1 then
    bdev:print''
    bdev:print'Select a filesystem to boot from:'
    for i,fst in ipairs(bFSs) do
        local fsLabel = bdev.invoke(fst[1], 'getLabel')
        fsLabel = fsLabel and fsLabel..' ' or ''
        bdev:print(sf('%i) %s:%s', i, fsLabel .. fst[1], fst[2]))
    end

    local v = 0
    repeat
        e = table.pack(bdev:pullsig())
        if e[1] == 'component_removed' or e[1] == 'component_added' then
            bdev.comp.shutdown(true) end
        if e[1] == 'key_down' and tonumber(e[3]) then v = tonumber(e[3]) - 48
        end
    until e[1] == 'key_down' and v > 0 and v <= nbFSs
    sFS = v
    bdev:print''
else bdev:panic'No bootable medium' end

local bootaddr = bFSs[sFS][1]
local bootfile = bFSs[sFS][2]
bdev.bootfile = bootfile
bdev.bootaddress = bootaddr
bdev:print(sf('Loading %s:%s', bootaddr, bootfile))

local bfh, reason = bdev.invoke(bootaddr, 'open', bootfile)
if not bfh then bdev:panic('Couldnt open boot file', reason) end
local buffer = ''
repeat
    local data, reason = bdev.invoke(bootaddr, 'read', bfh, math.huge)
    if not data and reason then bdev:panic('Couldnt read boot file', reason)
    end
    buffer = buffer .. (data or '')
until not data
bdev.invoke(bootaddr, 'close', bfh)
if not buffer then bdev:panic'Empty buffer' end

bdev.comp.beep(2000, 0.2)
bdev.comp.setBootAddress(bootaddr)
local env = { bootdevice = bdev }
setmetatable(env, {__index = _G})
local boot = load(buffer, '@'..bootfile, 'bt', env)
if not boot then bdev:panic('Booting failed.', 'Errors in boot file') end
boot()