-- install.lua — installs OpenOS Yaru over a standard OpenOS (or onto any disk).
-- Needs an internet card. Downloads yaru.pack and writes it straight to the
-- chosen disk while it streams in (nothing big is kept in memory).
--
--   wget http://<server>/install.lua /tmp/install.lua
--   /tmp/install.lua [url-of-yaru.pack] [-y] [--disk=N|address|label]
--
-- Keeps: everything in /home that already exists, your /etc/rc.cfg (the new
-- one is written as /etc/rc.cfg.yaru), and all files Yaru does not ship.
local component = require("component")
local computer = require("computer")
local shell = require("shell")
local term = require("term")

local DEFAULT_URL = "http://vpn.itrubin.com/yaru.pack"

local args, opts = shell.parse(...)
local url = args[1] or DEFAULT_URL
if url == "" then
  io.stderr:write("usage: install [url of yaru.pack] [-y] [--disk=N|address|label]\n")
  return 1
end
if not component.isAvailable("internet") then
  io.stderr:write("install: an internet card is needed\n")
  return 1
end
local internet = require("internet")

local function ask(q)
  if opts.y then return true end
  io.write(q .. " [Y/n] ")
  local a = (io.read() or ""):lower()
  return a == "" or a == "y" or a == "yes" or a == "д" or a == "да"
end

-- ------------------------------------------------------------ target disk
local boot, tmp = computer.getBootAddress(), computer.tmpAddress()
local disks = {}
for addr in component.list("filesystem") do
  local p = component.proxy(addr)
  if addr ~= tmp and not p.isReadOnly() then
    disks[#disks + 1] = {addr = addr, proxy = p, label = p.getLabel() or "",
      free = p.spaceTotal() - p.spaceUsed(), total = p.spaceTotal(),
      os = p.exists("/init.lua") and p.exists("/lib/core") }
  end
end
table.sort(disks, function(a, b) return (a.addr == boot) and b.addr ~= boot or (a.addr ~= boot) == (b.addr ~= boot) and a.addr < b.addr end)
if #disks == 0 then io.stderr:write("install: no writable disk\n") return 1 end

print("OpenOS Yaru installer")
print("Disks:")
for i, d in ipairs(disks) do
  print(string.format("  %d) %s  %-12s %4d KB free%s%s", i, d.addr:sub(1, 8), d.label:sub(1, 12), d.free // 1024,
    d.os and "  (OpenOS)" or "", d.addr == boot and "  <- this computer boots from it" or ""))
end
-- --disk=N (number in the list), an address prefix or a label picks the disk;
-- otherwise it is asked (with -y: the boot disk)
local pick = 1
if opts.disk then
  pick = tonumber(opts.disk)
  if not pick or not disks[pick] then
    pick = nil
    for i, d in ipairs(disks) do
      if d.addr:sub(1, #opts.disk) == opts.disk or d.label == opts.disk then pick = i break end
    end
  end
elseif #disks > 1 and not opts.y then
  io.write("Install onto disk [1]: ")
  pick = tonumber(io.read() or "") or 1
end
local disk = disks[pick]
if not disk then io.stderr:write("install: no such disk\n") return 1 end
local fs = disk.proxy

-- ------------------------------------------------------------ download + unpack
local handle, reason = internet.request(url)
if not handle then io.stderr:write("install: " .. tostring(reason) .. "\n") return 1 end

local buf = ""
local stream_ok = true
local function more()
  local ok, chunk = pcall(handle)
  if not ok then stream_ok = false; error("download failed: " .. tostring(chunk), 0) end
  if not chunk then return false end
  buf = buf .. chunk
  return true
end
local function line()
  while true do
    local nl = buf:find("\n", 1, true)
    if nl then
      local l = buf:sub(1, nl - 1)
      buf = buf:sub(nl + 1)
      return l
    end
    if not more() then return nil end
  end
end

local head = line()
local nfiles, total = (head or ""):match("^YARUPACK 1 (%d+) (%d+)$")
if not nfiles then io.stderr:write("install: " .. url .. " is not a Yaru pack\n") return 1 end
nfiles, total = tonumber(nfiles), tonumber(total)
print(string.format("%d files, %d KB, onto %s %s", nfiles, total // 1024, disk.addr:sub(1, 8), disk.label))
if disk.free + (disk.os and 400 * 1024 or 0) < total then
  print("Warning: the disk may be too small.")
end
if not ask("Install now? Existing system files are replaced, /home is kept.") then print("Cancelled.") return end

local done, bytes, kept = 0, 0, 0
local lastPct = -1
local function progress()
  local pct = total > 0 and bytes * 100 // total or 100
  if pct ~= lastPct then
    lastPct = pct
    local _, y = term.getCursor()
    term.setCursor(1, y)
    io.write(string.format("Installing... %3d%%  (%d of %d files)", pct, done, nfiles))
  end
end

local ok, err = pcall(function()
  while true do
    local l = line()
    if not l then error("the download ended early", 0) end
    local kind = l:sub(1, 1)
    if kind == "E" then break
    elseif kind == "D" then
      fs.makeDirectory(l:sub(3))
    elseif kind == "F" then
      local size, path = l:match("^F (%d+) (.+)$")
      size = tonumber(size)
      local target = path
      local skip = false
      if path:sub(1, 6) == "/home/" and fs.exists(path) then skip = true; kept = kept + 1 end
      if path == "/etc/rc.cfg" and fs.exists(path) then target = "/etc/rc.cfg.yaru" end
      local fh
      if not skip then
        local dir = target:match("^(.*)/[^/]*$")
        if dir and dir ~= "" then fs.makeDirectory(dir) end
        local reason2
        fh, reason2 = fs.open(target, "w")
        if not fh then error(target .. ": " .. tostring(reason2), 0) end
      end
      local left = size
      while left > 0 do
        if #buf == 0 and not more() then error("the download ended early", 0) end
        local n = math.min(left, #buf, 8192)
        if fh then fs.write(fh, buf:sub(1, n)) end
        buf = buf:sub(n + 1)
        left = left - n
        bytes = bytes + n
      end
      if fh then fs.close(fh) end
      done = done + 1
      progress()
    end
  end
end)
pcall(handle.close)
print()
if not ok then
  io.stderr:write("install failed: " .. tostring(err) .. "\n")
  io.stderr:write("Run it again; files already written are simply replaced.\n")
  return 1
end

if (fs.getLabel() or "") == "" then pcall(fs.setLabel, "Yaru") end
computer.setBootAddress(disk.addr)
print(string.format("Done: %d files written%s.", done - kept, kept > 0 and (", " .. kept .. " of your files in /home kept") or ""))
if fs.exists("/etc/rc.cfg.yaru") then print("Your /etc/rc.cfg was kept (the new one is /etc/rc.cfg.yaru).") end
if ask("Reboot into Yaru now?") then computer.shutdown(true) end