-- Network utilities module for auto-boot-ollama-host
-- Provides port checking and Wake-on-LAN functionality

local socket = require("socket")
local utils = require("utils")

local network = {}

-- Check if a TCP port is accepting connections within a timeout (seconds)
function network.port_is_up(host, port, timeout_sec)
  host = tostring(host or "127.0.0.1")
  port = tonumber(port or 0) or 0
  local timeout = tonumber(timeout_sec or 1) or 1
  if port <= 0 then return false end

  local deadline = socket.gettime() + timeout
  while socket.gettime() < deadline do
    local tcp = socket.tcp()
    if not tcp then return false end
    tcp:settimeout(1)
    local ok = tcp:connect(host, port)
    tcp:close()
    if ok then return true end
    socket.sleep(0.5)
  end
  return false
end

-- Convert MAC address string to bytes
-- "AA:BB:CC:DD:EE:FF" -> 6 bytes
local function mac_to_bytes(mac)
  local bytes = {}
  for byte in mac:gmatch("(%x%x)") do 
    table.insert(bytes, tonumber(byte, 16)) 
  end
  if #bytes ~= 6 then return nil end
  return string.char(table.unpack(bytes))
end

-- Send Wake-on-LAN magic packet
function network.send_wol(mac_str, bcast_ip, port)
  -- Build magic packet
  local bytes = {}
  for byte in mac_str:gmatch("(%x%x)") do 
    table.insert(bytes, tonumber(byte, 16)) 
  end
  if #bytes ~= 6 then return false, "invalid MAC" end
  
  local mac = string.char(table.unpack(bytes))
  local packet = string.rep(string.char(0xFF), 6) .. mac:rep(16)

  -- Create IPv4 UDP socket (udp4 if available), bind to IPv4 wildcard to lock AF_INET
  local udp = assert((socket.udp4 or socket.udp)())
  udp:settimeout(2)
  assert(udp:setsockname("0.0.0.0", 0))       -- force IPv4 family
  assert(udp:setoption("broadcast", true))    -- allow broadcast

  local ok, err = udp:sendto(packet, bcast_ip, port)
  udp:close()
  return ok ~= nil, err
end

return network