-- Purpose: Minimal log watcher using `docker logs -f` as input.
-- Requirements: lua 5.4 + luasocket + docker CLI inside the container.
-- Notes:
-- - Pattern match is plain substring (fast & simple).
-- - Optional Wake-on-LAN is native (no external tools).
-- - Optional port-wait is provided but commented out (mirrors original bash idea).

local socket = require("socket")

local function getenv(name, def)
  local v = os.getenv(name)
  return (v ~= nil and v ~= "") and v or def
end

-- ---- Config via env ----
local CONTAINER_NAME = getenv("CONTAINER_NAME", "paperless-ai")
local SINCE          = getenv("SINCE", "0s")
local OLLAMA_HOST    = getenv("OLLAMA_HOST", "192.168.222.12")
local OLLAMA_PORT    = tonumber(getenv("OLLAMA_PORT", "11434"))
local ERROR_PATTERN  = getenv(
  "ERROR_PATTERN",
  ("connect EHOSTUNREACH %s:%d"):format(OLLAMA_HOST, OLLAMA_PORT)
)

-- Optional Wake-on-LAN
local WOL_MAC   = getenv("WOL_MAC", "")                       -- e.g. "AA:BB:CC:DD:EE:FF"
local WOL_BCAST = getenv("WOL_BCAST", "192.168.222.255")
local WOL_PORT  = tonumber(getenv("WOL_PORT", "9"))

-- Optional: wait for service to come up (kept commented to stay minimal)
-- local UP_WAIT_TIMEOUT = tonumber(getenv("UP_WAIT_TIMEOUT", "90"))

local function log(msg)
  io.stdout:write(os.date("[%F %T] "), msg, "\n"); io.stdout:flush()
end

-- "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

local function 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




-- Kept for reference; not used to keep parity with your minimal bash
-- local function port_is_up(host, port, timeout_sec)
--   local deadline = socket.gettime() + (timeout_sec or 1)
--   repeat
--     local tcp = socket.tcp(); tcp:settimeout(1)
--     if tcp:connect(host, port) then tcp:close(); return true end
--     tcp:close(); socket.sleep(0.5)
--   until socket.gettime() >= deadline
--   return false
-- end

local function main()
  log(("Watching container='%s' since='%s'"):format(CONTAINER_NAME, SINCE))
  log(("Looking for pattern: %q"):format(ERROR_PATTERN))

  local cmd = ("docker logs -f --since %q %q 2>&1"):format(SINCE, CONTAINER_NAME)
  local fh = assert(io.popen(cmd, "r"))

  for line in fh:lines() do
    -- Plain substring match (no regex)
    if line:find(ERROR_PATTERN, 1, true) ~= nil then
      log(("Detected EHOSTUNREACH for Ollama (%s:%d)."):format(OLLAMA_HOST, OLLAMA_PORT))

      if WOL_MAC ~= "" then
				log(("Sending WOL to %s via %s:%d"):format(WOL_MAC, WOL_BCAST, WOL_PORT))
        local ok, err = send_wol(WOL_MAC, WOL_BCAST, WOL_PORT)
        if ok then
          log(("Sucessfully sent WOL to %s via %s:%d"):format(WOL_MAC, WOL_BCAST, WOL_PORT))
        else
          log("WOL failed: " .. tostring(err))
        end
      end

      -- Optional wait (kept commented for minimal parity)
      -- if port_is_up(OLLAMA_HOST, OLLAMA_PORT, UP_WAIT_TIMEOUT) then
      --   log("Ollama reachable again.")
      -- else
      --   log("Timeout waiting for Ollama.")
      -- end
    end
  end

  fh:close()
  log("Log stream ended.")
end

main()