control.lua

-- Container Cargo Ship - runtime integration with Cargo Ships
-- Defensive, crash-free.
-- Register on the first post-init/configuration tick so Cargo Ships has already
-- finished rebuilding its ship database.
local RETRY_INTERVAL_TICKS = 1
local MOD_NAME = "container-cargo-ship"
local CARGO_SHIPS_MOD_NAME = "cargo-ships"
local CARGO_SHIPS_INTERFACE_NAME = "cargo-ships"
local SHIP_NAME = "container_cargo_ship"
local INDEP_SHIP_NAME = "indep-container_cargo_ship"

local function ensure_global()
  global = global or {}
  global.schema = global.schema or {}
  global.schema.version = global.schema.version or 1
  global.schema.registered = global.schema.registered or false
  global.schema.register_attempts = global.schema.register_attempts or 0
end

local function try_register()
  ensure_global()
  if global.schema.registered then return true end

  -- Wait until Cargo Ships interface is available
  local cargo_ships_interface = remote and remote.interfaces and remote.interfaces[CARGO_SHIPS_INTERFACE_NAME]
  if not (cargo_ships_interface and cargo_ships_interface.add_ship and cargo_ships_interface.add_boat) then
    return false
  end

  global.schema.register_attempts = (global.schema.register_attempts or 0) + 1

  local ok_ship = pcall(function()
    remote.call(CARGO_SHIPS_INTERFACE_NAME, "add_ship", {
      name = SHIP_NAME,
      engine = "cargo_ship_engine",
      engine_scale = 1,
      engine_at_front = false,
    })
  end)

  local ok_boat = pcall(function()
    remote.call(CARGO_SHIPS_INTERFACE_NAME, "add_boat", {
      name = INDEP_SHIP_NAME,
      rail_version = SHIP_NAME,
    })
  end)

  if ok_ship and ok_boat then
    global.schema.registered = true
    return true
  end
  return false
end

local function stop_retry_handler()
  script.on_nth_tick(RETRY_INTERVAL_TICKS, nil)
end

local function retry_register_on_nth_tick(_)
  ensure_global()
  if try_register() then
    stop_retry_handler()
  end
end

local function ensure_registered_with_retry()
  ensure_global()
  global.schema.registered = false
  script.on_nth_tick(RETRY_INTERVAL_TICKS, retry_register_on_nth_tick)
end

local function configuration_change_affects_registration(event)
  local mod_changes = event and event.mod_changes
  if not mod_changes then
    return true
  end
  return mod_changes[MOD_NAME] ~= nil or mod_changes[CARGO_SHIPS_MOD_NAME] ~= nil
end

script.on_init(function()
  ensure_registered_with_retry()
end)

script.on_load(function()
  if global and global.schema and not global.schema.registered then
    script.on_nth_tick(RETRY_INTERVAL_TICKS, retry_register_on_nth_tick)
  end
end)

script.on_configuration_changed(function(event)
  ensure_global()

  -- Re-register only when this mod or Cargo Ships actually changed.
  if not configuration_change_affects_registration(event) then
    return
  end

  -- Re-register in case Cargo Ships or this mod was updated/reset.
  global.schema.registered = false
  ensure_registered_with_retry()
end)