Rename Slave to Host

The role of a slave as a host for Factorio servers is not well reflected
in its name and has caused confusion among users.  Rename slave to host
to better reflect its role as a host of Factorio servers.

packages/host/modules/clusterio/impl.lua

@@ -0,0 +1,88 @@
+local api = require('modules/clusterio/api')
+
+
+local function check_patch()
+	if global.clusterio_patch_number ~= clusterio_patch_number then
+		global.clusterio_patch_number = clusterio_patch_number
+		script.raise_event(api.events.on_server_startup, {})
+	end
+end
+
+local impl = {}
+impl.events = {}
+
+impl.events[defines.events.on_tick] = check_patch
+
+impl.events[api.events.on_server_startup] = function()
+	if not global.clusterio then
+		global.clusterio = {
+			instance_id = nil,
+			instance_name = nil,
+		}
+	end
+
+	-- Replay will just desync after the save is patched
+	game.disable_replay()
+end
+
+impl.events[defines.events.on_player_joined_game] = function(event)
+	local player = game.players[event.player_index]
+	api.send_json("player_event", { type = "join", name = player.name })
+end
+
+local disconnect_reason_name = {}
+if defines.disconnect_reason then
+	for name, i in pairs(defines.disconnect_reason) do
+		disconnect_reason_name[i] = name
+	end
+end
+
+impl.events[defines.events.on_player_left_game] = function(event)
+	local player = game.players[event.player_index]
+	api.send_json("player_event", {
+		type = "leave",
+		name = player.name,
+		reason = disconnect_reason_name[event.reason] or "quit",
+	})
+end
+
+-- Internal API
+clusterio_private = {}
+function clusterio_private.update_instance(new_id, new_name)
+	check_patch()
+	global.clusterio.instance_id = new_id
+	global.clusterio.instance_name = new_name
+	script.raise_event(api.events.on_instance_updated, {
+		instance_id = new_id,
+		instance_name = new_name,
+	})
+end
+
+
+-- This is not part of the add_remote_interface callback to ensure it is
+-- available when the clusterio_lib mod is loaded.  The reason this is
+-- neccessary is that on_init for newly added mods happen before on_load
+-- for existing mods, and the add_remote_interface callback is done in
+-- on_load.  See https://forums.factorio.com/viewtopic.php?f=25&t=81552 for
+-- more details.
+remote.add_interface('clusterio_api', {
+	get_events = function()
+		return api.events
+	end,
+
+	get_instance_id = function()
+		return global.clusterio.instance_id
+	end,
+
+	get_instance_name = function()
+		return global.clusterio.instance_name
+	end,
+
+	get_file_no = function()
+		global.clusterio_file_no = (global.clusterio_file_no or 0) + 1
+		return global.clusterio_file_no
+	end,
+})
+
+
+return impl