Changed usage of globals, worked around edge cases

plugins/inventory_sync/module/inventory_sync.lua

@@ -5,6 +5,7 @@ When a player leaves the game, serialize their inventory and upload it to the ma
 When a player joins the game, send a request to the master server for the players inventory.
 
 When the master sends an inventory, parse it and give it to the player.
+If the master responds that its a new player, show a welcome message.
 
 ]]
 
@@ -12,42 +13,62 @@ local clusterio_api = require("modules/clusterio/api")
 local add_commands = require("modules/inventory_sync/commands")
 local upload_inventory = require("modules/inventory_sync/upload_inventory")
 local download_inventory = require("modules/inventory_sync/download_inventory")
+local welcome_new_player = require("modules/inventory_sync/welcome_new_player")
 
 inventory_sync = {}
+inventory_sync.welcome_new_player = welcome_new_player
+-- This function is called by instance.js as /sc inventory_sync.download_inventory("danielv", Escaped JSON string, package_number, total_packages_count) with data from the master
+inventory_sync.download_inventory = download_inventory
+-- This function is called internally when a player leaves the game for their inventory to upload to the master
+inventory_sync.upload_inventory = upload_inventory
 
 inventory_sync.add_commands = add_commands
 inventory_sync.events = {}
+inventory_sync.events[clusterio_api.events.on_server_startup] = function(event)
+    -- set up global table
+    if not global.inventory_sync then
+        global.inventory_sync = {
+            download_start_tick = {},
+            saved_crafting_queue = {},
+            download_cache = {},
+        }
+    end
+end
+
 -- Cleanup
 inventory_sync.events[defines.events.on_player_removed] = function(event)
     local player = game.get_player(event.player_index)
 
     -- Remove inventory download performance counter
-    global["inv_sync_download_start_tick "..player.name] = nil
+    global.inventory_sync.download_start_tick[player.name] = nil
     -- Remove stored crafting queue
-    global["saved_crafting_queue_"..player.name] = nil
+    global.inventory_sync.saved_crafting_queue[player.name] = nil
 end
 
 -- Download inventory from master
 inventory_sync.events[defines.events.on_player_joined_game] = function(event)
 	local playerIndex = event.player_index
-    inventory_sync.initiateInventoryDownload(playerIndex)
+    inventory_sync.initiate_inventory_download(playerIndex)
 end
 
 -- Upload inventory when a player leaves the game. Triggers on restart after crash if player was online during crash.
 inventory_sync.events[defines.events.on_pre_player_left_game] = function(event)
-    local playerIndex = event.player_index
-    inventory_sync.uploadInventory(playerIndex)
-    global.download_cache[playerIndex] = "" -- Clear cache to avoid leaking memory to people quitting during download
+    -- for some reason, on_pre_player_left_game gets called before on_server_startup so global isn't ready yet
+    if not global.inventory_sync then 
+        log("ERROR: Global inventory sync not defined")
+        return
+    end
+
+    local player_index = event.player_index
+    inventory_sync.upload_inventory(player_index)
+    global.inventory_sync.download_cache[player_index] = "" -- Clear cache to avoid leaking memory to people quitting during download
 end
 
-function inventory_sync.initiateInventoryDownload(playerIndex)
+function inventory_sync.initiate_inventory_download(playerIndex)
     local player = game.get_player(playerIndex)
     player.print("Initiating inventory download...")
-    global["inv_sync_download_start_tick "..player.name] = game.tick
-    if global.download_cache == nil then
-        global.download_cache = {}
-    end
-    global.download_cache[playerIndex] = ""
+    global.inventory_sync.download_start_tick[player.name] = game.tick
+    global.inventory_sync.download_cache[playerIndex] = ""
     clusterio_api.send_json("inventory_sync_download", {
         player_name = player.name
     })
@@ -60,9 +81,4 @@ function inventory_sync.initiateInventoryDownload(playerIndex)
     if character ~= nil then character.destroy() end
 end
 
--- This function is called by instance.js as /sc inventory_sync.downloadInventory("danielv", Escaped JSON string, package_number, total_packages_count) with data from the master
-inventory_sync.downloadInventory = download_inventory
--- This function is called internally when a player leaves the game for their inventory to upload to the master
-inventory_sync.uploadInventory = upload_inventory
-
 return inventory_sync