Config JSON Tweaks (GodotModding#108)

* `get_mod_config` - fix missing space in log string

* `get_mod_config` - log improvements

- Generally improve log messages, giving them better user notices that are more accurate to the current issue.
- Use assert for cases where there are definite code errors that need addressing (eg. an invalid mod ID)

* `get_mod_config` - use enums for the error codes

* `get_mod_config` - rename "error" (eg. "error code") to "status"

* `get_mod_config` - remove a redundant bit of text

addons/mod_loader/mod_loader.gd

@@ -561,64 +561,75 @@ func save_scene(modified_scene: Node, scene_path: String) -> void:
 	_saved_objects.append(packed_scene)
 
 
+enum MLConfigStatus {
+	OK,                  # 0 = No errors
+	INVALID_MOD_ID,      # 1 = Invalid mod ID
+	NO_JSON_OK,          # 2 = No custom JSON. File probably does not exist. Defaults will be used if available
+	NO_JSON_INVALID_KEY, # 3 = No custom JSON, and key was invalid when trying to get the default from your manifest defaults (`extra.godot.config_defaults`)
+	INVALID_KEY          # 4 = Invalid key, although config data does exists
+}
+
 # Get the config data for a specific mod. Always returns a dictionary with two
 # keys: `error` and `data`.
 # Data (`data`) is either the full config, or data from a specific key if one was specified.
 # Error (`error`) is 0 if there were no errors, or > 0 if the setting could not be retrieved:
-# 0 = No errors
-# 1 = Invalid mod ID
-# 2 = No custom JSON. File probably does not exist. Defaults will be used if available
-# 3 = No custom JSON, and key was invalid when trying to get the default from your manifest defaults (`extra.godot.config_defaults`)
-# 4 = Invalid key, although config data does exists
 func get_mod_config(mod_dir_name: String = "", key: String = "") -> Dictionary:
-	var error_num := 0
-	var error_msg := ""
+	var status_code = MLConfigStatus.OK
+	var status_msg := ""
 	var data = {} # can be anything
 	var defaults := {}
 
 	# Invalid mod ID
 	if not mod_data.has(mod_dir_name):
-		error_num = 1
-		error_msg = "ERROR - Mod ID was invalid: %s" % mod_dir_name
+		status_code = MLConfigStatus.INVALID_MOD_ID
+		status_msg = "Mod ID was invalid: %s" % mod_dir_name
 
 	# Mod ID is valid
-	if error_num == 0:
+	if status_code == MLConfigStatus.OK:
 		var mod := mod_data[mod_dir_name] as ModData
 		var config_data := mod.config
 		defaults = mod.manifest.config_defaults
 
 		# No custom JSON file
-		if config_data.size() == 0:
-			error_num = 2
-			error_msg = "WARNING - No config file for %s.json." % mod_dir_name
+		if config_data.size() == MLConfigStatus.OK:
+			status_code = MLConfigStatus.NO_JSON_OK
+			var noconfig_msg = "No config file for %s.json. " % mod_dir_name
 			if key == "":
 				data = defaults
-				error_msg += "Using defaults (extra.godot.config_defaults)"
+				status_msg += str(noconfig_msg, "Using defaults (extra.godot.config_defaults)")
 			else:
 				if defaults.has(key):
 					data = defaults[key]
-					error_msg += "Using defaults for key '%s' (extra.godot.config_defaults.%s)" % [key, key]
+					status_msg += str(noconfig_msg, "Using defaults for key '%s' (extra.godot.config_defaults.%s)" % [key, key])
 				else:
-					error_num = 3
-					error_msg += "Requested key '%s' is not present in the defaults (extra.godot.config_defaults.%s)" % [key, key]
+					status_code = MLConfigStatus.NO_JSON_INVALID_KEY
+					status_msg += str(
+						"Could not get the requested data for %s: " % mod_dir_name,
+						"Requested key '%s' is not present in the 'config_defaults' of the mod's manifest.json file (extra.godot.config_defaults.%s). " % [key, key]
+					)
 
 		# JSON file exists
-		if error_num == 0:
+		if status_code == MLConfigStatus.OK:
 			if key == "":
 				data = config_data
 			else:
 				if config_data.has(key):
 					data = config_data[key]
 				else:
-					error_num = 4
-					error_msg = "WARNING - Invalid key '%s' for mod ID: %s" % [key, mod_dir_name]
+					status_code = MLConfigStatus.INVALID_KEY
+					status_msg = "Invalid key '%s' for mod ID: %s" % [key, mod_dir_name]
 
 	# Log if any errors occured
-	if not error_num == 0:
-		ModLoaderUtils.log_debug("Config Error: %s" % error_msg, mod_dir_name)
+	if not status_code == MLConfigStatus.OK:
+		if status_code == MLConfigStatus.NO_JSON_OK:
+			# No user config file exists. Low importance as very likely to trigger
+			ModLoaderUtils.log_debug("Config JSON Notice: %s" % status_msg, mod_dir_name)
+		else:
+			# Code error (eg. invalid mod ID)
+			ModLoaderUtils.log_fatal("Config JSON Error (%s): %s" % [status_code, status_msg], mod_dir_name)
 
 	return {
-		"error": error_num,
-		"error_msg": error_msg,
+		"status_code": status_code,
+		"status_msg": status_msg,
 		"data": data,
 	}