Make enum values typed strings (#18)

This also moves validation into the parsing process and refactors a bunch of code related to the config.

Reviewed-on: #18
Co-authored-by: Anna Rose Wiggins <annabunches@gmail.com>
Co-committed-by: Anna Rose Wiggins <annabunches@gmail.com>

internal/configparser/ruleconfig.go

@@ -0,0 +1,60 @@
+package configparser
+
+type RuleConfig struct {
+	Type   RuleType
+	Name   string
+	Modes  []string
+	Config interface{}
+}
+
+func (dc *RuleConfig) UnmarshalYAML(unmarshal func(data interface{}) error) error {
+	metaConfig := &struct {
+		Type  RuleType
+		Name  string
+		Modes []string
+	}{}
+	err := unmarshal(metaConfig)
+	if err != nil {
+		return err
+	}
+	dc.Type = metaConfig.Type
+	dc.Name = metaConfig.Name
+	dc.Modes = metaConfig.Modes
+
+	switch dc.Type {
+	case RuleTypeButton:
+		config := RuleConfigButton{}
+		err = unmarshal(&config)
+		dc.Config = config
+	case RuleTypeButtonCombo:
+		config := RuleConfigButtonCombo{}
+		err = unmarshal(&config)
+		dc.Config = config
+	case RuleTypeButtonLatched:
+		config := RuleConfigButtonLatched{}
+		err = unmarshal(&config)
+		dc.Config = config
+	case RuleTypeAxis:
+		config := RuleConfigAxis{}
+		err = unmarshal(&config)
+		dc.Config = config
+	case RuleTypeAxisCombined:
+		config := RuleConfigAxisCombined{}
+		err = unmarshal(&config)
+		dc.Config = config
+	case RuleTypeAxisToButton:
+		config := RuleConfigAxisToButton{}
+		err = unmarshal(&config)
+		dc.Config = config
+	case RuleTypeAxisToRelaxis:
+		config := RuleConfigAxisToRelaxis{}
+		err = unmarshal(&config)
+		dc.Config = config
+	case RuleTypeModeSelect:
+		config := RuleConfigModeSelect{}
+		err = unmarshal(&config)
+		dc.Config = config
+	}
+
+	return err
+}