WIP: handle empty aliases key

internal/config/alias_config.go

@@ -1,6 +1,7 @@
 package config
 
 import (
+	"errors"
 	"fmt"
 
 	"gopkg.in/yaml.v3"
@@ -11,14 +12,6 @@ type AliasConfig struct {
 	Parent Config
 }
 
-// TODO at what point should the alias top level be added? Lazily on first write, I think;
-// but then we aren't initializing the default aliases that we want. also want to ensure that we
-// don't re-add the default aliases if people delete them.
-//
-// I think I'm not going to worry about it for now; config setup will add the aliases and existing
-// users can take some step later on to add them if they want them. we'll otherwise lazily create
-// the aliases: section on first write.
-
 func (a *AliasConfig) Exists(alias string) bool {
 	if a.Empty() {
 		return false
@@ -36,10 +29,13 @@ func (a *AliasConfig) Get(alias string) string {
 
 func (a *AliasConfig) Add(alias, expansion string) error {
 	if a.Root == nil {
-		// then we don't actually have an aliases stanza in the config yet.
-		keyNode := &yaml.Node{
-			Kind:  yaml.ScalarNode,
-			Value: "aliases",
+		// TODO awful hack bad type conversion i'm sorry
+		entry, err := a.Parent.(*fileConfig).FindEntryPrime("aliases")
+
+		var notFound *NotFoundError
+
+		if err != nil && !errors.As(err, &notFound) {
+			return err
 		}
 		valueNode := &yaml.Node{
 			Kind:  yaml.MappingNode,
@@ -47,7 +43,29 @@ func (a *AliasConfig) Add(alias, expansion string) error {
 		}
 
 		a.Root = valueNode
-		a.Parent.Root().Content = append(a.Parent.Root().Content, keyNode, valueNode)
+		if errors.As(err, &notFound) {
+			// No aliases: key; just append new aliases key and empty map to end
+			keyNode := &yaml.Node{
+				Kind:  yaml.ScalarNode,
+				Value: "aliases",
+			}
+			a.Parent.Root().Content = append(a.Parent.Root().Content, keyNode, valueNode)
+		} else {
+			// Empty aliases; inject new value node after existing aliases key
+			newContent := []*yaml.Node{}
+			for i := 0; i < len(a.Parent.Root().Content); i++ {
+				node := a.Parent.Root().Content[i]
+				if i == entry.Index {
+				}
+				if i == entry.Index {
+					newContent = append(newContent, entry.KeyNode, valueNode)
+					i++
+				} else {
+					newContent = append(newContent, a.Parent.Root().Content[i])
+				}
+			}
+			a.Parent.Root().Content = newContent
+		}
 	}
 
 	err := a.SetStringValue(alias, expansion)

internal/config/config_type.go

@@ -73,6 +73,32 @@ func (cm *ConfigMap) SetStringValue(key, value string) error {
 	return nil
 }
 
+type ConfigEntry struct {
+	KeyNode   *yaml.Node
+	ValueNode *yaml.Node
+	Index     int
+}
+
+func (cm *ConfigMap) FindEntryPrime(key string) (ce *ConfigEntry, err error) {
+	err = nil
+
+	ce = &ConfigEntry{}
+
+	topLevelKeys := cm.Root.Content
+	for i, v := range topLevelKeys {
+		if v.Value == key {
+			ce.KeyNode = v
+			ce.Index = i
+			if i+1 < len(topLevelKeys) {
+				ce.ValueNode = topLevelKeys[i+1]
+			}
+			return
+		}
+	}
+
+	return ce, &NotFoundError{errors.New("not found")}
+}
+
 func (cm *ConfigMap) FindEntry(key string) (keyNode, valueNode *yaml.Node, err error) {
 	err = nil
 
@@ -195,7 +221,9 @@ func (c *fileConfig) Aliases() (*AliasConfig, error) {
 
 func (c *fileConfig) parseAliasConfig(aliasesEntry *yaml.Node) (*AliasConfig, error) {
 	if aliasesEntry.Kind != yaml.MappingNode {
-		return nil, errors.New("expected aliases to be a map")
+		return &AliasConfig{
+			Parent: c,
+		}, nil
 	}
 
 	aliasConfig := AliasConfig{