improve subcommand selection

Signed-off-by: Achille Roussel <[email protected]>

internal/cmd/get.go

@@ -65,7 +65,7 @@ var resources = [...]resource{
  },
  {
  name: "module",
- alt: []string{"mo", "mods", "modules"},
+ alt: []string{"mo", "mod", "mods", "modules"},
  get: getModules,
  },
  {
@@ -94,30 +94,27 @@ func get(ctx context.Context, args []string) error {
 
  args = flagSet.Args()
  if len(args) == 0 {
- return errors.New(`expected exactly one resource name as argument`)
+ return errors.New(`expected exactly one resource name as argument` + useGet())
  }
  resourceNamePrefix := args[0]
  parseFlags(flagSet, args[1:])
 
- matchingResources := selectMatchingResources(resourceNamePrefix, resources[:])
- if len(matchingResources) == 0 {
- return fmt.Errorf(`no resources matching '%s'`, resourceNamePrefix)
- }
- if len(matchingResources) > 1 {
+ resource, ok := findResource(resourceNamePrefix, resources[:])
+ if !ok {
+ matchingResources := findMatchingResources(resourceNamePrefix, resources[:])
+ if len(matchingResources) == 0 {
+ return fmt.Errorf(`no resources matching '%s'`+useGet(), resourceNamePrefix)
+ }
  return fmt.Errorf(`no resources matching '%s'
 
-Did you mean?
-
- $ timecraft get %s
-`, resourceNamePrefix, matchingResources[0].name)
+Did you mean?%s`, resourceNamePrefix, joinResourceNames(matchingResources, "\n "))
  }
 
  registry, err := openRegistry(registryPath)
  if err != nil {
  return err
  }
 
- resource := matchingResources[0]
  reader := registry.ListResources(ctx, resource.name, timeRange)
  defer reader.Close()
 
@@ -226,22 +223,53 @@ func newDescTableWriter[T any](w io.Writer, conv func(*format.Descriptor) (T, er
  return stream.NewWriteCloser(cw, tw)
 }
 
-func selectMatchingResources(name string, options []resource) []resource {
- var matches []resource
-
+func findResource(name string, options []resource) (resource, bool) {
  for _, option := range options {
  if option.name == name {
- return []resource{option}
+ return option, true
  }
  for _, alt := range option.alt {
  if alt == name {
- return []resource{option}
+ return option, true
  }
  }
- if strings.HasPrefix(option.name, name) {
+ }
+ return resource{}, false
+}
+
+func findMatchingResources(name string, options []resource) (matches []resource) {
+ for _, option := range options {
+ if prefixLength(option.name, name) > 1 || prefixLength(name, option.name) > 1 {
  matches = append(matches, option)
  }
  }
-
  return matches
 }
+
+func prefixLength(base, prefix string) int {
+ n := 0
+ for n < len(base) && n < len(prefix) && base[n] == prefix[n] {
+ n++
+ }
+ return n
+}
+
+func joinResourceNames(resources []resource, prefix string) string {
+ s := new(strings.Builder)
+ for _, r := range resources {
+ s.WriteString(prefix)
+ s.WriteString(r.name)
+ }
+ return s.String()
+}
+
+func useGet() string {
+ s := new(strings.Builder)
+ s.WriteString("\n\n")
+ s.WriteString(`Use 'timecraft <resource>' where the supported resource names are:`)
+ for _, r := range resources {
+ s.WriteString("\n ")
+ s.WriteString(r.name)
+ }
+ return s.String()
+}