Draft: Fuzzy autocomplete replacement

internal/pkg/completion/completion.go

@@ -4,6 +4,7 @@ import (
 	"log/slog"
 	"slices"
 	"strings"
+	"unicode/utf8"
 
 	"github.com/spf13/cobra"
 
@@ -25,20 +26,88 @@ func ClusterID(clustersInventoryFile string, stopAfterFirst bool, filter func(li
 			return nil, cobra.ShellCompDirectiveNoFileComp | cobra.ShellCompDirectiveError
 		}
 
-		suggestions := make([]string, 0, len(clusters))
-		for _, cluster := range clusters {
-			if cluster.ID == "" {
-				continue
-			}
-			if filter != nil && !filter(cluster) {
-				continue
-			}
-			if cur == "" || strings.HasPrefix(cluster.ID, cur) {
-				suggestions = append(suggestions, cluster.ID)
+		return suggestClusterIDs(clusters, cur, filter), cobra.ShellCompDirectiveNoFileComp
+	}
+}
+
+func suggestClusterIDs(clusters []lieutenant.Cluster, cur string, filter func(lieutenant.Cluster) bool) []string {
+	type rankedSuggestion struct {
+		suggestion string
+		distance   int
+	}
+
+	suggestions := make([]rankedSuggestion, 0, len(clusters))
+	for _, cluster := range clusters {
+		if cluster.ID == "" {
+			continue
+		}
+		if filter != nil && !filter(cluster) {
+			continue
+		}
+
+		if !match(cluster.ID, cur) && !match(strings.ToLower(cur), strings.ToLower(cluster.DisplayName)) {
+			continue
+		}
+
+		idDistance := levenshteinDistance(cur, cluster.ID)
+		displayNameDistance := 100 * levenshteinDistance(strings.ToLower(cur), strings.ToLower(cluster.DisplayName))
+		suggestions = append(suggestions, rankedSuggestion{suggestion: cluster.ID, distance: idDistance + displayNameDistance})
+	}
+
+	slices.SortFunc(suggestions, func(a, b rankedSuggestion) int {
+		return 10*(a.distance-b.distance) + strings.Compare(a.suggestion, b.suggestion)
+	})
+
+	result := make([]string, len(suggestions))
+	for i, s := range suggestions {
+		result[i] = s.suggestion
+	}
+	return result
+}
+
+func match(source, target string) bool {
+	if source == target {
+		return true
+	}
+	if len(target)-len(source) < 0 {
+		return false
+	}
+
+outer:
+	for _, r1 := range source {
+		for i, r2 := range target {
+			if r1 == r2 {
+				target = target[i+utf8.RuneLen(r2):]
+				continue outer
 			}
 		}
-		slices.Sort(suggestions)
+		return false
+	}
+
+	return true
+}
 
-		return suggestions, cobra.ShellCompDirectiveNoFileComp
+func levenshteinDistance(s, t string) int {
+	r1, r2 := []rune(s), []rune(t)
+	column := make([]int, len(r1)+1)
+
+	for j := range column {
+		column[j] = j
 	}
+
+	for x := 1; x <= len(r2); x++ {
+		column[0] = x
+
+		for y, lastDiag := 1, x-1; y <= len(r1); y++ {
+			oldDiag := column[y]
+			cost := 0
+			if r1[y-1] != r2[x-1] {
+				cost = 1
+			}
+			column[y] = min(column[y]+1, column[y-1]+1, lastDiag+cost)
+			lastDiag = oldDiag
+		}
+	}
+
+	return column[len(r1)]
 }