Compute the edit distance and complement the URL

config.go

@@ -4,12 +4,14 @@ import (
 	"encoding/json"
 	"fmt"
 	"io/ioutil"
+	"math"
 	neturl "net/url"
 	"os"
 	"os/exec"
 	"path/filepath"
 	"runtime"
-	"strings"
+
+	"github.com/agext/levenshtein"
 )
 
 type Config struct {
@@ -83,15 +85,14 @@ func (cfg *Config) LoadFile(file string) error {
 }
 
 func (cfg *Config) GetEnv(url string) (env Env, err error) {
-	u, err := neturl.Parse(url)
-	if err != nil {
-		return
-	}
+	u1, _ := neturl.Parse(url)
 	for _, service := range cfg.Services {
-		if strings.Contains(service.URL, u.Host) {
+		u2, _ := neturl.Parse(service.URL)
+		if u1.Host == u2.Host {
 			return service.Env, nil
 		}
 	}
+	err = fmt.Errorf("%s: no such host in config file", u1.Host)
 	return
 }
 
@@ -121,3 +122,19 @@ func (cfg *Config) Edit() error {
 	cmd.Stdin = os.Stdin
 	return cmd.Run()
 }
+
+func (cfg *Config) SimilarURLs(url string) (urls []string) {
+	u1, _ := neturl.Parse(url)
+	for _, service := range cfg.Services {
+		u2, _ := neturl.Parse(service.URL)
+		degree := round(levenshtein.Similarity(u1.Host, u2.Host, nil) * 100)
+		if degree > 50 {
+			urls = append(urls, service.URL)
+		}
+	}
+	return
+}
+
+func round(f float64) float64 {
+	return math.Floor(f + .5)
+}

main.go

@@ -48,6 +48,7 @@ func main() {
 }
 
 func run(args []string) int {
+	var url string
 	if len(args) > 0 {
 		switch args[0] {
 		case "-h", "--help":
@@ -63,11 +64,16 @@ func run(args []string) int {
 			}
 			fmt.Fprintf(os.Stderr, "Error: %s\n", err.Error())
 			return 1
+		default:
+			url = args[0]
 		}
 
-		env, err := cfg.GetEnv(args[0])
+		env, err := cfg.GetEnv(url)
 		if err != nil {
 			fmt.Fprintf(os.Stderr, "Error: %s\n", err.Error())
+			for _, url := range cfg.SimilarURLs(url) {
+			}
+			fmt.Fprintf(os.Stderr, "       similar urls found %q\n")
 			return 1
 		}
 		if credentials == "" {