fix: menu size calculation bug

cmd/ttg/main.go

@@ -3,13 +3,15 @@ package main
 import (
 	"flag"
 	"log"
+	"os"
 
 	"github.com/ivanilves/ttg/pkg/directory"
 	"github.com/ivanilves/ttg/pkg/file"
 	"github.com/ivanilves/ttg/pkg/filter"
 	"github.com/ivanilves/ttg/pkg/menu"
 	"github.com/ivanilves/ttg/pkg/scm"
 	"github.com/ivanilves/ttg/pkg/shell"
+	"github.com/ivanilves/ttg/pkg/terminal"
 )
 
 var appVersion = "default"
@@ -38,7 +40,9 @@ func main() {
 	flag.Parse()
 
 	if version {
-		shell.PrintAndExit(appVersion)
+		println(appVersion)
+
+		os.Exit(0)
 	}
 
 	matches := flag.Args()
@@ -59,7 +63,7 @@ func main() {
 		log.Fatalf("invalid filter: %s", err.Error())
 	}
 
-	selected, err := menu.Build(filter.Apply(entries, matches))
+	selected, err := menu.Build(filter.Apply(entries, matches), terminal.Height())
 
 	if err != nil {
 		log.Fatalf("failed to build menu: %s", err.Error())

go.mod

@@ -6,6 +6,7 @@ require (
 	github.com/go-git/go-git/v5 v5.4.2
 	github.com/manifoldco/promptui v0.9.0
 	github.com/stretchr/testify v1.8.0
+	golang.org/x/term v0.0.0-20210927222741-03fcf44c2211
 )
 
 require (

go.sum

@@ -98,6 +98,7 @@ golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f h1:v4INt8xihDGvnrfjMDVXGxw9w
 golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211 h1:JGgROgKl9N8DuW20oFS5gxc+lE67/N3FcwmBPMe7ArY=
+golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.3.7 h1:olpwvP2KacW1ZWvsR7uQhoyTYvKAupfQrRGBFM352Gk=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=

pkg/menu/menu.go

@@ -9,8 +9,26 @@ import (
 
 const label = "Select Terragrunt project to travel"
 
+// Overhead shows how many lines are occupied by menu control elements
+const Overhead = 3
+
+// MinSize stands for minimal menu size
+const MinSize = 5
+
+func getSize(itemCount int, size int) int {
+	if itemCount <= size {
+		return itemCount
+	}
+
+	if size <= MinSize {
+		return MinSize
+	}
+
+	return size
+}
+
 // Build creates an interactive menu to chose Terragrunt project from
-func Build(items []string) (selected string, err error) {
+func Build(items []string, maxSize int) (selected string, err error) {
 	if len(items) == 0 {
 		return "", fmt.Errorf("no items")
 	}
@@ -26,7 +44,7 @@ func Build(items []string) (selected string, err error) {
 	prompt := promptui.Select{
 		Label:    label,
 		Items:    items,
-		Size:     len(items),
+		Size:     getSize(len(items), maxSize-Overhead),
 		Searcher: searcher,
 	}
 

pkg/shell/shell.go

@@ -9,7 +9,6 @@ import (
 )
 
 const defaultShell = "bash"
-const defaultLines = 20
 
 func detectShell() string {
 	shell := os.Getenv("SHELL")
@@ -29,28 +28,6 @@ func detectShell() string {
 	return defaultShell
 }
 
-func detectLines() int {
-	lines := os.Getenv("LINES")
-
-	if len(lines) == 0 {
-		return defaultLines
-	}
-
-	lnum, err := strconv.Atoi(lines)
-
-	if err != nil {
-		return defaultLines
-	}
-
-	return lnum
-}
-
-func isMocked() bool {
-	shell := detectShell()
-
-	return shell == "/bin/true" || shell == "/bin/false"
-}
-
 // Name returns a called binary name
 func Name() string {
 	return os.Args[0]
@@ -83,12 +60,3 @@ func Spawn(path string) error {
 
 	return cmd.Run()
 }
-
-// PrintAndExit prints a string passed and exits after
-func PrintAndExit(s string) {
-	fmt.Printf("%s\n", s)
-
-	if !isMocked() {
-		os.Exit(0)
-	}
-}

pkg/shell/shell_test.go

@@ -25,39 +25,6 @@ func TestDetectShell(t *testing.T) {
 	}
 }
 
-func TestDetectLines(t *testing.T) {
-	assert := assert.New(t)
-
-	cases := map[string]int{
-		"50":  50,
-		"xyz": defaultLines,
-		"":    defaultLines,
-	}
-
-	for input, expected := range cases {
-		os.Setenv("LINES", input)
-
-		assert.Equal(expected, detectLines())
-	}
-}
-
-func TestIsMocked(t *testing.T) {
-	assert := assert.New(t)
-
-	cases := map[string]bool{
-		"/bin/bash":  false,
-		"/bin/zsh":   false,
-		"/bin/true":  true,
-		"/bin/false": true,
-	}
-
-	for input, expected := range cases {
-		os.Setenv("SHELL", input)
-
-		assert.Equal(expected, isMocked())
-	}
-}
-
 func TestName(t *testing.T) {
 	assert := assert.New(t)
 

pkg/terminal/terminal.go

@@ -0,0 +1,18 @@
+package terminal
+
+import (
+	"golang.org/x/term"
+)
+
+const defautHeight = 20
+
+// Height reveals a number of lines we have in our terminal
+func Height() int {
+	_, h, err := term.GetSize(0)
+
+	if err != nil {
+		return defautHeight
+	}
+
+	return h
+}