feat: x/editor (#15)

Signed-off-by: Carlos Alexandro Becker <[email protected]>

editor/editor.go

@@ -0,0 +1,31 @@
+package editor
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"strings"
+)
+
+const defaultEditor = "nano"
+
+// Cmd returns a *exec.Cmd editing the given path with $EDITOR or nano if no
+// $EDITOR is set.
+func Cmd(app, path string) (*exec.Cmd, error) {
+	if os.Getenv("SNAP_REVISION") != "" {
+		return nil, fmt.Errorf("Did you install with Snap? %[1]s is sandboxed and unable to open an editor. Please install %[1]s with Go or another package manager to enable editing.", app)
+	}
+	editor, args := getEditor()
+	return exec.Command(editor, append(args, path)...), nil
+}
+
+func getEditor() (string, []string) {
+	editor := strings.Fields(os.Getenv("EDITOR"))
+	if len(editor) > 1 {
+		return editor[0], editor[1:]
+	}
+	if len(editor) == 1 {
+		return editor[0], []string{}
+	}
+	return defaultEditor, []string{}
+}

editor/editor_test.go

@@ -0,0 +1,37 @@
+package editor
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestEditor(t *testing.T) {
+	filename := "README.md"
+	for k, v := range map[string][]string{
+		"":             {"nano", filename},
+		"nvim":         {"nvim", filename},
+		"vim":          {"vim", filename},
+		"vscode --foo": {"vscode", "--foo", filename},
+		"nvim -a -b":   {"nvim", "-a", "-b", filename},
+	} {
+		t.Run(k, func(t *testing.T) {
+			t.Setenv("EDITOR", k)
+			cmd, _ := Cmd("X", "README.md")
+			got := cmd.Args
+			if !reflect.DeepEqual(got, v) {
+				t.Fatalf("expected %v; got %v", v, got)
+			}
+		})
+	}
+
+	t.Run("inside snap", func(t *testing.T) {
+		t.Setenv("SNAP_REVISION", "10")
+		got, err := Cmd("X", "foo")
+		if err == nil {
+			t.Fatalf("expected an error, got nil")
+		}
+		if got != nil {
+			t.Fatalf("should have returned nil, got %v", got)
+		}
+	})
+}

editor/go.mod

@@ -0,0 +1,3 @@
+module github.com/charmbracelet/x/editor
+
+go 1.20

go.work

@@ -1,6 +1,7 @@
 go 1.20
 
 use (
+	./editor
 	./exp/higherorder
 	./exp/ordered
 	./exp/slice