Move text editor determination to cli package

src/cli/init.go

@@ -27,7 +27,10 @@ func TempInitCli() {
 	}
 
 	// textEditor
-	textEditor := input("Text editor (leave blank for $EDITOR, falls back to \"" + backend.FallbackEditor + "\"):")
+	textEditor := input("Text editor (leave blank for $EDITOR, falls back to \"" + fallbackEditor + "\"):")
+	if textEditor == "" {
+		textEditor = textEditorFallback()
+	}
 
 	// SSH info
 	configSSH := inputBinary("Configure SSH settings (for synchronization)?")

src/cli/initUNIX.go

@@ -0,0 +1,19 @@
+//go:build !windows
+
+package cli
+
+import (
+	"os"
+)
+
+const fallbackEditor = "vi" // vi is pre-installed on most UNIX systems
+
+// textEditorFallback returns the value of the $EDITOR environment variable, or FallbackEditor if it is not set
+func textEditorFallback() string {
+	// ensure textEditor is set
+	textEditor := os.Getenv("EDITOR")
+	if textEditor == "" {
+		textEditor = fallbackEditor
+	}
+	return textEditor
+}

src/cli/initWIN.go

@@ -0,0 +1,10 @@
+//go:build windows
+
+package cli
+
+const fallbackEditor = "nvim" // since there is no pre-installed CLI editor on Windows, default to the most popular one
+
+// textEditorFallback returns FallbackEditor
+func textEditorFallback() string {
+	return fallbackEditor
+}