When advising on a TERM upgrade, use tcell's database too

Tcell comes with a built-in database of terminal types. It can also use
infocmp to construct one on the target machine. Termshark will advise a
user to use a more colorful TERM variable if the -256color definition is
available. This change has termshark check tcell's DB first, falling
back to infocmp if necessary.

ui/lastline.go

@@ -19,8 +19,6 @@ import (
 	"github.com/gcla/termshark/v2/theme"
 	"github.com/gcla/termshark/v2/widgets/mapkeys"
 	"github.com/gcla/termshark/v2/widgets/minibuffer"
-	"github.com/gdamore/tcell/terminfo"
-	"github.com/gdamore/tcell/terminfo/dynamic"
 	"github.com/rakyll/statik/fs"
 	"github.com/shibukawa/configdir"
 
@@ -311,15 +309,6 @@ func parseOnOff(str string) (bool, error) {
 	return false, strconv.ErrSyntax
 }
 
-func validateTerm(term string) error {
-	var err error
-	_, err = terminfo.LookupTerminfo(term)
-	if err != nil {
-		_, _, err = dynamic.LoadTerminfo(term)
-	}
-	return err
-}
-
 type setCommand struct{}
 
 var _ minibuffer.IAction = setCommand{}
@@ -359,7 +348,7 @@ func (d setCommand) Run(app gowid.IApp, args ...string) error {
 				OpenMessage(fmt.Sprintf("Packet colors are now %s", gwutil.If(b, "on", "off").(string)), appView, app)
 			}
 		case "term":
-			if err = validateTerm(args[2]); err == nil {
+			if err = termshark.ValidateTerm(args[2]); err == nil {
 				termshark.SetConf("main.term", args[2])
 				OpenMessage(fmt.Sprintf("Terminal type is now %s\n(Requires restart)", args[2]), appView, app)
 			}

ui/switchterm.go

@@ -48,7 +48,7 @@ func SuggestSwitchingTerm(app gowid.IApp) {
 	term256 := term + "-256color"
 
 	switchTerm = dialog.New(
-		framed.NewSpace(paragraph.New(fmt.Sprintf("Termshark is running with TERM=%s. Your terminal database contains %s. Would you like to switch for a more colorful experience? Termshark will need to restart.", term, term256))),
+		framed.NewSpace(paragraph.New(fmt.Sprintf("Termshark is running with TERM=%s. The terminal database contains %s. Would you like to switch for a more colorful experience? Termshark will need to restart.", term, term256))),
 		dialog.Options{
 			Buttons:         []dialog.Button{Yes, No, NoAsk},
 			NoShadow:        true,

utils.go

@@ -40,6 +40,7 @@ import (
 	"github.com/gcla/termshark/v2/system"
 	"github.com/gcla/termshark/v2/widgets/resizable"
 	"github.com/gdamore/tcell"
+	"github.com/gdamore/tcell/terminfo"
 	"github.com/gdamore/tcell/terminfo/dynamic"
 	"github.com/mattn/go-isatty"
 	"github.com/pkg/errors"
@@ -1327,8 +1328,16 @@ func FileSizeDifferentTo(filename string, cur int64) (int64, bool) {
 }
 
 func Does256ColorTermExist() error {
-	_, _, e := dynamic.LoadTerminfo(fmt.Sprintf("%s-256color", os.Getenv("TERM")))
-	return e
+	return ValidateTerm(fmt.Sprintf("%s-256color", os.Getenv("TERM")))
+}
+
+func ValidateTerm(term string) error {
+	var err error
+	_, err = terminfo.LookupTerminfo(term)
+	if err != nil {
+		_, _, err = dynamic.LoadTerminfo(term)
+	}
+	return err
 }
 
 //======================================================================