feat(wireguard): Add completions for root interfaces

handlers/wireguard/parser_completions_test.go

@@ -45,3 +45,54 @@ PrivateKey = 1234567890
 		t.Fatalf("getCompletionsForEmptyLine: Expected %v completions, but got %v", expected, len(completions))
 	}
 }
+
+func TestEmptyRootCompletionsWork(
+	t *testing.T,
+) {
+	sample := dedent(`
+	`)
+
+	parser := createWireguardParser()
+	parser.parseFromString(sample)
+
+	completions := parser.getRootCompletionsForEmptyLine()
+
+	if len(completions) != 2 {
+		t.Fatalf("getRootCompletionsForEmptyLine: Expected 2 completions, but got %v", len(completions))
+	}
+}
+
+func TestInterfaceSectionRootCompletionsBeforeWork(
+	t *testing.T,
+) {
+	sample := dedent(`
+
+[Interface]
+`)
+	parser := createWireguardParser()
+	parser.parseFromString(sample)
+
+	completions := parser.getRootCompletionsForEmptyLine()
+
+	if len(completions) != 1 {
+		t.Fatalf("getRootCompletionsForEmptyLine: Expected 1 completions, but got %v", len(completions))
+	}
+}
+
+func TestInterfaceAndPeerSectionRootCompletionsWork(
+	t *testing.T,
+) {
+	sample := dedent(`
+[Interface]
+
+[Peer]
+`)
+	parser := createWireguardParser()
+	parser.parseFromString(sample)
+
+	completions := parser.getRootCompletionsForEmptyLine()
+
+	if len(completions) != 1 {
+		t.Fatalf("getRootCompletionsForEmptyLine: Expected 1 completions, but got %v", len(completions))
+	}
+}

handlers/wireguard/text-document-completion.go

@@ -20,7 +20,7 @@ func TextDocumentCompletion(context *glsp.Context, params *protocol.CompletionPa
 		return nil, nil
 	case LineTypeEmpty:
 		if section == nil {
-			return nil, nil
+			return parser.getRootCompletionsForEmptyLine(), nil
 		}
 
 		return section.getCompletionsForEmptyLine()

handlers/wireguard/wg-parser.go

@@ -5,6 +5,8 @@ import (
 	"regexp"
 	"slices"
 	"strings"
+
+	protocol "github.com/tliron/glsp/protocol_3_16"
 )
 
 var commentPattern = regexp.MustCompile(`^\s*(;|#)`)
@@ -27,6 +29,45 @@ func (p *wireguardParser) clear() {
 	p.CommentLines = map[uint32]struct{}{}
 }
 
+func (p wireguardParser) hasInterfaceSection() bool {
+	for _, section := range p.Sections {
+		if section.Name != nil && *section.Name == "Interface" {
+			return true
+		}
+	}
+
+	return false
+}
+
+func (p wireguardParser) getRootCompletionsForEmptyLine() []protocol.CompletionItem {
+	kind := protocol.CompletionItemKindInterface
+	completions := []protocol.CompletionItem{}
+
+	if !p.hasInterfaceSection() {
+		sortText := "Z"
+		insertText := "[Interface]\n"
+		completions = append(completions, protocol.CompletionItem{
+			Label:         "[Interface]",
+			InsertText:    &insertText,
+			Kind:          &kind,
+			Documentation: "An interface section represents the local node's configuration",
+			SortText:      &sortText,
+		})
+	}
+
+	sortText := "A"
+	insertText := "[Peer]\n"
+	completions = append(completions, protocol.CompletionItem{
+		Label:         "[Peer]",
+		InsertText:    &insertText,
+		Kind:          &kind,
+		Documentation: "A peer section represents a peer that this node communicates with",
+		SortText:      &sortText,
+	})
+
+	return completions
+}
+
 func createWireguardParser() wireguardParser {
 	parser := wireguardParser{}
 	parser.clear()