From 55ca313b73949ccf961a0c42b0c3141672fdc68a Mon Sep 17 00:00:00 2001
From: Martino Ferrari <martinogiordano.ferrari@iter.org>
Date: Mon, 2 Feb 2026 14:37:03 +0100
Subject: [PATCH] added suggestion for variables

---
 internal/lsp/server.go      | 83 ++++++++++++++++++++++++++++++++-----
 test/lsp_completion_test.go | 64 +++++++++++++++++++++++++++-
 2 files changed, 136 insertions(+), 11 deletions(-)

diff --git a/internal/lsp/server.go b/internal/lsp/server.go
index 24e9389..f0c2f60 100644
--- a/internal/lsp/server.go
+++ b/internal/lsp/server.go
@@ -265,7 +265,7 @@ func HandleMessage(msg *JsonRpcMessage) {
 				"documentFormattingProvider": true,
 				"renameProvider":             true,
 				"completionProvider": map[string]any{
-					"triggerCharacters": []string{"=", " "},
+					"triggerCharacters": []string{"=", " ", "@"},
 				},
 			},
 		})
@@ -675,6 +675,20 @@ func HandleCompletion(params CompletionParams) *CompletionList {
 
 	prefix := lineStr[:col]
 
+	// Case 3: Variable completion
+	varRegex := regexp.MustCompile(`([@$])([a-zA-Z0-9_]*)$`)
+	if matches := varRegex.FindStringSubmatch(prefix); matches != nil {
+		container := Tree.GetNodeContaining(path, parser.Position{Line: params.Position.Line + 1, Column: col + 1})
+		if container == nil {
+			if iso, ok := Tree.IsolatedFiles[path]; ok {
+				container = iso
+			} else {
+				container = Tree.Root
+			}
+		}
+		return suggestVariables(container)
+	}
+
 	// Case 1: Assigning a value (Ends with "=" or "= ")
 	if strings.Contains(prefix, "=") {
 		lastIdx := strings.LastIndex(prefix, "=")
@@ -907,20 +921,41 @@ func suggestFieldValues(container *index.ProjectNode, field string, path string)
 		root = Tree.Root
 	}
 
+	var items []CompletionItem
+
 	if field == "DataSource" {
-		return suggestObjects(root, "DataSource")
-	}
-	if field == "Functions" {
-		return suggestObjects(root, "GAM")
-	}
-	if field == "Type" {
-		return suggestSignalTypes()
+		if list := suggestObjects(root, "DataSource"); list != nil {
+			items = append(items, list.Items...)
+		}
+	} else if field == "Functions" {
+		if list := suggestObjects(root, "GAM"); list != nil {
+			items = append(items, list.Items...)
+		}
+	} else if field == "Type" {
+		if list := suggestSignalTypes(); list != nil {
+			items = append(items, list.Items...)
+		}
+	} else {
+		if list := suggestCUEEnums(container, field); list != nil {
+			items = append(items, list.Items...)
+		}
 	}
 
-	if list := suggestCUEEnums(container, field); list != nil {
-		return list
+	// Add variables
+	vars := suggestVariables(container)
+	if vars != nil {
+		for _, item := range vars.Items {
+			// Create copy to modify label
+			newItem := item
+			newItem.Label = "@" + newItem.Label
+			newItem.InsertText = "@" + item.Label
+			items = append(items, newItem)
+		}
 	}
 
+	if len(items) > 0 {
+		return &CompletionList{Items: items}
+	}
 	return nil
 }
 
@@ -1518,3 +1553,31 @@ func send(msg any) {
 	body, _ := json.Marshal(msg)
 	fmt.Fprintf(Output, "Content-Length: %d\r\n\r\n%s", len(body), body)
 }
+
+func suggestVariables(container *index.ProjectNode) *CompletionList {
+	items := []CompletionItem{}
+	seen := make(map[string]bool)
+
+	curr := container
+	for curr != nil {
+		for name, info := range curr.Variables {
+			if !seen[name] {
+				seen[name] = true
+
+				doc := ""
+				if info.Def.DefaultValue != nil {
+					doc = fmt.Sprintf("Default: %s", valueToString(info.Def.DefaultValue))
+				}
+
+				items = append(items, CompletionItem{
+					Label:         name,
+					Kind:          6, // Variable
+					Detail:        fmt.Sprintf("Variable (%s)", info.Def.TypeExpr),
+					Documentation: doc,
+				})
+			}
+		}
+		curr = curr.Parent
+	}
+	return &CompletionList{Items: items}
+}
diff --git a/test/lsp_completion_test.go b/test/lsp_completion_test.go
index 07822d3..c290ad4 100644
--- a/test/lsp_completion_test.go
+++ b/test/lsp_completion_test.go
@@ -163,7 +163,7 @@ $App = {
 		}
 	})
 
-		t.Run("Scope-aware suggestions", func(t *testing.T) {
+	t.Run("Scope-aware suggestions", func(t *testing.T) {
 		setup()
 		// Define a project DataSource in one file
 		cfg1, _ := parser.NewParser("#package MYPROJ.Data\n+ProjectDS = { Class = FileReader +Signals = { S1 = { Type = int32 } } }").Parse()
@@ -317,4 +317,66 @@ package schema
 			}
 		}
 	})
+
+	t.Run("Suggest Variables", func(t *testing.T) {
+		setup()
+		content := `
+#var MyVar: uint = 10
++App = {
+    Field = 
+}
+`
+		lsp.Documents[uri] = content
+		p := parser.NewParser(content)
+		cfg, _ := p.Parse()
+		lsp.Tree.AddFile(path, cfg)
+
+		// 1. Triggered by =
+		params := lsp.CompletionParams{
+			TextDocument: lsp.TextDocumentIdentifier{URI: uri},
+			Position:     lsp.Position{Line: 3, Character: 12}, // After "Field = "
+		}
+		list := lsp.HandleCompletion(params)
+		if list == nil {
+			t.Fatal("Expected suggestions")
+		}
+
+		found := false
+		for _, item := range list.Items {
+			if item.Label == "@MyVar" {
+				found = true
+				break
+			}
+		}
+		if !found {
+			t.Error("Expected @MyVar in suggestions for =")
+		}
+
+		// 2. Triggered by $
+		// "Field = $"
+		lsp.Documents[uri] = `
+#var MyVar: uint = 10
++App = {
+    Field = $
+}
+`
+		params2 := lsp.CompletionParams{
+			TextDocument: lsp.TextDocumentIdentifier{URI: uri},
+			Position:     lsp.Position{Line: 3, Character: 13}, // After "Field = $"
+		}
+		list2 := lsp.HandleCompletion(params2)
+		if list2 == nil {
+			t.Fatal("Expected suggestions for $")
+		}
+		found = false
+		for _, item := range list2.Items {
+			if item.Label == "MyVar" { // suggestVariables returns "MyVar"
+				found = true
+				break
+			}
+		}
+		if !found {
+			t.Error("Expected MyVar in suggestions for $")
+		}
+	})
 }