lsp: split monolithic server.go into modules; add configurable max tokens and context strategies (minimal|window|file-on-new-func|always-full); provide flags/env fallbacks; add unit tests for helpers and context; update README; remove obsolete files

1 files changed, 126 insertions, 0 deletions

diff --git a/internal/lsp/handlers_test.go b/internal/lsp/handlers_test.go
new file mode 100644
index 0000000..bde9b82
--- /dev/null
+++ b/internal/lsp/handlers_test.go
@@ -0,0 +1,126 @@
+package lsp
+
+import (
+    "strings"
+    "testing"
+)
+
+func TestInParamList(t *testing.T) {
+    line := "func foo(a int, b string) int {"
+    if !inParamList(line, 15) { // inside params
+        t.Fatalf("expected inParamList true for cursor inside params")
+    }
+    if inParamList(line, 2) { // before 'func'
+        t.Fatalf("expected inParamList false for cursor before params")
+    }
+    if inParamList(line, len(line)) { // after ')'
+        t.Fatalf("expected inParamList false for cursor after params")
+    }
+}
+
+func TestComputeWordStart(t *testing.T) {
+    current := "fmt.Prin"
+    // Cursor after the word (index 8)
+    got := computeWordStart(current, 8)
+    // should stop after the dot at index 4
+    if want := 4; got != want {
+        t.Fatalf("computeWordStart got %d want %d", got, want)
+    }
+}
+
+func TestComputeTextEditAndFilter_InParams(t *testing.T) {
+    current := "func foo(a int, b string) {" // ')' at index 26
+    p := CompletionParams{Position: Position{Line: 10, Character: 20}}
+    te, filter := computeTextEditAndFilter("x int, y string", true, current, p)
+
+    if te == nil {
+        t.Fatalf("expected TextEdit")
+    }
+    // left should be after '(' which is at index 8
+    if te.Range.Start.Line != 10 || te.Range.Start.Character != 9 {
+        t.Fatalf("start got line=%d char=%d want line=10 char=9", te.Range.Start.Line, te.Range.Start.Character)
+    }
+    // right should clamp to cursor (20)
+    if te.Range.End.Line != 10 || te.Range.End.Character != 20 {
+        t.Fatalf("end got line=%d char=%d want line=10 char=20", te.Range.End.Line, te.Range.End.Character)
+    }
+    if filter == "" {
+        t.Fatalf("expected non-empty filter inside params")
+    }
+}
+
+func TestComputeTextEditAndFilter_Word(t *testing.T) {
+    current := "fmt.Prin"
+    p := CompletionParams{Position: Position{Line: 2, Character: len(current)}}
+    te, filter := computeTextEditAndFilter("Println", false, current, p)
+    if te == nil {
+        t.Fatalf("expected TextEdit")
+    }
+    if te.Range.Start.Character != 4 || te.Range.End.Character != len(current) {
+        t.Fatalf("range chars got %d..%d want 4..%d", te.Range.Start.Character, te.Range.End.Character, len(current))
+    }
+    if filter != "Prin" {
+        t.Fatalf("filter got %q want %q", filter, "Prin")
+    }
+}
+
+func TestLabelForCompletion(t *testing.T) {
+    if got := labelForCompletion("Println", "Pri"); got != "Println" {
+        t.Fatalf("label mismatch got %q want %q", got, "Println")
+    }
+    if got := labelForCompletion("Println", "X"); got != "X" {
+        t.Fatalf("label mismatch with filter got %q want %q", got, "X")
+    }
+    if got := labelForCompletion("Println\nmore", ""); got != "Println" {
+        t.Fatalf("label firstLine got %q want %q", got, "Println")
+    }
+}
+
+func TestBuildPrompts_InParams(t *testing.T) {
+    p := CompletionParams{TextDocument: TextDocumentIdentifier{URI: "file:///t.go"}, Position: Position{Line: 1, Character: 12}}
+    sys, user := buildPrompts(true, p, "above", "func foo(", "below", "func foo(")
+    if sys == "" || user == "" {
+        t.Fatalf("expected non-empty prompts")
+    }
+    if want := "function signatures"; !contains(sys, want) {
+        t.Fatalf("system prompt missing %q: %q", want, sys)
+    }
+    if want := "parameter list"; !contains(user, want) {
+        t.Fatalf("user prompt missing %q: %q", want, user)
+    }
+}
+
+func TestBuildPrompts_Outside(t *testing.T) {
+    p := CompletionParams{TextDocument: TextDocumentIdentifier{URI: "file:///t.go"}, Position: Position{Line: 1, Character: 5}}
+    sys, user := buildPrompts(false, p, "ab", "cur", "be", "fnctx")
+    if sys == "" || user == "" {
+        t.Fatalf("expected non-empty prompts")
+    }
+    if want := "completion engine"; !contains(sys, want) {
+        t.Fatalf("system prompt missing %q: %q", want, sys)
+    }
+    if want := "Provide the next likely code"; !contains(user, want) {
+        t.Fatalf("user prompt missing %q: %q", want, user)
+    }
+}
+
+func TestComputeTextEditAndFilter_NoParensFallback(t *testing.T) {
+    current := "func foo bar" // no parentheses
+    cursor := len(current)
+    p := CompletionParams{Position: Position{Line: 0, Character: cursor}}
+    te, filter := computeTextEditAndFilter("baz", true, current, p)
+    if te == nil {
+        t.Fatalf("expected TextEdit from fallback path")
+    }
+    // fallback should behave like word edit; start at last space + 1
+    lastSpace := strings.LastIndex(current, " ")
+    if te.Range.Start.Character != lastSpace+1 || te.Range.End.Character != cursor {
+        t.Fatalf("range got %d..%d want %d..%d", te.Range.Start.Character, te.Range.End.Character, lastSpace+1, cursor)
+    }
+    if filter != "bar" {
+        t.Fatalf("filter got %q want %q", filter, "bar")
+    }
+}
+
+// small helper to avoid importing strings
+func contains(s, sub string) bool { return len(s) >= len(sub) && (func() bool { i := 0; for i+len(sub) <= len(s) { if s[i:i+len(sub)] == sub { return true }; i++ }; return false })() }