Phase 2: add configurable completion debounce\n\n- App config: completion_debounce_ms (default 200)\n- Server: wait until no input for debounce before LLM calls\n- Applies to chat and provider-native completion paths\n- Tests: add debounce and adjust to verify behavior\n\nAll unit tests pass.

1 files changed, 84 insertions, 0 deletions

diff --git a/internal/lsp/debounce_throttle_test.go b/internal/lsp/debounce_throttle_test.go
new file mode 100644
index 0000000..012ec68
--- /dev/null
+++ b/internal/lsp/debounce_throttle_test.go
@@ -0,0 +1,84 @@
+package lsp
+
+import (
+    "context"
+    "encoding/json"
+    "testing"
+    "time"
+    "codeberg.org/snonux/hexai/internal/llm"
+)
+
+// timeLLM records the time when Chat is invoked.
+type timeLLM struct{ t time.Time }
+
+func (t *timeLLM) Chat(ctx context.Context, _ []llm.Message, _ ...llm.RequestOption) (string, error) {
+    t.t = time.Now()
+    return "ok", nil
+}
+func (t *timeLLM) Name() string         { return "fake" }
+func (t *timeLLM) DefaultModel() string { return "m" }
+
+func TestCompletionDebounce_WaitsUntilQuiet(t *testing.T) {
+    s := newTestServer()
+    s.compCache = make(map[string]string)
+    s.triggerChars = []string{".", ":", "/", "_"}
+    s.maxTokens = 32
+    s.completionDebounce = 30 * time.Millisecond
+    s.markActivity() // simulate recent input
+
+    f := &timeLLM{}
+    s.llmClient = f
+
+    line := "func f(i int) "
+    p := CompletionParams{Position: Position{Line: 0, Character: len(line)}, TextDocument: TextDocumentIdentifier{URI: "file://debounce.go"}}
+    p.Context = json.RawMessage([]byte(`{"triggerKind":1}`))
+
+    start := time.Now()
+    _, ok := s.tryLLMCompletion(p, "", line, "", "", "", false, "")
+    if !ok {
+        t.Fatalf("expected ok=true")
+    }
+    if f.t.IsZero() {
+        t.Fatalf("expected LLM to be called")
+    }
+    if f.t.Sub(start) < 25*time.Millisecond { // allow minor timing noise
+        t.Fatalf("expected debounce delay, got %s", f.t.Sub(start))
+    }
+}
+
+func TestCompletionThrottle_SerializesCalls(t *testing.T) {
+    s := newTestServer()
+    s.compCache = make(map[string]string)
+    s.triggerChars = []string{".", ":", "/", "_"}
+    s.maxTokens = 32
+    s.throttleInterval = 25 * time.Millisecond
+
+    // first call uses timeLLM to record time
+    f1 := &timeLLM{}
+    s.llmClient = f1
+    line := "func f(i int) "
+    p := CompletionParams{Position: Position{Line: 0, Character: len(line)}, TextDocument: TextDocumentIdentifier{URI: "file://throttle.go"}}
+    p.Context = json.RawMessage([]byte(`{"triggerKind":1}`))
+    start := time.Now()
+    if _, ok := s.tryLLMCompletion(p, "", line, "", "", "", false, ""); !ok {
+        t.Fatalf("first call expected ok=true")
+    }
+    if f1.t.IsZero() {
+        t.Fatalf("expected first call time recorded")
+    }
+
+    // second call immediately after; should be delayed by ~interval.
+    // Clear cache to ensure we actually call the LLM again.
+    s.compCache = make(map[string]string)
+    f2 := &timeLLM{}
+    s.llmClient = f2
+    if _, ok := s.tryLLMCompletion(p, "", line, "", "", "", false, ""); !ok {
+        t.Fatalf("second call expected ok=true")
+    }
+    if f2.t.IsZero() {
+        t.Fatalf("expected second call time recorded")
+    }
+    if f2.t.Sub(start) < s.throttleInterval {
+        t.Fatalf("expected throttle spacing >= %s, got %s", s.throttleInterval, f2.t.Sub(start))
+    }
+}