refactor(lsp,llm,hexailsp,appconfig): split long funcs; add tests

- Extract helpers to keep funcs <=50 lines; no behavior changes
- Add tests for prompt removal, code actions, and LLM request builders
- Table-drive TestInParamList; run gofmt

1 files changed, 92 insertions, 74 deletions

diff --git a/internal/llm/copilot.go b/internal/llm/copilot.go
index 47ce11e..67cffc9 100644
--- a/internal/llm/copilot.go
+++ b/internal/llm/copilot.go
@@ -17,20 +17,20 @@ import (
 
 // copilotClient implements Client against GitHub Copilot's Chat Completions API.
 type copilotClient struct {
-    httpClient   *http.Client
-    apiKey       string
-    baseURL      string
-    defaultModel string
-    chatLogger   logging.ChatLogger
-    defaultTemperature *float64
+	httpClient         *http.Client
+	apiKey             string
+	baseURL            string
+	defaultModel       string
+	chatLogger         logging.ChatLogger
+	defaultTemperature *float64
 }
 
 type copilotChatRequest struct {
-    Model       string           `json:"model"`
-    Messages    []copilotMessage `json:"messages"`
-    Temperature *float64         `json:"temperature,omitempty"`
-    MaxTokens   *int             `json:"max_tokens,omitempty"`
-    Stop        []string         `json:"stop,omitempty"`
+	Model       string           `json:"model"`
+	Messages    []copilotMessage `json:"messages"`
+	Temperature *float64         `json:"temperature,omitempty"`
+	MaxTokens   *int             `json:"max_tokens,omitempty"`
+	Stop        []string         `json:"stop,omitempty"`
 }
 
 type copilotMessage struct {
@@ -57,20 +57,20 @@ type copilotChatResponse struct {
 
 // Constructor (kept among the first functions by convention)
 func newCopilot(baseURL, model, apiKey string, defaultTemp *float64) Client {
-    if strings.TrimSpace(baseURL) == "" {
-        baseURL = "https://api.githubcopilot.com"
-    }
-    if strings.TrimSpace(model) == "" {
-        model = "gpt-4.1"
-    }
-    return copilotClient{
-        httpClient:   &http.Client{Timeout: 30 * time.Second},
-        apiKey:       apiKey,
-        baseURL:      strings.TrimRight(baseURL, "/"),
-        defaultModel: model,
-        chatLogger:   logging.NewChatLogger("copilot"),
-        defaultTemperature: defaultTemp,
-    }
+	if strings.TrimSpace(baseURL) == "" {
+		baseURL = "https://api.githubcopilot.com"
+	}
+	if strings.TrimSpace(model) == "" {
+		model = "gpt-4.1"
+	}
+	return copilotClient{
+		httpClient:         &http.Client{Timeout: 30 * time.Second},
+		apiKey:             apiKey,
+		baseURL:            strings.TrimRight(baseURL, "/"),
+		defaultModel:       model,
+		chatLogger:         logging.NewChatLogger("copilot"),
+		defaultTemperature: defaultTemp,
+	}
 }
 
 func (c copilotClient) Chat(ctx context.Context, messages []Message, opts ...RequestOption) (string, error) {
@@ -84,38 +84,14 @@ func (c copilotClient) Chat(ctx context.Context, messages []Message, opts ...Req
 	if o.Model == "" {
 		o.Model = c.defaultModel
 	}
-
 	start := time.Now()
-	logMessages := make([]struct {
-		Role    string
-		Content string
-	}, len(messages))
+	logMessages := make([]struct{ Role, Content string }, len(messages))
 	for i, m := range messages {
-		logMessages[i] = struct {
-			Role    string
-			Content string
-		}{Role: m.Role, Content: m.Content}
+		logMessages[i] = struct{ Role, Content string }{m.Role, m.Content}
 	}
 	c.chatLogger.LogStart(false, o.Model, o.Temperature, o.MaxTokens, o.Stop, logMessages)
 
-	req := copilotChatRequest{Model: o.Model}
-	req.Messages = make([]copilotMessage, len(messages))
-	for i, m := range messages {
-		req.Messages[i] = copilotMessage{Role: m.Role, Content: m.Content}
-	}
-    if o.Temperature != 0 {
-        req.Temperature = &o.Temperature
-    } else if c.defaultTemperature != nil {
-        t := *c.defaultTemperature
-        req.Temperature = &t
-    }
-	if o.MaxTokens > 0 {
-		req.MaxTokens = &o.MaxTokens
-	}
-	if len(o.Stop) > 0 {
-		req.Stop = o.Stop
-	}
-
+	req := buildCopilotChatRequest(o, messages, c.defaultTemperature)
 	body, err := json.Marshal(req)
 	if err != nil {
 		logging.Logf("llm/copilot ", "marshal error: %v", err)
@@ -124,34 +100,19 @@ func (c copilotClient) Chat(ctx context.Context, messages []Message, opts ...Req
 
 	endpoint := c.baseURL + "/chat/completions"
 	logging.Logf("llm/copilot ", "POST %s", endpoint)
-	httpReq, err := http.NewRequestWithContext(ctx, http.MethodPost, endpoint, bytes.NewReader(body))
-	if err != nil {
-		logging.Logf("llm/copilot ", "new request error: %v", err)
-		return "", err
-	}
-	httpReq.Header.Set("Content-Type", "application/json")
-	httpReq.Header.Set("Authorization", "Bearer "+c.apiKey)
-
-	resp, err := c.httpClient.Do(httpReq)
+	resp, err := c.doJSON(ctx, endpoint, body, map[string]string{
+		"Authorization": "Bearer " + c.apiKey,
+	})
 	if err != nil {
 		logging.Logf("llm/copilot ", "%shttp error after %s: %v%s", logging.AnsiRed, time.Since(start), err, logging.AnsiBase)
 		return "", err
 	}
 	defer resp.Body.Close()
-	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
-		var apiErr copilotChatResponse
-		_ = json.NewDecoder(resp.Body).Decode(&apiErr)
-		if apiErr.Error != nil && strings.TrimSpace(apiErr.Error.Message) != "" {
-			logging.Logf("llm/copilot ", "%sapi error status=%d type=%s msg=%s duration=%s%s", logging.AnsiRed, resp.StatusCode, apiErr.Error.Type, apiErr.Error.Message, time.Since(start), logging.AnsiBase)
-			return "", fmt.Errorf("copilot error: %s (status %d)", apiErr.Error.Message, resp.StatusCode)
-		}
-		logging.Logf("llm/copilot ", "%shttp non-2xx status=%d duration=%s%s", logging.AnsiRed, resp.StatusCode, time.Since(start), logging.AnsiBase)
-		return "", fmt.Errorf("copilot http error: status %d", resp.StatusCode)
+	if err := handleCopilotNon2xx(resp, start); err != nil {
+		return "", err
 	}
-
-	var out copilotChatResponse
-	if err := json.NewDecoder(resp.Body).Decode(&out); err != nil {
-		logging.Logf("llm/copilot ", "%sdecode error after %s: %v%s", logging.AnsiRed, time.Since(start), err, logging.AnsiBase)
+	out, err := decodeCopilotChat(resp, start)
+	if err != nil {
 		return "", err
 	}
 	if len(out.Choices) == 0 {
@@ -166,3 +127,60 @@ func (c copilotClient) Chat(ctx context.Context, messages []Message, opts ...Req
 // Provider metadata
 func (c copilotClient) Name() string         { return "copilot" }
 func (c copilotClient) DefaultModel() string { return c.defaultModel }
+
+// helpers
+func buildCopilotChatRequest(o Options, messages []Message, defaultTemp *float64) copilotChatRequest {
+	req := copilotChatRequest{Model: o.Model}
+	req.Messages = make([]copilotMessage, len(messages))
+	for i, m := range messages {
+		req.Messages[i] = copilotMessage{Role: m.Role, Content: m.Content}
+	}
+	if o.Temperature != 0 {
+		req.Temperature = &o.Temperature
+	} else if defaultTemp != nil {
+		t := *defaultTemp
+		req.Temperature = &t
+	}
+	if o.MaxTokens > 0 {
+		req.MaxTokens = &o.MaxTokens
+	}
+	if len(o.Stop) > 0 {
+		req.Stop = o.Stop
+	}
+	return req
+}
+
+func (c copilotClient) doJSON(ctx context.Context, url string, body []byte, headers map[string]string) (*http.Response, error) {
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewReader(body))
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("Content-Type", "application/json")
+	for k, v := range headers {
+		req.Header.Set(k, v)
+	}
+	return c.httpClient.Do(req)
+}
+
+func handleCopilotNon2xx(resp *http.Response, start time.Time) error {
+	if resp.StatusCode >= 200 && resp.StatusCode < 300 {
+		return nil
+	}
+	var apiErr copilotChatResponse
+	_ = json.NewDecoder(resp.Body).Decode(&apiErr)
+	if apiErr.Error != nil && strings.TrimSpace(apiErr.Error.Message) != "" {
+		logging.Logf("llm/copilot ", "%sapi error status=%d type=%s msg=%s duration=%s%s", logging.AnsiRed, resp.StatusCode, apiErr.Error.Type, apiErr.Error.Message, time.Since(start), logging.AnsiBase)
+		return fmt.Errorf("copilot error: %s (status %d)", apiErr.Error.Message, resp.StatusCode)
+	}
+	logging.Logf("llm/copilot ", "%shttp non-2xx status=%d duration=%s%s", logging.AnsiRed, resp.StatusCode, time.Since(start), logging.AnsiBase)
+	return fmt.Errorf("copilot http error: status %d", resp.StatusCode)
+}
+
+func decodeCopilotChat(resp *http.Response, start time.Time) (copilotChatResponse, error) {
+	var out copilotChatResponse
+	if err := json.NewDecoder(resp.Body).Decode(&out); err != nil {
+		logging.Logf("llm/copilot ", "%sdecode error after %s: %v%s", logging.AnsiRed, time.Since(start), err, logging.AnsiBase)
+		return copilotChatResponse{}, err
+	}
+	return out, nil
+}