1// Package copilot provides GitHub Copilot integration.
2package copilot
3
4import (
5 "bytes"
6 "fmt"
7 "io"
8 "log/slog"
9 "net/http"
10 "regexp"
11
12 "github.com/charmbracelet/crush/internal/log"
13)
14
15// NewClient creates a new HTTP client with a custom transport that adds the
16// X-Initiator header based on message history in the request body.
17func NewClient(debug bool) *http.Client {
18 return &http.Client{
19 Transport: &initiatorTransport{debug: debug},
20 }
21}
22
23type initiatorTransport struct {
24 debug bool
25}
26
27func (t *initiatorTransport) RoundTrip(req *http.Request) (*http.Response, error) {
28 const (
29 xInitiatorHeader = "X-Initiator"
30 userInitiator = "user"
31 agentInitiator = "agent"
32 )
33
34 if req == nil {
35 return nil, fmt.Errorf("HTTP request is nil")
36 }
37 if req.Body == http.NoBody {
38 // No body to inspect; default to user.
39 req.Header.Set(xInitiatorHeader, userInitiator)
40 slog.Debug("Setting X-Initiator header to user (no request body)")
41 return t.roundTrip(req)
42 }
43
44 // Clone request to avoid modifying the original.
45 req = req.Clone(req.Context())
46
47 // Read the original body into bytes so we can examine it.
48 bodyBytes, err := io.ReadAll(req.Body)
49 if err != nil {
50 return nil, fmt.Errorf("failed to read request body: %w", err)
51 }
52 defer req.Body.Close()
53
54 // Restore the original body using the preserved bytes.
55 req.Body = io.NopCloser(bytes.NewReader(bodyBytes))
56
57 // Check for assistant messages using regex to handle whitespace
58 // variations in the JSON while avoiding full unmarshalling overhead.
59 initiator := userInitiator
60 assistantRolePattern := regexp.MustCompile(`"role"\s*:\s*"assistant"`)
61 if assistantRolePattern.Match(bodyBytes) {
62 slog.Debug("Setting X-Initiator header to agent (found assistant messages in history)")
63 initiator = agentInitiator
64 } else {
65 slog.Debug("Setting X-Initiator header to user (no assistant messages)")
66 }
67 req.Header.Set(xInitiatorHeader, initiator)
68
69 return t.roundTrip(req)
70}
71
72func (t *initiatorTransport) roundTrip(req *http.Request) (*http.Response, error) {
73 if t.debug {
74 return log.NewHTTPClient().Transport.RoundTrip(req)
75 }
76 return http.DefaultTransport.RoundTrip(req)
77}