experimental: codex / ai integration

ai_diff.go

@@ -0,0 +1,188 @@
+package main
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"path"
+	"path/filepath"
+	"strconv"
+	"strings"
+)
+
+func (c *GitHubClient) PullRequestDiff(ctx context.Context, owner, repo string, number int) (string, error) {
+	base := strings.TrimSuffix(c.endpoint, "/")
+	switch {
+	case base == "https://api.github.com/graphql":
+		base = "https://api.github.com"
+	case strings.HasSuffix(base, "/api/graphql"):
+		base = strings.TrimSuffix(base, "/api/graphql") + "/api/v3"
+	default:
+		base = strings.TrimSuffix(base, "/graphql")
+	}
+	requestURL := base + "/repos/" + url.PathEscape(owner) + "/" + url.PathEscape(repo) +
+		"/pulls/" + strconv.Itoa(number)
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, requestURL, nil)
+	if err != nil {
+		return "", err
+	}
+	req.Header.Set("Authorization", "Bearer "+c.token)
+	req.Header.Set("Accept", "application/vnd.github.v3.diff")
+	req.Header.Set("User-Agent", "diple")
+	response, err := c.http.Do(req)
+	if err != nil {
+		return "", err
+	}
+	defer response.Body.Close()
+	if response.StatusCode != http.StatusOK {
+		body, _ := io.ReadAll(io.LimitReader(response.Body, 4096))
+		return "", fmt.Errorf("GitHub returned %s: %s", response.Status, strings.TrimSpace(string(body)))
+	}
+	body, err := io.ReadAll(io.LimitReader(response.Body, (32<<20)+1))
+	if err != nil {
+		return "", err
+	}
+	if len(body) > 32<<20 {
+		return "", fmt.Errorf("PR diff exceeds the 32 MiB safety limit")
+	}
+	return string(body), nil
+}
+
+func (c *CachedGitHubService) PullRequestDiff(ctx context.Context, owner, repo string, number int) (string, error) {
+	service, ok := c.remote.(AIDiffService)
+	if !ok {
+		return "", fmt.Errorf("configured GitHub service cannot load pull request diffs")
+	}
+	return service.PullRequestDiff(ctx, owner, repo, number)
+}
+
+func prepareAIDiff(raw string, config AIConfig) ([]aiDiffFile, []string, int) {
+	sections := strings.Split(raw, "\ndiff --git ")
+	var files []aiDiffFile
+	var excluded []string
+	redactions := 0
+	for sectionIndex, section := range sections {
+		if sectionIndex > 0 {
+			section = "diff --git " + section
+		}
+		file, ok := parseAIDiffFile(section)
+		if !ok {
+			continue
+		}
+		reason := aiExcludedReason(file, config)
+		if reason != "" {
+			excluded = append(excluded, file.Path+" ("+reason+")")
+			continue
+		}
+		redacted, count := redactAISecrets(file.Text)
+		file.Text = sanitizeAIControls(redacted)
+		redactions += count
+		files = append(files, file)
+	}
+	return files, excluded, redactions
+}
+
+func parseAIDiffFile(section string) (aiDiffFile, bool) {
+	scanner := bufio.NewScanner(strings.NewReader(section))
+	scanner.Buffer(make([]byte, 4096), 2<<20)
+	file := aiDiffFile{
+		ChangedLines: make(map[int]bool), DeletedLines: make(map[int]bool), Text: section,
+	}
+	oldPath := ""
+	oldLine := 0
+	newLine := 0
+	inHunk := false
+	for scanner.Scan() {
+		line := scanner.Text()
+		if strings.HasPrefix(line, "--- ") && !inHunk {
+			candidate := strings.TrimPrefix(line, "--- ")
+			if strings.HasPrefix(candidate, `"`) {
+				if unquoted, err := strconv.Unquote(candidate); err == nil {
+					candidate = unquoted
+				}
+			}
+			if strings.HasPrefix(candidate, "a/") {
+				oldPath = strings.TrimPrefix(candidate, "a/")
+			}
+		}
+		if strings.HasPrefix(line, "+++ ") && !inHunk {
+			candidate := strings.TrimPrefix(line, "+++ ")
+			if strings.HasPrefix(candidate, `"`) {
+				if unquoted, err := strconv.Unquote(candidate); err == nil {
+					candidate = unquoted
+				}
+			}
+			if strings.HasPrefix(candidate, "b/") {
+				file.Path = strings.TrimPrefix(candidate, "b/")
+			}
+		}
+		if strings.HasPrefix(line, "@@ ") {
+			parts := strings.Fields(line)
+			if len(parts) >= 3 {
+				oldRange := strings.TrimPrefix(parts[1], "-")
+				oldStart := strings.SplitN(oldRange, ",", 2)[0]
+				oldLine, _ = strconv.Atoi(oldStart)
+				rangePart := strings.TrimPrefix(parts[2], "+")
+				start := strings.SplitN(rangePart, ",", 2)[0]
+				newLine, _ = strconv.Atoi(start)
+				inHunk = true
+			}
+			continue
+		}
+		if !inHunk || line == "" {
+			continue
+		}
+		switch line[0] {
+		case '+':
+			file.ChangedLines[newLine] = true
+			newLine++
+		case '-':
+			file.DeletedLines[oldLine] = true
+			oldLine++
+		default:
+			oldLine++
+			newLine++
+		}
+	}
+	if file.Path == "" {
+		file.Path = oldPath
+	}
+	if file.Path == "" || file.Path == "/dev/null" {
+		return aiDiffFile{}, false
+	}
+	file.Path = filepath.ToSlash(filepath.Clean(file.Path))
+	if strings.HasPrefix(file.Path, "../") || filepath.IsAbs(file.Path) {
+		return aiDiffFile{}, false
+	}
+	return file, len(file.ChangedLines) > 0 || len(file.DeletedLines) > 0
+}
+
+func aiExcludedReason(file aiDiffFile, config AIConfig) string {
+	if len(file.Text) > config.MaxFileBytes {
+		return "oversized"
+	}
+	if strings.Contains(file.Text, "GIT binary patch") ||
+		strings.Contains(file.Text, "Binary files ") || strings.IndexByte(file.Text, 0) >= 0 {
+		return "binary"
+	}
+	lower := strings.ToLower(file.Path)
+	for _, pattern := range config.Exclude {
+		pattern = filepath.ToSlash(pattern)
+		if strings.HasSuffix(pattern, "/") {
+			directory := strings.ToLower(pattern)
+			if strings.HasPrefix(lower, directory) || strings.Contains(lower, "/"+directory) {
+				return "excluded"
+			}
+		}
+		if matched, _ := path.Match(strings.ToLower(pattern), path.Base(lower)); matched {
+			return "excluded"
+		}
+		if matched, _ := path.Match(strings.ToLower(pattern), lower); matched {
+			return "excluded"
+		}
+	}
+	return ""
+}