Add brief ai subcommand

cmd/brief/ai.go

@@ -0,0 +1,177 @@
+package main
+
+import (
+	"encoding/json"
+	"flag"
+	"fmt"
+	"io"
+	"os"
+	"sort"
+
+	"github.com/chaoss/ai-detection-action/detection"
+	"github.com/chaoss/ai-detection-action/detection/coauthor"
+	"github.com/chaoss/ai-detection-action/detection/committer"
+	"github.com/chaoss/ai-detection-action/detection/message"
+	"github.com/chaoss/ai-detection-action/detection/toolmention"
+	"github.com/chaoss/ai-detection-action/scan"
+)
+
+func cmdAI(args []string) {
+	fs := flag.NewFlagSet("brief ai", flag.ExitOnError)
+	jsonFlag := fs.Bool("json", false, "Force JSON output")
+	humanFlag := fs.Bool("human", false, "Force human-readable output")
+	markdownFlag := fs.Bool("markdown", false, "Force markdown output")
+	commitRange := fs.String("range", "", "Commit range to scan (e.g. base..head)")
+	minConfidence := fs.String("min-confidence", "low", "Minimum confidence level: low, medium, or high")
+	_ = fs.Parse(args)
+
+	path := "."
+	if fs.NArg() > 0 {
+		path = fs.Arg(0)
+	}
+
+	minConf, err := parseConfidence(*minConfidence)
+	if err != nil {
+		_, _ = fmt.Fprintf(os.Stderr, "error: %v\n", err)
+		os.Exit(1)
+	}
+
+	detectors := []detection.Detector{
+		&committer.Detector{},
+		&coauthor.Detector{},
+		&message.Detector{},
+		&toolmention.Detector{},
+	}
+
+	report, err := scan.ScanCommitRange(path, *commitRange, detectors)
+	if err != nil {
+		_, _ = fmt.Fprintf(os.Stderr, "error: %v\n", err)
+		os.Exit(1)
+	}
+
+	report = filterByConfidence(report, minConf)
+
+	switch {
+	case *markdownFlag:
+		aiMarkdown(os.Stdout, report)
+	case *jsonFlag || (!*humanFlag && !isTTY()):
+		enc := json.NewEncoder(os.Stdout)
+		enc.SetIndent("", "  ")
+		if err := enc.Encode(report); err != nil {
+			_, _ = fmt.Fprintf(os.Stderr, "error writing JSON: %v\n", err)
+			os.Exit(1)
+		}
+	default:
+		aiHuman(os.Stdout, report)
+	}
+
+	if report.Summary.AICommits > 0 {
+		os.Exit(1)
+	}
+}
+
+func parseConfidence(s string) (detection.Confidence, error) {
+	switch s {
+	case "low":
+		return detection.ConfidenceLow, nil
+	case "medium":
+		return detection.ConfidenceMedium, nil
+	case "high":
+		return detection.ConfidenceHigh, nil
+	default:
+		return 0, fmt.Errorf("invalid confidence level %q, expected low, medium, or high", s)
+	}
+}
+
+func filterByConfidence(r scan.Report, minConf detection.Confidence) scan.Report {
+	var filtered []scan.CommitResult
+	for _, cr := range r.Commits {
+		var findings []detection.Finding
+		for _, f := range cr.Findings {
+			if f.Confidence >= minConf {
+				findings = append(findings, f)
+			}
+		}
+		if len(findings) > 0 {
+			filtered = append(filtered, scan.CommitResult{
+				Hash:     cr.Hash,
+				Findings: findings,
+			})
+		}
+	}
+
+	// Rebuild summary from filtered results.
+	summary := scan.Summary{
+		TotalCommits: len(r.Commits),
+		AICommits:    len(filtered),
+		ToolCounts:   map[string]int{},
+		ByConfidence: map[string]int{},
+	}
+	for _, cr := range filtered {
+		for _, f := range cr.Findings {
+			summary.ToolCounts[f.Tool]++
+			summary.ByConfidence[f.Confidence.String()]++
+		}
+	}
+
+	return scan.Report{
+		Commits: filtered,
+		Summary: summary,
+	}
+}
+
+func sortedToolNames(counts map[string]int) []string {
+	names := make([]string, 0, len(counts))
+	for name := range counts {
+		names = append(names, name)
+	}
+	sort.Strings(names)
+	return names
+}
+
+const shortHashLen = 12
+
+func aiHuman(w io.Writer, r scan.Report) {
+	_, _ = fmt.Fprintf(w, "%d commits scanned, %d with AI signals\n", r.Summary.TotalCommits, r.Summary.AICommits)
+
+	if r.Summary.AICommits == 0 {
+		return
+	}
+
+	_, _ = fmt.Fprintln(w)
+	for _, tool := range sortedToolNames(r.Summary.ToolCounts) {
+		_, _ = fmt.Fprintf(w, "  %-25s %d commits\n", tool, r.Summary.ToolCounts[tool])
+	}
+
+	_, _ = fmt.Fprintln(w)
+	for _, cr := range r.Commits {
+		_, _ = fmt.Fprintf(w, "%s\n", cr.Hash[:min(len(cr.Hash), shortHashLen)])
+		for _, f := range cr.Findings {
+			_, _ = fmt.Fprintf(w, "  [%s] %s: %s\n", f.Confidence, f.Tool, f.Detail)
+		}
+	}
+}
+
+func aiMarkdown(w io.Writer, r scan.Report) {
+	_, _ = fmt.Fprintf(w, "## AI Detection\n\n")
+	_, _ = fmt.Fprintf(w, "%d commits scanned, %d with AI signals\n\n", r.Summary.TotalCommits, r.Summary.AICommits)
+
+	if r.Summary.AICommits == 0 {
+		return
+	}
+
+	_, _ = fmt.Fprintln(w, "| Tool | Commits |")
+	_, _ = fmt.Fprintln(w, "|------|---------|")
+	for _, tool := range sortedToolNames(r.Summary.ToolCounts) {
+		_, _ = fmt.Fprintf(w, "| %s | %d |\n", tool, r.Summary.ToolCounts[tool])
+	}
+
+	_, _ = fmt.Fprintf(w, "\n### Findings\n\n")
+	for _, cr := range r.Commits {
+		_, _ = fmt.Fprintf(w, "**%s**\n\n", cr.Hash[:min(len(cr.Hash), shortHashLen)])
+		for _, f := range cr.Findings {
+			_, _ = fmt.Fprintf(w, "- [%s] %s: %s\n", f.Confidence, f.Tool, f.Detail)
+		}
+		_, _ = fmt.Fprintln(w)
+	}
+}