feat: add knowledge-silo command to detect team knowledge silos

cmd/nightshift/commands/silo.go

@@ -0,0 +1,173 @@
+package commands
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+	"time"
+
+	"github.com/spf13/cobra"
+
+	"github.com/marcus/nightshift/internal/analysis"
+	"github.com/marcus/nightshift/internal/config"
+	"github.com/marcus/nightshift/internal/db"
+	"github.com/marcus/nightshift/internal/logging"
+)
+
+var siloCmd = &cobra.Command{
+	Use:   "knowledge-silo [path]",
+	Short: "Detect knowledge silos in the codebase",
+	Long: `Analyze git history per directory to identify knowledge silos — areas where
+only one or two people have contributed.
+
+Directories are ranked by silo risk based on contributor concentration. Use this
+to find areas that need knowledge transfer, pairing sessions, or documentation.
+
+The silo score (0-1) combines commit concentration (Herfindahl index) with
+contributor count. Higher scores indicate greater knowledge isolation.`,
+	RunE: func(cmd *cobra.Command, args []string) error {
+		path, _ := cmd.Flags().GetString("path")
+		if path == "" && len(args) > 0 {
+			path = args[0]
+		}
+		if path == "" {
+			var err error
+			path, err = os.Getwd()
+			if err != nil {
+				return fmt.Errorf("getting current directory: %w", err)
+			}
+		}
+
+		depth, _ := cmd.Flags().GetInt("depth")
+		minCommits, _ := cmd.Flags().GetInt("min-commits")
+		jsonOutput, _ := cmd.Flags().GetBool("json")
+		since, _ := cmd.Flags().GetString("since")
+		until, _ := cmd.Flags().GetString("until")
+		saveReport, _ := cmd.Flags().GetBool("save")
+		dbPath, _ := cmd.Flags().GetString("db")
+
+		return runSilo(path, depth, minCommits, jsonOutput, since, until, saveReport, dbPath)
+	},
+}
+
+func init() {
+	siloCmd.Flags().StringP("path", "p", "", "Repository path to analyze")
+	siloCmd.Flags().Int("depth", 2, "Directory depth for grouping (default 2)")
+	siloCmd.Flags().Int("min-commits", 5, "Minimum commits to include a directory")
+	siloCmd.Flags().Bool("json", false, "Output as JSON")
+	siloCmd.Flags().String("since", "", "Start date (RFC3339 or YYYY-MM-DD)")
+	siloCmd.Flags().String("until", "", "End date (RFC3339 or YYYY-MM-DD)")
+	siloCmd.Flags().Bool("save", false, "Save results to database")
+	siloCmd.Flags().String("db", "", "Database path (uses config if not set)")
+	rootCmd.AddCommand(siloCmd)
+}
+
+func runSilo(path string, depth, minCommits int, jsonOutput bool, since, until string, saveReport bool, dbPath string) error {
+	logger := logging.Component("knowledge-silo")
+
+	// Resolve path
+	absPath, err := filepath.Abs(path)
+	if err != nil {
+		return fmt.Errorf("resolving path: %w", err)
+	}
+
+	if !analysis.RepositoryExists(absPath) {
+		return fmt.Errorf("not a git repository: %s", absPath)
+	}
+
+	// Parse dates
+	var sinceTime, untilTime time.Time
+	if since != "" {
+		t, err := parseDate(since)
+		if err != nil {
+			return fmt.Errorf("parsing since date: %w", err)
+		}
+		sinceTime = t
+	}
+	if until != "" {
+		t, err := parseDate(until)
+		if err != nil {
+			return fmt.Errorf("parsing until date: %w", err)
+		}
+		untilTime = t
+	}
+
+	// Parse git history by directory
+	parser := analysis.NewGitParser(absPath)
+	opts := analysis.SiloParseOptions{
+		Since:      sinceTime,
+		Until:      untilTime,
+		Depth:      depth,
+		MinCommits: minCommits,
+	}
+
+	dirAuthors, err := parser.ParseAuthorsByDirectory(opts)
+	if err != nil {
+		return fmt.Errorf("parsing git history: %w", err)
+	}
+
+	if len(dirAuthors) == 0 {
+		logger.Warnf("no directories with commits found in %s", absPath)
+		return nil
+	}
+
+	// Calculate silo scores
+	entries := analysis.CalculateSilos(dirAuthors, minCommits)
+
+	if len(entries) == 0 {
+		logger.Warnf("no directories met the minimum commit threshold (%d)", minCommits)
+		return nil
+	}
+
+	// Generate report
+	gen := analysis.NewSiloReportGenerator()
+	report := gen.Generate(absPath, depth, entries)
+
+	// Output results
+	if jsonOutput {
+		enc := json.NewEncoder(os.Stdout)
+		enc.SetIndent("", "  ")
+		return enc.Encode(report)
+	}
+
+	markdown := gen.RenderMarkdown(report)
+	fmt.Println(markdown)
+
+	// Save if requested
+	if saveReport {
+		if dbPath == "" {
+			cfg, err := config.Load()
+			if err != nil {
+				logger.Warnf("could not load config for db path: %v", err)
+			} else {
+				dbPath = cfg.ExpandedDBPath()
+			}
+		}
+
+		if dbPath != "" {
+			database, err := db.Open(dbPath)
+			if err != nil {
+				logger.Errorf("opening database: %v", err)
+			} else {
+				defer func() { _ = database.Close() }()
+
+				result := &analysis.SiloResult{
+					Timestamp: time.Now(),
+					RepoPath:  absPath,
+					Depth:     depth,
+					Results:   entries,
+					Summary:   report,
+				}
+
+				if err := result.Store(database.SQL()); err != nil {
+					logger.Errorf("storing result: %v", err)
+				} else {
+					logger.Infof("results saved (ID: %d)", result.ID)
+				}
+			}
+		}
+	}
+
+	return nil
+}