feat(v0.5.3): SessionName deterministic tmux session naming

internal/session/sessionname.go

@@ -0,0 +1,68 @@
+package session
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"path/filepath"
+	"runtime"
+	"strings"
+)
+
+// SessionName returns a stable tmux session name for the given workspace.
+// Format: ctask-<category>-<slug>-<hash6>.
+//
+// category and slug are sanitized to [A-Za-z0-9_-]; characters outside that
+// set become '_'; runs of '_' collapse; both are lowercased. slug is
+// truncated to 30 characters maximum (after sanitization). hash6 is the
+// first six lowercase-hex characters of sha256(canonical absolute path).
+//
+// On Windows the path is lowercased before hashing to match
+// config.searchRootKey conventions for case-insensitive filesystems.
+func SessionName(category, slug, absWsPath string) string {
+	cat := sanitizeNameComponent(category)
+	sl := sanitizeNameComponent(slug)
+	if len(sl) > 30 {
+		sl = sl[:30]
+		sl = strings.TrimRight(sl, "_")
+	}
+	clean := filepath.Clean(absWsPath)
+	if runtime.GOOS == "windows" {
+		clean = strings.ToLower(clean)
+	}
+	sum := sha256.Sum256([]byte(clean))
+	hash := hex.EncodeToString(sum[:])[:6]
+	return "ctask-" + cat + "-" + sl + "-" + hash
+}
+
+// sanitizeNameComponent replaces every char outside [A-Za-z0-9_-] with '_',
+// collapses runs of '_', trims leading/trailing '_' and '-', and lowercases.
+func sanitizeNameComponent(s string) string {
+	if s == "" {
+		return "_"
+	}
+	var b strings.Builder
+	b.Grow(len(s))
+	for _, r := range s {
+		switch {
+		case r >= 'a' && r <= 'z':
+			b.WriteRune(r)
+		case r >= 'A' && r <= 'Z':
+			b.WriteRune(r + ('a' - 'A'))
+		case r >= '0' && r <= '9':
+			b.WriteRune(r)
+		case r == '_' || r == '-':
+			b.WriteRune(r)
+		default:
+			b.WriteByte('_')
+		}
+	}
+	out := b.String()
+	for strings.Contains(out, "__") {
+		out = strings.ReplaceAll(out, "__", "_")
+	}
+	out = strings.Trim(out, "_-")
+	if out == "" {
+		return "_"
+	}
+	return out
+}