feat: slug generation and directory collision resolution

Slugify, AutoTitle, DirName, ResolveDir with -2, -3 suffixing. Full test coverage.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

internal/workspace/slug.go

@@ -0,0 +1,50 @@
+package workspace
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+	"time"
+)
+
+var nonAlnum = regexp.MustCompile(`[^a-z0-9]+`)
+var leadTrailHyphen = regexp.MustCompile(`^-+|-+$`)
+
+// Slugify converts a title to a URL-friendly slug.
+// Lowercase, non-alphanumeric replaced with hyphens, trimmed.
+func Slugify(title string) string {
+	s := strings.ToLower(strings.TrimSpace(title))
+	s = nonAlnum.ReplaceAllString(s, "-")
+	s = leadTrailHyphen.ReplaceAllString(s, "")
+	return s
+}
+
+// AutoTitle generates a default title when none is provided: task-HHMMSS.
+func AutoTitle() string {
+	now := time.Now()
+	return fmt.Sprintf("task-%s", now.Format("150405"))
+}
+
+// DirName produces the workspace directory name: YYYY-MM-DD_slug.
+func DirName(date, slug string) string {
+	return date + "_" + slug
+}
+
+// ResolveDir returns the full path for a new workspace, appending -2, -3, etc.
+// if a directory with the same date+slug already exists.
+func ResolveDir(categoryDir, date, slug string) string {
+	base := DirName(date, slug)
+	candidate := filepath.Join(categoryDir, base)
+	if _, err := os.Stat(candidate); os.IsNotExist(err) {
+		return candidate
+	}
+	for i := 2; ; i++ {
+		suffixed := fmt.Sprintf("%s-%d", base, i)
+		candidate = filepath.Join(categoryDir, suffixed)
+		if _, err := os.Stat(candidate); os.IsNotExist(err) {
+			return candidate
+		}
+	}
+}

internal/workspace/slug_test.go

@@ -0,0 +1,94 @@
+package workspace
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestSlugify(t *testing.T) {
+	tests := []struct {
+		input string
+		want  string
+	}{
+		{"arch notes", "arch-notes"},
+		{"Arch Notes", "arch-notes"},
+		{"  hello  world  ", "hello-world"},
+		{"foo---bar", "foo-bar"},
+		{"Test 123!", "test-123"},
+		{"---leading---", "leading"},
+		{"trailing---", "trailing"},
+		{"UPPERCASE", "uppercase"},
+		{"a", "a"},
+		{"", ""},
+		{"hello_world", "hello-world"},
+		{"foo@bar#baz", "foo-bar-baz"},
+		{"  multiple   spaces  ", "multiple-spaces"},
+	}
+
+	for _, tt := range tests {
+		got := Slugify(tt.input)
+		if got != tt.want {
+			t.Errorf("Slugify(%q) = %q, want %q", tt.input, got, tt.want)
+		}
+	}
+}
+
+func TestAutoTitle(t *testing.T) {
+	title := AutoTitle()
+	if title == "" {
+		t.Error("AutoTitle() returned empty string")
+	}
+	if len(title) != 11 { // "task-" + 6 digits
+		t.Errorf("AutoTitle() = %q, expected 11 chars", title)
+	}
+	if title[:5] != "task-" {
+		t.Errorf("AutoTitle() = %q, expected prefix \"task-\"", title)
+	}
+}
+
+func TestDirName(t *testing.T) {
+	name := DirName("2026-04-05", "arch-notes")
+	if name != "2026-04-05_arch-notes" {
+		t.Errorf("DirName = %q, want \"2026-04-05_arch-notes\"", name)
+	}
+}
+
+func TestResolveDirNoCollision(t *testing.T) {
+	root := t.TempDir()
+	cat := filepath.Join(root, "general")
+	os.MkdirAll(cat, 0755)
+
+	got := ResolveDir(cat, "2026-04-05", "test")
+	if filepath.Base(got) != "2026-04-05_test" {
+		t.Errorf("no collision: got %q, want dir ending in 2026-04-05_test", got)
+	}
+}
+
+func TestResolveDirCollision(t *testing.T) {
+	root := t.TempDir()
+	cat := filepath.Join(root, "general")
+	os.MkdirAll(cat, 0755)
+
+	date := "2026-04-05"
+	slug := "test"
+
+	// First call: no collision
+	got := ResolveDir(cat, date, slug)
+	os.MkdirAll(got, 0755)
+
+	// Second call: should get -2
+	got2 := ResolveDir(cat, date, slug)
+	if filepath.Base(got2) != "2026-04-05_test-2" {
+		t.Errorf("second call: got %q, want dir ending in 2026-04-05_test-2", got2)
+	}
+
+	// Create that too
+	os.MkdirAll(got2, 0755)
+
+	// Third call: should get -3
+	got3 := ResolveDir(cat, date, slug)
+	if filepath.Base(got3) != "2026-04-05_test-3" {
+		t.Errorf("third call: got %q, want dir ending in 2026-04-05_test-3", got3)
+	}
+}