feat: settings service — key-value store with upsert

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

internal/settings/service.go

@@ -0,0 +1,41 @@
+package settings
+
+import "database/sql"
+
+type SettingsService struct {
+	db *sql.DB
+}
+
+func NewSettingsService(db *sql.DB) *SettingsService {
+	return &SettingsService{db: db}
+}
+
+func (s *SettingsService) Get(key string) (string, error) {
+	var value string
+	err := s.db.QueryRow("SELECT value FROM settings WHERE key = ?", key).Scan(&value)
+	if err == sql.ErrNoRows {
+		return "", nil
+	}
+	return value, err
+}
+
+func (s *SettingsService) GetDefault(key, defaultValue string) string {
+	val, err := s.Get(key)
+	if err != nil || val == "" {
+		return defaultValue
+	}
+	return val
+}
+
+func (s *SettingsService) Set(key, value string) error {
+	_, err := s.db.Exec(
+		"INSERT INTO settings (key, value) VALUES (?, ?) ON CONFLICT(key) DO UPDATE SET value = ?",
+		key, value, value,
+	)
+	return err
+}
+
+func (s *SettingsService) Delete(key string) error {
+	_, err := s.db.Exec("DELETE FROM settings WHERE key = ?", key)
+	return err
+}

internal/settings/service_test.go

@@ -0,0 +1,70 @@
+package settings
+
+import (
+	"path/filepath"
+	"testing"
+
+	"github.com/vstockwell/wraith/internal/db"
+)
+
+func setupTestDB(t *testing.T) *SettingsService {
+	t.Helper()
+	d, err := db.Open(filepath.Join(t.TempDir(), "test.db"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := db.Migrate(d); err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { d.Close() })
+	return NewSettingsService(d)
+}
+
+func TestSetAndGet(t *testing.T) {
+	s := setupTestDB(t)
+
+	if err := s.Set("theme", "dracula"); err != nil {
+		t.Fatalf("Set() error: %v", err)
+	}
+
+	val, err := s.Get("theme")
+	if err != nil {
+		t.Fatalf("Get() error: %v", err)
+	}
+	if val != "dracula" {
+		t.Errorf("Get() = %q, want %q", val, "dracula")
+	}
+}
+
+func TestGetMissing(t *testing.T) {
+	s := setupTestDB(t)
+
+	val, err := s.Get("nonexistent")
+	if err != nil {
+		t.Fatalf("Get() error: %v", err)
+	}
+	if val != "" {
+		t.Errorf("Get() = %q, want empty string", val)
+	}
+}
+
+func TestSetOverwrites(t *testing.T) {
+	s := setupTestDB(t)
+
+	s.Set("key", "value1")
+	s.Set("key", "value2")
+
+	val, _ := s.Get("key")
+	if val != "value2" {
+		t.Errorf("Get() = %q, want %q", val, "value2")
+	}
+}
+
+func TestGetWithDefault(t *testing.T) {
+	s := setupTestDB(t)
+
+	val := s.GetDefault("missing", "fallback")
+	if val != "fallback" {
+		t.Errorf("GetDefault() = %q, want %q", val, "fallback")
+	}
+}