Added Configuration from Item and Plate

internal/store/configuration.go

@@ -0,0 +1,65 @@
+package store
+
+import (
+	"fmt"
+	"path/filepath"
+	"time"
+
+	"github.com/google/uuid"
+	"printer.backend/internal/model"
+	"printer.backend/internal/paths"
+)
+
+// ConfigurationStore persists configurations as JSON files.
+type ConfigurationStore struct {
+	dir string
+}
+
+// NewConfigurationStore creates a store under dir (default data/configurations).
+func NewConfigurationStore(dir string) *ConfigurationStore {
+	if dir == "" {
+		dir = paths.ConfigurationsDir
+	}
+	return &ConfigurationStore{dir: dir}
+}
+
+// List returns all configurations sorted by creation time (newest first).
+func (s *ConfigurationStore) List() ([]model.Configuration, error) {
+	return listFromDir(s.dir,
+		func(name string) bool { return filepath.Ext(name) == ".json" },
+		"configurations dir",
+		func(c model.Configuration) time.Time { return c.CreatedAt },
+	)
+}
+
+// Get returns a configuration by ID.
+func (s *ConfigurationStore) Get(id string) (model.Configuration, error) {
+	list, err := s.List()
+	if err != nil {
+		return model.Configuration{}, err
+	}
+	return findByID(list, id, func(c model.Configuration) string { return c.ID })
+}
+
+// Save writes a new configuration and assigns an ID when empty.
+func (s *ConfigurationStore) Save(c model.Configuration) (model.Configuration, error) {
+	if err := ensureDir(s.dir); err != nil {
+		return model.Configuration{}, err
+	}
+	if c.ID == "" {
+		c.ID = uuid.NewString()
+	}
+	c.CreatedAt = stampNew(&c.CreatedAt)
+
+	path := filepath.Join(s.dir, c.ID+".json")
+	if err := writeJSON(path, c); err != nil {
+		return model.Configuration{}, fmt.Errorf("write configuration: %w", err)
+	}
+	return c, nil
+}
+
+// Delete removes a configuration by ID.
+func (s *ConfigurationStore) Delete(id string) error {
+	path := filepath.Join(s.dir, id+".json")
+	return removeFile(path, fmt.Sprintf("configuration not found: %s", id))
+}