feat: bootstrap reusable GoOmni framework

examples/reference/repository/memory.go

@@ -0,0 +1,126 @@
+package repository
+
+import (
+	"context"
+	"sort"
+	"sync"
+	"time"
+
+	"git.yuntuo.hk/k2safe/go-omni/examples/reference/model"
+)
+
+// MemoryUsers stores data only for this process. Replace it with a database
+// implementation of service.UserRepository when persistence is required.
+type MemoryUsers struct {
+	mu     sync.RWMutex
+	users  map[int64]model.User
+	emails map[string]int64
+	nextID int64
+}
+
+func NewMemoryUsers() *MemoryUsers {
+	return &MemoryUsers{
+		users:  make(map[int64]model.User),
+		emails: make(map[string]int64),
+		nextID: 1,
+	}
+}
+
+func (r *MemoryUsers) Create(ctx context.Context, input model.UserInput) (model.User, error) {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	if err := ctx.Err(); err != nil {
+		return model.User{}, err
+	}
+	if _, exists := r.emails[input.Email]; exists {
+		return model.User{}, model.ErrEmailTaken
+	}
+	now := time.Now().UTC()
+	user := model.User{
+		ID: r.nextID, Name: input.Name, Email: input.Email,
+		CreatedAt: now, UpdatedAt: now,
+	}
+	r.nextID++
+	r.users[user.ID] = user
+	r.emails[user.Email] = user.ID
+	return user, nil
+}
+
+func (r *MemoryUsers) Get(ctx context.Context, id int64) (model.User, error) {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+	if err := ctx.Err(); err != nil {
+		return model.User{}, err
+	}
+	user, exists := r.users[id]
+	if !exists {
+		return model.User{}, model.ErrUserNotFound
+	}
+	return user, nil
+}
+
+func (r *MemoryUsers) List(ctx context.Context, page, pageSize int) (model.UserPage, error) {
+	if page < 1 || pageSize < 1 || pageSize > 100 {
+		return model.UserPage{}, model.ErrInvalidPage
+	}
+	r.mu.RLock()
+	if err := ctx.Err(); err != nil {
+		r.mu.RUnlock()
+		return model.UserPage{}, err
+	}
+	users := make([]model.User, 0, len(r.users))
+	for _, user := range r.users {
+		users = append(users, user)
+	}
+	r.mu.RUnlock()
+
+	// A stable order is essential: Go map iteration order changes between calls.
+	sort.Slice(users, func(i, j int) bool { return users[i].ID < users[j].ID })
+	result := model.UserPage{
+		Items: []model.User{}, Total: len(users), Page: page, PageSize: pageSize,
+	}
+	// Check the page before multiplying so even a very large page cannot overflow.
+	if len(users) == 0 || page-1 > (len(users)-1)/pageSize {
+		return result, nil
+	}
+	start := (page - 1) * pageSize
+	count := min(pageSize, len(users)-start)
+	result.Items = users[start : start+count]
+	return result, nil
+}
+
+func (r *MemoryUsers) Update(ctx context.Context, id int64, input model.UserInput) (model.User, error) {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	if err := ctx.Err(); err != nil {
+		return model.User{}, err
+	}
+	user, exists := r.users[id]
+	if !exists {
+		return model.User{}, model.ErrUserNotFound
+	}
+	if owner, exists := r.emails[input.Email]; exists && owner != id {
+		return model.User{}, model.ErrEmailTaken
+	}
+	delete(r.emails, user.Email)
+	user.Name, user.Email = input.Name, input.Email
+	user.UpdatedAt = time.Now().UTC()
+	r.users[id] = user
+	r.emails[user.Email] = id
+	return user, nil
+}
+
+func (r *MemoryUsers) Delete(ctx context.Context, id int64) error {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	if err := ctx.Err(); err != nil {
+		return err
+	}
+	user, exists := r.users[id]
+	if !exists {
+		return model.ErrUserNotFound
+	}
+	delete(r.users, id)
+	delete(r.emails, user.Email)
+	return nil
+}