feat: task system

backend/internal/application/dto/dto.go

@@ -452,6 +452,141 @@ func NewCategoryDTO(category *entities.Category) *CategoryDTO {
 	}
 }
 
+// ========== TASK DTOs ==========
+
+// CreateTaskRequest represents task creation input.
+type CreateTaskRequest struct {
+	Title        string   `json:"title" validate:"required,min=1,max=255"`
+	Description  string   `json:"description" validate:"max=2000"`
+	CategoryID   *string  `json:"category_id,omitempty"`
+	StatusID     string   `json:"status_id" validate:"required"`
+	ParentTaskID *string  `json:"parent_task_id,omitempty"`
+	NoteLinks    []string `json:"note_links"`
+}
+
+// UpdateTaskRequest represents task update input.
+type UpdateTaskRequest struct {
+	Title        *string  `json:"title,omitempty"`
+	Description  *string  `json:"description,omitempty"`
+	CategoryID   *string  `json:"category_id,omitempty"`
+	StatusID     *string  `json:"status_id,omitempty"`
+	ParentTaskID *string  `json:"parent_task_id,omitempty"`
+	NoteLinks    []string `json:"note_links,omitempty"`
+}
+
+// TaskTransitionRequest allows moving task status by one step.
+type TaskTransitionRequest struct {
+	Direction string `json:"direction" validate:"required,oneof=forward backward"`
+}
+
+// LinkTaskNoteRequest links/unlinks a note from a task.
+type LinkTaskNoteRequest struct {
+	NoteID string `json:"note_id" validate:"required"`
+}
+
+// TaskDTO represents a task in API responses.
+type TaskDTO struct {
+	ID           string   `json:"id"`
+	SpaceID      string   `json:"space_id"`
+	Title        string   `json:"title"`
+	Description  string   `json:"description"`
+	CategoryID   *string  `json:"category_id,omitempty"`
+	StatusID     string   `json:"status_id"`
+	ParentTaskID *string  `json:"parent_task_id,omitempty"`
+	Depth        int      `json:"depth"`
+	NoteLinks    []string `json:"note_links"`
+	CreatedBy    string   `json:"created_by"`
+	UpdatedBy    string   `json:"updated_by"`
+	CreatedAt    string   `json:"created_at"`
+	UpdatedAt    string   `json:"updated_at"`
+}
+
+// TaskWithStatusDTO includes status details and child tasks for detail views.
+type TaskWithStatusDTO struct {
+	*TaskDTO
+	StatusName  string     `json:"status_name"`
+	StatusColor string     `json:"status_color,omitempty"`
+	StatusOrder int        `json:"status_order"`
+	Subtasks    []*TaskDTO `json:"subtasks"`
+}
+
+// CreateTaskStatusRequest represents task status creation input.
+type CreateTaskStatusRequest struct {
+	Name  string `json:"name" validate:"required,min=1,max=100"`
+	Color string `json:"color,omitempty" validate:"max=20"`
+}
+
+// UpdateTaskStatusRequest represents task status updates.
+type UpdateTaskStatusRequest struct {
+	Name  string `json:"name" validate:"required,min=1,max=100"`
+	Color string `json:"color,omitempty" validate:"max=20"`
+}
+
+// ReorderTaskStatusesRequest represents a full ordered status ID list.
+type ReorderTaskStatusesRequest struct {
+	OrderedStatusIDs []string `json:"ordered_status_ids"`
+}
+
+// TaskStatusDTO represents a task status in API responses.
+type TaskStatusDTO struct {
+	ID        string `json:"id"`
+	SpaceID   string `json:"space_id"`
+	Name      string `json:"name"`
+	Color     string `json:"color,omitempty"`
+	Order     int    `json:"order"`
+	CreatedAt string `json:"created_at"`
+	UpdatedAt string `json:"updated_at"`
+}
+
+// NewTaskDTO creates a DTO from a task entity.
+func NewTaskDTO(task *entities.Task) *TaskDTO {
+	var categoryID *string
+	if task.CategoryID != nil {
+		id := task.CategoryID.Hex()
+		categoryID = &id
+	}
+
+	var parentTaskID *string
+	if task.ParentTaskID != nil {
+		id := task.ParentTaskID.Hex()
+		parentTaskID = &id
+	}
+
+	noteLinks := make([]string, 0, len(task.NoteLinks))
+	for _, noteID := range task.NoteLinks {
+		noteLinks = append(noteLinks, noteID.Hex())
+	}
+
+	return &TaskDTO{
+		ID:           task.ID.Hex(),
+		SpaceID:      task.SpaceID.Hex(),
+		Title:        task.Title,
+		Description:  task.Description,
+		CategoryID:   categoryID,
+		StatusID:     task.StatusID.Hex(),
+		ParentTaskID: parentTaskID,
+		Depth:        task.Depth,
+		NoteLinks:    noteLinks,
+		CreatedBy:    task.CreatedBy.Hex(),
+		UpdatedBy:    task.UpdatedBy.Hex(),
+		CreatedAt:    task.CreatedAt.Format("2006-01-02T15:04:05Z"),
+		UpdatedAt:    task.UpdatedAt.Format("2006-01-02T15:04:05Z"),
+	}
+}
+
+// NewTaskStatusDTO creates a DTO from a task status entity.
+func NewTaskStatusDTO(status *entities.TaskStatus) *TaskStatusDTO {
+	return &TaskStatusDTO{
+		ID:        status.ID.Hex(),
+		SpaceID:   status.SpaceID.Hex(),
+		Name:      status.Name,
+		Color:     status.Color,
+		Order:     status.Order,
+		CreatedAt: status.CreatedAt.Format("2006-01-02T15:04:05Z"),
+		UpdatedAt: status.UpdatedAt.Format("2006-01-02T15:04:05Z"),
+	}
+}
+
 // ========== ERROR DTOs ==========
 
 // ErrorResponse represents an error response