opcotech/elemo

package model

import (
    "errors"
    "time"

    "github.com/opcotech/elemo/internal/pkg/validate"
)

const (
    TodoPriorityNormal    TodoPriority = iota + 1 // the todo is normal
    TodoPriorityImportant                         // the todo is important
    TodoPriorityUrgent                            // the todo is urgent
    TodoPriorityCritical                          // the todo is critical
)

var (
    todoPriorityKeys = map[TodoPriority]string{
        TodoPriorityNormal:    "normal",
        TodoPriorityImportant: "important",
        TodoPriorityUrgent:    "urgent",
        TodoPriorityCritical:  "critical",
    }
    todoPriorityValues = map[string]TodoPriority{
        "normal":    TodoPriorityNormal,
        "important": TodoPriorityImportant,
        "urgent":    TodoPriorityUrgent,
        "critical":  TodoPriorityCritical,
    }
)

// TodoPriority represents the priority of the Todo item.
type TodoPriority uint8

// String returns the string representation of the TodoPriority.
func (p TodoPriority) String() string {
    return todoPriorityKeys[p]
}

// MarshalText implements the encoding.TextMarshaler interface.
func (p TodoPriority) MarshalText() (text []byte, err error) {
    if p < 1 || p > 4 {
        return nil, ErrInvalidTodoPriority
    }
    return []byte(p.String()), nil
}

// UnmarshalText implements the encoding.TextUnmarshaler interface.
func (p *TodoPriority) UnmarshalText(text []byte) error {
    if v, ok := todoPriorityValues[string(text)]; ok {
        *p = v
        return nil
    }
    return ErrInvalidTodoPriority
}

// Todo represents a todo in the system.
type Todo struct {
    ID          ID           `json:"id" validate:"required"`
    Title       string       `json:"title" validate:"required,min=3,max=120"`
    Description string       `json:"description" validate:"omitempty,min=10,max=500"`
    Priority    TodoPriority `json:"priority" validate:"required,min=1,max=4"`
    Completed   bool         `json:"completed"`
    OwnedBy     ID           `json:"owned_by" validate:"required"`
    CreatedBy   ID           `json:"created_by" validate:"required"`
    DueDate     *time.Time   `json:"due_date" validate:"omitempty"`
    CreatedAt   *time.Time   `json:"created_at" validate:"omitempty"`
    UpdatedAt   *time.Time   `json:"updated_at" validate:"omitempty"`
}

func (t *Todo) Validate() error {
    if err := validate.Struct(t); err != nil {
        return errors.Join(ErrInvalidTodoDetails, err)
    }
    if err := t.ID.Validate(); err != nil {
        return errors.Join(ErrInvalidTodoDetails, err)
    }
    if err := t.OwnedBy.Validate(); err != nil {
        return errors.Join(ErrInvalidTodoDetails, err)
    }
    if err := t.CreatedBy.Validate(); err != nil {
        return errors.Join(ErrInvalidTodoDetails, err)
    }
    return nil
}

// NewTodo creates a new todo.
func NewTodo(title string, ownedBy, createdBy ID) (*Todo, error) {
    todo := &Todo{
        ID:        MustNewNilID(ResourceTypeTodo),
        Title:     title,
        Priority:  TodoPriorityNormal,
        OwnedBy:   ownedBy,
        CreatedBy: createdBy,
    }

    if err := todo.Validate(); err != nil {
        return nil, err
    }

    return todo, nil
}