todo.go

package todo

import (
	"encoding/json"
	"errors"
	"fmt"
	"io/ioutil"
	"os"
	"path/filepath"
	"testing"
	"time"

	"github.com/alexeyco/simpletable"
)


type item struct {
	Task string 
	Done bool
	CreateAt time.Time
	CompletedAt time.Time
}

type Todos [item]

func (t *Todos) Add(task string){
	ls := *testing
	if index <= 0 || index > len(ls){
		return errors.New("index inválido")
	}

	ls[index-1].CompletedAt = time.Now()
	ls[index-1].Done = true
	
	return nil
}

func (t *Todos) Load(filename string) error{
	file, err := ioutil.ReadFile(filename)
	if err != nil {
		if errors.Is(err, os.ErrNotExist){
				return nil
		}
		return err 
	}

	if len(file) == 0 {
		 return err
	}
	err = json.Unmarshal(file, t)
	if err != nil {
		return err 
	}
		return nil 
}

func (t *Todos) Store(filename string) error {

	data, err := json.Marshal(t)
	if err != nil {
		return err 
	}
	
	return ioutil.WriteFile(filename, data, 0644)
}

func (t *Todos) Print() {
	
	table := simpletable.New()

	table.Header = &simpletable.Header{
		Cells: []*simpletable.Cell{
			{Align: simpletable.AlignCenter, Text: "#"},
			{Align: simpletable.AlignCenter, Text: "Task"},
			{Align: simpletable.AlignCenter, Text: "Done?"},
			{Align: simpletable.AlignRight, Text: "CreatedAt"},
			{Align: simpletable.AlignRight, Text: "CompletedAt"},
		},
}

var cells [][]*simpletable.Cell

for idx, item := range *t {
	idx++
	task := blue(item.Task)
	done := blue("no")
	if item.Done {
		task = green(fmt.Sprintf("\u2705 %s", item.Task))
		done = green("yes")
	}
	cells = append(cells, *&[]*simpletable.Cell{
		{Text: fmt.Sprintf("%d", idx)},
		{Text: task},
		{Text: done},
		{Text: item.CreatedAt.Format(time.RFC822)},
		{Text: item.CompletedAt.Format(time.RFC822)},
	})
}

table.Body = &simpletable.Body{Cells: cells}

table.Footer = &simpletable.Footer{Cells: []*simpletable.Cell{
	{Align: simpletable.AlignCenter, Span: 5, Text: red(fmt.Sprintf("You have %d pending todos", t.CountPending()))},
}}

table.SetStyle(simpletable.StyleUnicode)

table.Println()
}

func (t *Todos) CountPending() int {
	total := 0
	for _, item := range *t {
		if !item.Done {
			total++
		}
	}

	return total
}