command.go

package main

import (
	"flag"
	"fmt"
	"os"
	"strconv"
	"strings"
)

type cmdFlags struct {
	Add    string
	Del    int
	Edit   string
	Toggle int
	List   bool
}

func newCmdFlags() *cmdFlags {
	cf := cmdFlags{}

	flag.StringVar(&cf.Add, "add", "", "add a new todo specify title")
	flag.StringVar(&cf.Edit, "edit", "", "edit a todo by index & specify a new title, id:new_title")
	flag.IntVar(&cf.Del, "del", -1, "specigy a todo by index to delete")
	flag.IntVar(&cf.Toggle, "toggle", -1, "specify a todo by index to toggle")
	flag.BoolVar(&cf.List, "list", false, "List all todo")

	flag.Parse()

	return &cf
}

func (cf *cmdFlags) Execute (todos *Todos) {
	switch {
	case cf.List:
		todos.print()
	case cf.Add != "":
	    todos.add(cf.Add)
	case cf.Edit != "":
	parts := strings.SplitN(cf.Edit, ":", 2)
	if len(parts) != 2 {
		fmt.Println("error, invalid format Edit. please use id:new_title")
		os.Exit(1)
	}

	index,err := strconv.Atoi(parts[0])
	if err != nil {
		fmt.Println("error: invalid index fot edit")
		os.Exit(1)
	}

	todos.edit(index, parts[1])

case cf.Toggle != -1:
	todos.toggle(cf.Toggle)
case cf.Del != -1:
	todos.delete(cf.Del)	
default: 
    fmt.Println("Invalid Command")
	}
}