package main

import (
	"errors"
	"regexp"
	"time"
)

type Entry struct {
	Id      int
	Date    time.Time
	From    *Time
	To      *Time
	Tag     *string
	Comment string
}

type Task struct {
	Id      int
	Group   *string
	Ident   *string
	Text    string
}

type Date string

type Time string

var timeMatch = regexp.MustCompile("\\d\\d:\\d\\d")
var dateMatch = regexp.MustCompile("\\d\\d\\d\\d-\\d\\d-\\d\\d")

var (
	ErrInvalidTime = errors.New("Invalid time string")
	ErrInvalidDate = errors.New("Invalid date string")
)

func TimeFromStd(time time.Time) Time {
	return Time(time.Format("15:04"))
}

func TimeFromString(str string) (*Time, error) {
	if str == "" {
		return nil, nil
	}

	matched := timeMatch.MatchString(str)
	if !matched {
		return nil, ErrInvalidTime
	}
	time := Time(str)
	return &time, nil
}

func DateFromStd(time time.Time) Date {
	return Date(time.Format("2006-01-02"))
}

func DateFromString(str string) (*Date, error) {
	if str == "" {
		return nil, nil
	}

	matched := dateMatch.MatchString(str)
	if !matched {
		return nil, ErrInvalidTime
	}
	date := Date(str)
	return &date, nil
}