package people

import (
	"encoding/json"
	"time"
)

// Declaring birthday layout constant
const birthdayLayout = "2006-01-02" // YYYY-MM-DD - is default birthday layout

// Birthday is a custom encapsulation type for time.Time to handle birthdays
// by decoding and encoding from and to JSON format
type Birthday struct {
	time.Time       // Embedding time.Time
	err       error // Time parsing error
}

// UnmarshalJSON decodes a date text to time.Time object
func (t *Birthday) UnmarshalJSON(bytes []byte) (err error) {
	// 1. Decode the bytes into an int64
	// 2. Parse the unix timestamp

	// Is value quoted?
	if rune(bytes[0]) == '"' || rune(bytes[0]) == '\'' {
		bytes = bytes[1 : len(bytes)-1] // remove quotes
	}

	// Parse string to time.Time
	t.Time, t.err = time.Parse(birthdayLayout, string(bytes))
	t.err = err
	return
}

// MarshalJSON encodes a time.Time object to date JSON text
func (t Birthday) MarshalJSON() ([]byte, error) {
	return json.Marshal(t.Time.Format(birthdayLayout))
}