package pasien

import (
	"testing"
	"time"
)

type testDataAgeCalculator struct {
	name     string
	birthday time.Time
	now      time.Time
	expected Age
}

func parseDate(s string) time.Time {
	t, err := time.Parse("2006-01-02", s)
	if err != nil {
		panic(err)
	}

	return t
}

func TestAgeCalculator(t *testing.T) {
	dataSet := []testDataAgeCalculator{
		{
			name:     "2 month 1 day difference",
			birthday: parseDate("1998-07-15"),
			now:      parseDate("1998-09-16"),
			expected: Age{Years: 0, Months: 2, Days: 1},
		},
		{
			name:     "same day",
			birthday: parseDate("1998-07-15"),
			now:      parseDate("1998-07-15"),
			expected: Age{Years: 0, Months: 0, Days: 0},
		},
		{
			name:     "1 Year 2 month 3 day difference",
			birthday: parseDate("1998-07-15"),
			now:      parseDate("1999-09-18"),
			expected: Age{Years: 1, Months: 2, Days: 3},
		},
		{
			name:     "1 Year 1 month 29 day difference",
			birthday: parseDate("1998-07-15"),
			now:      parseDate("1999-09-13"),
			expected: Age{Years: 1, Months: 1, Days: 29},
		},
		{
			name:     "0 Year 10 month 29 day difference",
			birthday: parseDate("1998-07-15"),
			now:      parseDate("1999-05-13"),
			expected: Age{Years: 0, Months: 9, Days: 28},
		},
		{
			name:     "birthday after now",
			birthday: parseDate("1998-07-15"),
			now:      parseDate("1997-05-13"),
			expected: Age{Years: 0, Months: 0, Days: 0},
		},
	}

	for _, tt := range dataSet {
		t.Run(tt.name, func(t *testing.T) {
			calc := CalculateAge(tt.birthday, tt.now)

			if calc != tt.expected {
				t.Fatalf(
					"expected %+v, got %+v",
					tt.expected,
					calc,
				)
			}
		})
	}
}