package julian

import (
	"fmt"
	"testing"
	"time"
)

func TestMonthLength(t *testing.T) {
	var tests = []struct {
		y    int
		m    time.Month
		want int
	}{
		{2001, time.January, 31},
		{2001, time.February, 28},
		{2000, time.February, 29},
		{2001, time.March, 31},
		{2001, time.April, 30},
		{2001, time.May, 31},
		{2001, time.June, 30},
		{2001, time.July, 31},
		{2001, time.August, 31},
		{2001, time.September, 30},
		{2001, time.October, 31},
		{2001, time.November, 30},
		{2001, time.December, 31},
	}

	for _, tt := range tests {
		testname := fmt.Sprintf("%v, %d", tt.m, tt.y)
		t.Run(testname, func(t *testing.T) {
			ans := monthLength(tt.y, tt.m)
			if ans != tt.want {
				t.Errorf("got %d, want %d", ans, tt.want)
			}
		})
	}
}

func TestDateDiff(t *testing.T) {
	var tests = []struct {
		d    Date
		days int
		want Date
	}{
		{Date{2001, time.January, 20}, 5, Date{2001, time.January, 25}},
		{Date{2001, time.February, 28}, 5, Date{2001, time.March, 5}},
		{Date{2004, time.February, 28}, 5, Date{2004, time.March, 4}},
	}

	for _, tt := range tests {
		testname := fmt.Sprintf("%v, %d", tt.d, tt.days)
		t.Run(testname, func(t *testing.T) {
			ans := dateDiff(tt.d, tt.days)
			if ans != tt.want {
				t.Errorf("got %d, want %d", ans, tt.want)
			}
		})
	}
}

func TestNextMonth(t *testing.T) {
	ans1, ans2 := nextMonth(2000, time.December)
	if ans1 != 2001 || ans2 != time.January {
		t.Errorf("nextMonth(2000, time.December) = %d, %v; want 2001, time.January", ans1, ans2)
	}
}

func TestToTime(t *testing.T) {
	gDate := func(year int, month time.Month, day int) time.Time {
		return time.Date(year, month, day, 0, 0, 0, 0, time.UTC)
	}
	var tests = []struct {
		d    Date
		want time.Time
	}{
		{Date{100, time.February, 29}, gDate(100, time.February, 27)},
		{Date{100, time.March, 1}, gDate(100, time.February, 28)},
		{Date{100, time.March, 2}, gDate(100, time.March, 1)},
		{Date{200, time.February, 28}, gDate(200, time.February, 27)},
		{Date{200, time.February, 29}, gDate(200, time.February, 28)},
		{Date{200, time.March, 1}, gDate(200, time.March, 1)},
		{Date{300, time.February, 28}, gDate(300, time.February, 28)},
		{Date{300, time.February, 29}, gDate(300, time.March, 1)},
		{Date{300, time.March, 1}, gDate(300, time.March, 2)},
		{Date{500, time.February, 28}, gDate(500, time.March, 1)},
		{Date{500, time.February, 29}, gDate(500, time.March, 2)},
		{Date{500, time.March, 1}, gDate(500, time.March, 3)},
		{Date{600, time.February, 28}, gDate(600, time.March, 2)},
		{Date{600, time.February, 29}, gDate(600, time.March, 3)},
		{Date{600, time.March, 1}, gDate(600, time.March, 4)},
		{Date{700, time.February, 28}, gDate(700, time.March, 3)},
		{Date{700, time.February, 29}, gDate(700, time.March, 4)},
		{Date{700, time.March, 1}, gDate(700, time.March, 5)},
		{Date{900, time.February, 28}, gDate(900, time.March, 4)},
		{Date{900, time.February, 29}, gDate(900, time.March, 5)},
		{Date{900, time.March, 1}, gDate(900, time.March, 6)},
		{Date{1000, time.February, 28}, gDate(1000, time.March, 5)},
		{Date{1000, time.February, 29}, gDate(1000, time.March, 6)},
		{Date{1000, time.March, 1}, gDate(1000, time.March, 7)},
		{Date{1100, time.February, 28}, gDate(1100, time.March, 6)},
		{Date{1100, time.February, 29}, gDate(1100, time.March, 7)},
		{Date{1100, time.March, 1}, gDate(1100, time.March, 8)},
		{Date{1300, time.February, 28}, gDate(1300, time.March, 7)},
		{Date{1300, time.February, 29}, gDate(1300, time.March, 8)},
		{Date{1300, time.March, 1}, gDate(1300, time.March, 9)},
		{Date{1400, time.February, 28}, gDate(1400, time.March, 8)},
		{Date{1400, time.February, 29}, gDate(1400, time.March, 9)},
		{Date{1400, time.March, 1}, gDate(1400, time.March, 10)},
		{Date{1500, time.February, 28}, gDate(1500, time.March, 9)},
		{Date{1500, time.February, 29}, gDate(1500, time.March, 10)},
		{Date{1500, time.March, 1}, gDate(1500, time.March, 11)},
		{Date{1582, time.October, 4}, gDate(1582, time.October, 14)},
		{Date{1582, time.October, 5}, gDate(1582, time.October, 15)},
		{Date{1582, time.October, 6}, gDate(1582, time.October, 16)},
		{Date{1700, time.February, 18}, gDate(1700, time.February, 28)},
		{Date{1700, time.February, 19}, gDate(1700, time.March, 1)},
		{Date{1700, time.February, 28}, gDate(1700, time.March, 10)},
		{Date{1700, time.February, 29}, gDate(1700, time.March, 11)},
		{Date{1700, time.March, 1}, gDate(1700, time.March, 12)},
		{Date{1800, time.February, 17}, gDate(1800, time.February, 28)},
		{Date{1800, time.February, 18}, gDate(1800, time.March, 1)},
		{Date{1800, time.February, 28}, gDate(1800, time.March, 11)},
		{Date{1800, time.February, 29}, gDate(1800, time.March, 12)},
		{Date{1800, time.March, 1}, gDate(1800, time.March, 13)},
		{Date{1900, time.February, 16}, gDate(1900, time.February, 28)},
		{Date{1900, time.February, 17}, gDate(1900, time.March, 1)},
		{Date{1900, time.February, 28}, gDate(1900, time.March, 12)},
		{Date{1900, time.February, 29}, gDate(1900, time.March, 13)},
		{Date{1900, time.March, 1}, gDate(1900, time.March, 14)},
		{Date{2100, time.February, 15}, gDate(2100, time.February, 28)},
		{Date{2100, time.February, 16}, gDate(2100, time.March, 1)},
		{Date{2100, time.February, 28}, gDate(2100, time.March, 13)},
		{Date{2100, time.February, 29}, gDate(2100, time.March, 14)},
	}

	for _, tt := range tests {
		testname := fmt.Sprintf("%v, %v", tt.d, tt.want)
		t.Run(testname, func(t *testing.T) {
			ans := ToTime(tt.d)
			if ans != tt.want {
				t.Errorf("got %v, want %v", ans, tt.want)
			}
		})
	}
}