init

Readme.md

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+This is little library to operate with bank holidays in Poland.
+
+```go
+
+import "git.ma-al.com/goc_marek/holidayspl"
+
+holidays := holidayspl.New()
+
+// to get list of all holidays
+holidays.GetHolidaysList(d.Year())
+
+// get holiday by date or false as second returned value
+hh, ok := holidays.GetByDate(time.Date(2024, time.March, 31, 0, 0, 0, 0, time.UTC))
+
+```
+For more info just look at th tests file.

go.mod

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+module git.ma-al.com/goc_marek/holidayspl
+
+go 1.23.0

holidays.go

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+package holidayspl
+
+import (
+	"time"
+)
+
+type Holidays struct {
+	list  []Holiday
+	cache map[int][]Holiday
+}
+
+func New() *Holidays {
+	return &Holidays{
+		list:  createList(),
+		cache: make(map[int][]Holiday),
+	}
+}
+
+func (hol *Holidays) GetEasterDate(year int) time.Time {
+	a := year % 19
+	b := year / 100
+	c := year % 100
+	d := b / 4
+	e := b % 4
+	f := (b + 8) / 25
+	g := (b - f + 1) / 3
+	h := (19*a + b - d - g + 15) % 30
+	i := c / 4
+	k := c % 4
+	l := (32 + 2*e + 2*i - h - k) % 7
+	m := (a + 11*h + 22*l) / 451
+	n := (h + l - 7*m + 114) / 31
+	o := (h + l - 7*m + 114) % 31
+	return time.Date(year, time.Month(n), o+1, 0, 0, 0, 0, time.UTC)
+}
+
+func (hol *Holidays) GetHolidaysList(year int) []Holiday {
+	// Check if the holiday list for this year is already cached
+	if holidays, ok := hol.cache[year]; ok {
+		return holidays
+	}
+
+	// Calculate and store holidays in the cache
+	easter := hol.GetEasterDate(year)
+	for i, h := range hol.list {
+		if h.HolidayType == FIXED {
+			hol.list[i].Date = time.Date(year, h.Month, h.Day, 0, 0, 0, 0, time.UTC)
+		} else if h.HolidayType == MOVABLE {
+			hol.list[i].Date = easter.AddDate(0, 0, h.PlusEaster)
+		}
+	}
+
+	// Cache the computed holiday list
+	hol.cache[year] = hol.list
+	return hol.list
+}
+
+func (hol *Holidays) GetByDate(d time.Time) (Holiday, bool) {
+	for _, h := range hol.GetHolidaysList(d.Year()) {
+		if h.Date.Equal(d) {
+			return h, true
+		}
+	}
+	return Holiday{}, false
+}
+
+func (hol *Holidays) GetCache() map[int][]Holiday {
+	return hol.cache
+}
+
+func createList() []Holiday {
+
+	return []Holiday{
+		{
+			Name:        "New Year",
+			NamePL:      "Nowy Rok",
+			Month:       time.Month(1),
+			Day:         1,
+			HolidayType: FIXED,
+		},
+		{
+			Name:        "Three Kings' Day",
+			NamePL:      "Święto Trzech Króli",
+			Month:       time.Month(1),
+			Day:         6,
+			HolidayType: FIXED,
+		},
+		{
+			Name:        "Labour Day",
+			NamePL:      "Święto Pracy",
+			Month:       time.Month(5),
+			Day:         1,
+			HolidayType: FIXED,
+		},
+		{
+			Name:        "3 May Constitution Day",
+			NamePL:      "Narodowe Święto Konstytucji Trzeciego Maja",
+			Month:       time.Month(5),
+			Day:         3,
+			HolidayType: FIXED,
+		},
+		{
+			Name:        "Assumption of Mary",
+			NamePL:      "Wniebowzięcie Najświętszej Maryi Panny",
+			Month:       time.Month(8),
+			Day:         15,
+			HolidayType: FIXED,
+		},
+		{
+			Name:        "All Saints' Day",
+			NamePL:      "Wszystkich Świętych",
+			Month:       time.Month(11),
+			Day:         1,
+			HolidayType: FIXED,
+		},
+		{
+			Name:        "National Independence Day",
+			NamePL:      "Narodowe Święto Niepodległości",
+			Month:       time.Month(11),
+			Day:         11,
+			HolidayType: FIXED,
+		},
+		{
+			Name:        "Christmas",
+			NamePL:      "Boże Narodzenie",
+			Month:       time.Month(12),
+			Day:         25,
+			HolidayType: FIXED,
+		},
+		{
+			Name:        "Second Day of Christmas",
+			NamePL:      "Boże Narodzenie - drugi dzień",
+			Month:       time.Month(12),
+			Day:         26,
+			HolidayType: FIXED,
+		},
+		{
+			Name:        "Easter Sunday",
+			NamePL:      "Niedziela Wielkanocna",
+			Month:       time.Month(5),
+			Day:         3,
+			HolidayType: MOVABLE,
+			PlusEaster:  0,
+		},
+		{
+			Name:        "Easter Monday",
+			NamePL:      "Poniedziałek Wielkanocny",
+			Month:       time.Month(5),
+			Day:         3,
+			HolidayType: MOVABLE,
+			PlusEaster:  1,
+		},
+		{
+			Name:        "Green Week",
+			NamePL:      "Zielone Świątki",
+			Month:       time.Month(5),
+			Day:         3,
+			HolidayType: MOVABLE,
+			PlusEaster:  49,
+		},
+		{
+			Name:        "Feast of Corpus Christi",
+			NamePL:      "Boże Ciało",
+			Month:       time.Month(5),
+			Day:         3,
+			HolidayType: MOVABLE,
+			PlusEaster:  60,
+		},
+	}
+}

holidays_test.go

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+package holidayspl_test
+
+import (
+	"testing"
+	"time"
+
+	"git.ma-al.com/goc_marek/holidayspl"
+)
+
+func TestGetEasterDate(t *testing.T) {
+	holidays := holidayspl.New()
+
+	tests := []struct {
+		year     int
+		expected time.Time
+	}{
+		{2024, time.Date(2024, time.March, 31, 0, 0, 0, 0, time.UTC)},
+		{2025, time.Date(2025, time.April, 20, 0, 0, 0, 0, time.UTC)},
+		{2026, time.Date(2026, time.April, 5, 0, 0, 0, 0, time.UTC)},
+	}
+
+	for _, test := range tests {
+		result := holidays.GetEasterDate(test.year)
+		if !result.Equal(test.expected) {
+			t.Errorf("GetEasterDate(%d) = %v; want %v", test.year, result, test.expected)
+		}
+	}
+}
+
+func TestGetByDate(t *testing.T) {
+	holidays := holidayspl.New()
+
+	tests := []struct {
+		date     time.Time
+		expected string
+		found    bool
+	}{
+		{time.Date(2024, time.January, 1, 0, 0, 0, 0, time.UTC), "New Year", true},
+		{time.Date(2024, time.March, 31, 0, 0, 0, 0, time.UTC), "Easter Sunday", true},
+		{time.Date(2024, time.December, 25, 0, 0, 0, 0, time.UTC), "Christmas", true},
+		{time.Date(2024, time.August, 15, 0, 0, 0, 0, time.UTC), "Assumption of Mary", true},
+		{time.Date(2024, time.July, 4, 0, 0, 0, 0, time.UTC), "", false}, // No holiday on this date
+	}
+
+	for _, test := range tests {
+		result, found := holidays.GetByDate(test.date)
+		if found != test.found {
+			t.Errorf("GetByDate(%v) = %v; want %v", test.date, found, test.found)
+		}
+		if found && result.Name != test.expected {
+			t.Errorf("GetByDate(%v) = %v; want %v", test.date, result.Name, test.expected)
+		}
+	}
+}
+
+func TestCaching(t *testing.T) {
+	holidays := holidayspl.New()
+
+	year := 2024
+	// First call should calculate and cache holidays for the year
+	holidays.GetHolidaysList(year)
+	// Modify the cache and see if the function returns the cached value
+	holidays.GetCache()[year][0].Name = "Modified New Year"
+
+	result := holidays.GetHolidaysList(year)
+	if result[0].Name != "Modified New Year" {
+		t.Errorf("Caching not working properly. Got %v, expected %v", result[0].Name, "Modified New Year")
+	}
+}

models.go

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+package holidayspl
+
+import "time"
+
+type HolidayType int
+
+const (
+	FIXED HolidayType = iota
+	MOVABLE
+)
+
+func (d HolidayType) String() string {
+	return [...]string{"fixed", "movable"}[d]
+}
+
+type Holiday struct {
+	Name        string
+	NamePL      string
+	Month       time.Month
+	Day         int
+	HolidayType HolidayType
+	PlusEaster  int
+	Date        time.Time
+}