package calendartest

import (
	"fmt"
	"sync"
	"testing"

	calendar "amadan.net/oficina/calendar/internal/calendar"
)

// TestZoneIsSafeUnderConcurrentGarbage drives Zone() the way the
// public booking page will: many requests at once, most of them asking
// for names nobody has ever heard of.
//
// Two things must hold. The cache must survive concurrent use — run
// this under -race — and a name that failed to load must not be kept,
// or a stranger with a ?zone= parameter grows the map without bound.
func TestZoneIsSafeUnderConcurrentGarbage(t *testing.T) {
	var wg sync.WaitGroup
	for i := 0; i < 100; i++ {
		wg.Add(1)
		go func(i int) {
			defer wg.Done()
			if _, err := calendar.Zone(fmt.Sprintf("Nowhere/Town%d", i)); err == nil {
				t.Errorf("Nowhere/Town%d resolved", i)
			}
			if _, err := calendar.Zone("Europe/Dublin"); err != nil {
				t.Errorf("Europe/Dublin: %v", err)
			}
		}(i)
	}
	wg.Wait()

	// The bound leaves room for the handful of real zones other tests
	// in this package load; a hundred garbage names cannot fit inside it.
	if n, limit := calendar.ZoneCacheSizeForTest(), len(calendar.CommonZones)+5; n > limit {
		t.Errorf("zone cache holds %d entries after 100 garbage names (limit %d): failures are being cached", n, limit)
	}
}

func TestIsCommonZoneKnowsTheList(t *testing.T) {
	if !calendar.IsCommonZone("Europe/Dublin") {
		t.Error("Europe/Dublin is not common")
	}
	if calendar.IsCommonZone("Nowhere/Town1") {
		t.Error("Nowhere/Town1 is common")
	}
	if calendar.IsCommonZone("") {
		t.Error("the empty name is common")
	}
}