package calendartest

import (
	"regexp"
	"testing"
)

// The view switcher keeps the date you were looking at, through Month too.
// A month URL names only the month, so the switcher carries the day as
// ?date= and Month's Day and Week tabs go back to it, not to the 1st.
func TestViewTabsKeepTheSelectedDateThroughMonth(t *testing.T) {
	app, session := signedIn(t, "someone@example.com")
	h := app.Handler()
	tab := func(path, label string) string {
		t.Helper()
		rec := getAs(t, h, session, path)
		if rec.Code != 200 {
			t.Fatalf("GET %s: %d", path, rec.Code)
		}
		m := regexp.MustCompile(`<a cal-tab="` + label + `" href="([^"]*)"`).FindStringSubmatch(rec.Body.String())
		if m == nil {
			t.Fatalf("GET %s: no %s tab", path, label)
		}
		return m[1]
	}
	for _, c := range []struct{ path, label, want string }{
		{"/day/2026-09-24", "Month", "/month/2026-09?date=2026-09-24"},
		{"/week/2026-09-24", "Month", "/month/2026-09?date=2026-09-21"},
		{"/agenda?from=2026-09-24", "Month", "/month/2026-09?date=2026-09-24"},
		{"/month/2026-09?date=2026-09-24", "Day", "/day/2026-09-24"},
		{"/month/2026-09?date=2026-09-24", "Week", "/week/2026-09-24"},
		{"/month/2026-09?date=2026-09-24", "Agenda", "/agenda?from=2026-09-24"},
		// A date outside the month, or none, falls back to the 1st (this
		// month is not the current one, where it would be today).
		{"/month/2026-09?date=2026-10-02", "Day", "/day/2026-09-01"},
		{"/month/2020-02", "Week", "/week/2020-02-01"},
	} {
		if got := tab(c.path, c.label); got != c.want {
			t.Errorf("%s: %s tab = %s, want %s", c.path, c.label, got, c.want)
		}
	}
}