package email

import "testing"

func TestConfirmUnderstoodPhrase(t *testing.T) {
	if ConfirmUnderstoodPhrase != "I understand" {
		t.Fatalf("unexpected phrase %q", ConfirmUnderstoodPhrase)
	}
}

func TestDomainOfEmail(t *testing.T) {
	if got := domainOfEmail("Alice@Example.COM"); got != "example.com" {
		t.Fatalf("got %q", got)
	}
}

func TestInjectUnsubscribeFooter(t *testing.T) {
	html, text := injectUnsubscribeFooter("<p>Hi</p>", "Hi", "https://app/unsubscribe?token=x")
	if !containsFold(html, "unsubscribe") || !containsFold(text, "unsubscribe") {
		t.Fatalf("expected unsubscribe footer")
	}
}

func containsFold(s, sub string) bool {
	return len(s) >= len(sub) && (s == sub || len(sub) == 0 ||
		(len(s) > 0 && (stringIndexFold(s, sub) >= 0)))
}

func stringIndexFold(s, sub string) int {
	ls, lsub := len(s), len(sub)
	for i := 0; i+lsub <= ls; i++ {
		ok := true
		for j := 0; j < lsub; j++ {
			a, b := s[i+j], sub[j]
			if a >= 'A' && a <= 'Z' {
				a += 'a' - 'A'
			}
			if b >= 'A' && b <= 'Z' {
				b += 'a' - 'A'
			}
			if a != b {
				ok = false
				break
			}
		}
		if ok {
			return i
		}
	}
	return -1
}

func TestListUnsubscribeHeaders(t *testing.T) {
	h := listUnsubscribeHeaders("https://api/u?t=1", "")
	if h["List-Unsubscribe"] == "" || h["List-Unsubscribe-Post"] == "" {
		t.Fatal("missing headers")
	}
}