feat: add functional options pattern for email verifier

option.go

@@ -0,0 +1,80 @@
+package emailverifier
+
+import "time"
+
+// New creates a new email verifier, modified by the given options.
+// Use "emailverifier.With*" to modify the default behavior.
+func New(options ...Option) *Verifier {
+	v := NewVerifier()
+
+	for _, option := range options {
+		option(v)
+	}
+	return v
+}
+
+// Option represents a modification to the default behavior of a email verifier.
+type Option func(*Verifier)
+
+// WithEnableSMTPCheck enables the SMTP check.
+func WithEnableSMTPCheck() Option {
+	return func(v *Verifier) {
+		v.smtpCheckEnabled = true
+	}
+}
+
+// WithDisableCatchAllCheck enables the catch-all email check.
+func WithDisableCatchAllCheck() Option {
+	return func(v *Verifier) {
+		v.catchAllCheckEnabled = false
+	}
+}
+
+// WithEnableDomainSuggest enables the domain suggestion if the domain may be misspelled.
+func WithEnableDomainSuggest() Option {
+	return func(v *Verifier) {
+		v.domainSuggestEnabled = true
+	}
+}
+
+// WithEnableGravatarCheck enables the email check by Gravatar service.
+func WithEnableGravatarCheck() Option {
+	return func(v *Verifier) {
+		v.gravatarCheckEnabled = true
+	}
+}
+
+// WithFromEmail sets the email address to use as the sender.
+func WithFromEmail(email string) Option {
+	return func(v *Verifier) {
+		v.fromEmail = email
+	}
+}
+
+// WithHelloName sets the name to use in the `EHLO:` SMTP command.
+func WithHelloName(email string) Option {
+	return func(v *Verifier) {
+		v.helloName = email
+	}
+}
+
+// WithProxyURI sets verify the email request through specified proxy server.
+func WithProxyURI(uri string) Option {
+	return func(v *Verifier) {
+		v.proxyURI = uri
+	}
+}
+
+// WithConnectTimeout overrides the default timeout for establishing connections.
+func WithConnectTimeout(timeout time.Duration) Option {
+	return func(v *Verifier) {
+		v.connectTimeout = timeout
+	}
+}
+
+// WithOperationTimeout overrides the default timeout for each SMTP operation.
+func WithOperationTimeout(timeout time.Duration) Option {
+	return func(v *Verifier) {
+		v.operationTimeout = timeout
+	}
+}