package checker

import (
	"context"

	sdk "git.happydns.org/checker-sdk-go/checker"
)

// nullMXRule reports whether the domain declares a null MX (RFC 7505).
// This is surfaced as a distinct rule so the rest of the rules can short
// out cleanly: every other rule skips when data.MX.NullMX is true.
type nullMXRule struct{}

func (r *nullMXRule) Name() string { return "smtp.null_mx" }
func (r *nullMXRule) Description() string {
	return "Reports whether the domain publishes a null MX (RFC 7505), which declares it does not accept mail."
}

func (r *nullMXRule) Evaluate(ctx context.Context, obs sdk.ObservationGetter, _ sdk.CheckerOptions) []sdk.CheckState {
	data, errSt := loadSMTPData(ctx, obs)
	if errSt != nil {
		return []sdk.CheckState{*errSt}
	}
	if data.MX.NullMX {
		return []sdk.CheckState{{
			Status:  sdk.StatusInfo,
			Message: "Domain refuses all email via null MX (RFC 7505).",
			Code:    CodeNullMX,
			Meta:    map[string]any{"null_mx": true},
		}}
	}
	return []sdk.CheckState{passState("smtp.null_mx.ok", "Domain does not declare a null MX.")}
}