package rules

import "strings"

// WhitelistRule accepts emails from configured senders.
// An empty list accepts all senders.
type WhitelistRule struct {
	emails map[string]bool
}

// NewWhitelistRule creates a whitelist rule from a list of email addresses.
func NewWhitelistRule(emails []string) *WhitelistRule {
	m := make(map[string]bool, len(emails))
	for _, e := range emails {
		m[strings.ToLower(e)] = true
	}
	return &WhitelistRule{emails: m}
}

func (r *WhitelistRule) Name() string { return "whitelist" }

func (r *WhitelistRule) Evaluate(ctx EmailContext) RuleResult {
	if len(r.emails) == 0 {
		return Accept()
	}
	if r.emails[strings.ToLower(ctx.Sender)] {
		return Accept()
	}
	return Reject("not whitelisted")
}