package resolver

import "strings"

type WildcardMatcher struct {
	exact  map[string]struct{}
	suffix []string
}

func NormalizeWildcardDomain(raw string) string {
	d := strings.TrimSpace(strings.SplitN(raw, "#", 2)[0])
	d = strings.ToLower(d)
	d = strings.TrimPrefix(d, "*.")
	d = strings.TrimPrefix(d, ".")
	d = strings.TrimSuffix(d, ".")
	return d
}

func NewWildcardMatcher(domains []string) WildcardMatcher {
	seen := map[string]struct{}{}
	m := WildcardMatcher{exact: map[string]struct{}{}}
	for _, raw := range domains {
		d := NormalizeWildcardDomain(raw)
		if d == "" {
			continue
		}
		if _, ok := seen[d]; ok {
			continue
		}
		seen[d] = struct{}{}
		m.exact[d] = struct{}{}
		m.suffix = append(m.suffix, "."+d)
	}
	return m
}

func (m WildcardMatcher) Match(host string) bool {
	if len(m.exact) == 0 {
		return false
	}
	h := strings.TrimSuffix(strings.ToLower(strings.TrimSpace(host)), ".")
	if h == "" {
		return false
	}
	if _, ok := m.exact[h]; ok {
		return true
	}
	for _, suffix := range m.suffix {
		if strings.HasSuffix(h, suffix) {
			return true
		}
	}
	return false
}

func (m WildcardMatcher) IsExact(host string) bool {
	if len(m.exact) == 0 {
		return false
	}
	h := strings.TrimSuffix(strings.ToLower(strings.TrimSpace(host)), ".")
	if h == "" {
		return false
	}
	_, ok := m.exact[h]
	return ok
}

func (m WildcardMatcher) Count() int {
	return len(m.exact)
}