package whois

import (
	"strings"
)

func commonParser(domain, data string) (Result, error) {
	p := newCommonParsePipeline(domain, data)
	p.run()
	return p.result, nil
}

type commonParsePipeline struct {
	queryDomain string
	result      Result
	register    PersonalInfo
	admin       PersonalInfo
	tech        PersonalInfo
	statusSet   map[string]struct{}
	pendingKey  string
	terminated  bool
}

func newCommonParsePipeline(domain, data string) *commonParsePipeline {
	return &commonParsePipeline{
		queryDomain: strings.ToLower(strings.Trim(strings.TrimSpace(domain), ".")),
		result: Result{
			domain:  strings.TrimSpace(domain),
			rawData: data,
		},
		statusSet: make(map[string]struct{}),
	}
}

func (p *commonParsePipeline) run() {
	for _, rawLine := range splitParseLines(p.result.rawData) {
		if p.terminated {
			break
		}
		p.consumeLine(rawLine)
	}
	p.finalize()
}

func splitParseLines(raw string) []string {
	raw = strings.ReplaceAll(raw, "\r\n", "\n")
	raw = strings.ReplaceAll(raw, "\r", "\n")
	return strings.Split(raw, "\n")
}

func (p *commonParsePipeline) consumeLine(rawLine string) {
	line := strings.TrimSpace(rawLine)
	if line == "" {
		p.onBlankLine()
		return
	}

	if p.handleTerminalLine(line) {
		return
	}
	if p.handlePendingLine(line) {
		return
	}
	if p.handleKVLine(line) {
		return
	}
	p.handleInlineLine(line)
}

func (p *commonParsePipeline) onBlankLine() {
	if p.pendingKey == "status" || p.pendingKey == "domain" {
		p.pendingKey = ""
	}
}

func (p *commonParsePipeline) handleTerminalLine(line string) bool {
	if !isNotFoundLine(line) {
		return false
	}
	if p.result.exists && p.result.hasRegisterDate {
		return false
	}
	p.result.exists = false
	p.pendingKey = ""
	p.terminated = true
	return true
}

func (p *commonParsePipeline) handlePendingLine(line string) bool {
	if p.pendingKey == "" {
		return false
	}
	switch p.pendingKey {
	case "domain":
		if d := extractDomainToken(line); d != "" {
			p.result.exists = true
			p.result.domain = d
			p.pendingKey = ""
			return true
		}
		p.pendingKey = ""
		return false
	case "nameserver":
		if ns, ok := parseNameServerCandidate(line); ok {
			p.result.nsServers = appendUnique(p.result.nsServers, ns)
			return true
		}
		p.pendingKey = ""
		return false
	case "status":
		if s := firstToken(line); s != "" {
			p.statusSet[s] = struct{}{}
			return true
		}
		p.pendingKey = ""
		return false
	default:
		p.pendingKey = ""
		return false
	}
}

func (p *commonParsePipeline) handleKVLine(line string) bool {
	key, val, ok := splitKV(line)
	if !ok {
		return false
	}

	canonical := canonicalKey(key)
	if val == "" {
		switch canonical {
		case "domain", "nameserver", "status":
			p.pendingKey = canonical
			return true
		}
	}

	if applyCanonicalKV(&p.result, canonical, val, p.statusSet) {
		return true
	}
	applyContactAlias(key, val, &p.register, &p.admin, &p.tech)
	return true
}

func (p *commonParsePipeline) handleInlineLine(line string) {
	if d, ok := parseInlineDomain(line); ok {
		p.result.exists = true
		p.result.domain = d
	}
}

func (p *commonParsePipeline) finalize() {
	if p.result.exists && strings.TrimSpace(p.result.domain) == "" {
		if d := extractDomainFromRaw(p.result.rawData, p.queryDomain); d != "" {
			p.result.domain = d
		}
	}
	if p.result.exists && strings.TrimSpace(p.result.registrar) == "" {
		if v := extractDomainManagersName(p.result.rawData); v != "" {
			p.result.registrar = v
		}
	}
	for s := range p.statusSet {
		p.result.statusRaw = append(p.result.statusRaw, s)
	}
	p.result.registerInfo = p.register
	p.result.adminInfo = p.admin
	p.result.techInfo = p.tech
}

func applyCanonicalKV(res *Result, canonical, val string, statusSet map[string]struct{}) bool {
	switch canonical {
	case "domain":
		res.exists = true
		if d := extractDomainToken(val); d != "" {
			res.domain = d
		}
		return true
	case "domain_id":
		res.domainID = strings.TrimSpace(val)
		return true
	case "updated_at":
		if d := parseDateAuto(val); !d.IsZero() {
			res.hasUpdateDate = true
			res.updateDate = d
		}
		return true
	case "created_at":
		if d := parseDateAuto(val); !d.IsZero() {
			res.hasRegisterDate = true
			res.registerDate = d
		}
		return true
	case "expired_at":
		if d := parseDateAuto(val); !d.IsZero() {
			res.hasExpireDate = true
			res.expireDate = d
		}
		return true
	case "registrar":
		res.registrar = strings.TrimSpace(val)
		return true
	case "status":
		if s := firstToken(val); s != "" {
			statusSet[s] = struct{}{}
		}
		return true
	case "nameserver":
		if ns, ok := parseNameServerCandidate(val); ok {
			res.nsServers = appendUnique(res.nsServers, ns)
		} else if v := strings.TrimSpace(val); v != "" {
			res.nsServers = appendUnique(res.nsServers, v)
		}
		return true
	case "dnssec":
		res.dnssec = strings.TrimSpace(val)
		return true
	default:
		return false
	}
}

func applyContactAlias(key, val string, r, a, t *PersonalInfo) {
	k := normalizeKey(key)
	switch k {
	case "registrant name":
		r.Name = val
	case "registrant organization":
		r.Org = val
	case "registrant street":
		r.Addr = val
	case "registrant city":
		r.City = val
	case "registrant state province":
		r.State = val
	case "registrant postal code":
		r.Zip = val
	case "registrant country":
		r.Country = val
	case "registrant phone":
		r.Phone = val
	case "registrant phone ext":
		r.PhoneExt = val
	case "registrant fax":
		r.Fax = val
	case "registrant fax ext":
		r.FaxExt = val
	case "registrant email", "registrant contact email":
		r.Email = val

	case "admin name":
		a.Name = val
	case "admin organization":
		a.Org = val
	case "admin street":
		a.Addr = val
	case "admin city":
		a.City = val
	case "admin state province":
		a.State = val
	case "admin postal code":
		a.Zip = val
	case "admin country":
		a.Country = val
	case "admin phone":
		a.Phone = val
	case "admin phone ext":
		a.PhoneExt = val
	case "admin fax":
		a.Fax = val
	case "admin fax ext":
		a.FaxExt = val
	case "admin email":
		a.Email = val

	case "tech name", "tech contact name":
		t.Name = val
	case "tech organization", "tech contact organisation", "tech contact organization":
		t.Org = val
	case "tech street":
		t.Addr = val
	case "tech city":
		t.City = val
	case "tech state province":
		t.State = val
	case "tech postal code":
		t.Zip = val
	case "tech country":
		t.Country = val
	case "tech phone":
		t.Phone = val
	case "tech phone ext":
		t.PhoneExt = val
	case "tech fax":
		t.Fax = val
	case "tech fax ext":
		t.FaxExt = val
	case "tech email", "tech contact email":
		t.Email = val
	}
}

func firstToken(s string) string {
	fields := strings.Fields(strings.TrimSpace(s))
	if len(fields) == 0 {
		return ""
	}
	return fields[0]
}

func parseNameServerCandidate(s string) (string, bool) {
	d := extractDomainToken(s)
	if d == "" {
		return "", false
	}
	if isIPv4Token(d) {
		return "", false
	}
	return d, true
}

func parseInlineDomain(line string) (string, bool) {
	l := strings.ToLower(strings.TrimSpace(line))
	if !strings.HasPrefix(l, "domain ") {
		return "", false
	}
	if strings.HasPrefix(l, "domain name") || strings.HasPrefix(l, "domain status") || strings.HasPrefix(l, "domain information") || strings.HasPrefix(l, "domain managers") {
		return "", false
	}
	d := extractDomainToken(line)
	if d == "" {
		return "", false
	}
	return d, true
}

func extractDomainToken(s string) string {
	for _, field := range strings.Fields(strings.TrimSpace(s)) {
		token := strings.ToLower(strings.Trim(field, "[]()<>\"'`,;"))
		token = strings.Trim(token, ".")
		if token == "" {
			continue
		}
		if strings.HasPrefix(token, "http://") || strings.HasPrefix(token, "https://") {
			continue
		}
		if strings.Contains(token, "@") || strings.Contains(token, "/") {
			continue
		}
		if strings.Count(token, ".") < 1 {
			continue
		}
		return token
	}
	return ""
}

func isIPv4Token(s string) bool {
	parts := strings.Split(s, ".")
	if len(parts) != 4 {
		return false
	}
	for _, p := range parts {
		if p == "" {
			return false
		}
		for _, ch := range p {
			if ch < '0' || ch > '9' {
				return false
			}
		}
	}
	return true
}

func appendUnique(list []string, v string) []string {
	v = strings.TrimSpace(v)
	if v == "" {
		return list
	}
	for _, cur := range list {
		if strings.EqualFold(cur, v) {
			return list
		}
	}
	return append(list, v)
}

func extractDomainManagersName(raw string) string {
	lines := splitParseLines(raw)
	inManagers := false
	waitingName := false

	for _, rawLine := range lines {
		line := strings.TrimSpace(rawLine)
		if line == "" || strings.HasPrefix(line, "%") {
			continue
		}

		key := normalizeKey(line)
		if key == "domain managers" {
			inManagers = true
			waitingName = false
			continue
		}
		if !inManagers {
			continue
		}

		if key == "name" {
			waitingName = true
			continue
		}
		if waitingName {
			return strings.TrimSpace(line)
		}
	}
	return ""
}

func extractDomainFromRaw(raw, query string) string {
	q := strings.ToLower(strings.TrimSpace(query))
	if q == "" {
		return ""
	}
	if strings.Contains(strings.ToLower(raw), q) {
		return q
	}
	return ""
}