package service

import (
	"fmt"
	"strings"

	"github.com/rs/zerolog"

	"github.com/gosec/gsc-ops-api/internal/client"
	"github.com/gosec/gsc-ops-api/pkg/types"
)

// DNSService handles PowerDNS zone and record operations
type DNSService struct {
	client *client.PowerDNSClient
	logger zerolog.Logger
}

// NewDNSService creates a new DNS service
func NewDNSService(pdnsClient *client.PowerDNSClient, logger zerolog.Logger) *DNSService {
	return &DNSService{
		client: pdnsClient,
		logger: logger.With().Str("service", "dns").Logger(),
	}
}

// ListZones lists all DNS zones
func (s *DNSService) ListZones() ([]types.DNSZone, error) {
	zones, err := s.client.ListZones()
	if err != nil {
		return nil, err
	}

	result := make([]types.DNSZone, 0, len(zones))
	for _, z := range zones {
		result = append(result, types.DNSZone{
			ID:             z.ID,
			Name:           z.Name,
			Kind:           z.Kind,
			DNSSec:         z.DNSSec,
			Serial:         z.Serial,
			NotifiedSerial: z.NotifiedSerial,
		})
	}
	return result, nil
}

// GetZone gets a zone with records
func (s *DNSService) GetZone(zoneID string) (*types.DNSZone, error) {
	z, err := s.client.GetZone(zoneID)
	if err != nil {
		return nil, err
	}

	zone := &types.DNSZone{
		ID:             z.ID,
		Name:           z.Name,
		Kind:           z.Kind,
		DNSSec:         z.DNSSec,
		Serial:         z.Serial,
		NotifiedSerial: z.NotifiedSerial,
		SOAEdit:        z.SOAEdit,
		SOAEditAPI:     z.SOAEditAPI,
	}

	records := make([]types.DNSRecord, 0, len(z.RRSets))
	for _, rr := range z.RRSets {
		entries := make([]types.DNSRecordEntry, 0, len(rr.Records))
		for _, r := range rr.Records {
			entries = append(entries, types.DNSRecordEntry{
				Content:  r.Content,
				Disabled: r.Disabled,
			})
		}
		records = append(records, types.DNSRecord{
			Name:    rr.Name,
			Type:    rr.Type,
			TTL:     rr.TTL,
			Records: entries,
		})
	}
	zone.Records = records

	return zone, nil
}

// CreateZone creates a new DNS zone
func (s *DNSService) CreateZone(req *types.DNSZoneCreate) (*types.DNSZone, error) {
	kind := req.Kind
	if kind == "" {
		kind = "Native"
	}

	name := req.Name
	if !strings.HasSuffix(name, ".") {
		name += "."
	}

	z, err := s.client.CreateZone(&client.ZoneCreate{
		Name:        name,
		Kind:        kind,
		Nameservers: req.Nameservers,
		Masters:     req.Masters,
	})
	if err != nil {
		return nil, err
	}

	return &types.DNSZone{
		ID:   z.ID,
		Name: z.Name,
		Kind: z.Kind,
	}, nil
}

// UpdateZone updates zone metadata
func (s *DNSService) UpdateZone(zoneID string, req *types.DNSZoneUpdate) error {
	data := make(map[string]interface{})
	if req.Kind != nil {
		data["kind"] = *req.Kind
	}
	if req.Masters != nil {
		data["masters"] = req.Masters
	}
	return s.client.UpdateZone(zoneID, data)
}

// DeleteZone deletes a zone
func (s *DNSService) DeleteZone(zoneID string) error {
	return s.client.DeleteZone(zoneID)
}

// NotifyZone sends NOTIFY to slaves
func (s *DNSService) NotifyZone(zoneID string) error {
	return s.client.NotifyZone(zoneID)
}

// ListRecords lists records in a zone
func (s *DNSService) ListRecords(zoneID string) ([]types.DNSRecord, error) {
	zone, err := s.GetZone(zoneID)
	if err != nil {
		return nil, err
	}
	return zone.Records, nil
}

// ChangeRecords applies record changes to a zone using PATCH semantics
func (s *DNSService) ChangeRecords(zoneID string, changes []types.DNSRecordChange) error {
	rrsets := make([]client.RRSet, 0, len(changes))
	for _, ch := range changes {
		name := ch.Name
		if !strings.HasSuffix(name, ".") {
			name += "."
		}

		records := make([]client.Record, 0, len(ch.Records))
		for _, r := range ch.Records {
			records = append(records, client.Record{
				Content:  r.Content,
				Disabled: r.Disabled,
			})
		}

		ttl := ch.TTL
		if ttl == 0 {
			ttl = 3600
		}

		rrsets = append(rrsets, client.RRSet{
			Name:       name,
			Type:       ch.Type,
			TTL:        ttl,
			ChangeType: ch.ChangeType,
			Records:    records,
		})
	}
	return s.client.PatchRRSets(zoneID, rrsets)
}

// SetupDomain creates a zone with standard mail DNS records (MX, SPF, DKIM, DMARC)
func (s *DNSService) SetupDomain(req *types.DomainSetup) (*types.DNSZone, error) {
	domain := req.Domain
	if !strings.HasSuffix(domain, ".") {
		domain += "."
	}

	// Create zone first
	zone, err := s.client.CreateZone(&client.ZoneCreate{
		Name: domain,
		Kind: "Native",
		Nameservers: []string{
			"ns1.gosec.cloud.",
			"ns2.gosec.cloud.",
		},
	})
	if err != nil {
		return nil, fmt.Errorf("failed to create zone: %w", err)
	}

	// Build standard mail records
	mxHost := req.MXHost
	if mxHost == "" {
		mxHost = "mail.gosec.cloud."
	}
	if !strings.HasSuffix(mxHost, ".") {
		mxHost += "."
	}

	rrsets := []client.RRSet{
		{
			Name:       domain,
			Type:       "MX",
			TTL:        3600,
			ChangeType: "REPLACE",
			Records:    []client.Record{{Content: "10 " + mxHost}},
		},
	}

	// SPF record
	spf := "v=spf1"
	if len(req.SPFIncludes) > 0 {
		for _, inc := range req.SPFIncludes {
			spf += " include:" + inc
		}
	}
	spf += " mx -all"
	rrsets = append(rrsets, client.RRSet{
		Name:       domain,
		Type:       "TXT",
		TTL:        3600,
		ChangeType: "REPLACE",
		Records:    []client.Record{{Content: fmt.Sprintf(`"%s"`, spf)}},
	})

	// DKIM record
	if req.DKIMKey != "" {
		rrsets = append(rrsets, client.RRSet{
			Name:       "default._domainkey." + domain,
			Type:       "TXT",
			TTL:        3600,
			ChangeType: "REPLACE",
			Records:    []client.Record{{Content: fmt.Sprintf(`"v=DKIM1; k=rsa; p=%s"`, req.DKIMKey)}},
		})
	}

	// DMARC record
	rrsets = append(rrsets, client.RRSet{
		Name:       "_dmarc." + domain,
		Type:       "TXT",
		TTL:        3600,
		ChangeType: "REPLACE",
		Records:    []client.Record{{Content: fmt.Sprintf(`"v=DMARC1; p=quarantine; rua=mailto:postmaster@%s"`, strings.TrimSuffix(domain, "."))}},
	})

	if err := s.client.PatchRRSets(zone.ID, rrsets); err != nil {
		return nil, fmt.Errorf("zone created but record setup failed: %w", err)
	}

	result := &types.DNSZone{
		ID:   zone.ID,
		Name: zone.Name,
		Kind: zone.Kind,
	}
	return result, nil
}

// VerifyDomain checks DNS propagation for a domain
func (s *DNSService) VerifyDomain(domain string) (*types.DomainVerifyResult, error) {
	if !strings.HasSuffix(domain, ".") {
		domain += "."
	}

	zone, err := s.client.GetZone(domain)
	if err != nil {
		return nil, fmt.Errorf("zone not found: %w", err)
	}

	results := make(map[string]string)
	hasMX, hasSPF, hasDMARC := false, false, false

	for _, rr := range zone.RRSets {
		switch {
		case rr.Type == "MX" && rr.Name == domain:
			hasMX = true
			results["MX"] = "OK"
		case rr.Type == "TXT" && rr.Name == domain:
			for _, r := range rr.Records {
				if strings.Contains(r.Content, "v=spf1") {
					hasSPF = true
					results["SPF"] = "OK"
				}
			}
		case rr.Type == "TXT" && rr.Name == "_dmarc."+domain:
			hasDMARC = true
			results["DMARC"] = "OK"
		case rr.Type == "TXT" && strings.HasSuffix(rr.Name, "._domainkey."+domain):
			results["DKIM"] = "OK"
		}
	}

	if !hasMX {
		results["MX"] = "MISSING"
	}
	if !hasSPF {
		results["SPF"] = "MISSING"
	}
	if !hasDMARC {
		results["DMARC"] = "MISSING"
	}

	allOK := true
	for _, v := range results {
		if v != "OK" {
			allOK = false
			break
		}
	}

	return &types.DomainVerifyResult{
		Domain:  strings.TrimSuffix(domain, "."),
		Results: results,
		AllOK:   allOK,
	}, nil
}