package porkbun

import (
	"encoding/json"
	"errors"
	"fmt"
	"sort"
	"strconv"
	"strings"
	"time"

	"github.com/StackExchange/dnscontrol/v4/models"
	"github.com/StackExchange/dnscontrol/v4/pkg/diff2"
	"github.com/StackExchange/dnscontrol/v4/pkg/printer"
	"github.com/StackExchange/dnscontrol/v4/providers"
	"github.com/miekg/dns/dnsutil"
)

const (
	minimumTTL = 600
)

const (
	metaType        = "type"
	metaIncludePath = "includePath"
	metaWildcard    = "wildcard"
)

const (
	defaultMaxAttempts = 5
)

// https://kb.porkbun.com/article/63-how-to-switch-to-porkbuns-nameservers
var defaultNS = []string{
	"curitiba.ns.porkbun.com",
	"fortaleza.ns.porkbun.com",
	"maceio.ns.porkbun.com",
	"salvador.ns.porkbun.com",
}

func newReg(conf map[string]string) (providers.Registrar, error) {
	return newPorkbun(conf, nil)
}

func newDsp(conf map[string]string, metadata json.RawMessage) (providers.DNSServiceProvider, error) {
	return newPorkbun(conf, metadata)
}

// newPorkbun creates the provider.
func newPorkbun(m map[string]string, _ json.RawMessage) (*porkbunProvider, error) {
	c := &porkbunProvider{
		maxAttempts: defaultMaxAttempts,
	}

	c.apiKey, c.secretKey = m["api_key"], m["secret_key"]

	if c.apiKey == "" || c.secretKey == "" {
		return nil, errors.New("missing porkbun api_key or secret_key")
	}

	if maxAttempts, ok := m["max_attempts"]; ok && maxAttempts != "" {
		i, err := strconv.Atoi(maxAttempts)
		if err != nil {
			return nil, fmt.Errorf("porkbun: invalid max_attempts %q: must be a whole number", maxAttempts)
		}
		c.maxAttempts = i
	}
	if maxDuration, ok := m["max_duration"]; ok && maxDuration != "" {
		d, err := time.ParseDuration(maxDuration)
		if err != nil {
			return nil, fmt.Errorf("porkbun: invalid max_duration %q: valid units are ns, us, ms, s, m, h", maxDuration)
		}
		c.maxDuration = d
	}

	return c, nil
}

var features = providers.DocumentationNotes{
	// The default for unlisted capabilities is 'Cannot'.
	// See providers/capabilities.go for the entire list of capabilities.
	providers.CanAutoDNSSEC:          providers.Cannot(),
	providers.CanGetZones:            providers.Can(),
	providers.CanConcur:              providers.Can(),
	providers.CanUseAlias:            providers.Can(),
	providers.CanUseCAA:              providers.Can(),
	providers.CanUseDS:               providers.Cannot(),
	providers.CanUseDSForChildren:    providers.Cannot(),
	providers.CanUseLOC:              providers.Cannot(),
	providers.CanUseNAPTR:            providers.Cannot(),
	providers.CanUsePTR:              providers.Cannot(),
	providers.CanUseSOA:              providers.Cannot(),
	providers.CanUseSRV:              providers.Can(),
	providers.CanUseSSHFP:            providers.Cannot(),
	providers.CanUseTLSA:             providers.Can(),
	providers.CanUseHTTPS:            providers.Can(),
	providers.CanUseSVCB:             providers.Can(),
	providers.DocCreateDomains:       providers.Cannot(),
	providers.DocDualHost:            providers.Cannot(),
	providers.DocOfficiallySupported: providers.Cannot(),
}

func init() {
	const providerName = "PORKBUN"
	const providerMaintainer = "@imlonghao"
	providers.RegisterRegistrarType(providerName, newReg)
	fns := providers.DspFuncs{
		Initializer:   newDsp,
		RecordAuditor: AuditRecords,
	}
	providers.RegisterDomainServiceProviderType(providerName, fns, features)
	providers.RegisterMaintainer(providerName, providerMaintainer)
	providers.RegisterCustomRecordType("PORKBUN_URLFWD", providerName, "")
}

// GetNameservers returns the nameservers for a domain.
func (c *porkbunProvider) GetNameservers(domain string) ([]*models.Nameserver, error) {
	return models.ToNameservers(defaultNS)
}

func genComparable(rec *models.RecordConfig) string {
	if rec.Type == "PORKBUN_URLFWD" {
		return fmt.Sprintf("type=%s includePath=%s wildcard=%s", rec.Metadata[metaType], rec.Metadata[metaIncludePath], rec.Metadata[metaWildcard])
	}
	return ""
}

// GetZoneRecordsCorrections returns a list of corrections that will turn existing records into dc.Records.
func (c *porkbunProvider) GetZoneRecordsCorrections(dc *models.DomainConfig, existingRecords models.Records) ([]*models.Correction, int, error) {
	var corrections []*models.Correction

	// Block changes to NS records for base domain
	checkNSModifications(dc)

	// Make sure TTL larger than the minimum TTL
	for _, record := range dc.Records {
		record.TTL = fixTTL(record.TTL)
		if record.Type == "PORKBUN_URLFWD" {
			record.TTL = 0
			if record.Metadata == nil {
				record.Metadata = make(map[string]string)
			}
			if record.Metadata[metaType] == "" {
				record.Metadata[metaType] = "temporary"
			}
			if record.Metadata[metaIncludePath] == "" {
				record.Metadata[metaIncludePath] = "no"
			}
			if record.Metadata[metaWildcard] == "" {
				record.Metadata[metaWildcard] = "yes"
			}
		}
	}

	changes, actualChangeCount, err := diff2.ByRecord(existingRecords, dc, genComparable)
	if err != nil {
		return nil, 0, err
	}
	for _, change := range changes {
		var corr *models.Correction
		switch change.Type {
		case diff2.REPORT:
			corr = &models.Correction{Msg: change.MsgsJoined}
		case diff2.CREATE:
			req, err := toReq(change.New[0])
			if err != nil {
				return nil, 0, err
			}
			corr = &models.Correction{
				Msg: change.Msgs[0],
				F: func() error {
					if change.New[0].Type == "PORKBUN_URLFWD" {
						return c.createURLForwardingRecord(dc.Name, req)
					}
					return c.createRecord(dc.Name, req)
				},
			}
		case diff2.CHANGE:
			id := change.Old[0].Original.(*domainRecord).ID
			req, err := toReq(change.New[0])
			if err != nil {
				return nil, 0, err
			}
			corr = &models.Correction{
				Msg: fmt.Sprintf("%s, porkbun ID: %s", change.Msgs[0], id),
				F: func() error {
					if change.New[0].Type == "PORKBUN_URLFWD" {
						return c.modifyURLForwardingRecord(dc.Name, id, req)
					}
					return c.modifyRecord(dc.Name, id, req)
				},
			}
		case diff2.DELETE:
			id := change.Old[0].Original.(*domainRecord).ID
			corr = &models.Correction{
				Msg: fmt.Sprintf("%s, porkbun ID: %s", change.Msgs[0], id),
				F: func() error {
					if change.Old[0].Type == "PORKBUN_URLFWD" {
						return c.deleteURLForwardingRecord(dc.Name, id)
					}
					return c.deleteRecord(dc.Name, id)
				},
			}
		default:
			panic(fmt.Sprintf("unhandled change.Type %s", change.Type))
		}
		corrections = append(corrections, corr)
	}

	return corrections, actualChangeCount, nil
}

// GetZoneRecords gets the records of a zone and returns them in RecordConfig format.
func (c *porkbunProvider) GetZoneRecords(domain string, meta map[string]string) (models.Records, error) {
	records, err := c.getRecords(domain)
	if err != nil {
		return nil, err
	}
	forwards, err := c.getURLForwardingRecords(domain)
	if err != nil {
		return nil, err
	}
	existingRecords := make([]*models.RecordConfig, 0)
	for i := range records {
		shouldSkip := false
		if strings.HasSuffix(records[i].Content, ".porkbun.com") {
			name := dnsutil.TrimDomainName(records[i].Name, domain)
			if name == "@" {
				name = ""
			}
			if records[i].Type == "ALIAS" {
				for _, forward := range forwards {
					if name == forward.Subdomain {
						shouldSkip = true
						break
					}
				}
			}
			if records[i].Type == "CNAME" {
				for _, forward := range forwards {
					if name == "*."+forward.Subdomain {
						shouldSkip = true
						break
					}
				}
			}
		}
		if shouldSkip {
			continue
		}
		newr, err := toRc(domain, &records[i])
		if err != nil {
			return nil, err
		}
		existingRecords = append(existingRecords, newr)
	}
	for i := range forwards {
		r := &forwards[i]
		rc := &models.RecordConfig{
			Type:     "PORKBUN_URLFWD",
			Original: r,
			Metadata: map[string]string{
				metaType:        r.Type,
				metaIncludePath: r.IncludePath,
				metaWildcard:    r.Wildcard,
			},
		}
		rc.SetLabel(r.Subdomain, domain)
		if err := rc.SetTarget(r.Location); err != nil {
			return nil, err
		}
		existingRecords = append(existingRecords, rc)
	}
	return existingRecords, nil
}

// parses the porkbun format into our standard RecordConfig
func toRc(domain string, r *domainRecord) (*models.RecordConfig, error) {
	ttl, _ := strconv.ParseUint(r.TTL, 10, 32)
	priority, _ := strconv.ParseUint(r.Prio, 10, 16)

	rc := &models.RecordConfig{
		Type:         r.Type,
		TTL:          uint32(ttl),
		MxPreference: uint16(priority),
		SrvPriority:  uint16(priority),
		Original:     r,
	}
	rc.SetLabelFromFQDN(r.Name, domain)

	var err error
	switch rtype := r.Type; rtype { // #rtype_variations
	case "TXT":
		err = rc.SetTargetTXT(r.Content)
	case "MX", "CNAME", "ALIAS", "NS":
		if strings.HasSuffix(r.Content, ".") {
			err = rc.SetTarget(r.Content)
		} else {
			err = rc.SetTarget(r.Content + ".")
		}
	case "CAA":
		// 0, issue, "letsencrypt.org"
		c := strings.Split(r.Content, " ")

		caaFlag, _ := strconv.ParseUint(c[0], 10, 8)
		rc.CaaFlag = uint8(caaFlag)
		rc.CaaTag = c[1]
		err = rc.SetTarget(strings.ReplaceAll(c[2], "\"", ""))
	case "TLSA":
		// 0 0 0 00000000000000000000000
		c := strings.Split(r.Content, " ")

		tlsaUsage, _ := strconv.ParseUint(c[0], 10, 8)
		rc.TlsaUsage = uint8(tlsaUsage)
		tlsaSelector, _ := strconv.ParseUint(c[1], 10, 8)
		rc.TlsaSelector = uint8(tlsaSelector)
		tlsaMatchingType, _ := strconv.ParseUint(c[2], 10, 8)
		rc.TlsaMatchingType = uint8(tlsaMatchingType)
		err = rc.SetTarget(c[3])
	case "SRV":
		// 5 5060 sip.example.com
		c := strings.Split(r.Content, " ")

		srvWeight, _ := strconv.ParseUint(c[0], 10, 16)
		rc.SrvWeight = uint16(srvWeight)
		srvPort, _ := strconv.ParseUint(c[1], 10, 16)
		rc.SrvPort = uint16(srvPort)
		err = rc.SetTarget(c[2])
	case "HTTPS":
		fallthrough
	case "SVCB":
		// 5 . ech=AAAAABBBBB...
		c := strings.Split(r.Content, " ")

		svcPriority, _ := strconv.ParseUint(c[0], 10, 16)
		rc.SvcPriority = uint16(svcPriority)
		if len(c) > 2 {
			rc.SvcParams = strings.Join(c[2:], " ")
		}
		err = rc.SetTarget(c[1])
	default:
		err = rc.SetTarget(r.Content)
	}
	return rc, err
}

// toReq takes a RecordConfig and turns it into the native format used by the API.
func toReq(rc *models.RecordConfig) (requestParams, error) {
	if rc.Type == "PORKBUN_URLFWD" {
		subdomain := rc.GetLabel()
		if subdomain == "@" {
			subdomain = ""
		}
		return requestParams{
			"subdomain":   subdomain,
			"location":    rc.GetTargetField(),
			"type":        rc.Metadata[metaType],
			"includePath": rc.Metadata[metaIncludePath],
			"wildcard":    rc.Metadata[metaWildcard],
		}, nil
	}

	req := requestParams{
		"type":    rc.Type,
		"name":    rc.GetLabel(),
		"content": rc.GetTargetField(),
		"ttl":     strconv.Itoa(int(rc.TTL)),
	}

	// porkbun doesn't use "@", it uses an empty name
	if req["name"] == "@" {
		req["name"] = ""
	}

	switch rc.Type { // #rtype_variations
	case "A", "AAAA", "NS", "ALIAS", "CNAME":
	// Nothing special.
	case "TXT":
		req["content"] = rc.GetTargetTXTJoined()
	case "MX":
		req["prio"] = strconv.Itoa(int(rc.MxPreference))
	case "SRV":
		req["prio"] = strconv.Itoa(int(rc.SrvPriority))
		req["content"] = fmt.Sprintf("%d %d %s", rc.SrvWeight, rc.SrvPort, rc.GetTargetField())
	case "CAA":
		req["content"] = fmt.Sprintf("%d %s \"%s\"", rc.CaaFlag, rc.CaaTag, rc.GetTargetField())
	case "TLSA":
		req["content"] = fmt.Sprintf("%d %d %d %s",
			rc.TlsaUsage, rc.TlsaSelector, rc.TlsaMatchingType, rc.GetTargetField())
	case "HTTPS":
		fallthrough
	case "SVCB":
		req["content"] = fmt.Sprintf("%d %s %s",
			rc.SvcPriority, rc.GetTargetField(), rc.SvcParams)
	default:
		return nil, fmt.Errorf("porkbun.toReq rtype %q unimplemented", rc.Type)
	}

	return req, nil
}

func checkNSModifications(dc *models.DomainConfig) {
	newList := make([]*models.RecordConfig, 0, len(dc.Records))
	for _, rec := range dc.Records {
		if rec.Type == "NS" && rec.GetLabelFQDN() == dc.Name {
			if strings.HasSuffix(rec.GetTargetField(), ".porkbun.com") {
				printer.Warnf("porkbun does not support modifying NS records on base domain. %s will not be added.\n", rec.GetTargetField())
			}
			continue
		}
		newList = append(newList, rec)
	}
	dc.Records = newList
}

func fixTTL(ttl uint32) uint32 {
	if ttl > minimumTTL {
		return ttl
	}
	return minimumTTL
}

func (c *porkbunProvider) GetRegistrarCorrections(dc *models.DomainConfig) ([]*models.Correction, error) {
	nss, err := c.getNameservers(dc.Name)
	if err != nil {
		return nil, err
	}
	foundNameservers := strings.Join(nss, ",")

	expected := []string{}
	for _, ns := range dc.Nameservers {
		expected = append(expected, ns.Name)
	}
	sort.Strings(expected)
	expectedNameservers := strings.Join(expected, ",")

	if foundNameservers == expectedNameservers {
		return nil, nil
	}

	return []*models.Correction{
		{
			Msg: fmt.Sprintf("Update nameservers %s -> %s", foundNameservers, expectedNameservers),
			F: func() error {
				return c.updateNameservers(expected, dc.Name)
			},
		},
	}, nil
}
