package huaweicloud

import (
	"encoding/json"
	"strings"
	"time"

	"github.com/StackExchange/dnscontrol/v4/models"
	"github.com/StackExchange/dnscontrol/v4/pkg/printer"
	"github.com/StackExchange/dnscontrol/v4/providers"
	"github.com/huaweicloud/huaweicloud-sdk-go-v3/core/auth/basic"
	"github.com/huaweicloud/huaweicloud-sdk-go-v3/core/region"
	dnssdk "github.com/huaweicloud/huaweicloud-sdk-go-v3/services/dns/v2"
	"github.com/huaweicloud/huaweicloud-sdk-go-v3/services/dns/v2/model"
	dnsRegion "github.com/huaweicloud/huaweicloud-sdk-go-v3/services/dns/v2/region"
)

// Support for Huawei Cloud DNS.
// API Documentation: https://www.huaweicloud.com/intl/en-us/product/dns.html

/*
Huaweicloud API DNS provider:

Info required in `creds.json`:
   - KeyId
   - SecretKey
   - Region

Record level metadata available:
   - hw_line (refer below Huawei Cloud DNS API documentation for available lines, default "default_view")
             (https://support.huaweicloud.com/intl/en-us/api-dns/en-us_topic_0085546214.html)
   - hw_weight (0-1000, default "1")
   - hw_rrset_key (default "")

*/

type huaweicloudProvider struct {
	client         *dnssdk.DnsClient
	domainByZoneID map[string]string
	zoneIDByDomain map[string]string
	region         *region.Region
}

const (
	metaWeight    = "hw_weight"
	metaLine      = "hw_line"
	metaKey       = "hw_rrset_key"
	defaultWeight = "1"
	defaultLine   = "default_view"
)

// newHuaweicloud creates the provider.
func newHuaweicloud(m map[string]string, metadata json.RawMessage) (providers.DNSServiceProvider, error) {
	auth, err := basic.NewCredentialsBuilder().
		WithAk(m["KeyId"]).
		WithSk(m["SecretKey"]).
		SafeBuild()
	if err != nil {
		return nil, err
	}
	region, err := dnsRegion.SafeValueOf(m["Region"])
	if err != nil {
		return nil, err
	}

	client, err := dnssdk.DnsClientBuilder().
		WithRegion(region).
		WithCredential(auth).
		SafeBuild()
	if err != nil {
		return nil, err
	}

	c := &huaweicloudProvider{
		client: dnssdk.NewDnsClient(client),
		region: region,
	}

	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.Unimplemented("No public api provided, but can be turned on manually in the console."),
	providers.CanGetZones:            providers.Can(),
	providers.CanUseAlias:            providers.Cannot(),
	providers.CanUseCAA:              providers.Can(),
	providers.CanUseDS:               providers.Cannot(),
	providers.CanUseLOC:              providers.Cannot(),
	providers.CanUseNAPTR:            providers.Cannot(),
	providers.CanUsePTR:              providers.Cannot(),
	providers.CanUseSRV:              providers.Can(),
	providers.CanUseSSHFP:            providers.Cannot(),
	providers.CanUseTLSA:             providers.Cannot(),
	providers.CanUseHTTPS:            providers.Cannot(),
	providers.CanUseSVCB:             providers.Cannot(),
	providers.CanUseSOA:              providers.Cannot(),
	providers.DocCreateDomains:       providers.Can(),
	providers.DocDualHost:            providers.Can(),
	providers.DocOfficiallySupported: providers.Cannot(),
}

var defaultNameServerNames = []string{
	// DNS server for regions in the Chinese mainland
	"ns1.huaweicloud-dns.com.",
	"ns1.huaweicloud-dns.cn.",
	// DNS server for countries or regions outside the Chinese mainland
	"ns1.huaweicloud-dns.net.",
	"ns1.huaweicloud-dns.org.",
}

func init() {
	const providerName = "HUAWEICLOUD"
	const providerMaintainer = "@huihuimoe"
	fns := providers.DspFuncs{
		Initializer:   newHuaweicloud,
		RecordAuditor: AuditRecords,
	}
	providers.RegisterDomainServiceProviderType(providerName, fns, features)
	providers.RegisterMaintainer(providerName, providerMaintainer)
}

// huaweicloud has request limiting like above.
// "The throttling threshold has been reached: policy user over ratelimit,limit:100,time:1 minute"
func withRetry(f func() error) {
	const maxRetries = 23
	const sleepTime = 5 * time.Second
	var currentRetry int
	for {
		err := f()
		if err == nil {
			return
		}
		if strings.Contains(err.Error(), "over ratelimit") {
			currentRetry++
			if currentRetry >= maxRetries {
				return
			}
			printer.Printf("Huaweicloud rate limit exceeded. Waiting %s to retry.\n", sleepTime)
			time.Sleep(sleepTime)
		} else {
			return
		}
	}
}

// GetNameservers returns the nameservers for a domain.
func (c *huaweicloudProvider) GetNameservers(domain string) ([]*models.Nameserver, error) {
	if err := c.getZones(); err != nil {
		return nil, err
	}

	payload := &model.ShowPublicZoneNameServerRequest{
		ZoneId: c.zoneIDByDomain[domain],
	}
	res, err := c.client.ShowPublicZoneNameServer(payload)
	if err != nil {
		return nil, err
	}
	nameservers := []string{}
	if res.Nameservers != nil {
		for _, record := range *res.Nameservers {
			if record.Hostname != nil {
				nameservers = append(nameservers, *record.Hostname)
			}
		}
	}
	if len(nameservers) != 0 {
		return models.ToNameserversStripTD(nameservers)
	}

	return models.ToNameserversStripTD(defaultNameServerNames)
}