package eureka

import (
	"encoding/xml"
	"fmt"
	"strconv"

	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promscrape/discoveryutils"

	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promauth"
)

const appsAPIPath = "/apps"

// SDConfig represents service discovery config for eureka.
//
// See https://prometheus.io/docs/prometheus/latest/configuration/configuration/#eureka
type SDConfig struct {
	Server     string              `yaml:"server,omitempty"`
	Token      *string             `yaml:"token"`
	Datacenter string              `yaml:"datacenter"`
	Scheme     string              `yaml:"scheme,omitempty"`
	Username   string              `yaml:"username"`
	Password   string              `yaml:"password"`
	TLSConfig  *promauth.TLSConfig `yaml:"tls_config,omitempty"`
	// RefreshInterval time.Duration `yaml:"refresh_interval"`
	// refresh_interval is obtained from `-promscrape.ec2SDCheckInterval` command-line option.
	Port *int `yaml:"port,omitempty"`
}

type applications struct {
	Applications []Application `xml:"application"`
}

// Application - eureka application https://github.com/Netflix/eureka/wiki/Eureka-REST-operations/
type Application struct {
	Name      string     `xml:"name"`
	Instances []Instance `xml:"instance"`
}

// Port - eureka instance port.
type Port struct {
	Port    int  `xml:",chardata"`
	Enabled bool `xml:"enabled,attr"`
}

// Instance - eureka instance https://github.com/Netflix/eureka/wiki/Eureka-REST-operations
type Instance struct {
	HostName         string         `xml:"hostName"`
	HomePageURL      string         `xml:"homePageUrl"`
	StatusPageURL    string         `xml:"statusPageUrl"`
	HealthCheckURL   string         `xml:"healthCheckUrl"`
	App              string         `xml:"app"`
	IPAddr           string         `xml:"ipAddr"`
	VipAddress       string         `xml:"vipAddress"`
	SecureVipAddress string         `xml:"secureVipAddress"`
	Status           string         `xml:"status"`
	Port             Port           `xml:"port"`
	SecurePort       Port           `xml:"securePort"`
	DataCenterInfo   DataCenterInfo `xml:"dataCenterInfo"`
	Metadata         MetaData       `xml:"metadata"`
	CountryID        int            `xml:"countryId"`
	InstanceID       string         `xml:"instanceId"`
}

// MetaData - eureka objects metadata.
type MetaData struct {
	Items []Tag `xml:",any"`
}

// Tag - eureka metadata tag - list of k/v values.
type Tag struct {
	XMLName xml.Name
	Content string `xml:",innerxml"`
}

// DataCenterInfo -eureka datacentre metadata
type DataCenterInfo struct {
	Name     string   `xml:"name"`
	Metadata MetaData `xml:"metadata"`
}

// GetLabels returns Eureka labels according to sdc.
func GetLabels(sdc *SDConfig, baseDir string) ([]map[string]string, error) {
	cfg, err := getAPIConfig(sdc, baseDir)
	if err != nil {
		return nil, fmt.Errorf("cannot get API config: %w", err)
	}
	data, err := getAPIResponse(cfg, appsAPIPath)
	if err != nil {
		return nil, err
	}
	apps, err := parseAPIResponse(data)
	if err != nil {
		return nil, err
	}
	port := 80
	if sdc.Port != nil {
		port = *sdc.Port
	}
	return addInstanceLabels(apps, port), nil
}

func addInstanceLabels(apps *applications, port int) []map[string]string {
	var ms []map[string]string
	for _, app := range apps.Applications {
		for _, instance := range app.Instances {
			instancePort := port
			if instance.Port.Port != 0 {
				instancePort = instance.Port.Port
			}
			targetAddress := discoveryutils.JoinHostPort(instance.HostName, instancePort)
			m := map[string]string{
				"__address__":                                   targetAddress,
				"instance":                                      instance.InstanceID,
				"__meta_eureka_app_name":                        app.Name,
				"__meta_eureka_app_instance_hostname":           instance.HostName,
				"__meta_eureka_app_instance_homepage_url":       instance.HomePageURL,
				"__meta_eureka_app_instance_statuspage_url":     instance.StatusPageURL,
				"__meta_eureka_app_instance_healthcheck_url":    instance.HealthCheckURL,
				"__meta_eureka_app_instance_ip_addr":            instance.IPAddr,
				"__meta_eureka_app_instance_vip_address":        instance.VipAddress,
				"__meta_eureka_app_instance_secure_vip_address": instance.SecureVipAddress,
				"__meta_eureka_app_instance_status":             instance.Status,
				"__meta_eureka_app_instance_country_id":         strconv.Itoa(instance.CountryID),
				"__meta_eureka_app_instance_id":                 instance.InstanceID,
			}
			if instance.Port.Port != 0 {
				m["__meta_eureka_app_instance_port"] = strconv.Itoa(instance.Port.Port)
				m["__meta_eureka_app_instance_port_enabled"] = strconv.FormatBool(instance.Port.Enabled)
			}
			if instance.SecurePort.Port != 0 {
				m["__meta_eureka_app_instance_secure_port"] = strconv.Itoa(instance.SecurePort.Port)
				m["__meta_eureka_app_instance_secure_port_enabled"] = strconv.FormatBool(instance.SecurePort.Enabled)

			}
			if len(instance.DataCenterInfo.Name) > 0 {
				m["__meta_eureka_app_instance_datacenterinfo_name"] = instance.DataCenterInfo.Name
				for _, tag := range instance.DataCenterInfo.Metadata.Items {
					m["__meta_eureka_app_instance_datacenterinfo_metadata_"+discoveryutils.SanitizeLabelName(tag.XMLName.Local)] = tag.Content
				}
			}
			for _, tag := range instance.Metadata.Items {
				m["__meta_eureka_app_instance_metadata_"+discoveryutils.SanitizeLabelName(tag.XMLName.Local)] = tag.Content
			}
			ms = append(ms, m)
		}
	}
	return ms
}