package grs

import (
	"errors"
	"fmt"
	"net"
	"net/url"
	"regexp"
	"time"

	"gopkg.in/jmcvetta/napping.v3"
	"gopkg.in/mgo.v2/bson"
)

const (
	GRS_URL = "http://rest.db.ripe.net/search.json"
)

type GRS struct {
	ID          bson.ObjectId `bson:"_id,omitempty" json:"id"`
	Source      string        `bson:"source" json:"source"`
	IpFrom      string        `bson:"ip_from" json:"ip_from"`
	IpTo        string        `bson:"ip_to" json:"ip_to"`
	IpFromRaw   []byte        `bson:"ip_from_raw" json:"ip_from_raw"`
	IpToRaw     []byte        `bson:"ip_to_raw" json:"ip_to_raw"`
	Description string        `bson:"description" json:"description"`
	Country     string        `bson:"country" json:"country"`
	Status      string        `bson:"status" json:"status"`
	Cidr        string        `bson:"cidr" json:"cidr"`
	Name        string        `bson:"name" json:"name"`
	Org         string        `bson:"org" json:"org"`
	CreatedAt   time.Time     `bson:"created_at" json:"created_at"`
}

type GRSRaw struct {
	Service       Name          `json:"service"`
	Parameters    Parameters    `json:"parameters"`
	Objects       Objects       `json:"objects"`
	Terms         Terms         `json:"terms-and-conditions"`
	ErrorMessages ErrorMessages `json:"errormessages"`
}

type Name struct {
	Name string `json:"name"`
}

type Parameters struct {
	InverseLookup map[string]interface{} `json:"inverse-lookup"`
	TypeFilters   map[string]interface{} `json:"type-filters"`
	Flags         map[string]interface{} `json:"flags"`
	QueryStrings  QueryString            `json:"query-strings"`
	Sources       Sources                `json:"sources"`
}

type QueryString struct {
	QueryString []Value `json:"query-string"`
}

type Value struct {
	Value string `json:"value"`
}

type Sources struct {
	Ids []Id `json:"source"`
}

type Id struct {
	ID string `json:"id"`
}

type Objects struct {
	Objects []Object `json:"object"`
}

type Object struct {
	Type       string     `json:"type"`
	Link       Link       `json:"link"`
	Source     Id         `json:source"`
	PrimaryKey Attributes `json:"primary-key"`
	Attributes Attributes `json:"attributes"`
	Tags       Tags       `json:"tags"`
}

type Link struct {
	Type string `json:"type"`
	Href string `json:"href"`
}

type Attributes struct {
	Attributes []Attribute `json:"attribute"`
}

type Attribute struct {
	Link           Link   `json:"link"`
	Name           string `json:"name"`
	Value          string `json:"value"`
	ReferencedType string `json:"referenced-type"`
}

type Tags struct {
	Tags []Tag `json:"tag"`
}

type Tag struct {
	ID   string `json:"id"`
	Data string `json:"data"`
}

type Terms struct {
	Type string `json:"type"`
	Href string `json:"href"`
}

type ErrorMessages struct {
	ErrorMessage []ErrorMessage `json:"errormessage"`
}

type ErrorMessage struct {
	Severity string `json:"severity"`
	Text     string `json:"text"`
}

func Lookup(ip string) (GRS, error) {
	// var data map[string]interface{}
	var data GRSRaw

	args := url.Values{}
	args.Set("query-string", ip)
	args.Add("source", "ripe-grs")
	args.Add("source", "arin-grs")
	args.Add("source", "apnic-grs")
	args.Add("source", "lacnic-grs")
	args.Add("source", "afrinic-grs")

	resp, err := napping.Get(GRS_URL, &args, &data, nil)

	if err != nil {
		return GRS{}, errors.New(fmt.Sprint("Failed to load data from ", resp.Url, ": ", err))
	}

	if resp.Status() != 200 {
		return GRS{}, errors.New(fmt.Sprint("Failed to load data from GRS server: ", resp.Status()))
	}

	if len(data.ErrorMessages.ErrorMessage) > 0 {
		return GRS{}, errors.New(fmt.Sprint("No GRS data for ", ip, ": ", data.ErrorMessages.ErrorMessage[0].Text))
	}

	grs := GRS{}
	var grs_inetnum *Object
	var grs_route *Object
	var inetnum string

	for i, e := range data.Objects.Objects {
		switch e.Type {
		case "inetnum":
			grs_inetnum = &data.Objects.Objects[i]
		case "inet6num":
			grs_inetnum = &data.Objects.Objects[i]
		case "route":
			grs_route = &data.Objects.Objects[i]
		}
	}

	// Inetnum fields
	//
	if grs_inetnum != nil {
		for _, e := range grs_inetnum.Attributes.Attributes {
			switch e.Name {
			case "inetnum":
				inetnum = e.Value
			case "inet6num":
				inetnum = e.Value
			case "netname":
				grs.Name = e.Value
			case "descr":
				grs.Description = e.Value
			case "country":
				grs.Country = e.Value
			case "status":
				grs.Status = e.Value
			case "org":
				grs.Org = e.Value
			}
		}
	}

	// Route fields
	//
	if grs_route != nil {
		for _, e := range grs_route.Attributes.Attributes {
			switch e.Name {
			case "route":
				grs.Cidr = e.Value
			case "descr":
				grs.Description = e.Value
			}
		}
	}

	var ip_from net.IP
	var ip_to net.IP

	if inetnum != "" {

		_, network, err := net.ParseCIDR(inetnum)

		if err == nil {
			ip_from, ip_to = networkRange(network)
			grs.IpFrom = ip_from.String()
			grs.IpTo = ip_to.String()
			if grs.Cidr == "" {
				grs.Cidr = network.String()
			}
		} else {
			reg := regexp.MustCompile(`^\s*(\d+\.\d+\.\d+\.\d+)\s*-\s*(\d+\.\d+\.\d+\.\d+)\s*$`)
			matches := reg.FindAllStringSubmatch(inetnum, -1)

			if matches != nil && matches[0] != nil && matches[0][1] != "" && matches[0][2] != "" {
				grs.IpFrom = matches[0][1]
				grs.IpTo = matches[0][2]

				ip_from = net.ParseIP(grs.IpFrom)
				ip_to = net.ParseIP(grs.IpTo)

			}

		}
		grs.IpFromRaw = ip_from.To16()
		grs.IpToRaw = ip_to.To16()

	}

	return grs, nil
}

// Calculates the first and last IP addresses in an IPNet
func networkRange(network *net.IPNet) (net.IP, net.IP) {
	netIP := network.IP.To16()
	firstIP := netIP.Mask(network.Mask)
	lastIP := net.ParseIP("::").To16()
	for i := 0; i < len(lastIP); i++ {
		lastIP[i] = netIP[i] | ^network.Mask[i]
	}
	return firstIP, lastIP
}