/*
   Copyright 2014 CoreOS, Inc.

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/

package cloudsigma

import (
	"bytes"
	"encoding/base64"
	"encoding/json"
	"errors"
	"io/ioutil"
	"net"
	"os"
	"strings"

	"github.com/coreos/coreos-cloudinit/Godeps/_workspace/src/github.com/cloudsigma/cepgo"
)

const (
	userDataFieldName = "cloudinit-user-data"
)

type serverContextService struct {
	client interface {
		All() (interface{}, error)
		Key(string) (interface{}, error)
		Meta() (map[string]string, error)
		FetchRaw(string) ([]byte, error)
	}
}

func NewServerContextService() *serverContextService {
	return &serverContextService{
		client: cepgo.NewCepgo(),
	}
}

func (_ *serverContextService) IsAvailable() bool {
	productNameFile, err := os.Open("/sys/class/dmi/id/product_name")
	if err != nil {
		return false
	}
	productName := make([]byte, 10)
	_, err = productNameFile.Read(productName)

	return err == nil && string(productName) == "CloudSigma" && hasDHCPLeases()
}

func (_ *serverContextService) AvailabilityChanges() bool {
	return true
}

func (_ *serverContextService) ConfigRoot() string {
	return ""
}

func (_ *serverContextService) Type() string {
	return "server-context"
}

func (scs *serverContextService) FetchMetadata() ([]byte, error) {
	var (
		inputMetadata struct {
			Name string            `json:"name"`
			UUID string            `json:"uuid"`
			Meta map[string]string `json:"meta"`
			Nics []struct {
				Mac      string `json:"mac"`
				IPv4Conf struct {
					InterfaceType string `json:"interface_type"`
					IP            struct {
						UUID string `json:"uuid"`
					} `json:"ip"`
				} `json:"ip_v4_conf"`
				VLAN struct {
					UUID string `json:"uuid"`
				} `json:"vlan"`
			} `json:"nics"`
		}
		outputMetadata struct {
			Hostname   string            `json:"name"`
			PublicKeys map[string]string `json:"public_keys"`
			LocalIPv4  string            `json:"local-ipv4"`
			PublicIPv4 string            `json:"public-ipv4"`
		}
	)

	rawMetadata, err := scs.client.FetchRaw("")
	if err != nil {
		return []byte{}, err
	}

	err = json.Unmarshal(rawMetadata, &inputMetadata)
	if err != nil {
		return []byte{}, err
	}

	if inputMetadata.Name != "" {
		outputMetadata.Hostname = inputMetadata.Name
	} else {
		outputMetadata.Hostname = inputMetadata.UUID
	}

	if key, ok := inputMetadata.Meta["ssh_public_key"]; ok {
		splitted := strings.Split(key, " ")
		outputMetadata.PublicKeys = make(map[string]string)
		outputMetadata.PublicKeys[splitted[len(splitted)-1]] = key
	}

	for _, nic := range inputMetadata.Nics {
		if nic.IPv4Conf.IP.UUID != "" {
			outputMetadata.PublicIPv4 = nic.IPv4Conf.IP.UUID
		}
		if nic.VLAN.UUID != "" {
			if localIP, err := scs.findLocalIP(nic.Mac); err == nil {
				outputMetadata.LocalIPv4 = localIP
			}
		}
	}

	return json.Marshal(outputMetadata)
}

func (scs *serverContextService) FetchUserdata() ([]byte, error) {
	metadata, err := scs.client.Meta()
	if err != nil {
		return []byte{}, err
	}

	userData, ok := metadata[userDataFieldName]
	if ok && isBase64Encoded(userDataFieldName, metadata) {
		if decodedUserData, err := base64.StdEncoding.DecodeString(userData); err == nil {
			return decodedUserData, nil
		} else {
			return []byte{}, nil
		}
	}

	return []byte(userData), nil
}

func (scs *serverContextService) FetchNetworkConfig(a string) ([]byte, error) {
	return nil, nil
}

func (scs *serverContextService) findLocalIP(mac string) (string, error) {
	ifaces, err := net.Interfaces()
	if err != nil {
		return "", err
	}
	ifaceMac, err := net.ParseMAC(mac)
	if err != nil {
		return "", err
	}
	for _, iface := range ifaces {
		if !bytes.Equal(iface.HardwareAddr, ifaceMac) {
			continue
		}
		addrs, err := iface.Addrs()
		if err != nil {
			continue
		}

		for _, addr := range addrs {
			switch ip := addr.(type) {
			case *net.IPNet:
				if ip.IP.To4() != nil {
					return ip.IP.To4().String(), nil
				}
			}
		}
	}
	return "", errors.New("Local IP not found")
}

func isBase64Encoded(field string, userdata map[string]string) bool {
	base64Fields, ok := userdata["base64_fields"]
	if !ok {
		return false
	}

	for _, base64Field := range strings.Split(base64Fields, ",") {
		if field == base64Field {
			return true
		}
	}
	return false
}

func hasDHCPLeases() bool {
	files, err := ioutil.ReadDir("/run/systemd/netif/leases/")
	return err == nil && len(files) > 0
}