// Copyright 2015 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 digitalocean

import (
	"encoding/json"
	"fmt"
	"net"
	"strconv"

	"github.com/rancher/os/config/cloudinit/datasource"
	"github.com/rancher/os/config/cloudinit/datasource/metadata"
	"github.com/rancher/os/pkg/netconf"
)

const (
	DefaultAddress = "http://169.254.169.254/"
	apiVersion     = "metadata/v1"
	userdataURL    = apiVersion + "/user-data"
	metadataPath   = apiVersion + ".json"
)

type Address struct {
	IPAddress string `json:"ip_address"`
	Netmask   string `json:"netmask"`
	Cidr      int    `json:"cidr"`
	Gateway   string `json:"gateway"`
}

type Interface struct {
	IPv4       *Address `json:"ipv4"`
	IPv6       *Address `json:"ipv6"`
	AnchorIPv4 *Address `json:"anchor_ipv4"`
	MAC        string   `json:"mac"`
	Type       string   `json:"type"`
}

type Interfaces struct {
	Public  []Interface `json:"public"`
	Private []Interface `json:"private"`
}

type DNS struct {
	Nameservers []string `json:"nameservers"`
}

type Metadata struct {
	Hostname   string     `json:"hostname"`
	Interfaces Interfaces `json:"interfaces"`
	PublicKeys []string   `json:"public_keys"`
	DNS        DNS        `json:"dns"`
}

type MetadataService struct {
	metadata.Service
}

func NewDatasource(root string) *MetadataService {
	if root == "" {
		root = DefaultAddress
	}
	return &MetadataService{Service: metadata.NewDatasource(root, apiVersion, userdataURL, metadataPath, nil)}
}

func (ms MetadataService) AvailabilityChanges() bool {
	// TODO: if it can't find the network, maybe we can start it?
	return false
}

// Parse IPv4 netmask written in IP form (e.g. "255.255.255.0").
func ipmask(addr *Address) string {
	ip := net.ParseIP(addr.IPAddress)
	var mask net.IPMask
	if addr.Netmask != "" {
		mask = net.IPMask(net.ParseIP(addr.Netmask))
	} else {
		mask = net.CIDRMask(addr.Cidr, 32)
	}
	ipnet := net.IPNet{
		IP:   ip,
		Mask: mask,
	}
	return ipnet.String()
}

func (ms *MetadataService) FetchMetadata() (metadata datasource.Metadata, err error) {
	var data []byte
	var m Metadata

	if data, err = ms.FetchData(ms.MetadataURL()); err != nil || len(data) == 0 {
		return
	}
	if err = json.Unmarshal(data, &m); err != nil {
		return
	}

	if len(m.Interfaces.Public) > 0 {
		if m.Interfaces.Public[0].IPv4 != nil {
			metadata.PublicIPv4 = net.ParseIP(m.Interfaces.Public[0].IPv4.IPAddress)
		}
		if m.Interfaces.Public[0].IPv6 != nil {
			metadata.PublicIPv6 = net.ParseIP(m.Interfaces.Public[0].IPv6.IPAddress)
		}
	}
	if len(m.Interfaces.Private) > 0 {
		if m.Interfaces.Private[0].IPv4 != nil {
			metadata.PrivateIPv4 = net.ParseIP(m.Interfaces.Private[0].IPv4.IPAddress)
		}
		if m.Interfaces.Private[0].IPv6 != nil {
			metadata.PrivateIPv6 = net.ParseIP(m.Interfaces.Private[0].IPv6.IPAddress)
		}
	}

	metadata.NetworkConfig.Interfaces = make(map[string]netconf.InterfaceConfig)

	ethNumber := 0

	for _, eth := range m.Interfaces.Public {
		network := netconf.InterfaceConfig{}

		if eth.IPv4 != nil {
			network.Gateway = eth.IPv4.Gateway

			network.Addresses = append(network.Addresses, ipmask(eth.IPv4))
			if metadata.PublicIPv4 == nil {
				metadata.PublicIPv4 = net.ParseIP(eth.IPv4.IPAddress)
			}
		}
		if eth.AnchorIPv4 != nil {
			network.Addresses = append(network.Addresses, ipmask(eth.AnchorIPv4))
		}
		if eth.IPv6 != nil {
			network.Addresses = append(network.Addresses, fmt.Sprintf("%s/%d", eth.IPv6.IPAddress, eth.IPv6.Cidr))
			network.GatewayIpv6 = eth.IPv6.Gateway
			if metadata.PublicIPv6 == nil {
				metadata.PublicIPv6 = net.ParseIP(eth.IPv6.IPAddress)
			}
		}
		metadata.NetworkConfig.Interfaces[fmt.Sprintf("eth%d", ethNumber)] = network
		ethNumber = ethNumber + 1
	}

	for _, eth := range m.Interfaces.Private {
		network := netconf.InterfaceConfig{}
		if eth.IPv4 != nil {
			network.Gateway = eth.IPv4.Gateway

			network.Addresses = append(network.Addresses, ipmask(eth.IPv4))

			if metadata.PrivateIPv4 == nil {
				metadata.PrivateIPv4 = net.ParseIP(eth.IPv6.IPAddress)
			}
		}
		if eth.AnchorIPv4 != nil {
			network.Addresses = append(network.Addresses, ipmask(eth.AnchorIPv4))
		}
		if eth.IPv6 != nil {
			network.Addresses = append(network.Addresses, fmt.Sprintf("%s/%d", eth.IPv6.IPAddress, eth.IPv6.Cidr))
			network.GatewayIpv6 = eth.IPv6.Gateway
			if metadata.PrivateIPv6 == nil {
				metadata.PrivateIPv6 = net.ParseIP(eth.IPv6.IPAddress)
			}
		}
		metadata.NetworkConfig.Interfaces[fmt.Sprintf("eth%d", ethNumber)] = network
		ethNumber = ethNumber + 1
	}

	metadata.NetworkConfig.DNS.Nameservers = m.DNS.Nameservers

	metadata.Hostname = m.Hostname
	metadata.SSHPublicKeys = map[string]string{}
	for i, key := range m.PublicKeys {
		metadata.SSHPublicKeys[strconv.Itoa(i)] = key
	}

	return
}

func (ms MetadataService) Type() string {
	return "digitalocean-metadata-service"
}