package ssh

import (
	"fmt"
	"net"
	"strings"

	"github.com/hashicorp/vault/logical"
	"github.com/hashicorp/vault/logical/framework"
)

func pathLookup(b *backend) *framework.Path {
	return &framework.Path{
		Pattern: "lookup",
		Fields: map[string]*framework.FieldSchema{
			"ip": &framework.FieldSchema{
				Type:        framework.TypeString,
				Description: "IP address of target",
			},
		},
		Callbacks: map[logical.Operation]framework.OperationFunc{
			logical.WriteOperation: b.pathLookupWrite,
		},
		HelpSynopsis:    pathLookupSyn,
		HelpDescription: pathLookupDesc,
	}
}

func (b *backend) pathLookupWrite(req *logical.Request, d *framework.FieldData) (*logical.Response, error) {
	ipAddr := d.Get("ip").(string)
	if ipAddr == "" {
		return logical.ErrorResponse("Missing 'ip'"), nil
	}
	ip := net.ParseIP(ipAddr)
	if ip == nil {
		return logical.ErrorResponse(fmt.Sprintf("Invalid IP '%s'", ip.String())), nil
	}

	keys, err := req.Storage.List("policy/")
	if err != nil {
		return nil, err
	}
	if len(keys) == 0 {
		return &logical.Response{
			Data: map[string]interface{}{
				"roles": "",
			},
		}, nil
	}

	var matchingRoles []string
	for _, item := range keys {
		if contains, _ := containsIP(req.Storage, item, ip.String()); contains {
			matchingRoles = append(matchingRoles, item)
		}
	}
	return &logical.Response{
		Data: map[string]interface{}{
			"roles": matchingRoles,
		},
	}, nil
}

func containsIP(s logical.Storage, roleName string, ip string) (bool, error) {
	if roleName == "" || ip == "" {
		return false, fmt.Errorf("invalid parameters")
	}
	roleEntry, err := s.Get("policy/" + roleName)
	if err != nil {
		return false, fmt.Errorf("error retrieving role '%s'", err)
	}
	if roleEntry == nil {
		return false, fmt.Errorf("role '%s' not found", roleName)
	}
	var role sshRole
	if err := roleEntry.DecodeJSON(&role); err != nil {
		return false, fmt.Errorf("error decoding role '%s'", roleName)
	}
	ipMatched := false
	for _, item := range strings.Split(role.CIDR, ",") {
		_, cidrIPNet, err := net.ParseCIDR(item)
		if err != nil {
			return false, fmt.Errorf("Invalid cidr entry '%s'", item)
		}
		ipMatched = cidrIPNet.Contains(net.ParseIP(ip))
		if ipMatched {
			break
		}
	}
	return ipMatched, nil
}

const pathLookupSyn = `
Lists 'roles' that can be used to create a dynamic key.
`

const pathLookupDesc = `
CIDR blocks will be associated with multiple 'roles'.
This endpoint lists all the 'roles' that are associated with the supplied IP address.
`