// Copyright 2024 Matthew Rich <matthewrich.conf@gmail.com>. All rights reserved.
 
package identity

import (
  "os"
  "fmt"
  "strings"
  "net/url"
  "feudal/sequence"
)

var Serial sequence.Serial32

var spid uint64
var serial uint64
var hostname string

type Addresser interface {
  Address() string
}

type Identifier interface {
  Addresser
  Instance() string
  Path() string
  Hostname() string
  String() string
  Parent() Identifier
  CreateChild(string) Identifier
}

type Id struct {
  parent Identifier
  Name string
  url *url.URL
  instance string
}

func init() {
  Serial = sequence.NewSerial32()
  spid = uint64(os.Getpid()) << 32
  hostname, _ = os.Hostname()
}

func New(parent Identifier, name string) Identifier {
  url,_ := url.Parse(parent.Address())
  url.Path += "/" + name
  i := &Id{ parent: parent, Name: name, url: url, instance: InstanceId() }
  return i
}

func NewRoot(name string) Identifier {
  return &Id{ parent: nil, Name: name, url: &url.URL{ Scheme: "feudal", User: url.User(name), Host: hostname, Path: "" }, instance: InstanceId() }
}

func NewFromAddress(address string) Identifier {
  id := &Id{ parent: nil, instance: InstanceId() }
  id.url,_ = url.Parse(address)

  elements := strings.Split(id.url.Path, "/")
  le := len(elements)

  if le == 0 {
    id.Name = id.url.User.Username()
  } else {
    id.Name = elements[le - 1]
  }
  return id
}

func InstanceId() string {
  return fmt.Sprintf("%x", spid | uint64(Serial()))
}

func (i *Id) Instance() string {
  return i.instance
}

func (i *Id) Path() string {
  return i.url.Path
}

func (i *Id) Hostname() string {
  return i.url.Hostname()
}

func (parent *Id) CreateChild(name string) Identifier {
  url,_ := url.Parse(parent.Address())
  url.Path += "/" + name
  i := &Id{ parent: parent, Name: name, url: url, instance: InstanceId() }
  return i
}

func (i *Id) Parent() Identifier {
  return i.parent
}

func (i *Id) Elements() []string {
  return strings.Split(i.url.Path, "/")
}

func (i *Id) String() string {
  return i.Address() + "#" + i.instance
}

func (i *Id) Address() string {
  return i.url.String()
}