node/node.go

package node

import (
	"encoding/json"
	"fmt"
	"io"
	"os"
	"reflect"
	"strings"
)

type Node struct {
	name     string
	data     any
	parent   *Node
	children []*Node
}

func NewNode() *Node {
	return &Node{}
}

func NewNodeWithName(name string) *Node {
	return &Node{name: name}
}

func NewNodeWithData(data any) *Node {
	return &Node{data: data}
}

func NewNodeWithNameAndData(name string, data any) *Node {
	return &Node{name: name, data: data}
}

func NewNodeWithDataAndName(data any, name string) *Node {
	return &Node{name: name, data: data}
}

func NewNodeFromJSON(data []byte) (*Node, error) {
	n := NewNode()
	err := json.Unmarshal(data, &n)
	if err != nil {
		return nil, err
	}
	return n, nil
}

func NewNodeFromFile(name string) (*Node, error) {
	pay, err := os.ReadFile(name)
	if err != nil {
		return nil, err
	}
	return NewNodeFromJSON(pay)
}

func NewNodeFromStream(r io.Reader) (*Node, error) {
	doc := json.NewDecoder(r)
	root := NewNode()
	work := root
	var (
		depth     int  = 0
		maplike   bool = false
		lastToken string
	)
	for {
		t, err := doc.Token()
		if err == io.EOF {
			break
		}
		if err != nil {
			return nil, err
		}
		delim, ok := t.(json.Delim)
		if ok {
			if rune(delim) == '{' || rune(delim) == '[' {
				work = work.NewKid()
				depth++
				if rune(delim) == '{' {
					maplike = true
				} else {
					maplike = false
				}
			} else if rune(delim) == '}' || rune(delim) == ']' {
				if work.Parent() != nil {
					depth--
					work = work.Parent()
					maplike = work.IsMapLike()
				}
			}
		} else {
			text := fmt.Sprintf("%v", t)
			if lastToken == "" {
				lastToken = text
			} else {
				lastToken = ""
			}
			fmt.Printf("%s%s", strings.Repeat("  ", depth), text)
			if doc.More() {
				fmt.Printf(" (more)")
			}
			fmt.Printf("\n")
			if work.Name() == "" && maplike {
				work.Name(text)
			} else if maplike {
				if !doc.More() {
					work.Data(t.(any))
				} else {
					work.NewKidWithData(t.(any))
				}
			} else if !maplike {
				work.NewKidWithData(t.(any))
			}
		}
	}
	return root, nil
}

func (n *Node) Name(name ...string) string {
	if len(name) != 0 {
		n.name = name[0]
	}
	return n.name
}

func (n *Node) Data(data ...any) any {
	if len(data) != 0 {
		n.data = data[0]
	}
	return n.data
}

func (n *Node) Len() int {
	return len(n.children)
}

func (n *Node) Parent(parent ...*Node) *Node {
	if len(parent) != 0 {
		n.parent = parent[0]
	}
	return n.parent
}

func (n *Node) Root() *Node {
	if n.Parent() == nil {
		return n
	}
	at := n.Parent()
	for at.Parent() != nil {
		at = at.Parent()
	}
	return at
}

func (n *Node) Depth() int {
	if n.Parent() == nil {
		return 0
	}
	var (
		depth int   = 1
		at    *Node = n.Parent()
	)
	for at.Parent() != nil {
		depth++
		at = at.Parent()
	}
	return depth
}

func (n *Node) Kids() []*Node {
	return n.children
}

func (n *Node) AddKid(kid *Node) bool {
	for _, k := range n.children {
		if k == kid {
			return false
		}
	}
	kid.Parent(n)
	n.children = append(n.children, kid)
	return true
}

func (n *Node) NewKid() *Node {
	k := &Node{}
	n.AddKid(k)
	return k
}

func (n *Node) NewKidWithName(name string) *Node {
	k := n.NewKid()
	k.Name(name)
	return k
}

func (n *Node) NewKidWithData(data any) *Node {
	k := n.NewKid()
	k.Data(data)
	return k
}

func (n *Node) NewKidWithNameAndData(name string, data any) *Node {
	k := n.NewKid()
	k.Name(name)
	k.Data(data)
	return k
}

func (n *Node) NewKidWithDataAndName(data any, name string) *Node {
	k := n.NewKid()
	k.Name(name)
	k.Data(data)
	return k
}

func (n *Node) Index() int {
	if n.Parent() == nil { // There is no parent, so it's not known
		return -1
	}
	// Iterate thru the children of the parent to find ourselves
	for i, kid := range n.Parent().Kids() {
		if kid == n {
			return i
		}
	}
	// Ok we for some reason are not in that list, so it's not known
	return -1
}

func (n *Node) Kid(index int) *Node {
	if n == nil || index > n.Len() || index < 0 {
		return nil
	}
	return n.children[index]
}

func (n *Node) KidByName(name string, recurse ...bool) *Node {
	for _, kid := range n.children {
		if kid.name == name {
			return kid
		}
	}
	if len(recurse) != 0 {
		if recurse[0] {
			for _, kid := range n.children {
				r := kid.KidByName(name, recurse...)
				if r != nil {
					return r
				}
			}
		}
	}
	return nil
}

func (n *Node) RemoveKid(index int) bool {
	if index > n.Len() || index < 0 {
		return false
	}
	n.children[index].Parent(nil)
	_, ok := arrayDelete(&n.children, index)
	return ok
}

func (n *Node) RemoveAllKids() {
	for _, kid := range n.children {
		kid.Parent(nil)
	}
	n.children = []*Node{}
}

func (n *Node) Detach() bool {
	if n.Parent() != nil {
		return false
	}
	index := n.Index()
	if index == -1 {
		return false
	}
	return n.Parent().RemoveKid(index)
}

func (n *Node) Destroy() {
	if n.Parent() != nil {
		n.Detach()
	}
	n.Data(nil)
	n.Name("")
	for _, kid := range n.children {
		kid.Destroy()
	}
}

// Checks if the children of this node are better represented as a map or an array
//
// This is determined by:
//
// * Totaling number of children without names
//
// * Comparing the percent of children without names to total children (if less than 50% use a map, if more than 50% use an array)
func (n *Node) IsMapLike() bool {
	if n.Len() == 0 {
		return false
	}
	var (
		total  int = n.Len() // number of children
		noname int = 0       // number of children with no name
	)
	for _, kid := range n.Kids() {
		if len(kid.Name()) == 0 { // When it has no name it's not map-like
			noname += 1
		}
	}
	// Form a percent of no name children and compare it to less than 50%
	return int((float32(noname)/float32(total))*100.0) <= 50
}

func (n *Node) from(A any) {
	switch reflect.TypeOf(A).Kind() {
	case reflect.Map:
		// Ok, key, value
		// key == name, value if not a map, array, slice is data
		m := A.(map[string]any)
		for k, v := range m {
			switch reflect.TypeOf(v).Kind() {
			case reflect.Map, reflect.Array, reflect.Slice:
				if n.Depth() != 0 || len(m) > 1 {
					// New kid, with name, and recurse
					kid := n.NewKidWithName(k)
					kid.from(v)
				} else {
					// This is within the "root" node
					n.Name(k)
					n.from(v)
				}
			default:
				// New kid, with name, and data
				n.NewKidWithNameAndData(k, v)
			}
		}
	case reflect.Array, reflect.Slice:
		// Ok, values
		// no name (use index), value if not a map, array, slice is data
		a := A.([]any)
		for idx, v := range a {
			switch reflect.TypeOf(v).Kind() {
			case reflect.Map, reflect.Array, reflect.Slice:
				if n.Depth() != 0 || len(a) > 1 {
					kid := n.NewKidWithName(fmt.Sprintf("%d", idx))
					kid.from(v)
				} else {
					n.Name(fmt.Sprintf("%d", idx))
					n.from(v)
				}
			default:
				n.NewKidWithNameAndData(fmt.Sprintf("%d", idx), v)
			}
		}
	default:
		// Ok it's just a single value (most likely)
		n.Data(A)
	}
}

func (n *Node) ToMap() any {
	if len(n.Name()) != 0 && n.Len() != 0 { // Name + Children
		if n.IsMapLike() {
			// Map
			m := map[string]any{}
			for i, kid := range n.children {
				if len(kid.Name()) != 0 {
					m[kid.Name()] = kid.ToMap()
				} else {
					m[fmt.Sprint(i)] = kid.ToMap()
				}
			}
			if n.Depth() != 0 {
				return m
			} else {
				return map[string]any{
					n.Name(): m,
				}
			}
		} else {
			// Array
			a := []any{}
			for _, kid := range n.children {
				a = append(a, kid.ToMap())
			}
			if n.Depth() != 0 {
				return a
			} else {
				return map[string]any{
					n.Name(): a,
				}
			}
		}
	} else if len(n.Name()) == 0 && n.Len() != 0 { // No Name + Children
		if n.IsMapLike() {
			// Map
			m := map[string]any{}
			for i, kid := range n.children {
				if len(kid.Name()) != 0 {
					m[kid.Name()] = kid.ToMap()
				} else {
					m[fmt.Sprint(i)] = kid.ToMap()
				}
			}
			return m
		} else {
			// Array
			a := []any{}
			for _, kid := range n.children {
				a = append(a, kid.ToMap())
			}
			if n.Depth() != 0 {
				return a
			} else {
				return map[string]any{
					fmt.Sprint(n.Index()): a,
				}
			}
		}
	} else if n.Data() != nil {
		if n.Depth() != 0 || len(n.Name()) == 0 {
			return n.Data()
		} else {
			return map[string]any{
				n.Name(): n.Data(),
			}
		}
	}
	return nil
}

// Marshals the results from ToMap
func (n *Node) MarshalJSON() ([]byte, error) {
	return json.Marshal(n.ToMap())
}

// Unmarshal function
func (n *Node) UnmarshalJSON(pay []byte) error {
	var m map[string]any
	err := json.Unmarshal(pay, &m)
	if err != nil {
		return err
	}
	n.Destroy()
	// In this case, the struct isn't in a invalid state, it's just a reset
	n.from(m)
	return nil
}