package tracker

import (

	"github.com/pelletier/go-toml/v2/internal/ast"

)

// KeyTracker is a tracker that keeps track of the current Key as the AST is

// walked.

type KeyTracker struct {

	k []string

}

// UpdateTable sets the state of the tracker with the AST table node.

func (t *KeyTracker) UpdateTable(node *ast.Node) {

	t.reset()

	t.Push(node)

}

// UpdateArrayTable sets the state of the tracker with the AST array table node.

func (t *KeyTracker) UpdateArrayTable(node *ast.Node) {

	t.reset()

	t.Push(node)

}

// Push the given key on the stack.

func (t *KeyTracker) Push(node *ast.Node) {

	it := node.Key()

	for it.Next() {

		t.k = append(t.k, string(it.Node().Data))

	}

}

// Pop key from stack.

func (t *KeyTracker) Pop(node *ast.Node) {

	it := node.Key()

	for it.Next() {

		t.k = t.k[:len(t.k)-1]

	}

}

// Key returns the current key

func (t *KeyTracker) Key() []string {

	k := make([]string, len(t.k))

	copy(k, t.k)

	return k

}

func (t *KeyTracker) reset() {

	t.k = t.k[:0]

}