// Copyright 2021 Google LLC
//
// 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 kubeconfig

import (
	"errors"
	"fmt"
	"slices"

	"sigs.k8s.io/kustomize/kyaml/yaml"
)

func (k *Kubeconfig) contextsNode() (*yaml.RNode, error) {
	contexts, err := k.config.Pipe(yaml.Get("contexts"))
	if err != nil {
		return nil, err
	}
	if contexts == nil {
		return nil, errors.New("\"contexts\" entry is nil")
	} else if contexts.YNode().Kind != yaml.SequenceNode {
		return nil, errors.New("\"contexts\" is not a sequence node")
	}
	return contexts, nil
}

func (k *Kubeconfig) contextNode(name string) (*yaml.RNode, error) {
	contexts, err := k.contextsNode()
	if err != nil {
		return nil, err
	}
	context, err := contexts.Pipe(yaml.Lookup("[name=" + name + "]"))
	if err != nil {
		return nil, err
	}
	if context == nil {
		return nil, fmt.Errorf("context with name \"%s\" not found", name)
	}
	return context, nil
}

func (k *Kubeconfig) ContextNames() ([]string, error) {
	contexts, err := k.config.Pipe(yaml.Get("contexts"))
	if err != nil {
		return nil, fmt.Errorf("failed to get contexts: %w", err)
	}
	if contexts == nil {
		return nil, nil
	}
	names, err := contexts.ElementValues("name")
	if err != nil {
		return nil, fmt.Errorf("failed to get context names: %w", err)
	}
	return names, nil
}

func (k *Kubeconfig) ContextExists(name string) (bool, error) {
	names, err := k.ContextNames()
	if err != nil {
		return false, err
	}
	return slices.Contains(names, name), nil
}