/*
Copyright 2018 The Kubernetes Authors.

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.
*/

// This code is directly lifted from the Kubernetes codebase.
// For reference:
// https://github.com/kubernetes/kubernetes/blob/release-1.23/staging/src/k8s.io/kubectl/pkg/cmd/taint/utils.go#L37-L126

package lifted

import (
	"fmt"
	"strings"

	corev1 "k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/util/sets"
	"k8s.io/apimachinery/pkg/util/validation"
)

// +lifted:source=https://github.com/kubernetes/kubernetes/blob/release-1.23/staging/src/k8s.io/kubectl/pkg/cmd/taint/utils.go#L37-L73

// ParseTaints takes a spec which is an array and creates slices for new taints to be added, taints to be deleted.
// It also validates the spec. For example, the form `<key>` may be used to remove a taint, but not to add one.
func ParseTaints(spec []string) ([]corev1.Taint, []corev1.Taint, error) {
	var taints, taintsToRemove []corev1.Taint
	uniqueTaints := map[corev1.TaintEffect]sets.String{}

	for _, taintSpec := range spec {
		if strings.HasSuffix(taintSpec, "-") {
			taintToRemove, err := parseTaint(strings.TrimSuffix(taintSpec, "-"))
			if err != nil {
				return nil, nil, err
			}
			taintsToRemove = append(taintsToRemove, corev1.Taint{Key: taintToRemove.Key, Effect: taintToRemove.Effect})
		} else {
			newTaint, err := parseTaint(taintSpec)
			if err != nil {
				return nil, nil, err
			}
			// validate that the taint has an effect, which is required to add the taint
			if len(newTaint.Effect) == 0 {
				return nil, nil, fmt.Errorf("invalid taint spec: %v", taintSpec)
			}
			// validate if taint is unique by <key, effect>
			if len(uniqueTaints[newTaint.Effect]) > 0 && uniqueTaints[newTaint.Effect].Has(newTaint.Key) {
				return nil, nil, fmt.Errorf("duplicated taints with the same key and effect: %v", newTaint)
			}
			// add taint to existingTaints for uniqueness check
			if len(uniqueTaints[newTaint.Effect]) == 0 {
				uniqueTaints[newTaint.Effect] = sets.String{}
			}
			uniqueTaints[newTaint.Effect].Insert(newTaint.Key)

			taints = append(taints, newTaint)
		}
	}
	return taints, taintsToRemove, nil
}

// +lifted:source=https://github.com/kubernetes/kubernetes/blob/release-1.23/staging/src/k8s.io/kubectl/pkg/cmd/taint/utils.go#L75-L118

// parseTaint parses a taint from a string, whose form must be either
// '<key>=<value>:<effect>', '<key>:<effect>', or '<key>'.
func parseTaint(st string) (corev1.Taint, error) {
	var taint corev1.Taint

	var key string
	var value string
	var effect corev1.TaintEffect

	parts := strings.Split(st, ":")
	switch len(parts) {
	case 1:
		key = parts[0]
	case 2:
		effect = corev1.TaintEffect(parts[1])
		if err := validateTaintEffect(effect); err != nil {
			return taint, err
		}

		partsKV := strings.Split(parts[0], "=")
		if len(partsKV) > 2 {
			return taint, fmt.Errorf("invalid taint spec: %v", st)
		}
		key = partsKV[0]
		if len(partsKV) == 2 {
			value = partsKV[1]
			if errs := validation.IsValidLabelValue(value); len(errs) > 0 {
				return taint, fmt.Errorf("invalid taint spec: %v, %s", st, strings.Join(errs, "; "))
			}
		}
	default:
		return taint, fmt.Errorf("invalid taint spec: %v", st)
	}

	if errs := validation.IsQualifiedName(key); len(errs) > 0 {
		return taint, fmt.Errorf("invalid taint spec: %v, %s", st, strings.Join(errs, "; "))
	}

	taint.Key = key
	taint.Value = value
	taint.Effect = effect

	return taint, nil
}

// +lifted:source=https://github.com/kubernetes/kubernetes/blob/release-1.23/staging/src/k8s.io/kubectl/pkg/cmd/taint/utils.go#L120-L126
func validateTaintEffect(effect corev1.TaintEffect) error {
	if effect != corev1.TaintEffectNoSchedule && effect != corev1.TaintEffectPreferNoSchedule && effect != corev1.TaintEffectNoExecute {
		return fmt.Errorf("invalid taint effect: %v, unsupported taint effect", effect)
	}

	return nil
}