/*
Copyright 2019 The Rook Authors. All rights reserved.

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 k8sutil

import (
	"encoding/json"
	"fmt"
	"strings"

	rookalpha "github.com/rook/rook/pkg/apis/rook.io/v1alpha2"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
)

// parseMultusSelector will parse short and JSON form of individual multus
// network attachment selection annotation. Valid JSON will be unmarshaled and
// return as is, while invalid JSON will be tried using
// <namespace>/<name>@<interface> short syntax.
func parseMultusSelector(selector string) (map[string]string, error) {
	rawMap := make(map[string]string)

	err := json.Unmarshal([]byte(selector), &rawMap)

	if err != nil {
		// it can be in short form
		nsEndIndex := strings.IndexAny(selector, "/")
		if nsEndIndex != -1 {
			rawMap["namespace"] = selector[:nsEndIndex]
		}

		ifStartIndex := strings.LastIndexAny(selector, "@")
		if ifStartIndex != -1 && len(selector)-ifStartIndex > 1 {
			rawMap["interface"] = selector[ifStartIndex+1:]
		}

		if nsEndIndex != -1 && ifStartIndex != -1 && ifStartIndex-nsEndIndex > 1 {
			rawMap["name"] = selector[nsEndIndex+1 : ifStartIndex]
		} else if nsEndIndex == -1 && ifStartIndex != -1 {
			rawMap["name"] = selector[:ifStartIndex]
		} else if nsEndIndex != -1 && ifStartIndex == -1 {
			rawMap["name"] = selector[nsEndIndex+1:]
		}
	}

	if name, ok := rawMap["name"]; !ok || name == "" {
		return nil, fmt.Errorf("parseMultusSelector: missing name")
	}

	return rawMap, nil
}

// GetMultusIfName return a network interface name that multus will assign when
// connected to the multus network.
func GetMultusIfName(selector string) (string, error) {
	multusMap, _ := parseMultusSelector(selector)
	var ifName string

	if name, ok := multusMap["interfaceRequest"]; ok {
		ifName = name
	}
	if name, ok := multusMap["interface"]; ok {
		ifName = name
	}

	// fail selector without inteface name
	if ifName == "" {
		return "", fmt.Errorf("GetMultusIfname: missing interface")
	}

	return ifName, nil
}

// ApplyMultus apply multus selector to Pods
// Multus supports short and json syntax, use only one kind at a time.
func ApplyMultus(net rookalpha.NetworkSpec, objectMeta *metav1.ObjectMeta) error {
	v := make([]string, 0, 2)
	shortSyntax := false
	jsonSyntax := false

	for _, ns := range net.Selectors {
		var multusMap map[string]string
		err := json.Unmarshal([]byte(ns), &multusMap)

		if err == nil {
			jsonSyntax = true
		} else {
			shortSyntax = true
		}

		v = append(v, string(ns))
	}

	if shortSyntax && jsonSyntax {
		return fmt.Errorf("ApplyMultus: Can't mix short and JSON form")
	}

	networks := strings.Join(v, ", ")
	if jsonSyntax {
		networks = "[" + networks + "]"
	}

	t := rookalpha.Annotations{
		"k8s.v1.cni.cncf.io/networks": networks,
	}
	t.ApplyToObjectMeta(objectMeta)

	return nil
}