/*
Copyright 2016 The Kubernetes 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 transformer

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"math/rand"
	"os"
	"strings"

	"github.com/Sirupsen/logrus"
	"github.com/ghodss/yaml"
	"github.com/kubernetes-incubator/kompose/pkg/kobject"

	"k8s.io/kubernetes/pkg/api"
	"k8s.io/kubernetes/pkg/api/unversioned"
	"k8s.io/kubernetes/pkg/runtime"
)

const letterBytes = "abcdefghijklmnopqrstuvwxyz0123456789"

// RandStringBytes generates randomly n-character string
func RandStringBytes(n int) string {
	b := make([]byte, n)
	for i := range b {
		b[i] = letterBytes[rand.Intn(len(letterBytes))]
	}
	return string(b)
}

// Create the file to write to if --out is specified
func CreateOutFile(out string) *os.File {
	var f *os.File
	var err error
	if len(out) != 0 {
		f, err = os.Create(out)
		if err != nil {
			logrus.Fatalf("error opening file: %v", err)
		}
	}
	return f
}

// parseVolume parse a given volume, which might be [name:][host:]container[:access_mode]
func ParseVolume(volume string) (name, host, container, mode string, err error) {
	separator := ":"
	volumeStrings := strings.Split(volume, separator)
	if len(volumeStrings) == 0 {
		return
	}
	// Set name if existed
	if !isPath(volumeStrings[0]) {
		name = volumeStrings[0]
		volumeStrings = volumeStrings[1:]
	}
	if len(volumeStrings) == 0 {
		err = fmt.Errorf("invalid volume format: %s", volume)
		return
	}
	if volumeStrings[len(volumeStrings)-1] == "rw" || volumeStrings[len(volumeStrings)-1] == "ro" {
		mode = volumeStrings[len(volumeStrings)-1]
		volumeStrings = volumeStrings[:len(volumeStrings)-1]
	}
	container = volumeStrings[len(volumeStrings)-1]
	volumeStrings = volumeStrings[:len(volumeStrings)-1]
	if len(volumeStrings) == 1 {
		host = volumeStrings[0]
	}
	if !isPath(container) || (len(host) > 0 && !isPath(host)) || len(volumeStrings) > 1 {
		err = fmt.Errorf("invalid volume format: %s", volume)
		return
	}
	return
}

func isPath(substring string) bool {
	return strings.Contains(substring, "/")
}

// Configure label
func ConfigLabels(name string) map[string]string {
	return map[string]string{"service": name}
}

// Configure annotations
func ConfigAnnotations(service kobject.ServiceConfig) map[string]string {
	annotations := map[string]string{}
	for key, value := range service.Annotations {
		annotations[key] = value
	}

	return annotations
}

// Transform data to json/yaml
func TransformData(obj runtime.Object, GenerateYaml bool) ([]byte, error) {
	//  Convert to versioned object
	objectVersion := obj.GetObjectKind().GroupVersionKind()
	version := unversioned.GroupVersion{Group: objectVersion.Group, Version: objectVersion.Version}
	versionedObj, err := api.Scheme.ConvertToVersion(obj, version)
	if err != nil {
		return nil, err
	}

	// convert data to json / yaml
	data, err := json.MarshalIndent(versionedObj, "", "  ")
	if GenerateYaml == true {
		data, err = yaml.Marshal(versionedObj)
	}
	if err != nil {
		return nil, err
	}
	logrus.Debugf("%s\n", data)
	return data, nil
}

// Either print to stdout or to file/s
func Print(name, trailing string, data []byte, toStdout, generateYaml bool, f *os.File) string {

	file := ""
	if generateYaml {
		file = fmt.Sprintf("%s-%s.yaml", name, trailing)
	} else {
		file = fmt.Sprintf("%s-%s.json", name, trailing)
	}
	if toStdout {
		fmt.Fprintf(os.Stdout, "%s\n", string(data))
		return ""
	} else if f != nil {
		// Write all content to a single file f
		if _, err := f.WriteString(fmt.Sprintf("%s\n", string(data))); err != nil {
			logrus.Fatalf("Failed to write %s to file: %v", trailing, err)
		}
		f.Sync()
	} else {
		// Write content separately to each file
		if err := ioutil.WriteFile(file, []byte(data), 0644); err != nil {
			logrus.Fatalf("Failed to write %s: %v", trailing, err)
		}
		logrus.Printf("file %q created", file)
	}
	return file
}
