/*
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 util

import (
	"fmt"
	"os"
	"os/user"
	"path/filepath"
	"strconv"

	"github.com/blang/semver"
	"github.com/docker/go-units"
	"github.com/pkg/errors"
)

const (
	downloadURL = "https://storage.googleapis.com/minikube/releases/%s/minikube-%s-amd64%s"
)

// CalculateSizeInMB returns the number of MB in the human readable string
func CalculateSizeInMB(humanReadableSize string) (int, error) {
	_, err := strconv.ParseInt(humanReadableSize, 10, 64)
	if err == nil {
		humanReadableSize += "mb"
	}
	// parse the size suffix binary instead of decimal so that 1G -> 1024MB instead of 1000MB
	size, err := units.RAMInBytes(humanReadableSize)
	if err != nil {
		return 0, fmt.Errorf("FromHumanSize: %v", err)
	}

	return int(size / units.MiB), nil
}

// GetBinaryDownloadURL returns a suitable URL for the platform
func GetBinaryDownloadURL(version, platform string) string {
	switch platform {
	case "windows":
		return fmt.Sprintf(downloadURL, version, platform, ".exe")
	default:
		return fmt.Sprintf(downloadURL, version, platform, "")
	}
}

// ChownR does a recursive os.Chown
func ChownR(path string, uid, gid int) error {
	return filepath.Walk(path, func(name string, info os.FileInfo, err error) error {
		if err == nil {
			err = os.Chown(name, uid, gid)
		}
		return err
	})
}

// MaybeChownDirRecursiveToMinikubeUser changes ownership of a dir, if requested
func MaybeChownDirRecursiveToMinikubeUser(dir string) error {
	if os.Getenv("CHANGE_MINIKUBE_NONE_USER") != "" && os.Getenv("SUDO_USER") != "" {
		username := os.Getenv("SUDO_USER")
		usr, err := user.Lookup(username)
		if err != nil {
			return errors.Wrap(err, "Error looking up user")
		}
		uid, err := strconv.Atoi(usr.Uid)
		if err != nil {
			return errors.Wrapf(err, "Error parsing uid for user: %s", username)
		}
		gid, err := strconv.Atoi(usr.Gid)
		if err != nil {
			return errors.Wrapf(err, "Error parsing gid for user: %s", username)
		}
		if err := ChownR(dir, uid, gid); err != nil {
			return errors.Wrapf(err, "Error changing ownership for: %s", dir)
		}
	}
	return nil
}

// ParseKubernetesVersion parses the Kubernetes version
func ParseKubernetesVersion(version string) (semver.Version, error) {
	return semver.Make(version[1:])
}