package main

import (
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"path"

	"github.com/mitchellh/go-homedir"
)

// createDirIfNotExists checks for the existence of a directory and creates it along with all required parents if not.
// It returns an error if the directory (or parents) couldn't be created and nil if it worked fine or if the path already exists.
func createDirIfNotExists(path string) error {
	if _, err := os.Stat(path); os.IsNotExist(err) {
		return os.MkdirAll(path, os.ModePerm)
	}
	return nil
}

// createClusterDir creates a directory with the cluster name under $HOME/.config/k3d/<cluster_name>.
// The cluster directory will be used e.g. to store the kubeconfig file.
func createClusterDir(name string) {
	clusterPath, _ := getClusterDir(name)
	if err := createDirIfNotExists(clusterPath); err != nil {
		log.Fatalf("ERROR: couldn't create cluster directory [%s] -> %+v", clusterPath, err)
	}
}

// deleteClusterDir contrary to createClusterDir, this deletes the cluster directory under $HOME/.config/k3d/<cluster_name>
func deleteClusterDir(name string) {
	clusterPath, _ := getClusterDir(name)
	if err := os.RemoveAll(clusterPath); err != nil {
		log.Printf("WARNING: couldn't delete cluster directory [%s]. You might want to delete it manually.", clusterPath)
	}
}

// getClusterDir returns the path to the cluster directory which is $HOME/.config/k3d/<cluster_name>
func getClusterDir(name string) (string, error) {
	homeDir, err := homedir.Dir()
	if err != nil {
		log.Printf("ERROR: Couldn't get user's home directory")
		return "", err
	}
	return path.Join(homeDir, ".config", "k3d", name), nil
}

// printClusters prints the names of existing clusters
func printClusters() {
	clusters, err := getClusters()
	if err != nil {
		log.Fatalf("ERROR: Couldn't list clusters -> %+v", err)
	}
	fmt.Println("NAME")
	// TODO: user docker client to get state of cluster
	for _, cluster := range clusters {
		fmt.Println(cluster)
	}
}

// getClusters returns a list of cluster names which are folder names in the config directory
func getClusters() ([]string, error) {
	homeDir, err := homedir.Dir()
	if err != nil {
		log.Printf("ERROR: Couldn't get user's home directory")
		return nil, err
	}
	configDir := path.Join(homeDir, ".config", "k3d")
	files, err := ioutil.ReadDir(configDir)
	if err != nil {
		log.Printf("ERROR: Couldn't list files in [%s]", configDir)
		return nil, err
	}
	clusters := []string{}
	for _, file := range files {
		if file.IsDir() {
			clusters = append(clusters, file.Name())
		}
	}
	return clusters, nil
}