package handlers

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"os"
	"path"
	"strings"

	"github.com/containerd/containerd"
	"github.com/openfaas/faas-provider/types"
)

const secretFilePermission = 0644

func MakeSecretHandler(c *containerd.Client, mountPath string) func(w http.ResponseWriter, r *http.Request) {

	err := os.MkdirAll(mountPath, secretFilePermission)
	if err != nil {
		log.Printf("Creating path: %s, error: %s\n", mountPath, err)
	}

	return func(w http.ResponseWriter, r *http.Request) {
		if r.Body != nil {
			defer r.Body.Close()
		}

		switch r.Method {
		case http.MethodGet:
			listSecrets(c, w, r, mountPath)
		case http.MethodPost:
			createSecret(c, w, r, mountPath)
		case http.MethodPut:
			createSecret(c, w, r, mountPath)
		case http.MethodDelete:
			deleteSecret(c, w, r, mountPath)
		default:
			w.WriteHeader(http.StatusBadRequest)
			return
		}

	}
}

func listSecrets(c *containerd.Client, w http.ResponseWriter, r *http.Request, mountPath string) {
	files, err := ioutil.ReadDir(mountPath)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	secrets := []types.Secret{}
	for _, f := range files {
		secrets = append(secrets, types.Secret{Name: f.Name()})
	}

	bytesOut, _ := json.Marshal(secrets)
	w.Write(bytesOut)
}

func createSecret(c *containerd.Client, w http.ResponseWriter, r *http.Request, mountPath string) {
	secret, err := parseSecret(r)
	if err != nil {
		log.Printf("[secret] error %s", err.Error())
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	err = ioutil.WriteFile(path.Join(mountPath, secret.Name), []byte(secret.Value), secretFilePermission)

	if err != nil {
		log.Printf("[secret] error %s", err.Error())
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
}

func deleteSecret(c *containerd.Client, w http.ResponseWriter, r *http.Request, mountPath string) {
	secret, err := parseSecret(r)
	if err != nil {
		log.Printf("[secret] error %s", err.Error())
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	err = os.Remove(path.Join(mountPath, secret.Name))

	if err != nil {
		log.Printf("[secret] error %s", err.Error())
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
}

func parseSecret(r *http.Request) (types.Secret, error) {
	secret := types.Secret{}
	bytesOut, err := ioutil.ReadAll(r.Body)
	if err != nil {
		return secret, err
	}

	err = json.Unmarshal(bytesOut, &secret)
	if err != nil {
		return secret, err
	}

	if isTraversal(secret.Name) {
		return secret, fmt.Errorf(traverseErrorSt)
	}

	return secret, err
}

const traverseErrorSt = "directory traversal found in name"

func isTraversal(name string) bool {
	return strings.Contains(name, fmt.Sprintf("%s", string(os.PathSeparator))) ||
		strings.Contains(name, "..")
}