package main

import (
	"crypto/sha512"
	"encoding/base32"
	"encoding/json"
	"errors"
	"io/ioutil"
	"net/http"
	"os"
	"path"
	"strings"

	"srs.epita.fr/fic-server/libfic"
)

type uploadedFile struct {
	URI string
}

func createExerciceFile(theme fic.Theme, exercice fic.Exercice, args []string, body []byte) (interface{}, error) {
	var uf uploadedFile
	if err := json.Unmarshal(body, &uf); err != nil {
		return nil, err
	}

	if len(uf.URI) == 0 {
		return nil, errors.New("URI not filled")
	}

	if body, err := getCloudFile(uf.URI); err != nil {
		return nil, err
	} else {
		hash := sha512.Sum512([]byte(uf.URI))
		pathname := path.Join(fic.FilesDir, strings.ToLower(base32.StdEncoding.EncodeToString(hash[:])), path.Base(uf.URI))
		if err := os.MkdirAll(path.Dir(pathname), 0777); err != nil {
			return nil, err
		}

		if err := ioutil.WriteFile(pathname, body, 0777); err != nil {
			return nil, err
		}

		return exercice.ImportFile(pathname, uf.URI)
	}
}

func getCloudFile(pathname string) ([]byte, error) {
	client := http.Client{}
	if req, err := http.NewRequest("GET", CloudDAVBase+pathname, nil); err != nil {
		return nil, err
	} else {
		req.SetBasicAuth(CloudUsername, CloudPassword)
		if resp, err := client.Do(req); err != nil {
			return nil, err
		} else {
			defer resp.Body.Close()
			if resp.StatusCode != http.StatusOK {
				return nil, errors.New(resp.Status)
			} else if body, err := ioutil.ReadAll(resp.Body); err != nil {
				return nil, err
			} else {
				return body, nil
			}
		}
	}
}