package helper

import (
	"crypto/rand"
	"fmt"
	"io"
	"io/ioutil"
	"log"
	"mime/multipart"
	"net"
	"net/http"
	"os"
	"path"
)

// IP returns IP address from requester
func IP(r *http.Request) (net.IP, error) {
	realip := r.Header.Get("x-forwarded-for")
	if realip != "" {
		return net.ParseIP(realip), nil
	}
	ip, _, err := net.SplitHostPort(r.RemoteAddr)
	if err != nil {
		return nil, err
	}
	return net.ParseIP(ip), nil
}

// Hostname returns hostname
func Hostname(ip net.IP) ([]string, error) {
	names, err := net.LookupAddr(ip.String())
	unknown := []string{"unknown host"}
	if err != nil {
		return unknown, err
	}
	if len(names) == 0 {
		return unknown, fmt.Errorf("unknown hostname for %v", ip.String())
	}
	return names, nil
}

// File reads data from file
func File(path string) ([]byte, error) {
	file, err := os.Open(path)
	if err != nil {
		log.Println("Error reading request. ", err)
		return nil, err
	}
	file.Close()
	byteValue, err := ioutil.ReadAll(file)
	if err != nil {
		log.Println(err)
		return nil, err
	}
	return byteValue, nil
}

// WriteFile Writes byte data to file
func WriteFile(path string, data []byte) error {
	file, err := os.Create(path)
	if err != nil {
		return err
	}
	if _, err = file.Write(data); err != nil {
		file.Close()
		return err
	}
	err = file.Close()
	if err != nil {
		return err
	}
	return nil
}

// UploadFile Create file from multpart form
func UploadFile(dir string, uuid uint64, file multipart.File, fileHeader *multipart.FileHeader) error {
	if _, err := os.Stat(dir); os.IsNotExist(err) {
		os.MkdirAll(dir, 0775)
		if err != nil {
			return err
		}
	}
	f, err := os.OpenFile(fmt.Sprintf("%v/%v%v", dir, uuid, path.Ext(fileHeader.Filename)), os.O_WRONLY|os.O_CREATE, 0666)
	if err != nil {
		f.Close()
		return err
	}
	defer f.Close()
	io.Copy(f, file)
	return nil
}

// GenKey Generates random 64 character string
func GenKey() {
	key := make([]byte, 32)
	_, err := rand.Read(key)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Printf("%x\n", key)
}

// GetContentType returns content mime type of file
func GetContentType(file *os.File) (string, error) {
	buffer := make([]byte, 512)
	_, err := file.Read(buffer)
	if err != nil {
		return "", err
	}
	return http.DetectContentType(buffer), nil
}