package app

import (
	"errors"
	"fmt"
	"io"
	"net/http"
	"os"
	"path/filepath"
	"strings"
)

func (s *Server) saveUpload(r *http.Request, field string) (string, bool, error) {
	if !strings.HasPrefix(r.Header.Get("Content-Type"), "multipart/form-data") {
		return "", false, nil
	}
	file, header, err := r.FormFile(field)
	if errors.Is(err, http.ErrMissingFile) {
		return "", false, nil
	}
	if err != nil {
		return "", false, err
	}
	defer file.Close()

	ext := strings.ToLower(filepath.Ext(header.Filename))
	switch ext {
	case ".jpg", ".jpeg", ".png", ".webp", ".gif":
	default:
		return "", false, fmt.Errorf("unsupported image type")
	}
	name, err := randomToken()
	if err != nil {
		return "", false, err
	}
	filename := name + ext
	target := filepath.Join(s.cfg.UploadDir, filename)
	out, err := os.OpenFile(target, os.O_WRONLY|os.O_CREATE|os.O_EXCL, 0o644)
	if err != nil {
		return "", false, err
	}
	defer out.Close()
	written, err := io.Copy(out, io.LimitReader(file, maxUploadBytes+1))
	if err != nil {
		return "", false, err
	}
	if written > maxUploadBytes {
		_ = out.Close()
		_ = os.Remove(target)
		return "", false, fmt.Errorf("is too large")
	}
	return "/uploads/" + filename, true, nil
}

func parseAdminForm(w http.ResponseWriter, r *http.Request, maxBytes int64) error {
	r.Body = http.MaxBytesReader(w, r.Body, maxBytes)
	if strings.HasPrefix(r.Header.Get("Content-Type"), "multipart/form-data") {
		return r.ParseMultipartForm(maxBytes)
	}
	return r.ParseForm()
}