package mail

import (
	"context"
	"errors"
	"io"
	"path"
	"strconv"
	"strings"
)

// DriveUploader copies mail attachment bytes into a user's Nextcloud drive.
type DriveUploader interface {
	EnsureNextcloudFolder(ctx context.Context, email, sub, displayName, folderPath string) error
	UploadFile(ctx context.Context, email, sub, displayName, destPath string, body io.Reader, contentType string, size int64) error
	FileExists(ctx context.Context, email, sub, displayName, filePath string) (bool, error)
	NotifyFileChanged(platformUserID, filePath string)
}

var ErrDriveUnavailable = errors.New("drive unavailable")

func normalizeDriveFolder(folderPath string) string {
	p := strings.TrimSpace(folderPath)
	if p == "" {
		return "/"
	}
	if !strings.HasPrefix(p, "/") {
		p = "/" + p
	}
	p = path.Clean(p)
	if p == "." {
		return "/"
	}
	return p
}

func uniqueDriveFilePath(ctx context.Context, uploader DriveUploader, email, sub, displayName, folderPath, filename string) (string, error) {
	base := strings.TrimSpace(filename)
	if base == "" {
		base = "piece-jointe"
	}
	ext := path.Ext(base)
	stem := strings.TrimSuffix(base, ext)
	if stem == "" {
		stem = base
		ext = ""
	}

	candidate := path.Join(folderPath, base)
	for i := 0; i < 100; i++ {
		exists, err := uploader.FileExists(ctx, email, sub, displayName, candidate)
		if err != nil {
			return "", err
		}
		if !exists {
			return candidate, nil
		}
		if i == 0 {
			candidate = path.Join(folderPath, stem+" (1)"+ext)
			continue
		}
		candidate = path.Join(folderPath, stem+" ("+strconv.Itoa(i+1)+")"+ext)
	}
	return "", errors.New("could not allocate unique drive path")
}