package davextra

import (
	"fmt"
	"net/url"
	"path/filepath"
	"regexp"
	"strings"
)

// GetLinkFragment returns the longest alphanumeric string from a link
func GetLinkFragment(link string) string {
	re := regexp.MustCompile(`\w+`)
	matches := re.FindAllString(link, -1) // Returns all matches
	var longestMatch string
	for _, match := range matches {
		if len(match) > len(longestMatch) {
			longestMatch = match
		}
	}
	return longestMatch[:4]
}

// InsertLinkFragment inserts the link ID into a filename
// returns the new filename
func InsertLinkFragment(filename, dupeID string) string {
	ext := filepath.Ext(filename)
	name := strings.TrimSuffix(filename, ext)
	return fmt.Sprintf("%s DMM%s%s", name, dupeID, ext)
}

// ExtractLinkFragment extracts the link ID from a filename
// returns the original filename and the link ID
func ExtractLinkFragment(filename string) (string, string) {
	filenameV2, err := url.PathUnescape(filename)
	if err != nil {
		filenameV2 = filename
	}
	ext := filepath.Ext(filenameV2)
	name := strings.TrimSuffix(filenameV2, ext)

	r := regexp.MustCompile(`\sDMM(\w+)`)
	matches := r.FindStringSubmatch(name)
	if len(matches) < 2 {
		// No ID found
		return filenameV2, ""
	}

	// Remove ID from filename
	originalName := strings.Replace(name, matches[0], "", 1)
	return originalName + ext, matches[1]
}