Renaming sub files of series according to their video file names

main.go

package main

import (
	"log"
	"os"
	"regexp"
	"strings"
)

func Renamify(path string) {
	files, err := os.ReadDir(path)
	if err != nil {
		log.Fatal(err)
	}
	// Map will store S<num>E<num>
	videos := make(map[string]string)
	subs := make(map[string]string)
	for _, f := range files {
		re := regexp.MustCompile(".*(S|s)0*([1-9]+)(E|e)0*([1-9]+).*\\.((?:mkv)|(?:srt))")
		ent := strings.Fields(re.ReplaceAllString(f.Name(), "$1$2$3$4 $5"))
		if ent[1] == "mkv" {
			videos[ent[0]] = f.Name()
		}
		if ent[1] == "srt" {
			subs[ent[0]] = f.Name()
		}
	}
	for key, sub := range subs {
		os.Rename(path+sub, path+strings.Replace(videos[key], ".mkv", ".srt", 1))
	}
}