package megauploader

import (
	"fmt"
	"strings"
)

type fileIncrement struct {
	pre  string
	post string
}

func (fi fileIncrement) Increment(i int) string {
	if i == 0 {
		return fmt.Sprintf("%s%s", fi.pre, fi.post)
	}
	return fmt.Sprintf("%s-%d%s", fi.pre, i, fi.post)
}

func newFileIncrement(fn string) fileIncrement {
	idx := strings.Index(fn, ".")
	if idx != -1 {
		return fileIncrement{pre: fn[0:idx], post: fn[idx:]}
	} else {
		return fileIncrement{pre: fn[0:], post: ""}
	}
}