package main

import (
	"os"
	"io"
	"log"
	"index/suffixarray"
	"strconv"
)

func main() {
	idx := os.Args[1] + ".suf"
	f, err := os.Open(os.Args[1])
	if err != nil {
		log.Fatal(err)
	}
	defer f.Close()

	n, err := strconv.Atoi(os.Args[2])
	if err != nil {
		log.Fatal(err)
	}
	
	outf, err := os.Create(idx + ".new")
	if err != nil {
		log.Fatal(err)
	}
	defer outf.Close()

	data := make([]byte, n)
	count, err := f.Read(data)
	if err != nil && err != io.EOF {
		log.Fatal(err)
	}
	err = suffixarray.New(data[:count]).Write(outf)
	if err != nil {
		os.Remove(idx + ".new")
		log.Fatal(err)
	}

	outf.Sync()
	outf.Close()
	err = os.Rename(idx + ".new", idx)
	if err != nil {
		log.Fatal(err)
	}
}