package bench

import (
	"bufio"
	"bytes"
	"errors"
	"io"
	"os"
	"strconv"
)

func Find(path, s string) (string, error) {
	if s == "" {
		return "", errors.New("")
	}
	var term []byte = []byte(s)
	var err error
	var file *os.File
	file, err = os.Open(path)
	defer file.Close()
	if err != nil {
		return "", err
	}
	var (
		r          *bufio.Reader = bufio.NewReader(file)
		line       []byte
		position   int
		i          int
		res        bytes.Buffer
		ln         int
		first      bool = true
		lineLength int
		sLength    int = len(term)
	)
	for {
		line, err = r.ReadBytes('\n')
		if err == io.EOF {
			break
		}
		ln++
		lineLength = len(line)
	Loop:
		for position = 0; position < lineLength; position++ {
			for i = 0; i < sLength; i++ {
				if term[i] != line[position+i] {
					continue Loop
				}
			}
			if first {
				first = false
				b := make([]byte, 0)
				b = strconv.AppendInt(b, int64(ln), 10)
				b = append(b, ':')
				b = strconv.AppendInt(b, int64(position), 10)
				res.Write(b)
			} else {
				b := make([]byte, 1)
				b[0] = ','
				b = strconv.AppendInt(b, int64(ln), 10)
				b = append(b, ':')
				b = strconv.AppendInt(b, int64(position), 10)
				res.Write(b)
			}
		}
	}
	return res.String(), nil
}