package main

import (
  "os"
  "fmt"
  "log"
  "strconv"
  "bufio"
)

func main() {
  // Create file to read
  inputFile, err := os.Open("input.txt")
  if err != nil {
      fmt.Println(err)
      log.Fatal("Failed to create file.")
  }
  inputFileScanner := bufio.NewScanner(inputFile)
  // For changing the buffer size
  //const maxCapacity int = 
  //buf := make([]byte,maxCapacity)
  //inputFileScanner.Buffer(buf, maxCapacity)

  // Loop to create file handler array
  var fileDescArray []*os.File
  numberOfFileDesc := 7
  for fileDescIndex := range numberOfFileDesc {

    // Create and open file
    handler, err := os.Create("file" + strconv.Itoa(fileDescIndex))
    if err != nil {
      log.Fatal(err)
    }

    // Append the handler to the list
    fileDescArray = append(fileDescArray,handler)
  }

  // Loop through open file and write to file handlers
  var fileArrayIndex int = 0
  fileDescArrayLen := len(fileDescArray)
  for inputFileScanner.Scan() {
    (fileDescArray[fileArrayIndex % fileDescArrayLen]).Write(append(inputFileScanner.Bytes(),'\n'))
    fileArrayIndex = fileArrayIndex + 1
  }

  // Loop to close all files
  for _, handler := range fileDescArray {
    if err := handler.Close(); err != nil {
      log.Fatal(err)
    }
  }
  // Close input file
  if err := inputFile.Close(); err != nil {
    log.Fatal(err)
  }
}