package arrayplay;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Scanner;

public class ReverseCopy {
    public static void main(String[] args) throws FileNotFoundException, IOException {
        String inputFileName = "ForeverYoung.text";
        String outputFileName = "ForeverYoungReversed.text";
        String[] words = readWordsFromFile(inputFileName);
        writeWordsToFile(words,outputFileName);
    }

    private static final int LIMIT = 1000;

    private static String[] readWordsFromFile(String inputFileName) throws FileNotFoundException{
        // Equate a scanner with the input file
        Scanner scanner = establishScanner(inputFileName);
        // Read the words from the file into an oversized array
        String[] temp = new String[LIMIT];

        int index = 0;
        while(scanner.hasNext()){
            String word = scanner.next();
            temp[index] = word;
            index = index +1;
        }

        int wordCount = index;
        //Transfer the words to a perfectly sized array
        String[] words = new String[wordCount];
        for( int x = 0; x < wordCount; x = x+1){
            words[x] = temp[x];
        }
        //Return the words
        return words;
    }

    private static void writeWordsToFile(String[] words, String outputFileName) throws IOException {
        //Equate a printer with an output file
        PrintWriter printer = getPrintWriter(outputFileName);
        //Print the words to the file
        for(int x = words.length - 1; x >= 0; x = x -1){
            printer.println(words[x]);
            // Q. What's the difference btw/ xxxx.out.println( ...); vs xxxx.println(...);
            // Q-1.what happens if .out. is dismissed?
        }
        printer.close();
        //Q. What the .close mean? how does it work in Java and especially in this code
    }

    private static Scanner establishScanner(String inputFileName) throws FileNotFoundException{
        String fullFileName = createFullFileName(inputFileName);
        return new Scanner(new File(fullFileName));
        // how the return can be in a type: new? And also what the Scanner(new File(...));
        // why it is possible that new Scanner, which has just been made, can have new Files in its parameter?
        // And how all operators in the line including return works?
    }


    private static PrintWriter getPrintWriter(String outputFileName) throws FileNotFoundException{
        String fullFileName = createFullFileName(outputFileName);
        PrintWriter printer = new PrintWriter(fullFileName);

        //Q. What's PrintWriter in Java? how does it work and why it is useful compared to using sout instead?
        return printer;
    }

    // Create the full file name for a simple file name, assuming that it will be found in the CS1Files/data ...
    // subdirectory of the user's home directory.
    private static String createFullFileName(String fileName) /* Q. why the throws isn't here? */ {
        String separator = System.getProperty("file.separator");
        String home = System.getProperty("user.home");
        String path = home + separator + "CS1Files" + separator + "data" +separator;
        String fullFileName = path + fileName;
        return fullFileName;

    }
}