/* Alvin Bello
 * OOP - Period 6
 * File IO Lab 2
 */
package main;

import java.util.*;
import java.io.*;

public class Main {

	static ArrayList<File> files = new ArrayList<File>();
	boolean cont;
	static Scanner scan = new Scanner(System.in);
	PrintWriter write;

	// thrown because I don't want to deal with such garbage.
	public static void main(String[] args) throws FileNotFoundException, UnsupportedEncodingException, IOException {
		Main test = new Main();
		test.run();
	}

	// accepts integers between bounds a and b.
	public static int getInt(int a, int b) {
		int input = getInt();
		while (input < a || input > b) {
			System.out.println("You must pick a number in-between " + a + " and " + b + "!");
			input = getInt();
		}
		return input;
	}

	// try-catch entering an integer.
	public static int getInt() {
		int output = 0;
		while (true) {
			try {
				output = scan.nextInt();
			} catch (InputMismatchException e) {
				System.out.printf("Please input an integer.\n");
				scan.nextLine();
				continue;
			} catch (Exception e) {
				System.out.println("Exception: " + e);
				return -1;
			}
			break;
		}
		scan.nextLine();
		return output;
	}

	// runs the menu and operations. Threw these here also because safety first.
	public void run() throws FileNotFoundException, UnsupportedEncodingException, IOException {
		cont = false;
		int input = 0;
        for( File f : (new File("./files/")).listFiles() )
        	files.add(f);

		do {
			System.out.println(
					  "If you would like to exit, enter 0.\n"
					+ "If you would like to create a file, enter 1.\n"
					+ "If you would like to write to a file, enter 2.\n"
					+ "If you would like to read a file, enter 3.\n");
			switch (getInt(0, 3)) {
			case 0:
				cont = false;
				break;
			case 1:
				System.out.println("Enter the file name.");
				File file = new File("./files/" + scan.nextLine() + ".txt");
				if (!file.exists()) {
					file.createNewFile();
					files.add(file);
					System.out.println("The file has been created.\n");
				} else {
					System.out.println("A file already exists with that name.");
				}
				cont = true;
				break;
			case 2:
				if (!(files.isEmpty())) {
					System.out.println("What file would you like to write to? Enter the integer next to it.");
					for (int i = 0; i < files.size(); i++) {
						System.out.println("[" + i + "] " + files.get(i).toString().substring(8));
					}
					input = getInt(0, files.size() - 1);
					write = new PrintWriter(files.get(input), "UTF-8");
					System.out.println("You may now write to the file.\n");
					write.println(scan.nextLine());
					write.close();
					System.out.println("\nYou have written to the file.\n");
				} else {
					System.out.println("There are no files to write to. Create one before writing to it.\n");
				}
				cont = true;
				break;
			case 3:
				if (!(files.isEmpty())) {
					System.out.println("What file would you like to read from? Enter the integer next to it.");
					for (int i = 0; i < files.size(); i++) {
						System.out.println("[" + i + "] " + files.get(i).toString().substring(8));
					}
					input = getInt(0, files.size() - 1);
					Scanner read = new Scanner(files.get(input));
					while (read.hasNext()) {
						System.out.println(read.nextLine());
					}
					read.close();
					System.out.println("\nYou have read from the file.");
				} else {
					System.out.println("There are no files to read from. Create one before reading from it.");
				}
				cont = true;
				break;
			default:
				System.out.println("Invalid operation, try again.");
				cont = true;
			}
		} while (cont);
	}
}