package xyz.thastertyn.Login;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

import xyz.thastertyn.Types.Credentials;

public class LocalCredentials {

	private static LocalCredentials localCredentials = new LocalCredentials();

	private String path;

	private File credentialsFile;
	private File credentialsPath;

	/**
	 * Checks for already saved credentials, at least if its file exists <br>
	 * for Windows it checks {@code AppData\Roaming\jecnak\credemtials.txt} <br>
	 * for Linux it checks {@code ~/.local/share/jecnak/credentials.txt} <br>
	 * @return
	 * <ul>
	 * <li> {@code true} a file exists </li>
	 * <li> {@code false} doesn't exist </li>
	 * </ul>
	 */
	public boolean checkForExistingCredentials()
	{
		if(System.getProperty("os.name").equals("Linux"))
		{
			// /home/user/.local/share/jecnak/...
			path = System.getProperty("user.home") + "/.local/share/jecnak/";
		}else if(System.getProperty("os.name").contains("Windows"))
		{
			// C:\Users\\user\AppData\Roaming\...
			path = System.getenv("APPDATA") + "\\jecnak\\";
		}else{
			return false;
		}

		credentialsPath = new File(path);
		credentialsFile = new File(credentialsPath, "credentials.txt");

		if(!credentialsFile.exists())
		{
			return false;
		}

		return true;
	}

	/**
	 * Try reading the credentails from a local file
	 * @return String[] with username on index 0, and password on index 1, <br>
	 * can also return null if credentials are corrupted, inaccessible, etc.
	 */
	public Credentials getCredentialsFile()
	{
		// TODO Use hashmap instead of array
		String user = null;
		String pass = null;

		if(credentialsFile == null)
		{
			return null;
		}

		try {
			BufferedReader reader = new BufferedReader(new FileReader(credentialsFile));

			String line = "";
			while((line = reader.readLine()) != null)
			{
				String[] currentValue = line.split("=");

				if(currentValue[0].equals("user"))
				{
					user = currentValue[1];
				}else if(currentValue[0].equals("pass"))
				{
					pass = currentValue[1];
				}
			}

			reader.close();
		} catch (IOException e) {
			e.printStackTrace();
			return null;
		}

		if(user == null || pass == null)
		{
			return null;
		}

		return new Credentials(user, pass);
	}

	/**
	 * appends the current credentials to the file
	 * @param credentials the array containing username and password. Username is on index 0, password on index 1
	 * @return
	 */
	public boolean saveCredentials(Credentials credentials)
	{
		if(credentialsFile == null)
		{
			return false;
		}

		if(!credentialsFile.exists())
		{
			try{
				credentialsPath.mkdirs();
				credentialsFile.createNewFile();
			}catch(IOException e)
			{
				return false;
			}
		}

		try {
			BufferedWriter writer = new BufferedWriter(new FileWriter(credentialsFile));
			writer.append(String.format(
				"user=%s\npass=%s\n",
				credentials.getUsername(),
				credentials.getPassword()));

			writer.close();
		} catch (IOException e) {
			e.printStackTrace();
			return false;
		}

		return true;
	}

	/**
	 * Deletes the credentials file
	 * @return
	 */
	public boolean deleteCredentials()
	{
		credentialsFile.delete();
		return true;
	}

	/**
	 * Returns a single instance to prevent creating and loading the files all over again when not much has changed
	 * @return {@link LocalCredentials} instance
	 */
	public static LocalCredentials getInstance()
	{
		return localCredentials;
	}

}