package com.example.dep.androidapp;

import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.annotation.TargetApi;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.support.annotation.NonNull;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.app.LoaderManager.LoaderCallbacks;
import android.content.CursorLoader;
import android.content.Loader;
import android.database.Cursor;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Build;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.text.TextUtils;
import android.view.KeyEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.inputmethod.EditorInfo;
import android.widget.ArrayAdapter;
import android.widget.AutoCompleteTextView;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import static android.Manifest.permission.READ_CONTACTS;

// A login screen that offers login via username/password.

public class LoginActivity extends AppCompatActivity {

    public static final Pattern VALID_USERNAME_REGEX = Pattern.compile("^p[0-9]{5}$", Pattern.CASE_INSENSITIVE);
    public static final Pattern VALID_PASSWORD_REGEX = Pattern.compile("^![0-9]{2}[A-Z]{2}!$", Pattern.CASE_INSENSITIVE);

    // A dummy authentication store containing known user names and passwords.
    // TODO: remove after connecting to a real authentication system.

    private static final String[] DUMMY_CREDENTIALS = new String[]{
            "p13053:!11AA!", "p13025:!22BB!"
    };

    // Keep track of the login task to ensure we can cancel it if requested.
    private UserLoginTask mAuthTask = null;

    private AutoCompleteTextView mUsernameView;
    private EditText mPasswordView;
    private View mProgressView;
    private View mLoginFormView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        mUsernameView = (AutoCompleteTextView) findViewById(R.id.username);
        mPasswordView = (EditText) findViewById(R.id.password);

        Button mUsernameSignInButton = (Button) findViewById(R.id.btn_login);
        mUsernameSignInButton.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View view) {
                attemptLogin();
            }
        });

        mLoginFormView = findViewById(R.id.login_form);
        mProgressView = findViewById(R.id.login_progress);
    }

    /* Attempts to sign in or register the account specified by the login form. If there are form
    errors (invalid username, missing fields, etc.), the errors are presented  */
    private void attemptLogin() {
        if (mAuthTask != null) {
            return;
        }

        // Reset errors.
        mUsernameView.setError(null);
        mPasswordView.setError(null);

        // Store values at the time of the login attempt.
        String username = mUsernameView.getText().toString();
        String password = mPasswordView.getText().toString();

        boolean cancel = false;
        View focusView = null;

        // Check for a valid password, if the user entered one.
        if (TextUtils.isEmpty(password)) {
            mPasswordView.setError(getString(R.string.error_field_required));
            focusView = mPasswordView;
            cancel = true;
        } else if (!isPasswordValid(password)) {
            mPasswordView.setError("The password is incorrect.");
            focusView = mPasswordView;
            cancel = true;
        }

        // Check for a valid username.
        if (TextUtils.isEmpty(username)) {
            mUsernameView.setError(getString(R.string.error_field_required));
            focusView = mUsernameView;
            cancel = true;
        } else if (!isUsernameValid(username)) {
            mUsernameView.setError("The username is incorrect.");
            focusView = mUsernameView;
            cancel = true;
        }

        if (cancel) { // There was an error; don't attempt login and focus the field with an error.
            focusView.requestFocus();
        } else { // Show a progress spinner, and kick off a background task to perform the user login attempt.
            showProgress(true);
            mAuthTask = new UserLoginTask(username, password);
            mAuthTask.execute((Void) null);
        }
    }

    private boolean isUsernameValid(String username) {
        Matcher matcher = VALID_USERNAME_REGEX .matcher(username);
        return matcher.find();
    }

    private boolean isPasswordValid(String password) {
        Matcher matcher = VALID_PASSWORD_REGEX .matcher(password);
        return matcher.find();
    }

    //Shows the progress UI and hides the login form.
    @TargetApi(Build.VERSION_CODES.HONEYCOMB_MR2)
    private void showProgress(final boolean show) {
        // On Honeycomb MR2 we have the ViewPropertyAnimator APIs, which allow
        // for very easy animations. If available, use these APIs to fade-in
        // the progress spinner.
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB_MR2) {
            int shortAnimTime = getResources().getInteger(android.R.integer.config_shortAnimTime);

            mLoginFormView.setVisibility(show ? View.GONE : View.VISIBLE);
            mLoginFormView.animate().setDuration(shortAnimTime).alpha(
                    show ? 0 : 1).setListener(new AnimatorListenerAdapter() {
                @Override
                public void onAnimationEnd(Animator animation) {
                    mLoginFormView.setVisibility(show ? View.GONE : View.VISIBLE);
                }
            });

            mProgressView.setVisibility(show ? View.VISIBLE : View.GONE);
            mProgressView.animate().setDuration(shortAnimTime).alpha(
                    show ? 1 : 0).setListener(new AnimatorListenerAdapter() {
                @Override
                public void onAnimationEnd(Animator animation) {
                    mProgressView.setVisibility(show ? View.VISIBLE : View.GONE);
                }
            });
        } else {
            // The ViewPropertyAnimator APIs are not available, so simply show
            // and hide the relevant UI components.
            mProgressView.setVisibility(show ? View.VISIBLE : View.GONE);
            mLoginFormView.setVisibility(show ? View.GONE : View.VISIBLE);
        }
    }

    public class UserLoginTask extends AsyncTask<Void, Void, Boolean> {

        private final String mUsername;
        private final String mPassword;

        UserLoginTask(String username, String password) {
            mUsername = username;
            mPassword = password;
        }

        @Override
        protected Boolean doInBackground(Void... params) {
            // TODO: attempt authentication against a network service.

            try { // Simulate network access.
                Thread.sleep(2000);
            } catch (InterruptedException e) {
                return false;
            }

            for (String credential : DUMMY_CREDENTIALS) {
                String[] pieces = credential.split(":");
                if (pieces[0].equals(mUsername)) {
                    // Account exists, return true if the password matches.
                    return pieces[1].equals(mPassword);
                }
            }
            return true;
        }

        @Override
        protected void onPostExecute(final Boolean success) {
            mAuthTask = null;
            showProgress(false);

            if (success) {
                //finish();
                Intent mainpageIntent = new Intent(LoginActivity.this, NavigationActivity.class);
                LoginActivity.this.startActivity(mainpageIntent);
            } else {
                mPasswordView.setError(getString(R.string.error_incorrect_password));
                mPasswordView.requestFocus();
            }
        }

        @Override
        protected void onCancelled() {
            mAuthTask = null;
            showProgress(false);
        }
    }
}