package com.dattz.sprout.activities;

import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.annotation.TargetApi;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.AsyncTask;
import android.os.Build;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
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.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import com.dattz.sprout.R;
import com.dattz.sprout.exceptions.FailedToConnectException;
import com.dattz.sprout.helpers.Helper;
import com.dattz.sprout.helpers.Server;

import org.json.JSONException;
import org.json.JSONObject;

import java.io.IOException;

/**
 * A login screen that offers login via email/password.
 */
public class LoginActivity extends AppCompatActivity {

    private static final String TAG = LoginActivity.class.getSimpleName();
    private UserLoginTask mAuthTask = null;

    // UI references.
    private EditText mEmailView;
    private EditText mPasswordView;
    private View mProgressView;
    private View mLoginFormView;

    private SharedPreferences spUser;

    private BroadcastReceiver mRegistrationBroadcastReceiver;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        // Set up the login form.
        mEmailView = (EditText) findViewById(R.id.email);
        mPasswordView = (EditText) findViewById(R.id.password);
        mPasswordView.setOnEditorActionListener(new TextView.OnEditorActionListener() {
            @Override
            public boolean onEditorAction(TextView textView, int id, KeyEvent keyEvent) {
                if (id == R.id.login || id == EditorInfo.IME_NULL) {
                    attemptLogin();
                    return true;
                }
                return false;
            }
        });

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

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

        spUser = getSharedPreferences(Helper.PREFERENCES_USER, Context.MODE_PRIVATE);
        if (spUser.contains("email")) {
            showProgress(true);
            Intent intent = new Intent(LoginActivity.this, HomeActivity.class);
            LoginActivity.this.startActivity(intent);
        }
    }

    /**
     * Attempts to sign in or register the account specified by the login form.
     * If there are form errors (invalid email, missing fields, etc.), the
     * errors are presented and no actual login attempt is made.
     */
    private void attemptLogin() {
        if (mAuthTask != null) {
            return;
        }

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

        // Store values at the time of the login attempt.
        String email = mEmailView.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) && !isPasswordValid(password)) {
            mPasswordView.setError(getString(R.string.error_invalid_password));
            focusView = mPasswordView;
            cancel = true;
        }

        // Check for a valid email address.
        if (TextUtils.isEmpty(email)) {
            mEmailView.setError(getString(R.string.error_field_required));
            focusView = mEmailView;
            cancel = true;
        } else if (!isEmailValid(email)) {
            mEmailView.setError(getString(R.string.error_invalid_email));
            focusView = mEmailView;
            cancel = true;
        }

        if (cancel) {
            // There was an error; don't attempt login and focus the first
            // form 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(email, password);
            mAuthTask.execute((Void) null);
        }
    }

    private boolean isEmailValid(String email) {
        return email.contains("@");
    }

    private boolean isPasswordValid(String password) {
        return password.length() > 4;
    }

    /**
     * Shows the progress UI and hides the login form.
     */
    @TargetApi(Build.VERSION_CODES.HONEYCOMB_MR2)
    private void showProgress(final boolean show) {
        if (show) Helper.hideKeyboard(this);
        else mEmailView.requestFocus();

        // 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);
        }


    }

    /**
     * Represents an asynchronous login/registration task used to authenticate
     * the user.
     */
    public class UserLoginTask extends AsyncTask<Void, Void, JSONObject> {

        private final String mEmail;
        private final String mPassword;

        private boolean connectionFail = false;

        UserLoginTask(String email, String password) {
            mEmail = email;
            mPassword = password;
        }

        @Override
        protected JSONObject doInBackground(Void... params) {
            try {
                return Server.attemptLogin(mEmail, mPassword);
            } catch (IOException e) {
                connectionFail = true;
            } catch (FailedToConnectException e) {
                connectionFail = true;
            } catch (JSONException e) {
                connectionFail = true;
            }
            return null;
        }

        protected void onPostExecute(final JSONObject jo) {
            mAuthTask = null;
            showProgress(false);

            if (jo != null) {
                try {
                    if (jo.getString("status").equals(Helper.JSON_ERROR))
                        throw new Exception();

                    // Login User:
                    SharedPreferences.Editor editor = spUser.edit();
                    editor.putString("email", jo.getString("email"));
                    editor.putString("name", jo.getString("name"));
                    editor.apply();

                    Toast.makeText(LoginActivity.this, "Logged in as " + jo.getString("name"),
                            Toast.LENGTH_SHORT).show();

                    // Move to Home Activity
                    Intent intent = new Intent(LoginActivity.this, HomeActivity.class);
                    LoginActivity.this.startActivity(intent);
                } catch (Exception e) { // We are mainly catching the JSONException.
                    mPasswordView.setError(getString(R.string.error_incorrect_password));
                    mPasswordView.requestFocus();
                }
            }
            else if (connectionFail == true) {
                Toast.makeText(LoginActivity.this, "There was a problem while connecting to the server.", Toast.LENGTH_SHORT).show();
                mEmailView.requestFocus();
            }
            else {
                mPasswordView.setError(getString(R.string.error_incorrect_password));
                mPasswordView.requestFocus();
            }

        }

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