/**
 * Copyright 2012 Facebook
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.facebook;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import com.facebook.android.R;

/**
 * This Activity is a necessary part of the overall Facebook login process
 * but is not meant to be used directly. Add this activity to your
 * AndroidManifest.xml to ensure proper handling of Facebook login.
 * <pre>
 * {@code
 * <activity android:name="com.facebook.LoginActivity"
 *           android:theme="@android:style/Theme.Translucent.NoTitleBar"
 *           android:label="@string/app_name" />
 * }
 * </pre>
 * Do not start this activity directly.
 */
public class LoginActivity extends Activity {
    static final String RESULT_KEY = "com.facebook.LoginActivity:Result";

    private static final String NULL_CALLING_PKG_ERROR_MSG =
            "Cannot call LoginActivity with a null calling package. " +
                    "This can occur if the launchMode of the caller is singleInstance.";
    private static final String SAVED_CALLING_PKG_KEY = "callingPackage";
    private static final String SAVED_AUTH_CLIENT = "authorizationClient";
    private static final String EXTRA_REQUEST = "request";

    private String callingPackage;
    private AuthorizationClient authorizationClient;
    private AuthorizationClient.AuthorizationRequest request;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.com_facebook_login_activity_layout);

        if (savedInstanceState != null) {
            callingPackage = savedInstanceState.getString(SAVED_CALLING_PKG_KEY);
            authorizationClient = (AuthorizationClient) savedInstanceState.getSerializable(SAVED_AUTH_CLIENT);
        } else {
            callingPackage = getCallingPackage();
            authorizationClient = new AuthorizationClient();
            request = (AuthorizationClient.AuthorizationRequest) getIntent().getSerializableExtra(EXTRA_REQUEST);
        }

        authorizationClient.setContext(this);
        authorizationClient.setOnCompletedListener(new AuthorizationClient.OnCompletedListener() {
            @Override
            public void onCompleted(AuthorizationClient.Result outcome) {
                onAuthClientCompleted(outcome);
            }
        });
        authorizationClient.setBackgroundProcessingListener(new AuthorizationClient.BackgroundProcessingListener() {
            @Override
            public void onBackgroundProcessingStarted() {
                findViewById(R.id.com_facebook_login_activity_progress_bar).setVisibility(View.VISIBLE);
            }

            @Override
            public void onBackgroundProcessingStopped() {
                findViewById(R.id.com_facebook_login_activity_progress_bar).setVisibility(View.GONE);
            }
        });
    }

    private void onAuthClientCompleted(AuthorizationClient.Result outcome) {
        request = null;

        int resultCode = (outcome.code == AuthorizationClient.Result.Code.CANCEL) ?
                RESULT_CANCELED : RESULT_OK;

        Bundle bundle = new Bundle();
        bundle.putSerializable(RESULT_KEY, outcome);

        Intent resultIntent = new Intent();
        resultIntent.putExtras(bundle);
        setResult(resultCode, resultIntent);

        finish();
    }

    @Override
    public void onResume() {
        super.onResume();

        // If the calling package is null, this generally means that the callee was started
        // with a launchMode of singleInstance. Unfortunately, Android does not allow a result
        // to be set when the callee is a singleInstance, so we throw an exception here.
        if (callingPackage == null) {
            throw new FacebookException(NULL_CALLING_PKG_ERROR_MSG);
        }

        authorizationClient.startOrContinueAuth(request);
    }

    @Override
    public void onPause() {
        super.onPause();

        authorizationClient.cancelCurrentHandler();
        findViewById(R.id.com_facebook_login_activity_progress_bar).setVisibility(View.GONE);
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);

        outState.putString(SAVED_CALLING_PKG_KEY, callingPackage);
        outState.putSerializable(SAVED_AUTH_CLIENT, authorizationClient);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        authorizationClient.onActivityResult(requestCode, resultCode, data);
    }

    static Bundle populateIntentExtras(AuthorizationClient.AuthorizationRequest request) {
        Bundle extras = new Bundle();
        extras.putSerializable(EXTRA_REQUEST, request);
        return extras;
    }
}