/*
 * Copyright (c) 2016, The Linux Foundation. All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above
      copyright notice, this list of conditions and the following
      disclaimer in the documentation and/or other materials provided
      with the distribution.
    * Neither the name of The Linux Foundation nor the names of its
      contributors may be used to endorse or promote products derived
      from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package com.android.calendar;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.os.Trace;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.Arrays;

/**
 * Activity that asks the user for all {@link #getDesiredPermissions} if any of
 * {@link #getRequiredPermissions} are missing.
 *
 * NOTE: As a result of b/22095159, this can behave oddly in the case where the
 * final permission you are requesting causes an application restart.
 */
public abstract class RequestPermissionsActivityBase extends Activity {
    public static final String PREVIOUS_ACTIVITY_INTENT = "previous_intent";
    private static final int PERMISSIONS_REQUEST_ALL_PERMISSIONS = 1;

    /**
     * @return list of permissions that are needed in order for
     *         {@link #PREVIOUS_ACTIVITY_INTENT} to operate. You only need to
     *         return a single permission per permission group you care about.
     */
    protected abstract String[] getRequiredPermissions();

    /**
     * @return list of permissions that would be useful for
     *         {@link #PREVIOUS_ACTIVITY_INTENT} to operate. You only need to
     *         return a single permission per permission group you care about.
     */
    protected abstract String[] getDesiredPermissions();

    private Intent mPreviousActivityIntent;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mPreviousActivityIntent = (Intent) getIntent().getExtras().get(
                PREVIOUS_ACTIVITY_INTENT);

        if (savedInstanceState == null) {
            requestPermissions();
        }
    }

    /**
     * If any permissions the canlendar app needs are missing, open an Activity
     * to prompt the user for these permissions. Moreover, finish the current
     * activity.
     *
     * This is designed to be called inside
     * {@link android.app.Activity#onCreate}
     */
    protected static boolean startPermissionActivity(Activity activity,
            String[] requiredPermissions, Class<?> newActivityClass) {
        if (!RequestPermissionsActivity.hasPermissions(activity,
                requiredPermissions)) {
            final Intent intent = new Intent(activity, newActivityClass);
            intent.putExtra(PREVIOUS_ACTIVITY_INTENT, activity.getIntent());
            activity.startActivity(intent);
            activity.finish();
            return true;
        }
        return false;
    }

    @Override
    public void onRequestPermissionsResult(int requestCode,
            String permissions[], int[] grantResults) {
        if (permissions != null && permissions.length > 0
                && isAllGranted(permissions, grantResults)) {
            mPreviousActivityIntent.setFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
            startActivity(mPreviousActivityIntent);
            finish();
            overridePendingTransition(0, 0);
        } else {
            Toast.makeText(this, R.string.on_permission_read_calendar, Toast.LENGTH_SHORT).show();
            finish();
        }
    }

    private boolean isAllGranted(String permissions[], int[] grantResult) {
        for (int i = 0; i < permissions.length; i++) {
            if (grantResult[i] != PackageManager.PERMISSION_GRANTED
                    && isPermissionRequired(permissions[i])) {
                return false;
            }
        }
        return true;
    }

    private boolean isPermissionRequired(String p) {
        return Arrays.asList(getRequiredPermissions()).contains(p);
    }

    private void requestPermissions() {
        Trace.beginSection("requestPermissions");
        try {
            // Construct a list of missing permissions
            final ArrayList<String> unsatisfiedPermissions = new ArrayList<>();
            for (String permission : getDesiredPermissions()) {
                if (checkSelfPermission(permission)
                        != PackageManager.PERMISSION_GRANTED) {
                    unsatisfiedPermissions.add(permission);
                }
            }
            if (unsatisfiedPermissions.size() == 0) {
                throw new RuntimeException("Request permission activity was called even"
                        + " though all permissions are satisfied.");
            }
            requestPermissions(
                    unsatisfiedPermissions.toArray(new String[unsatisfiedPermissions.size()]),
                    PERMISSIONS_REQUEST_ALL_PERMISSIONS);
        } finally {
            Trace.endSection();
        }
    }

    protected static boolean hasPermissions(Context context,
            String[] permissions) {
        Trace.beginSection("hasPermission");
        try {
            for (String permission : permissions) {
                if (context.checkSelfPermission(permission) != PackageManager.PERMISSION_GRANTED) {
                    return false;
                }
            }
            return true;
        } finally {
            Trace.endSection();
        }
    }
}