/*
 * Copyright (C) 2009 The Android Open Source Project
 *
 * 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.android.common;

import android.content.SharedPreferences;
import android.test.AndroidTestCase;
import android.test.suitebuilder.annotation.MediumTest;
import android.test.suitebuilder.annotation.SmallTest;

public class OperationSchedulerTest extends AndroidTestCase {
    /**
     * OperationScheduler subclass which uses an artificial time.
     * Set {@link #timeMillis} to whatever value you like.
     */
    private class TimeTravelScheduler extends OperationScheduler {
        static final long DEFAULT_TIME = 1250146800000L;  // 13-Aug-2009, 12:00:00 am
        public long timeMillis = DEFAULT_TIME;

        @Override
        protected long currentTimeMillis() { return timeMillis; }
        public TimeTravelScheduler() { super(getFreshStorage()); }
    }

    private SharedPreferences getFreshStorage() {
        SharedPreferences sp = getContext().getSharedPreferences("OperationSchedulerTest", 0);
        sp.edit().clear().commit();
        return sp;
    }

    @MediumTest
    public void testScheduler() throws Exception {
        TimeTravelScheduler scheduler = new TimeTravelScheduler();
        OperationScheduler.Options options = new OperationScheduler.Options();
        assertEquals(Long.MAX_VALUE, scheduler.getNextTimeMillis(options));
        assertEquals(0, scheduler.getLastSuccessTimeMillis());
        assertEquals(0, scheduler.getLastAttemptTimeMillis());

        long beforeTrigger = scheduler.timeMillis;
        scheduler.setTriggerTimeMillis(beforeTrigger + 1000000);
        assertEquals(beforeTrigger + 1000000, scheduler.getNextTimeMillis(options));

        // It will schedule for the later of the trigger and the moratorium...
        scheduler.setMoratoriumTimeMillis(beforeTrigger + 500000);
        assertEquals(beforeTrigger + 1000000, scheduler.getNextTimeMillis(options));
        scheduler.setMoratoriumTimeMillis(beforeTrigger + 1500000);
        assertEquals(beforeTrigger + 1500000, scheduler.getNextTimeMillis(options));

        // Test enable/disable toggle
        scheduler.setEnabledState(false);
        assertEquals(Long.MAX_VALUE, scheduler.getNextTimeMillis(options));
        scheduler.setEnabledState(true);
        assertEquals(beforeTrigger + 1500000, scheduler.getNextTimeMillis(options));

        // Backoff interval after an error
        long beforeError = (scheduler.timeMillis += 100);
        scheduler.onTransientError();
        assertEquals(0, scheduler.getLastSuccessTimeMillis());
        assertEquals(beforeError, scheduler.getLastAttemptTimeMillis());
        assertEquals(beforeTrigger + 1500000, scheduler.getNextTimeMillis(options));
        options.backoffFixedMillis = 1000000;
        options.backoffIncrementalMillis = 500000;
        assertEquals(beforeError + 1500000, scheduler.getNextTimeMillis(options));

        // Two errors: backoff interval increases
        beforeError = (scheduler.timeMillis += 100);
        scheduler.onTransientError();
        assertEquals(beforeError, scheduler.getLastAttemptTimeMillis());
        assertEquals(beforeError + 2000000, scheduler.getNextTimeMillis(options));

        // Reset transient error: no backoff interval
        scheduler.resetTransientError();
        assertEquals(0, scheduler.getLastSuccessTimeMillis());
        assertEquals(beforeTrigger + 1500000, scheduler.getNextTimeMillis(options));
        assertEquals(beforeError, scheduler.getLastAttemptTimeMillis());

        // Permanent error holds true even if transient errors are reset
        // However, we remember that the transient error was reset...
        scheduler.onPermanentError();
        assertEquals(Long.MAX_VALUE, scheduler.getNextTimeMillis(options));
        scheduler.resetTransientError();
        assertEquals(Long.MAX_VALUE, scheduler.getNextTimeMillis(options));
        scheduler.resetPermanentError();
        assertEquals(beforeTrigger + 1500000, scheduler.getNextTimeMillis(options));

        // Success resets the trigger
        long beforeSuccess = (scheduler.timeMillis += 100);
        scheduler.onSuccess();
        assertEquals(beforeSuccess, scheduler.getLastAttemptTimeMillis());
        assertEquals(beforeSuccess, scheduler.getLastSuccessTimeMillis());
        assertEquals(Long.MAX_VALUE, scheduler.getNextTimeMillis(options));

        // The moratorium is not reset by success!
        scheduler.setTriggerTimeMillis(0);
        assertEquals(beforeTrigger + 1500000, scheduler.getNextTimeMillis(options));
        scheduler.setMoratoriumTimeMillis(0);
        assertEquals(beforeSuccess, scheduler.getNextTimeMillis(options));

        // Periodic interval after success
        options.periodicIntervalMillis = 250000;
        scheduler.setTriggerTimeMillis(Long.MAX_VALUE);
        assertEquals(beforeSuccess + 250000, scheduler.getNextTimeMillis(options));

        // Trigger minimum is also since the last success
        options.minTriggerMillis = 1000000;
        assertEquals(beforeSuccess + 1000000, scheduler.getNextTimeMillis(options));
    }

    @MediumTest
    public void testExponentialBackoff() throws Exception {
        TimeTravelScheduler scheduler = new TimeTravelScheduler();
        OperationScheduler.Options options = new OperationScheduler.Options();
        options.backoffFixedMillis = 100;
        options.backoffIncrementalMillis = 1000;
        options.backoffExponentialMillis = 10000;
        scheduler.setTriggerTimeMillis(0);
        scheduler.setEnabledState(true);

        // Backoff interval after an error
        long beforeError = (scheduler.timeMillis += 10);
        scheduler.onTransientError();
        assertEquals(0, scheduler.getLastSuccessTimeMillis());
        assertEquals(beforeError, scheduler.getLastAttemptTimeMillis());
        assertEquals(beforeError + 11100, scheduler.getNextTimeMillis(options));

        // Second error
        beforeError = (scheduler.timeMillis += 10);
        scheduler.onTransientError();
        assertEquals(beforeError, scheduler.getLastAttemptTimeMillis());
        assertEquals(beforeError + 22100, scheduler.getNextTimeMillis(options));

        // Third error
        beforeError = (scheduler.timeMillis += 10);
        scheduler.onTransientError();
        assertEquals(beforeError, scheduler.getLastAttemptTimeMillis());
        assertEquals(beforeError + 43100, scheduler.getNextTimeMillis(options));

        // Fourth error
        beforeError = (scheduler.timeMillis += 10);
        scheduler.onTransientError();
        assertEquals(beforeError, scheduler.getLastAttemptTimeMillis());
        assertEquals(beforeError + 84100, scheduler.getNextTimeMillis(options));
    }

    @SmallTest
    public void testParseOptions() throws Exception {
         OperationScheduler.Options options = new OperationScheduler.Options();
         assertEquals(
                 "OperationScheduler.Options[backoff=0.0+5.0 max=86400.0 min=0.0 period=3600.0]",
                 OperationScheduler.parseOptions("3600", options).toString());

         assertEquals(
                 "OperationScheduler.Options[backoff=0.0+2.5 max=86400.0 min=0.0 period=3700.0]",
                 OperationScheduler.parseOptions("backoff=+2.5 3700", options).toString());

         assertEquals(
                 "OperationScheduler.Options[backoff=10.0+2.5 max=12345.6 min=7.0 period=3800.0]",
                 OperationScheduler.parseOptions("max=12345.6 min=7 backoff=10 period=3800",
                         options).toString());

         assertEquals(
                "OperationScheduler.Options[backoff=10.0+2.5 max=12345.6 min=7.0 period=3800.0]",
                 OperationScheduler.parseOptions("", options).toString());

         assertEquals(
                 "OperationScheduler.Options[backoff=5.0+2.5+10.0 max=12345.6 min=7.0 period=3600.0]",
                 OperationScheduler.parseOptions("backoff=5.0++10.0 3600", options).toString());
    }

    @SmallTest
    public void testMoratoriumWithHttpDate() throws Exception {
        TimeTravelScheduler scheduler = new TimeTravelScheduler();
        OperationScheduler.Options options = new OperationScheduler.Options();

        long beforeTrigger = scheduler.timeMillis;
        scheduler.setTriggerTimeMillis(beforeTrigger + 1000000);
        assertEquals(beforeTrigger + 1000000, scheduler.getNextTimeMillis(options));

        scheduler.setMoratoriumTimeMillis(beforeTrigger + 2000000);
        assertEquals(beforeTrigger + 2000000, scheduler.getNextTimeMillis(options));

        long beforeMoratorium = scheduler.timeMillis;
        assertTrue(scheduler.setMoratoriumTimeHttp("3000"));
        long afterMoratorium = scheduler.timeMillis;
        assertTrue(beforeMoratorium + 3000000 <= scheduler.getNextTimeMillis(options));
        assertTrue(afterMoratorium + 3000000 >= scheduler.getNextTimeMillis(options));

        options.maxMoratoriumMillis = Long.MAX_VALUE / 2;
        assertTrue(scheduler.setMoratoriumTimeHttp("Fri, 31 Dec 2030 23:59:59 GMT"));
        assertEquals(1924991999000L, scheduler.getNextTimeMillis(options));

        assertFalse(scheduler.setMoratoriumTimeHttp("not actually a date"));
    }

    @SmallTest
    public void testClockRollbackScenario() throws Exception {
        TimeTravelScheduler scheduler = new TimeTravelScheduler();
        OperationScheduler.Options options = new OperationScheduler.Options();
        options.minTriggerMillis = 2000;

        // First, set up a scheduler with reasons to wait: a transient
        // error with backoff and a moratorium for a few minutes.

        long beforeTrigger = scheduler.timeMillis;
        long triggerTime = beforeTrigger - 10000000;
        scheduler.setTriggerTimeMillis(triggerTime);
        assertEquals(triggerTime, scheduler.getNextTimeMillis(options));
        assertEquals(0, scheduler.getLastAttemptTimeMillis());

        long beforeSuccess = (scheduler.timeMillis += 100);
        scheduler.onSuccess();
        scheduler.setTriggerTimeMillis(triggerTime);
        assertEquals(beforeSuccess, scheduler.getLastAttemptTimeMillis());
        assertEquals(beforeSuccess + 2000, scheduler.getNextTimeMillis(options));

        long beforeError = (scheduler.timeMillis += 100);
        scheduler.onTransientError();
        assertEquals(beforeError, scheduler.getLastAttemptTimeMillis());
        assertEquals(beforeError + 5000, scheduler.getNextTimeMillis(options));

        long beforeMoratorium = (scheduler.timeMillis += 100);
        scheduler.setMoratoriumTimeMillis(beforeTrigger + 1000000);
        assertEquals(beforeTrigger + 1000000, scheduler.getNextTimeMillis(options));

        // Now set the time back a few seconds.
        // The moratorium time should still be honored.
        long beforeRollback = (scheduler.timeMillis = beforeTrigger - 10000);
        assertEquals(beforeTrigger + 1000000, scheduler.getNextTimeMillis(options));

        // The rollback also moved the last-attempt clock back to the rollback time.
        assertEquals(scheduler.timeMillis, scheduler.getLastAttemptTimeMillis());

        // But if we set the time back more than a day, the moratorium
        // resets to the maximum moratorium (a day, by default), exposing
        // the original trigger time.
        beforeRollback = (scheduler.timeMillis = beforeTrigger - 100000000);
        assertEquals(triggerTime, scheduler.getNextTimeMillis(options));
        assertEquals(beforeRollback, scheduler.getLastAttemptTimeMillis());

        // If we roll forward until after the re-set moratorium, then it expires.
        scheduler.timeMillis = triggerTime + 5000000;
        assertEquals(triggerTime, scheduler.getNextTimeMillis(options));
        assertEquals(beforeRollback, scheduler.getLastAttemptTimeMillis());
        assertEquals(beforeRollback, scheduler.getLastSuccessTimeMillis());
    }
}