/*
 * Copyright (C) 2006 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.internal.telephony;

import android.os.AsyncResult;
import android.os.Handler;
import android.os.Message;
import android.util.Log;

import com.android.internal.telephony.CommandException;


/**
 * {@hide}
 */
public abstract class CallTracker extends Handler {

    private static final boolean DBG_POLL = false;

    //***** Constants

    static final int POLL_DELAY_MSEC = 250;

    protected int pendingOperations;
    protected boolean needsPoll;
    protected Message lastRelevantPoll;

    public CommandsInterface cm;


    //***** Events

    protected static final int EVENT_POLL_CALLS_RESULT    = 1;
    protected static final int EVENT_CALL_STATE_CHANGE    = 2;
    protected static final int EVENT_REPOLL_AFTER_DELAY   = 3;
    protected static final int EVENT_OPERATION_COMPLETE       = 4;
    protected static final int EVENT_GET_LAST_CALL_FAIL_CAUSE = 5;

    protected static final int EVENT_SWITCH_RESULT        = 8;
    protected static final int EVENT_RADIO_AVAILABLE      = 9;
    protected static final int EVENT_RADIO_NOT_AVAILABLE  = 10;
    protected static final int EVENT_CONFERENCE_RESULT    = 11;
    protected static final int EVENT_SEPARATE_RESULT      = 12;
    protected static final int EVENT_ECT_RESULT           = 13;


    protected void pollCallsWhenSafe() {
        needsPoll = true;

        if (checkNoOperationsPending()) {
            lastRelevantPoll = obtainMessage(EVENT_POLL_CALLS_RESULT);
            cm.getCurrentCalls(lastRelevantPoll);
        }
    }

    protected void
    pollCallsAfterDelay() {
        Message msg = obtainMessage();

        msg.what = EVENT_REPOLL_AFTER_DELAY;
        sendMessageDelayed(msg, POLL_DELAY_MSEC);
    }

    protected boolean
    isCommandExceptionRadioNotAvailable(Throwable e) {
        return e != null && e instanceof CommandException
                && ((CommandException)e).getCommandError()
                        == CommandException.Error.RADIO_NOT_AVAILABLE;
    }

    protected abstract void handlePollCalls(AsyncResult ar);

    protected void handleRadioAvailable() {
        pollCallsWhenSafe();
    }

    /**
     * Obtain a complete message that indicates that this operation
     * does not require polling of getCurrentCalls(). However, if other
     * operations that do need getCurrentCalls() are pending or are
     * scheduled while this operation is pending, the invocation
     * of getCurrentCalls() will be postponed until this
     * operation is also complete.
     */
    protected Message
    obtainNoPollCompleteMessage(int what) {
        pendingOperations++;
        lastRelevantPoll = null;
        return obtainMessage(what);
    }

    /**
     * @return true if we're idle or there's a call to getCurrentCalls() pending
     * but nothing else
     */
    private boolean
    checkNoOperationsPending() {
        if (DBG_POLL) log("checkNoOperationsPending: pendingOperations=" +
                pendingOperations);
        return pendingOperations == 0;
    }


    //***** Overridden from Handler
    public abstract void handleMessage (Message msg);

    protected abstract void log(String msg);

}
