/*
 * Copyright 2014, 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.telecomm;

import android.telecomm.ICallServiceSelector;
import android.util.Log;

import com.google.common.collect.Maps;

import java.util.List;
import java.util.Map;
import java.util.Set;

/**
 * Responsible for placing all outgoing calls. For each outgoing call, this class creates an
 * instance of {@link OutgoingCallProcessor} which handles the details of connecting to the
 * appropriate call service and placing the call. This class maintains a mapping from call ID
 * to {@link OutgoingCallProcessor} so that other classes (Switchboard, CallServiceAdapter, etc),
 * can simply call into this class instead of individual OutgoingCallProcessors.
 */
final class OutgoingCallsManager {
    private static final String TAG = OutgoingCallsManager.class.getSimpleName();

    private final Switchboard mSwitchboard;

    /**
     * Maps call IDs to {@link OutgoingCallProcessor}s.
     */
    private Map<String, OutgoingCallProcessor> mOutgoingCallProcessors = Maps.newHashMap();

    /** Persists specified parameters. */
    OutgoingCallsManager(Switchboard switchboard) {
        mSwitchboard = switchboard;
    }

    /**
     * Starts the process of placing a call by constructing an outgoing call processor and asking
     * it to place the call. Upon success, execution will continue (via {@link CallServiceAdapter})
     * to {@link #handleSuccessfulCallAttempt}. Upon failure, execution will return to
     * {@link #handleFailedCallAttempt}.
     *
     * @param call The call to place.
     * @param callServices The set of call services which can potentially place the call.
     * @param selectors The ordered list of selectors used in placing the call.
     */
    void placeCall(
            Call call, Set<CallServiceWrapper> callServices, List<ICallServiceSelector> selectors) {

        Log.i(TAG, "Placing an outgoing call (" + call.getId() + ")");

        // Create the processor for this (outgoing) call and store it in a map such that call
        // attempts can be aborted etc.
        // TODO(gilad): Consider passing mSelector as an immutable set.
        OutgoingCallProcessor processor =
                new OutgoingCallProcessor(call, callServices, selectors, this, mSwitchboard);

        mOutgoingCallProcessors.put(call.getId(), processor);
        processor.process();
    }

    /**
     * Removes the outgoing call processor mapping for the successful call and returns execution to
     * the switchboard. This method is invoked from {@link CallServiceAdapter} after a call service
     * has notified Telecomm that it successfully placed the call.
     *
     * @param callId The ID of the call.
     */
    void handleSuccessfulCallAttempt(String callId) {
        OutgoingCallProcessor processor = mOutgoingCallProcessors.remove(callId);

        if (processor == null) {
            // Shouldn't happen, so log a wtf if it does.
            Log.wtf(TAG, "Received an unexpected placed-call notification.");
        } else {
            processor.handleSuccessfulCallAttempt();
        }
    }

    /**
     * Notifies the appropriate outgoing call processor that a call attempt to place the call has
     * failed and the processor should continue attempting to place the call with the next call
     * service. This method is called from {@link CallServiceAdapter} after a call service has
     * notified Telecomm that it could not place the call.
     *
     * @param callId The ID of the failed outgoing call.
     * @param reason The call-service supplied reason for the failed call attempt.
     */
    void handleFailedCallAttempt(String callId, String reason) {
        OutgoingCallProcessor processor = mOutgoingCallProcessors.get(callId);

        // TODO(santoscordon): Consider combining the check here and in handleSuccessfulCallAttempt.
        if (processor == null) {
            // Shouldn't happen, so log a wtf if it does.
            Log.wtf(TAG, "Received an unexpected failed-call notification.");
        } else {
            processor.handleFailedCallAttempt(reason);
        }
    }

    /**
     * Removes the outgoing call processor mapping for the failed call and returns execution to the
     * switchboard. In contrast to handleFailedCallAttempt which comes from the call-service and
     * goes to the outgoing-call processor indicating a single failed call attempt, this method is
     * invoked by the outgoing-call processor to indicate that the entire process has failed and we
     * should cleanup and notify Switchboard.
     *
     * @param call The failed outgoing call.
     */
    void handleFailedOutgoingCall(Call call) {
        mOutgoingCallProcessors.remove(call.getId());
        mSwitchboard.handleFailedOutgoingCall(call);
    }
}