///////////////////////////////////////////////////////////////////////////////
//
//  Microsoft Research Singularity
//
//  Copyright (c) Microsoft Corporation.  All rights reserved.
//
//  File:   SeattleTrafficProxyContract.sg
//  Note:   Contract definition for the Seattle Traffic service
//

using Microsoft.Singularity.Directory;
using Microsoft.Singularity.Channels;

namespace Microsoft.Singularity.SeattleTrafficProxy.Contracts
{
    public rep struct TrafficInfo {
        // There is a lot of traffic data. For now, we'll just provide
        // the bottlenecks and the approximate lat/long for their center.
        public int minUntilFree;    // estimate of time until the bottleneck clears
        public float latitude;
        public float longitude;
    }

    public contract SeattleTrafficProxyContract : ServiceContract
    {
        public const string ModuleName = "/dev/SeattleTrafficProxy";

        // Signal our identity
        out message Ready();

        in message GetTraffic();
        out message Traffic(TrafficInfo[]! in ExHeap trafficInfo);

        override state Start : one
        {
            Ready! -> ReadyState;
        }

        state ReadyState : one
        {
            GetTraffic? -> Traffic! -> ReadyState;
        }
    }
}