// Test that doing slaveOk reads from secondaries hits all the secondaries evenly

function testReadLoadBalancing(numReplicas) {

    var s = new ShardingTest({ shards: { rs0: { nodes: numReplicas }},
        verbose: 2, other: { chunkSize: 1 }});

    s.adminCommand({enablesharding : "test"});
    s.config.settings.find().forEach(printjson);

    s.adminCommand({shardcollection : "test.foo", key : {_id : 1}});

    s.getDB("test").foo.insert({a : 123});

    primary = s._rs[0].test.liveNodes.master;
    secondaries = s._rs[0].test.liveNodes.slaves;

    function rsStats() {
        return s.getDB("admin").runCommand("connPoolStats")["replicaSets"][s.rs0.name];
    }
    
    assert.eq( numReplicas , rsStats().hosts.length );
    
    function isMasterOrSecondary( info ){
        if ( ! info.ok )
            return false;
        if ( info.ismaster )
            return true;
        return info.secondary && ! info.hidden;
    }

    assert.soon( 
        function() {
            var x = rsStats().hosts;
            printjson(x);
            for ( var i=0; i<x.length; i++ ) 
                if ( ! isMasterOrSecondary( x[i] ) )
                    return false;
            return true;
        } 
    );
    
    for (var i = 0; i < secondaries.length; i++) {
        assert.soon( function(){ return secondaries[i].getDB("test").foo.count() > 0; } );
        secondaries[i].getDB('test').setProfilingLevel(2);
    }
    // Primary may change with reconfig
    primary.getDB('test').setProfilingLevel(2);

    // Store references to the connection so they won't be garbage collected.
    var connections = [];

    for (var i = 0; i < secondaries.length * 10; i++) {
        conn = new Mongo(s._mongos[0].host);
        conn.setSlaveOk();
        conn.getDB('test').foo.findOne();
        connections.push(conn);
    }

    var profileCriteria = { op: 'query', ns: 'test.foo' };

    for (var i = 0; i < secondaries.length; i++) {
        var profileCollection = secondaries[i].getDB('test').system.profile;
        assert.eq(10, profileCollection.find(profileCriteria).count(),
            "Wrong number of read queries sent to secondary " + i +
            " " + tojson( profileCollection.find().toArray() ));
    }
    
    db = primary.getDB( "test" );
    
    printjson(rs.status());
    c = rs.conf();
    print( "config before: " + tojson(c) );
    for ( i=0; i<c.members.length; i++ ) {
        if ( c.members[i].host == db.runCommand( "ismaster" ).primary )
            continue;
        c.members[i].hidden = true;
        c.members[i].priority = 0;
        break;
    }
    rs.reconfig( c );
    print( "config after: " + tojson( rs.conf() ) );
    
    assert.soon( 
        function() {
            var x = rsStats();
            printjson(x);
            var numOk = 0;
            // Now wait until the host disappears, since now we actually update our
            // replica sets via isMaster in mongos
            if( x.hosts.length == c["members"].length - 1 ) return true;
            /*
            for ( var i=0; i<x.hosts.length; i++ ) 
                if ( x.hosts[i].hidden )
                    return true;
            */
            return false;
        } , "one slave not ok" , 180000 , 5000
    );
    
    // Secondaries may change here
    secondaries = s._rs[0].test.liveNodes.slaves;
    
    for (var i = 0; i < secondaries.length * 10; i++) {
        conn = new Mongo(s._mongos[0].host);
        conn.setSlaveOk();
        conn.getDB('test').foo.findOne();
        connections.push(conn);
    }

    var counts = [];
    for (var i = 0; i < secondaries.length; i++) {
        var profileCollection = secondaries[i].getDB('test').system.profile;
        counts.push( profileCollection.find(profileCriteria).count() );
    }

    counts = counts.sort();
    assert.eq( 20 , Math.abs( counts[1] - counts[0] ), "counts wrong: " + tojson( counts ) );

    s.stop();
}

//for (var i = 1; i < 10; i++) {
//    testReadLoadBalancing(i)
//}

// Is there a way that this can be run multiple times with different values?
// Disabled until SERVER-11956 is solved
// testReadLoadBalancing(3)