// Tests that resharding a collection is detected correctly by all operation types
// 
// The idea here is that a collection may be resharded / unsharded at any point, and any type of
// operation on a mongos may be active when it happens.  All operations should handle gracefully.
//

var st = new ShardingTest({ shards : 2, mongos : 5, verbose : 1 });
// Balancer is by default stopped, thus it will not interfere

// Use separate mongos for reading, updating, inserting, removing data
var readMongos = st.s1;
var updateMongos = st.s2;
var insertMongos = st.s3;
var removeMongos = st.s4;

var config = st.s.getDB( "config" );
var admin = st.s.getDB( "admin" );
var coll = st.s.getCollection( "foo.bar" );

insertMongos.getDB( "admin" ).runCommand({ setParameter : 1, traceExceptions : true });

var shards = {};
config.shards.find().forEach( function( doc ){ 
    shards[ doc._id ] = new Mongo( doc.host );
});

//
// Set up a sharded collection
//

jsTest.log( "Enabling sharding for the first time..." );

admin.runCommand({ enableSharding : coll.getDB() + "" });
st.ensurePrimaryShard(coll.getDB().getName(), 'shard0001');
admin.runCommand({ shardCollection : coll  + "", key : { _id : 1 } });
    
assert.writeOK(coll.insert({ hello : "world" }));

jsTest.log( "Sharding collection across multiple shards..." );
    
var getOtherShard = function( shard ){
    for( id in shards ){
        if( id != shard ) return id;
    }
};
        
printjson( admin.runCommand({ split : coll + "", middle : { _id : 0 } }) );
printjson( admin.runCommand({ moveChunk : coll + "", find : { _id : 0 },
                              to : getOtherShard( config.databases.findOne({ _id : coll.getDB() + "" }).primary ) }) );

st.printShardingStatus();

//
// Force all mongoses to load the current status of the cluster
//

jsTest.log( "Loading this status in all mongoses..." );

for( var i = 0; i < st._mongos.length; i++ ){
    printjson( st._mongos[i].getDB( "admin" ).runCommand({ flushRouterConfig : 1 }) );
    assert.neq( null, st._mongos[i].getCollection( coll + "" ).findOne() );
}

//
// Drop and recreate a new sharded collection in the same namespace, where the shard and collection
// versions are the same, but the split is at a different point.
//

jsTest.log( "Rebuilding sharded collection with different split..." );

coll.drop();

var droppedCollDoc = config.collections.findOne({ _id: coll.getFullName() });
assert(droppedCollDoc != null);
assert.eq(true, droppedCollDoc.dropped);
assert(droppedCollDoc.lastmodEpoch != null);
assert(droppedCollDoc.lastmodEpoch.equals(new ObjectId("000000000000000000000000")),
       "epoch not zero: " + droppedCollDoc.lastmodEpoch);

admin.runCommand({ enableSharding : coll.getDB() + "" });
st.ensurePrimaryShard(coll.getDB().getName(), 'shard0001');
admin.runCommand({ shardCollection : coll  + "", key : { _id : 1 } });

var bulk = coll.initializeUnorderedBulkOp();
for( var i = 0; i < 100; i++ ) bulk.insert({ _id : i });
assert.writeOK(bulk.execute());

printjson( admin.runCommand({ split : coll + "", middle : { _id : 200 } }) );
printjson( admin.runCommand({ moveChunk : coll + "", find : { _id : 200 },
                              to : getOtherShard( config.databases.findOne({ _id : coll.getDB() + "" }).primary ) }) );

//
// Make sure all operations on mongoses aren't tricked by the change
//                              
                              
jsTest.log( "Checking other mongoses for detection of change..." );

jsTest.log( "Checking find..." );
// Ensure that finding an element works when resharding
assert.neq( null, readMongos.getCollection( coll + "" ).findOne({ _id : 1 }) );

jsTest.log( "Checking update...");
// Ensure that updating an element finds the right location
assert.writeOK(updateMongos.getCollection( coll + "" ).update({ _id : 1 },
                                                              { $set : { updated : true } }));
assert.neq( null, coll.findOne({ updated : true }) );

jsTest.log( "Checking insert..." );
// Ensure that inserting an element finds the right shard
assert.writeOK(insertMongos.getCollection( coll + "" ).insert({ _id : 101 }));
assert.neq( null, coll.findOne({ _id : 101 }) );

jsTest.log( "Checking remove..." );
// Ensure that removing an element finds the right shard, verified by the mongos doing the sharding
assert.writeOK(removeMongos.getCollection( coll + "" ).remove({ _id : 2 }));
assert.eq( null, coll.findOne({ _id : 2 }) );

coll.drop();

jsTest.log( "Done!" );

st.stop();