package waymaker.top.android; // Copyright © 2015 Michael Allan.  Licence MIT.

import java.util.Map;
import waymaker.gen.ThreadSafe;
import waymaker.spec.*;


/** A pollar count at the remote count server.
  */
public final @ThreadSafe class ServerCount
{


    /** Asynchronously requests the initial data for a group of peers.  The result set will include all
      * major peers of the group, if any.  Optionally it may be padded with minor peers to a convenient
      * size.  Subsequent {@linkplain #enqueuePeersRequest(VotingID,PeersReceiver,int,int) range
      * requests} may be used to complete the data, as necessary.
      *
      *     @param rootwardID The identity of the common node immediately to the rootward of the
      *       peers, or null if the peers themselves are roots.
      *     @param receiver The agent to handle any eventual response from the remote count server;
      *       normally this will be either the {@linkplain Forest#receivePeersResponse(Object)
      *       forest}, or an intermediary that delegates to it.
      *     @param paddedLimit The maximum size of the result set when padded by minor peers, or zero to
      *       prevent any such padding.  The actual size may exceed the paddedLimit when the result set
      *       comprises major peers alone, in which case the absolute size limit is determined by the
      *       count engine’s definition of ‘major’ versus ‘minor’.
      *
      *     @throws IllegalArgumentException if paddedLimit is less than zero.
      *
      *     @see <a href='../../../../peer' target='_top'>‘peer’</a>
      */
    public void enqueuePeersRequest( final VotingID rootwardID, final PeersReceiver receiver,
      final int paddedLimit )
    {
        if( paddedLimit < 0 ) throw new IllegalArgumentException();

        receiver.receivePeersResponse( rootwardID );
          // sending an immediate default response in lieu of a real response from the remote server
    }

        /* * *
        - count server may implement by querying for all peers of ordinal <= paddedLimit
            - then calculate from result count the highest ordinal to return,
              and immediately stream the response by filtering out any higher ones
        - major/minor distinction in count engine
            - purpose is to enable efficient paging together with a rough sorting
                - initial page contains all major peers
                    - client can present these in sorted order as desired
                - subsequent pages contain only minor, relatively uninteresting peers
                    - no matter then if client presents page boundaries to user for paging convenience,
                      rather than attempt a total sorting of all peers across all pages
            - maintenance
                - calculate threshold as gFlow/128 (integer)
                    - where gFlow is total flow of peer group
                        ( for voter group, inflow of candidate
                        ( for root group, total inflow of roots, viz. turnout
                            ( not using ground flow registers to calculate turnout, notebook 2015.9.30
                - major node has inflow > threshold
                - as threshold changes it should be easy to isolate range of nodes affected by change
                  and adjust their peer ordinals accordingly
          */



    /** Asynchronously requests the data for a range of minor peers.  The order of peers in the result
      * set is undefined.
      *
      *     @param rootwardID The identity of the node immediately to the rootward, or null if the
      *       peers themselves are roots.
      *     @param receiver The agent to handle any eventual response from the remote count server; normally
      *       this will be either the {@linkplain Forest#receivePeersResponse(Object) forest}, or an
      *       intermediary that delegates to it.
      *     @param peersStart The start ordinal of the range, inclusive.
      *     @param peersEndBound The end ordinal of the range, exclusive.
      *
      *     @throws IndexOutOfBoundsException if pStart is less than 1 or greater than pEndBound.
      */
    public void enqueuePeersRequest( VotingID rootwardID, PeersReceiver receiver,
      int peersStart, int peersEndBound )
    {
        if( peersStart < 1 || peersStart > peersEndBound ) throw new IndexOutOfBoundsException();

     // WaykitUI.setRemotelyUsable();
     /// when this is coded
        throw new UnsupportedOperationException( "Server counts not yet coded" );
    }

        /* * *
        - maintenance of ordinals for minor peers in count engine
            - kept unique and contiguous with minimal effort
            - deletion of minor accomplished by swapping in final minor
                - requires tracking highest ordinal
                    ( stored in candidate node for voters | in poll-wide store for roots
            - an upper limit (< Integer.MAX_VALUE) is imposed
                - thence all remaining peers share same ordinal
                ( not worth using long values here when the only purpose is paging in UI
          */



    /** Synchronously connects to the remote count server and returns from the latest count the identified
      * node complete with its {@linkplain CountNode#rootwardInThis() candidates}, constructing those too as
      * necessary; or returns null if the node is uncounted there.
      *
      *     @see CountNode#id()
      *     @param nodeMap A map of nodes keyed by identity tag.  Any candidate in the map is reused
      *       rather than constructed anew, while all newly constructed candidates are added to the map.
      *
      *     @throws AssertionError if assertions are enabled and nodeMap already keys the given tag.
      */
    public UnadjustedNode fetchNode( final VotingID id, final Map<VotingID,UnadjustedNode> nodeMap )
    {
        assert !nodeMap.containsKey(id): "Not fetching an already fetched node";
        return null; // server counts not yet coded
          // will also have to detect and throw exception on serial inconsitency (RepocastSer)
    }



    /** Answers whether the given string is a well formed poll name, that is a well formed rep
      * {@linkplain ID#isSerialForm(String) serial number}.
      */
    public static boolean isPollNameForm( final String string ) { return ID.isSerialForm( string ); }


}