package org.simantics.db.layer0.util;

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import org.simantics.databoard.Bindings;
import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.ResourceMap;
import org.simantics.db.common.request.ReadRequest;
import org.simantics.db.common.utils.Logger;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.layer0.adapter.SubgraphExtent.ExtentStatus;
import org.simantics.db.layer0.util.TransferableGraphConfiguration2.SeedSpec;
import org.simantics.db.layer0.util.TransferableGraphConfiguration2.SeedSpec.SeedSpecType;
import org.simantics.db.procedure.SyncContextMultiProcedure;
import org.simantics.db.service.DirectQuerySupport;
import org.simantics.layer0.Layer0;
import org.simantics.utils.datastructures.Pair;

class ConsistsOfProcess {

	final List<ConsistsOfProcessEntry> result;
	final Set<Resource> childrenWithNoName;
	final SyncContextMultiProcedure<ConsistsOfProcessEntry, Resource> structure;
	final SyncContextMultiProcedure<ConsistsOfProcessEntry, Resource> names;

	public static Pair<List<ConsistsOfProcessEntry>,Set<Resource>> walk(ReadGraph graph, Collection<SeedSpec> specs, boolean ignoreVirtual) throws DatabaseException {
		return walk(graph, null, specs, ignoreVirtual);
	}

	public static Pair<List<ConsistsOfProcessEntry>,Set<Resource>> walk(ReadGraph graph, ResourceMap<ExtentStatus> status, Collection<SeedSpec> specs, boolean ignoreVirtual) throws DatabaseException {
		
    	ConsistsOfProcess process = new ConsistsOfProcess(graph, status, specs, ignoreVirtual);
    	return Pair.make(process.result, process.childrenWithNoName);
    	
    }
    
    static class ConsistsOfProcessEntry {
    	public ConsistsOfProcessEntry parent;
    	public Resource resource;
    	public boolean valid = true;
    	public String name = null;
    	ConsistsOfProcessEntry(ConsistsOfProcessEntry parent, Resource resource) {
    		this.parent = parent;
    		this.resource = resource;
    	}
    }
	
    private ConsistsOfProcess(ReadGraph graph, ResourceMap<ExtentStatus> status, final Collection<SeedSpec> seeds, final boolean ignoreVirtual) throws DatabaseException {

		final Layer0 L0 = Layer0.getInstance(graph);
		final DirectQuerySupport dqs = graph.getService(DirectQuerySupport.class);
		
		result = new ArrayList<>();
		childrenWithNoName = new HashSet<>();
		names = dqs.compileForEachObject(graph, L0.HasName, new SyncContextMultiProcedure<ConsistsOfProcessEntry, Resource>() {

			@Override
			public void execute(ReadGraph graph, ConsistsOfProcessEntry entry, Resource nameResource) throws DatabaseException {
		
				if(status != null)
					status.put(nameResource, ExtentStatus.EXCLUDED);
				
			    if(!entry.valid) return;

				String name = graph.getValue(nameResource, Bindings.STRING);
				if(name == null) {
					entry.valid = false;
				} else if (entry.name != null) {
					entry.valid = false;
				} else {
					entry.name = name;
				}

				
			}

			@Override
			public void exception(ReadGraph graph, Throwable throwable) {
				Logger.defaultLogError(throwable);
			}

			@Override
			public void finished(ReadGraph graph, ConsistsOfProcessEntry entry) {
			    if(entry.valid) {
			        if(entry.name != null) {
			            result.add(entry);
			        } else {
			            // This one did not have a name - not a valid internal
			            childrenWithNoName.add(entry.resource);
			        }
			    } else {
			        // Something wrong has happened. Do not treat as valid internal
			        childrenWithNoName.add(entry.resource);
			    }
			}
		});
		
		structure = dqs.compileForEachObject(graph, L0.ConsistsOf, new SyncContextMultiProcedure<ConsistsOfProcessEntry, Resource>() {

			@Override
			public void execute(ReadGraph graph, ConsistsOfProcessEntry parent, Resource child) {

				if(status != null)
					if(ExtentStatus.EXCLUDED.equals(status.get(child))) return;
				
				if(!ignoreVirtual || child.isPersistent()) {
					ConsistsOfProcessEntry entry = new ConsistsOfProcessEntry(parent, child);
					dqs.forEachObjectCompiled(graph, child, entry, structure);
					dqs.forEachObjectCompiled(graph, child, entry, names);
				}
				
			}

			@Override
			public void finished(ReadGraph graph, ConsistsOfProcessEntry parent) {
			}

			@Override
			public void exception(ReadGraph graph, Throwable throwable) {
				Logger.defaultLogError(throwable);
			}

		});
		
		graph.syncRequest(new ReadRequest() {

			@Override
			public void run(ReadGraph graph) throws DatabaseException {
				for(SeedSpec seed  : seeds) {
					
					if(status != null) {
						ExtentStatus es = status.get(seed.resource);
						if(ExtentStatus.EXCLUDED.equals(es)) continue;
						if(ExtentStatus.EXTERNAL.equals(es)) continue;
					}
					
					ConsistsOfProcessEntry entry = new ConsistsOfProcessEntry(null, seed.resource);
					
					dqs.forEachObjectCompiled(graph, seed.resource, entry, structure);
					if(SeedSpecType.INTERNAL.equals(seed.specType)) {
						// Process names only for internal seeds
						dqs.forEachObjectCompiled(graph, seed.resource, entry, names);
					}
				}
			}
			
		});
		
	}
	
    
}