package org.simantics.spreadsheet.graph;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import org.simantics.Simantics;
import org.simantics.databoard.Bindings;
import org.simantics.databoard.binding.mutable.Variant;
import org.simantics.databoard.util.binary.RandomAccessBinary;
import org.simantics.datatypes.DatatypeResource;
import org.simantics.datatypes.literal.Font;
import org.simantics.datatypes.literal.RGB;
import org.simantics.datatypes.utils.BTree;
import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.WriteGraph;
import org.simantics.db.common.request.BinaryRead;
import org.simantics.db.common.request.ObjectsWithType;
import org.simantics.db.common.request.UnaryRead;
import org.simantics.db.common.request.WriteRequest;
import org.simantics.db.common.utils.LiteralFileUtil;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.exception.ServiceException;
import org.simantics.db.layer0.util.Layer0Utils;
import org.simantics.db.layer0.variable.StandardGraphChildVariable;
import org.simantics.db.layer0.variable.Variable;
import org.simantics.db.layer0.variable.Variables;
import org.simantics.db.procedure.Listener;
import org.simantics.db.service.ClusteringSupport;
import org.simantics.layer0.Layer0;
import org.simantics.scl.compiler.commands.CommandSession;
import org.simantics.scl.runtime.SCLContext;
import org.simantics.scl.runtime.function.Function;
import org.simantics.scl.runtime.tuple.Tuple0;
import org.simantics.scl.runtime.tuple.Tuple2;
import org.simantics.simulator.toolkit.StandardRealm;
import org.simantics.spreadsheet.CellEditor;
import org.simantics.spreadsheet.ExternalRef;
import org.simantics.spreadsheet.OperationMode;
import org.simantics.spreadsheet.Range;
import org.simantics.spreadsheet.Spreadsheets;
import org.simantics.spreadsheet.Transaction;
import org.simantics.spreadsheet.graph.synchronization.SpreadsheetSynchronizationEventHandler;
import org.simantics.spreadsheet.resource.SpreadsheetResource;
import org.simantics.spreadsheet.solver.SheetNode;
import org.simantics.spreadsheet.solver.SpreadsheetBook;
import org.simantics.spreadsheet.solver.SpreadsheetCell;
import org.simantics.spreadsheet.solver.SpreadsheetEngine;
import org.simantics.spreadsheet.solver.SpreadsheetLine;
import org.simantics.spreadsheet.solver.SpreadsheetStyle;
import org.simantics.spreadsheet.util.SpreadsheetUtils;
import org.simantics.structural.synchronization.client.Synchronizer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import gnu.trove.iterator.TObjectIntIterator;
import gnu.trove.map.hash.TObjectIntHashMap;

public class SpreadsheetGraphUtils {

    private static final Logger LOGGER = LoggerFactory.getLogger(SpreadsheetGraphUtils.class);

    public static File extractInitialCondition(ReadGraph graph, Resource ic) throws DatabaseException, IOException {

    	SpreadsheetResource SR = SpreadsheetResource.getInstance(graph);

        File temp = Simantics.getTempfile("excel","ic");

        LiteralFileUtil.copyRandomAccessBinaryToFile(graph, ic, SR.InitialCondition_bytes, temp);
        if (temp.length() == 0)
            throw new FileNotFoundException("Snapshot file does not exist.\nThis seems to be a database bug that manifests as total loss of state file data.\nThis error prevents the program from crashing.");

        return temp;
        
    }
	
    public static RandomAccessBinary getOrCreateRandomAccessBinary(WriteGraph graph, Resource initialCondition) throws DatabaseException, IOException {

    	SpreadsheetResource SR = SpreadsheetResource.getInstance(graph);
    	
        // We put snapshot literals in their own clusters for now just to be safe
        Resource literal = graph.getPossibleObject(initialCondition, SR.InitialCondition_bytes);
        if (literal != null) {
            RandomAccessBinary rab = graph.getRandomAccessBinary(literal);
            rab.position(0);
            rab.removeBytes(rab.length(), RandomAccessBinary.ByteSide.Right);
            return rab;
        } else {
            Layer0 L0 = Layer0.getInstance(graph);
            ClusteringSupport cs = graph.getService(ClusteringSupport.class);
            literal = graph.newResource(cs.createCluster());
            graph.claim(literal, L0.InstanceOf, null, L0.ByteArray);
            graph.claim(initialCondition, SR.InitialCondition_bytes, SR.InitialCondition_bytes_Inverse, literal);
            return graph.createRandomAccessBinary(literal, Bindings.BYTE_ARRAY.type(), null);
        }
    }

    public static Resource saveInitialCondition(WriteGraph graph, Variable run, Resource container, String name) throws DatabaseException {

		String sessionName = run.getParent(graph).getURI(graph);

		Resource bookResource = run.getRepresents(graph);
		
    	StandardRealm<SheetNode, SpreadsheetBook> realm = SpreadsheetSessionManager.getInstance().getOrCreateRealm(graph, sessionName);
    	SpreadsheetBook book = realm.getEngine();

    	try {
    	
	    	File temp = Simantics.getTempfile("excel", "ic");
	    	System.err.println("Saving initial condition to " + temp.getAbsolutePath());
	    	
			FileOutputStream fileOut = new FileOutputStream(temp);
			ObjectOutputStream out = new ObjectOutputStream(fileOut);
			out.writeObject(book);
			out.close();
			fileOut.close();
			
			Layer0 L0 = Layer0.getInstance(graph);
	    	SpreadsheetResource SR = SpreadsheetResource.getInstance(graph);
			Resource ic = graph.newResource();
			graph.claim(ic, L0.InstanceOf, SR.InitialCondition);
			graph.addLiteral(ic, L0.HasName, L0.NameOf, L0.String, name, Bindings.STRING);
	        
	        RandomAccessBinary rab = getOrCreateRandomAccessBinary(graph, ic);
	        LiteralFileUtil.copyRandomAccessBinaryFromFile(temp, rab);
	        
			graph.claim(container, L0.ConsistsOf, L0.PartOf, ic);
			
			graph.deny(bookResource, SR.HasInitialCondition);
			graph.claim(bookResource, SR.HasInitialCondition, ic);
			graph.claim(ic, SR.InitialCondition_ConditionOf, bookResource);
			
			setDefaultInitialConditionForBook(graph, bookResource, ic);

	        return ic;
	        
    	} catch (IOException e) {
    		
    		throw new DatabaseException(e);
    		
    	}
    }
    
    public static void setDefaultInitialConditionForBook(WriteGraph graph, Resource book, Resource ic) throws ServiceException {
        SpreadsheetResource SR = SpreadsheetResource.getInstance(graph);
        graph.deny(book, SR.Book_HasDefaultInitialCondition);
        graph.claim(ic, SR.InitialCondition_DefaultConditionOf, book);
    }

    public static void evaluateAll(ReadGraph graph, Variable run) throws DatabaseException {

		String sessionName = run.getParent(graph).getURI(graph);
    	StandardRealm<SheetNode, SpreadsheetBook> realm = SpreadsheetSessionManager.getInstance().getOrCreateRealm(graph, sessionName);
    	SpreadsheetBook book = realm.getEngine();
    	book.accept(new EvaluateAll(book));
    	
    }

    public static void invalidateAll(ReadGraph graph, Variable run) throws DatabaseException {

		String sessionName = run.getParent(graph).getURI(graph);
    	StandardRealm<SheetNode, SpreadsheetBook> realm = SpreadsheetSessionManager.getInstance().getOrCreateRealm(graph, sessionName);
    	SpreadsheetBook book = realm.getEngine();
    	book.accept(new InvalidateAll());
    	realm.getNodeManager().refreshVariables();
    	
    }
    
    public static boolean fullSynchronization(ReadGraph graph, Variable run) throws DatabaseException {
        return partialSynchronization(graph, run, null);
    }

    public static boolean partialSynchronization(ReadGraph graph, Variable run, TObjectIntHashMap<Variable> changeFlags) throws DatabaseException {

    	Synchronizer synchronizer = new Synchronizer(graph);
		String sessionName = run.getParent(graph).getURI(graph);
		
    	Resource bookResource = run.getRepresents(graph);
    	Variable configuration = Variables.getVariable(graph, bookResource);
    	
    	StandardRealm<SheetNode, SpreadsheetBook> realm = SpreadsheetSessionManager.getInstance().getOrCreateRealm(graph, sessionName);
    	SpreadsheetBook book = realm.getEngine();
    			
        SpreadsheetSynchronizationEventHandler handler = new SpreadsheetSynchronizationEventHandler(graph, book);
        
        if (changeFlags == null) {
            synchronizer.fullSynchronization(configuration, handler);
        } else {
            
            TObjectIntIterator<Variable> iter = changeFlags.iterator();
            iter.advance();
            Variable row = iter.key();
            
            Variable rowParent = row.getParent(graph);
            while (!rowParent.equals(configuration)) {
                changeFlags.put(rowParent, 1);
                rowParent = rowParent.getParent(graph);
            }
            
            changeFlags.put(configuration, 1);
            
            synchronizer.partialSynchronization(configuration, handler, changeFlags);
        }
        
        realm.getNodeManager().fireNodeListeners();
        return handler.getDidChanges();
        
    }

    public static Variable findCell(ReadGraph graph, Variable run, String reference) throws DatabaseException {

    	int pos = reference.indexOf("!");
    	String sheetName = reference.substring(0, pos);
    	String cellName = reference.substring(pos+1);

		String sessionName = run.getParent(graph).getURI(graph);
    	StandardRealm<SheetNode, SpreadsheetBook> realm = SpreadsheetSessionManager.getInstance().getOrCreateRealm(graph, sessionName);
    	SpreadsheetBook book = realm.getEngine();
    	SpreadsheetEngine engine = book.getEngine(sheetName);
    	if(engine == null) return null;
    	
    	Range r = Spreadsheets.decodeCellAbsolute(cellName);
    	SpreadsheetLine line = engine.getLine(r.startRow);
    	if(line == null) return null;
    	
    	String path = line.getPath();
    	if(path == null) return null;
    	
    	Variable lineVariable = run.browse(graph, path);
    	if(lineVariable==null) return null;
    	
    	return lineVariable.getChild(graph, cellName);
    	
    }

    

    public static List<Variable> possibleConfigurationCellVariables(ReadGraph graph, Variable sheet, Range range) throws DatabaseException {
        List<Variable> rowVariables = possibleConfigurationLineVariables(graph, sheet, range);
        List<Variable> result = new ArrayList<>();
        for (Variable variable : rowVariables) {
            Collection<Variable> children = variable.getChildren(graph);
            for (Variable child : children) {
                if (variableInRange(graph, child, range)) {
                    result.add(child);
                }
            }
        }
        return result;
    }
    
    public static Map<Integer, Resource> possibleConfigurationLineResources(ReadGraph graph, Variable sheet, Range range) throws DatabaseException {
        Variable lines = sheet.getPossibleChild(graph, "Lines");
        if (lines == null)
            throw new DatabaseException("Invalid input variable " + sheet.getURI(graph));
        Resource linesR = lines.getRepresents(graph);
        BTree bt = new BTree(graph, linesR);
        List<Tuple2> tuples = bt.searchRangeBTree(graph, Variant.ofInstance(range.startRow), Variant.ofInstance(range.endRow));
        Map<Integer, Resource> result = new HashMap<>(tuples.size());
        for (Tuple2 tuple : tuples) {
            Integer lineNumber = (Integer)((Variant)tuple.c0).getValue();
            Resource resource = (Resource)tuple.c1;
            result.put(lineNumber, resource);
        }
        return result; 
    }
    
    public static List<Variable> possibleConfigurationLineVariables(ReadGraph graph, Variable sheet, Range range) throws DatabaseException {
        Map<Integer, Resource> rows = possibleConfigurationLineResources(graph, sheet, range);
        List<Variable> result = new ArrayList<>(rows.size());
        for (Resource row: rows.values()) {
            Variable lineVar = Variables.getPossibleVariable(graph, row);
            if (lineVar != null)
                result.add(lineVar);
        }
        return result;
    }
    
    public static List<Variable> possibleRunLineVariables(ReadGraph graph, Variable sheetRun, Range range) throws DatabaseException {
    	
    	Variable run = sheetRun.getParent(graph);
    	
    	String sheetName = sheetRun.getName(graph);
    	String sessionName = run.getParent(graph).getURI(graph);
    	
    	StandardRealm<SheetNode, SpreadsheetBook> realm = SpreadsheetSessionManager.getInstance().getOrCreateRealm(graph, sessionName);
    	SpreadsheetBook book = realm.getEngine();
    	
    	SpreadsheetEngine engine = book.getEngine(sheetName);
    	if(engine == null) return null;
    	
    	List<Variable> result = new ArrayList<>();
    	
    	int end = range.endRow < engine.lines.getMaxRow() ? range.endRow : engine.lines.getMaxRow();
    	for (int i = range.startRow; i <= end; i++) {
        	SpreadsheetLine line = engine.getLine(i);
        	if(line == null)
        		continue;
        	
        	String path = line.getPath();
        	path = line.getPath();
        	if(path == null)
        		continue;
        	
        	Variable lineVariable = run.browse(graph, path);
        	if(lineVariable==null)
        		continue;
        	result.add(lineVariable);
    	}
    
        return result;
    }
    
    public static List<Variable> possibleRunCellVariables(ReadGraph graph, Variable sheetRun, Range range) throws DatabaseException {
        List<Variable> runLineVariable = possibleRunLineVariables(graph, sheetRun, range);
        List<Variable> result = new ArrayList<>();
        for (Variable variable : runLineVariable) {
//        	System.out.println("line: " + variable.getURI(graph));
            for (Variable child : variable.getChildren(graph)) {
//            	System.out.print("cell : " + child.getURI(graph));
                if (variableInRange(graph, child, range)) {
                    result.add(child);
                }
            }
        }
        return result;
    }
    
    private static boolean variableInRange(ReadGraph graph, Variable child, Range range) throws DatabaseException {
        String name = child.getName(graph);
        Range childRange = Spreadsheets.decodeCellAbsolute(name);
//        System.out.print(" and range " + childRange);
        if (childRange != null && range.contains(childRange)) {
//        	System.out.println(" => range.contains(childRange) = true");
            return true;
        }
//        System.out.println();
        return false;
    }
    
    public static Map<Integer, Resource> createConfigurationLineResources(WriteGraph graph, Variable sheet, Range range) throws DatabaseException {
        Layer0 L0 = Layer0.getInstance(graph);
        SpreadsheetResource SHEET = SpreadsheetResource.getInstance(graph);
        
        Variable lines = sheet.getPossibleChild(graph, "Lines");
        if (lines == null)
            throw new DatabaseException("Invalid input variable " + sheet.getURI(graph));
        Resource linesR = lines.getRepresents(graph);
        BTree bt = new BTree(graph, linesR);
        
        Map<Integer, Resource> result = new HashMap<>();
        for (int lineNumber = range.startRow; lineNumber <= range.endRow; lineNumber++) {
            Resource line = graph.newResource();
            graph.claim(line, L0.InstanceOf, null, SHEET.Line);
            graph.claimLiteral(line, L0.HasName, L0.NameOf, L0.String, "Row" + lineNumber, Bindings.STRING);
            bt.insertBTree(graph, Variant.ofInstance(lineNumber), line);
            result.put(lineNumber, line);
        }
        return result;
    }

    public static List<Variable> getOrCreateConfigurationCellVariables(WriteGraph graph, Variable sheet, Range range) throws DatabaseException {
        
        List<Variable> rows = possibleConfigurationLineVariables(graph, sheet, range);
        if (rows.isEmpty()) {
            createConfigurationLineResources(graph, sheet, range);
            rows = possibleConfigurationLineVariables(graph, sheet, range);
        }
        
        List<Variable> cells = possibleConfigurationCellVariables(graph, sheet, range);
        if (cells.isEmpty()) {
            Iterator<Variable> rowIterator = rows.iterator();
            for (int rowNumber = range.startRow; rowNumber <= range.endRow; rowNumber++) {
                Variable row = rowIterator.next();
                for (int colNumber = range.startColumn; colNumber <= range.endColumn; colNumber++) {
                    String location = Spreadsheets.cellName(rowNumber, colNumber);
                    defaultCreateCell(graph, row, location, new Variant(Bindings.STRING, ""));
                }
            }
        }
        
        cells = possibleConfigurationCellVariables(graph, sheet, range);
        if(cells.isEmpty())
            throw new DatabaseException("Unexpected problem while creating spreadsheet cell at '" + range + "'");
        
        return cells;
    }
    
    private static void defaultCreateCell(WriteGraph graph, Variable parent, String location, Variant value) throws DatabaseException {

        Layer0 L0 = Layer0.getInstance(graph);
        SpreadsheetResource SHEET = SpreadsheetResource.getInstance(graph);
        Resource container = parent.getRepresents(graph);
        
        Resource cell = graph.newResource();
        graph.claim(cell, L0.InstanceOf, null, SHEET.TextCell);
        graph.addLiteral(cell, L0.HasName, L0.NameOf, L0.String, location, Bindings.STRING);
        graph.addLiteral(cell, SHEET.Cell_content, SHEET.Cell_content_Inverse, L0.Variant, value, Bindings.VARIANT);
        graph.claim(cell, L0.PartOf, container);
        
        Resource book = Variables.getContext(graph, parent).getRepresents(graph);
        
        
        Collection<Resource> objects = graph.sync(new ObjectsWithType(book, L0.ConsistsOf, SHEET.Style));
        
        int styleId = SpreadsheetStyle.empty().getStyleId();
        Resource style = null;
        for (Resource possibleStyle : objects) {
            int possibleStyleId = graph.getRelatedValue2(possibleStyle, SHEET.Style_id, Bindings.INTEGER);
            if (possibleStyleId == styleId) {
                style = possibleStyle;
                break;
            }
        }
        
        if (style == null) {
            style = graph.newResource();
            graph.claim(style, L0.InstanceOf, null, SHEET.Style);
            graph.claim(style, L0.PartOf, book);
            
            int id = objects.size();
            graph.claimLiteral(style, L0.HasName, "Style_" + id);
            graph.claimLiteral(style, SHEET.Style_id, styleId, Bindings.INTEGER);
        }
        graph.claim(cell, SHEET.Cell_HasStyle, style);
        Layer0Utils.addCommentMetadata(graph, "Created cell on location " + location + " with value " + value.toString());
    }

    public static Resource createStyle(WriteGraph graph, Resource book, SpreadsheetStyle sstyle) throws DatabaseException {
        Layer0 L0 = Layer0.getInstance(graph);
        SpreadsheetResource SR = SpreadsheetResource.getInstance(graph);
        Resource style = graph.newResource();
        graph.claim(style, L0.InstanceOf, null, SR.Style);
        graph.claim(style, L0.PartOf, book);
        
        int styleId = sstyle.getStyleId();
        String styleName = sstyle.name;
        
        graph.claimLiteral(style, L0.HasName, styleName);
        //System.err.println("CREATING STYLE " + styleName + " WITH ID: " + styleId);
        graph.claimLiteral(style, SR.Style_id, styleId, Bindings.INTEGER);
        
        DatatypeResource DATATYPES = DatatypeResource.getInstance(graph);
        if (sstyle.foreground != null)
            graph.claimLiteral(style, SR.Cell_foreground, DATATYPES.RGB_Integer, sstyle.foreground, RGB.Integer.BINDING);
        if (sstyle.background != null)
            graph.claimLiteral(style, SR.Cell_background, DATATYPES.RGB_Integer, sstyle.background, RGB.Integer.BINDING);
        if (sstyle.align != -1)
            graph.claimLiteral(style, SR.Cell_align, sstyle.align, Bindings.INTEGER);
        if (sstyle.font != null)
            graph.claimLiteral(style, SR.Cell_font, DATATYPES.Font, sstyle.font, Font.BINDING);
        if (sstyle.border != -1)
            graph.claimLiteral(style, SR.Cell_border, sstyle.border);
        if (sstyle.formatString != null && !sstyle.formatString.isEmpty())
            graph.claimLiteral(style, SR.Cell_formatString, sstyle.formatString, Bindings.STRING);
        if (sstyle.formatIndex != -1)
            graph.claimLiteral(style, SR.Cell_formatIndex, sstyle.formatIndex, Bindings.INTEGER);
        
        return style;
    }
    
    public static Resource createBook(WriteGraph graph, Resource parent, String name) throws DatabaseException {
        Layer0 L0 = Layer0.getInstance(graph);
        SpreadsheetResource SR = SpreadsheetResource.getInstance(graph);
        Resource book = graph.newResource();
        graph.claim(book, L0.InstanceOf, SR.Book);
        graph.claimLiteral(book, L0.HasName, L0.NameOf, L0.String, name, Bindings.STRING);
        graph.claim(parent, L0.ConsistsOf, book);
        
        return book;
    }
    
    public static Variable constructAndInitializeRunVariable(WriteGraph graph, Resource root) throws DatabaseException {
        Variable run = SpreadsheetUtils.getBookVariable(graph, root);
        SpreadsheetGraphUtils.fullSynchronization(graph, run);
        SpreadsheetGraphUtils.evaluateAll(graph, run);
        SpreadsheetGraphUtils.saveInitialCondition(graph, run, root, "Initial");
        return run;
    }
    
    public static Variant extRefVariable(ReadGraph graph, Variable var) throws DatabaseException {
        return new Variant(Bindings.VOID, new ExternalRefVariable(graph, var));
    }
    
    static class ExternalRefVariable implements ExternalRef {

        final private String uri;
        
        public ExternalRefVariable(ReadGraph graph, Variable variable) throws DatabaseException {
            this.uri = variable.getURI(graph);
        }
        
        @Override
        public void listen(Object context, ExternalRefListener listener) {
            Simantics.getSession().asyncRequest(new UnaryRead<String, Variant>(uri) {

                @Override
                public Variant perform(ReadGraph graph) throws DatabaseException {
                    Variable variable = Variables.getVariable(graph, parameter);
                    return variable.getVariantValue(graph);
                }
                
            }, new Listener<Variant>() {

                @Override
                public void execute(Variant result) {
                    listener.newValue(result);
                }

                @Override
                public void exception(Throwable t) {
                    LOGGER.error("Error while evaluating variable value", t);
                }

                @Override
                public boolean isDisposed() {
                    return listener.isDisposed();
                }
                
            });
        }
        
        @Override
        public void modify(Object context, Variant newValue) {
            
            Simantics.getSession().asyncRequest(new WriteRequest() {

                @Override
                public void perform(WriteGraph graph) throws DatabaseException {
                    Variable variable = Variables.getVariable(graph, uri);
                    variable.setValue(graph, newValue);
                }
            });
            
        }
        
    }

    public static Variant extRefActiveVariable(ReadGraph graph, Variable var) throws DatabaseException {
        return new Variant(Bindings.VOID, new ExternalRefActiveVariable(graph, var));
    }
    
    static class ExternalRefActiveVariable implements ExternalRef {

        final private String uri;
        
        public ExternalRefActiveVariable(ReadGraph graph, Variable variable) throws DatabaseException {
            this.uri = variable.getURI(graph);
        }
        
        @Override
        public void listen(Object context, ExternalRefListener listener) {
            Simantics.getSession().asyncRequest(new BinaryRead<String, String, Variant>((String)context, uri) {

                @Override
                public Variant perform(ReadGraph graph) throws DatabaseException {
                    Variable contextVariable = Variables.getVariable(graph, parameter);
                    Variable configVariable = Variables.getVariable(graph, parameter2);
                    Variable activeVariable = Variables.switchPossibleContext(graph, configVariable, contextVariable.getRepresents(graph));
                    if(activeVariable == null) return Variant.ofInstance("Could not resolve " + configVariable.getURI(graph) + " for " + contextVariable.getURI(graph));
                    return activeVariable.getVariantValue(graph);
                }
            }, new Listener<Variant>() {

                @Override
                public void execute(Variant result) {
                    listener.newValue(result);
                }

                @Override
                public void exception(Throwable t) {
                    LOGGER.error("Error while evaluating variable value, context = " + context + " uri=" + uri, t);
                }

                @Override
                public boolean isDisposed() {
                    return listener.isDisposed();
                }
                
            });
        }
        
        @Override
        public void modify(Object context, Variant newValue) {
            
            Simantics.getSession().asyncRequest(new WriteRequest() {

                @Override
                public void perform(WriteGraph graph) throws DatabaseException {
                    Variable contextVariable = Variables.getVariable(graph, (String)context);
                    Variable configVariable = Variables.getVariable(graph,uri);
                    Variable activeVariable = Variables.switchPossibleContext(graph, configVariable, contextVariable.getRepresents(graph));
                    if(activeVariable == null) return;
                    activeVariable.setValue(graph, newValue.getValue(), newValue.getBinding());
                }
            });
            
        }
        
    }
    
    public static CellEditor cellEditor(ReadGraph graph, Resource sheet) throws DatabaseException {
        SpreadsheetResource SHEET = SpreadsheetResource.getInstance(graph);
        Variable sheetVariable = Variables.getVariable(graph, sheet);
        return sheetVariable.getPropertyValue(graph, SHEET.cellEditor);
    }
    
    public static final String SPREADSHEET_TRANSACTION = "spreadsheetTransaction";

    @SuppressWarnings({ "rawtypes", "unchecked" })
    public static Object syncExec(CellEditor editor, OperationMode mode, Function fun) throws InterruptedException {
        
        Transaction tr = editor.startTransaction(mode);
        
        SCLContext context = SCLContext.getCurrent();
        Transaction oldTransaction = (Transaction)context.put(SPREADSHEET_TRANSACTION, tr);
        
        Object result = null;
        
        try {

            result = fun.apply(Tuple0.INSTANCE);
            
        } finally {
            
            tr.commit();
            
            context.put(SPREADSHEET_TRANSACTION, oldTransaction);
            
        }
        
        return result;
        
    }
    
    public static int cellColumn(ReadGraph graph, Variable cell) {
        if(cell instanceof StandardGraphChildVariable) {
            StandardGraphChildVariable sgcv = (StandardGraphChildVariable)cell;
            SpreadsheetCell sc = (SpreadsheetCell)sgcv.node.node;
            return sc.getColumn();
        }
        throw new IllegalStateException("Expected StandardGraphChildVariable, got " + cell.getClass().getName());
    }
    
}