/*******************************************************************************
 * Copyright (c) 2007, 2010 Association for Decentralized Information Management
 * in Industry THTH ry.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Foster Wheeler Energia Oy - initial API and implementation
 *******************************************************************************/
package org.simantics.interop.test;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.Stack;

import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.Statement;
import org.simantics.db.common.utils.NameUtils;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.exception.DoesNotContainValueException;
import org.simantics.db.exception.ServiceException;
import org.simantics.db.exception.ValidationException;
import org.simantics.layer0.Layer0;
import org.simantics.utils.datastructures.BijectionMap;
import org.simantics.utils.datastructures.MapList;
import org.simantics.utils.datastructures.Pair;

/**
 * Compares two subgraphs and reports differences.
 * 
 * Assumes that subgraphs (defined using traverse relations) are not cyclic.
 * 
 * Assumes that properties can be used to identify objects, if relation type is not enough.
 * 
 * 
 * 
 * @author Marko Luukkainen <marko.luukkainen@vtt.fi>
 *
 */
public class GraphComparator {

	private Resource r1;
	private Resource r2;
	private List<Resource> traversed = new ArrayList<Resource>(); // list of relations that are traversed (and tested)
	private List<Resource> tested = new ArrayList<Resource>();    // list of relations that are tested, but not traversed
	private List<Resource> nonTraversed = new ArrayList<Resource>(); // list of relations that are not traversed
	private List<Resource> nonTested = new ArrayList<Resource>(); // list of relations that are not tested
	
	private List<Statement> changes1 = new ArrayList<Statement>();
	private List<Statement> changes2 = new ArrayList<Statement>();
	private List<Pair<Statement,Statement>> modifications = new ArrayList<Pair<Statement,Statement>>();
	private Set<Statement> changes1Set = new HashSet<Statement>();
	private Set<Statement> changes2Set = new HashSet<Statement>();
	private Set<Pair<Statement,Statement>> modificationsSet = new HashSet<Pair<Statement,Statement>>();

	private BijectionMap<Statement, Statement> comparableStatements = new BijectionMap<Statement, Statement>();
	private BijectionMap<Resource, Resource> comparableResources = new BijectionMap<Resource, Resource>();
	
	
	private ObjectComparator comparator;
	
	// runtime attributes
	
	private ReadGraph g;
	private Layer0 b;
	
	public GraphComparator() {
		 comparator = new TypeComparator();
	}
	
	public GraphComparator(ObjectComparator comparator) {
		 this.comparator = comparator;
	}
	
	ArrayList<Statement> ss1 = new ArrayList<Statement>();
	ArrayList<Statement> ss2 = new ArrayList<Statement>();
	
	Comparator<Statement> scomp = new PredicateComparator();
	Comparator<Resource> rcomp = new ResourceComparator();

	
	public void addTraversed(Resource rel) {
		traversed.add(rel);
	}
	
	public void addTraversed(Collection<Resource> rels) {
		traversed.addAll(rels);
	}
	
	public void addNonTraversed(Resource rel) {
		nonTraversed.add(rel);
	}
	
	public void addNonTraversed(Collection<Resource> rels) {
		nonTraversed.addAll(rels);
	}
	
	public void addTested(Resource rel) {
		tested.add(rel);
	}
	
	public void addTested(Collection<Resource> rels) {
		tested.addAll(rels);
	}
	
	public void addNonTested(Resource rel) {
		nonTested.add(rel);
	}
	
	public void addNonTested(Collection<Resource> rels) {
		nonTested.addAll(rels);
	}
	
	public void clearRels() {
		traversed.clear();
		tested.clear();
	}
	
	public void test(ReadGraph g, Resource r1, Resource r2) throws DatabaseException {
		this.g = g;
		this.b = Layer0.getInstance(g);
		
		this.r1 = r1;
		this.r2 = r2;
		changes1Set.clear();
		changes2Set.clear();
		modificationsSet.clear();
		changes1.clear();
		changes2.clear();
		modifications.clear();
		comparableResources.clear();
		
		Stack<Resource> stack1 = new Stack<Resource>();
		Stack<Resource> stack2 = new Stack<Resource>();
		stack1.push(r1);
		stack2.push(r2);
		
		
		List<Statement> ss1 = new ArrayList<Statement>();
		List<Statement> ss2 = new ArrayList<Statement>();
		
		while (!stack1.isEmpty()) {
			r1 = stack1.pop();
			r2 = stack2.pop();
		
			if (comparableResources.contains(r1, r2)) {
				System.out.println("already tested " + NameUtils.getSafeName(g, r1) + " " + NameUtils.getSafeName(g, r2));
				continue;
			}
			comparableResources.map(r1, r2);
			
			System.out.println("test " + NameUtils.getSafeName(g, r1) + " " + NameUtils.getSafeName(g, r2));
			compareProps(r1, r2);
			
			for (Resource rel : tested) {
				ss1.addAll(g.getStatements(r1, rel));
				ss2.addAll(g.getStatements(r2, rel));
				ss1 = filterAsserted(r1, ss1);
				ss2 = filterAsserted(r2, ss2);
				ss1 = filterTraversed(ss1);
				ss2 = filterTraversed(ss2);
				ss1 = filterNonTested(ss1);
				ss2 = filterNonTested(ss2);
				
				compareStatements(ss1, ss2, null, null);
				ss1.clear();
				ss2.clear();
			}
			
			for (Resource rel : traversed) {
				ss1.addAll(g.getStatements(r1, rel));
				ss2.addAll(g.getStatements(r2, rel));
				ss1 = filterAsserted(r1, ss1);
				ss2 = filterAsserted(r2, ss2);
				compareStatements(ss1, ss2, stack1, stack2);
				ss1.clear();
				ss2.clear();
			}
		}
 	}
	
	
	
	public BijectionMap<Statement, Statement> getComparableStatements() {
		return comparableStatements;
	}
	
	public GraphChanges getChanges() {
		return new GraphChanges(r1,r2,changes1,changes2,modifications);
	}
	
	private List<Statement> filterAsserted(Resource r, Collection<Statement> in) throws ServiceException {
		List<Statement> out = new ArrayList<Statement>();
		for (Statement s : in) {
			if (!s.isAsserted(r))
				out.add(s);
			
		}
		return out;
	}
	
	private String printStatement(ReadGraph graph, Statement s) throws ValidationException, ServiceException {
		return NameUtils.getSafeName(graph, s.getSubject()) + " " + NameUtils.getSafeName(graph, s.getPredicate()) + " " + NameUtils.getSafeName(graph, s.getObject());
	}
	
	private List<Statement> filterTraversed(List<Statement> in) throws ServiceException {
		return filter(traversed, in);
	}
	
	private List<Statement> filterNonTested(List<Statement> in) throws ServiceException {
		return filter(nonTested, in);
	}
	
	private List<Statement> filter(Collection<Resource> toFilter, List<Statement> in) throws ServiceException {
		if (toFilter.size() == 0)
			return in;
		List<Statement> out = new ArrayList<Statement>();
		for (Statement s : in) {
			boolean usable = true;
			for (Resource r : toFilter) {
				if (g.isSubrelationOf(s.getPredicate(),r)) {
					usable = false;
					break;
				}
			}
			if (usable) {
				out.add(s);
			}
			
		}
		return out;
	}
	
	
	private void addDeletion(Statement s) {
		if (!changes1Set.contains(s)) {
			changes1Set.add(s);
			changes1.add(s);
		}
	}
	
	private void addAddition(Statement s) {
		if (!changes2Set.contains(s)) {
			changes2Set.add(s);
			changes2.add(s);
		}
	}
	
	private void addModification(Statement s1, Statement s2) {
		Pair<Statement, Statement> mod = new Pair<Statement, Statement>(s1,s2);
		if (!modificationsSet.contains(mod)) {
			modificationsSet.add(mod);
			modifications.add(mod);
		}
	}
	
	private void compareStatements(List<Statement> ss1, List<Statement> ss2, Stack<Resource> stack1, Stack<Resource> stack2) throws DatabaseException {
		Collections.sort(ss1, scomp);
		Collections.sort(ss2, scomp);
		
		int i1 = 0;
		int i2 = 0;
		
		while (true) {
			if (i1 >= ss1.size()) {
				if (i2 >= ss2.size()) {
					break;
				} else {
					while (i2 < ss2.size()) {
						System.out.println("Compare Statement diff2 " + printStatement(g,ss2.get(i2)));
						
						addAddition(ss2.get(i2));
						i2++;
					}
					break;
				}
			} else if (i2 >= ss2.size()) {
				while (i1 < ss1.size()) {
					System.out.println("Compare Statement diff1 " + printStatement(g,ss1.get(i1)));
					addDeletion(ss1.get(i1));
					i1++;
				}
				break;
			}
			int same1 = sameRel(ss1, i1);
			int same2 = sameRel(ss2, i2);
			int c = rcomp.compare(ss1.get(i1).getPredicate(),ss2.get(i2).getPredicate());
			if (c == 0) {
				compareStatements(ss1, i1, same1, ss2, i2, same2,stack1,stack2);
				i1+=same1;
				i2+=same2;
			} else if (c < 0) {
				for (int i = 0; i < same1; i++) {
					System.out.println("Compare Statement diff1 " + printStatement(g,ss1.get(i+i1)));
					addDeletion(ss1.get(i+i1));
				}
				i1 += same1;
			} else {
				for (int i = 0; i < same2; i++) {
					System.out.println("Compare Statement diff2 " + printStatement(g,ss2.get(i+i2)));
					addAddition(ss2.get(i+i2));
				}
				
				i2 += same2;
			}
			
		}
	}
	
	private int sameRel(List<Statement> statements, int off) {
		if (statements.size() <= off)
			return 0;
		int same = 1;
		long id = statements.get(off).getPredicate().getResourceId();
		for (int i = off+1; i <statements.size(); i++) {
			if (statements.get(i).getPredicate().getResourceId() == id)
				same++;
			else 
				break;
		}
		return same;
		
	}

	private int compareObject(Resource o1, Resource o2) throws DatabaseException {
		if (comparableResources.contains(o1, o2))
			return (-1);
		return comparator.compare(g, o1, o2);
	}
	
	private void compareStatements(List<Statement> ss1, int off1, int len1, List<Statement> ss2, int off2, int len2, Stack<Resource> stack1, Stack<Resource> stack2) throws DatabaseException {
		boolean[] used1 = new boolean[len1];
		for (int i = 0; i < used1.length; i++) {
			used1[i] = false;
		}
		
		boolean[] used2 = new boolean[len2];
		for (int i = 0; i < used2.length; i++) {
			used2[i] = false;
		}
		
		// left, right, difference
		List<List<Integer>> differences = new ArrayList<List<Integer>>();
		for (int i1 = off1; i1 < off1 + len1; i1++) {
			Statement s1 = ss1.get(i1);
			List<Integer> diff = new ArrayList<Integer>();
			for (int i2 = off2; i2 < off2 + len2; i2++) {
				Statement s2 = ss2.get(i2);
				diff.add(compareObject(s1.getObject(), s2.getObject()));
			}
			differences.add(diff);
		}
		// difference, left
		MapList<Integer, Integer> priorities = new MapList<Integer, Integer>();
		for (int i = 0; i < differences.size(); i++) {
			List<Integer> list = differences.get(i);
			for (int j = 0; j < list.size(); j++) {
				priorities.add(list.get(j), i);
			}
		}
		
		Integer[] pris = priorities.getKeys(new Integer[]{});
		Arrays.sort(pris);
		
		for (Integer pri : pris) {
			if (pri == Integer.MAX_VALUE)
				continue;
			List<Integer> i1s = priorities.getValues(pri);
			for (Integer i1 : i1s) {
				if (used1[i1])
					continue;
				List<Integer> i2diff = differences.get(i1);
				for (int i2 = 0; i2 < i2diff.size(); i2++) {
					if (i2diff.get(i2) == pri) {
						if (used2[i2])
							continue;
						used1[i1] = true;
						used2[i2] = true;
						Statement s1  = ss1.get(i1+off1);
						Statement s2  = ss2.get(i2+off2);
						
						if (stack1 != null) {
							
								stack1.add(s1.getObject());
								stack2.add(s2.getObject());
							
						} else {
							// TODO : how should we report non traversed differences
							// using compareProps assumes that referenced objects are the same (references are not different)
							// using propsDiffCount assumes that objects are different, and cannot report changes in referred object.
							
							
//							int diff = propsDiffCount(ss1.get(i1+off1).getObject(), ss2.get(i2+off2).getObject());
//							if (diff != 0) {
//								//changes1.add(ss1.get(i1+off1));
//								//changes2.add(ss2.get(i2+off2));
//								modifies.add(new Pair<Statement, Statement>(ss1.get(i1+off1), ss2.get(i2+off2)));
//							}
						}
						comparableStatements.map(s1, s2);
						//comparableResources.map(s1.getObject(), s2.getObject());
						break;
					}
				}
			}
		}
		for (int i1 = off1; i1 < off1 + len1; i1++) {
			if (!used1[i1-off1]) {
				System.out.println("Compare Object diff1 " + printStatement(g,ss1.get(i1)));
				addDeletion(ss1.get(i1));
			}
		}
		for (int i2 = off2; i2 < off2 + len2; i2++) {
			if (!used2[i2-off2]) {
				System.out.println("Compare Object diff2 " + printStatement(g,ss2.get(i2)));
				addAddition(ss2.get(i2));
			}
		}
	}
	
	
	
	/**
	 * compares properties, assumes functional relations
	 * @param r1
	 * @param r2
	 * @throws ServiceException
	 * @throws DoesNotContainValueException
	 * @throws ValidationException 
	 */
	private void compareProps(Resource r1, Resource r2) throws ServiceException, DoesNotContainValueException, ValidationException {
		ArrayList<Statement> ss1 = new ArrayList<Statement>();
		ArrayList<Statement> ss2 = new ArrayList<Statement>();
		ss1.addAll(g.getStatements(r1, b.HasProperty));
		ss2.addAll(g.getStatements(r2, b.HasProperty));
		Collections.sort(ss1, scomp);
		Collections.sort(ss2, scomp);
		
		int i1 = 0; 
		int i2 = 0;
		
		while (true) {
			if (i1 >= ss1.size()) {
				if (i2 >= ss2.size())
					break;
				else {
					while (i2 < ss2.size()) {
						System.out.println("Compare Prop diff2 " + printStatement(g,ss2.get(i2)));
						addAddition(ss2.get(i2));
						i2++;
					}
					break;
				}
			} else if (i2 >= ss2.size()) {
				while (i1 < ss1.size()) {
					System.out.println("Compare Prop diff1 " + printStatement(g,ss1.get(i1)));
					addDeletion(ss1.get(i1));
					i1++;
				}
				break;
			}
			Statement s1 = ss1.get(i1);
			Statement s2 = ss2.get(i2);
			int c = scomp.compare(s1, s2);
			switch (c) {
			case 0:{
				boolean b1 = g.hasValue(s1.getObject());
				boolean b2 = g.hasValue(s2.getObject());
				if (b1 == b2) {
					if (b1) {
						Object v1 = g.getValue(s1.getObject());
						Object v2 = g.getValue(s2.getObject());
						boolean eq = compareValue(v1, v2);
						if (!eq) {
							addModification(s1, s2);
							comparableStatements.map(s1, s2);
							comparableResources.map(s1.getObject(),s2.getObject());
						}
					} else {
						compareProps(s1.getObject(), s2.getObject());
					}
				} else {
					addModification(s1, s2);
					comparableStatements.map(s1, s2);
					comparableResources.map(s1.getObject(),s2.getObject());
				}
				i1++;
				i2++;
				break;
			}
			case -1:{
				System.out.println("Compare Prop diff1s " + printStatement(g,s1));
				addDeletion(s1);
				i1++;
				break;
			}
				
			case 1:{
				System.out.println("Compare Prop diff2s " + printStatement(g,s2));
				addAddition(s2);
				i2++;
				break;
			}
			}
			
			
		}
		
		ss1.clear();
		ss2.clear();
		
	}
	
	
	public static boolean compareValue(Object v1, Object v2) {
		if (v1 instanceof Object[] && v2 instanceof Object[])
			return Arrays.deepEquals((Object[])v1, (Object[])v2);
		else if (v1 instanceof int[] && v2 instanceof int[]) 
			return Arrays.equals((int[])v1, (int[])v2);
		else if (v1 instanceof float[] && v2 instanceof float[]) 
			return Arrays.equals((float[])v1, (float[])v2);
		else if (v1 instanceof double[] && v2 instanceof double[]) 
			return Arrays.equals((double[])v1, (double[])v2);
		else if (v1 instanceof long[] && v2 instanceof long[]) 
			return  Arrays.equals((long[])v1, (long[])v2);
		else if (v1 instanceof byte[] && v2 instanceof byte[]) 
			return Arrays.equals((byte[])v1, (byte[])v2);
		else if (v1 instanceof boolean[] && v2 instanceof boolean[]) 
			return Arrays.equals((boolean[])v1, (boolean[])v2);
		else
			return v1.equals(v2);
	}

	
	
	public static class PredicateComparator implements Comparator<Statement> {
		@Override
		public int compare(Statement o1, Statement o2) {
			if (o1.getPredicate().getResourceId() < o2.getPredicate().getResourceId())
				return -1;
			if (o1.getPredicate().getResourceId() > o2.getPredicate().getResourceId())
				return 1;
			return 0;
		}
	}
	
	public static class FullStatementComparator implements Comparator<Statement> {
		@Override
		public int compare(Statement o1, Statement o2) {
			if (o1.getSubject().getResourceId() < o2.getSubject().getResourceId())
				return -1;
			if (o1.getSubject().getResourceId() > o2.getSubject().getResourceId())
				return 1;
			if (o1.getPredicate().getResourceId() < o2.getPredicate().getResourceId())
				return -1;
			if (o1.getPredicate().getResourceId() > o2.getPredicate().getResourceId())
				return 1;
			if (o1.getObject().getResourceId() < o2.getObject().getResourceId())
				return -1;
			if (o1.getObject().getResourceId() > o2.getObject().getResourceId())
				return 1;
			return 0;
		}
	}
	

	
	public static class ResourceComparator implements Comparator<Resource> {
		@Override
		public int compare(Resource o1, Resource o2) {
			if (o1.getResourceId() < o2.getResourceId())
				return -1;
			if (o1.getResourceId() > o2.getResourceId())
				return 1;
			return 0;
		}
	}
	
	
}