/*******************************************************************************
 * 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.List;
import java.util.Stack;

import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.Statement;
import org.simantics.db.exception.DoesNotContainValueException;
import org.simantics.db.exception.ManyObjectsForFunctionalRelationException;
import org.simantics.db.exception.ServiceException;
import org.simantics.db.exception.ValidationException;
import org.simantics.layer0.Layer0;
import org.simantics.layer0.utils.direct.GraphUtils;
import org.simantics.utils.datastructures.BijectionMap;
import org.simantics.utils.datastructures.MapList;

/**
 * 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 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<Statement> changes1 = new ArrayList<Statement>();
	private List<Statement> changes2 = new ArrayList<Statement>();
	private BijectionMap<Statement, Statement> comparable = new BijectionMap<Statement, Statement>();
	
	
	// runtime attributes
	
	private ReadGraph g;
	private Layer0 b;
	
	ArrayList<Resource> rs1 = new ArrayList<Resource>();
	ArrayList<Resource> rs2 = new ArrayList<Resource>();
	ArrayList<Statement> ss1 = new ArrayList<Statement>();
	ArrayList<Statement> ss2 = new ArrayList<Statement>();
	Comparator<Statement> scomp = new StatementComparator();
	Comparator<Resource> rcomp = new ResourceComparator();

	
	public void addTraversed(Resource rel) {
		traversed.add(rel);
	}
	
	public void addTraversed(Collection<Resource> rels) {
		traversed.addAll(rels);
	}
	
	public void addTested(Resource rel) {
		tested.add(rel);
	}
	
	public void addTested(Collection<Resource> rels) {
		tested.addAll(rels);
	}
	
	public void clearRels() {
		traversed.clear();
		tested.clear();
	}
	
	public void test(ReadGraph g, Resource r1, Resource r2) throws ServiceException, DoesNotContainValueException, ValidationException {
		this.g = g;
		this.b = Layer0.getInstance(g);
		
		changes1.clear();
		changes2.clear();
		
		Stack<Resource> stack1 = new Stack<Resource>();
		Stack<Resource> stack2 = new Stack<Resource>();
		stack1.push(r1);
		stack2.push(r2);
		
		ArrayList<Statement> ss1 = new ArrayList<Statement>();
		ArrayList<Statement> ss2 = new ArrayList<Statement>();
		
		while (!stack1.isEmpty()) {
			r1 = stack1.pop();
			r2 = stack2.pop();
			
			System.out.println("test " + GraphUtils.getReadableName(g, r1) + " " + GraphUtils.getReadableName(g, r2));
			compareProps(r1, r2);
			
			for (Resource rel : tested) {
				filterTraversed(g.getStatements(r1, rel), ss1);
				filterTraversed(g.getStatements(r2, rel), ss2);
				
				compareStatement(ss1, ss2, null, null);
				ss1.clear();
				ss2.clear();
			}
			
			for (Resource rel : traversed) {
				ss1.addAll(g.getStatements(r1, rel));
				ss2.addAll(g.getStatements(r2, rel));
				compareStatement(ss1, ss2, stack1, stack2);
				ss1.clear();
				ss2.clear();
			}
		}
 	}
	
	public Collection<Statement> getChanges1() {
		return changes1;
	}
	
	public Collection<Statement> getChanges2() {
		return changes2;
	}
	
	public BijectionMap<Statement, Statement> getComparable() {
		return comparable;
	}
	
	private void filterTraversed(Collection<Statement> in, Collection<Statement> out) throws ServiceException {
		for (Statement s : in) {
			boolean usable = true;
			for (Resource r : traversed) {
				if (g.isSubrelationOf(s.getPredicate(),r)) {
					usable = false;
					break;
				}
			}
			if (usable) {
				out.add(s);
			}
			
		}
	}
	
	private void compareStatement(List<Statement> ss1, List<Statement> ss2, Stack<Resource> stack1, Stack<Resource> stack2) throws ServiceException, DoesNotContainValueException, ValidationException {
		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()) {
						changes2.add(ss2.get(i2));
						i2++;
					}
					break;
				}
			} else if (i2 >= ss2.size()) {
				while (i1 < ss1.size()) {
					changes1.add(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) {
				compareObject(ss1, i1, same1, ss2, i2, same2,stack1,stack2);
				i1+=same1;
				i2+=same2;
			} else if (c < 0) {
				for (int i = 0; i < same1; i++) {
					changes1.add(ss1.get(i+i1));
				}
				i1 += same1;
				} else {
					for (int i = 0; i < same2; i++) {
					changes2.add(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 void compareObject(List<Statement> ss1, int off1, int len1, List<Statement> ss2, int off2, int len2, Stack<Resource> stack1, Stack<Resource> stack2) throws ServiceException, DoesNotContainValueException, ValidationException {
		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);
			//Map<Integer,Integer> differences = new HashMap<Integer, Integer>();
			List<Integer> diff = new ArrayList<Integer>();
			for (int i2 = off2; i2 < off2 + len2; i2++) {
				Statement s2 = ss2.get(i2);
				if (!compareType(s1.getObject(), s2.getObject())) {
					diff.add(Integer.MAX_VALUE);
					continue;
				}
				diff.add(propsDiffCount(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])
							break;
						used1[i1] = true;
						used2[i2] = true;
						if (stack1 != null) {
							stack1.add(ss1.get(i1+off1).getObject());
							stack2.add(ss2.get(i2+off2).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.
							
							//compareProps(ss1.get(i1+off1).getObject(), ss2.get(i2+off2).getObject());
							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));
							}
						}
					}
				}
			}
		}
		for (int i1 = off1; i1 < off1 + len1; i1++) {
			if (!used1[i1-off1])
				changes1.add(ss1.get(i1));
		}
		for (int i2 = off2; i2 < off2 + len2; i2++) {
			if (!used2[i2-off2])
				changes2.add(ss2.get(i2));
		}
	}
	
	private boolean compareType(Resource r1, Resource r2) throws ServiceException, ManyObjectsForFunctionalRelationException {
		rs1.addAll(g.getObjects(r1, b.InstanceOf));
		rs2.addAll(g.getObjects(r2, b.InstanceOf));
		if (rs1.size() != rs2.size()) {
			rs1.clear();
			rs2.clear();
			return false;
		}
		Collections.sort(rs1, rcomp);
		Collections.sort(rs2, rcomp);
		for (int i = 0; i < rs1.size(); i++) {
			int c = rcomp.compare(rs1.get(i), rs2.get(i));
			if (c != 0) {
				rs1.clear();
				rs2.clear();
				return false;
			}
		}
		
		rs1.clear();
		rs2.clear();
		
		return true;
	}
	
	/**
	 * compares properties, assumes functional relations
	 * @param r1
	 * @param r2
	 * @throws ManyObjectsForFunctionalRelationException
	 * @throws ServiceException
	 * @throws DoesNotContainValueException
	 */
	private void compareProps(Resource r1, Resource r2) throws ManyObjectsForFunctionalRelationException, ServiceException, DoesNotContainValueException {
		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()) {
						changes2.add(ss2.get(i2));
						i2++;
					}
					break;
				}
			} else if (i2 >= ss2.size()) {
				while (i1 < ss1.size()) {
					changes1.add(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 = false;
						if (v1 instanceof Object[] && v2 instanceof Object[])
							eq = Arrays.deepEquals((Object[])v1, (Object[])v2);
						else
							eq = v1.equals(v2);
						if (!eq) {
							changes1.add(s1);
							changes2.add(s2);
							comparable.map(s1, s2);
						}
					} else {
						compareProps(s1.getObject(), s2.getObject());
					}
				} else {
					changes1.add(s1);
					changes2.add(s2);
					comparable.map(s1, s2);
				}
				i1++;
				i2++;
				break;
			}
			case -1:{
				changes1.add(s1);
				i1++;
				break;
			}
				
			case 1:{
				changes2.add(s2);
				i2++;
				break;
			}
			}
			
			
		}
		
		ss1.clear();
		ss2.clear();
		
	}
	
	private int propsDiffCount(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));
		//System.out.println("Props count " + GraphUtils.getReadableName(g, r1) + " " + GraphUtils.getReadableName(g, r2));
		Collections.sort(ss1, scomp);
		Collections.sort(ss2, scomp);
		
		int count = 0;
		
		int i1 = 0; 
		int i2 = 0;
		
		while (true) {
			if (i1 >= ss1.size()) {
				if (i2 >= ss2.size())
					break;
				else {
					while (i2 < ss2.size()) {
						count++;
						i2++;
					}
					break;
				}
			} else if (i2 >= ss2.size()) {
				while (i1 < ss1.size()) {
					count++;
					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 = false;
						if (v1 instanceof Object[] && v2 instanceof Object[])
							eq = Arrays.deepEquals((Object[])v1, (Object[])v2);
						else
							eq = v1.equals(v2);
						if (!eq) {
							count++;
						}
						//System.out.println("Prop count values " + v1 + " " + v2);
					} else {
						count += propsDiffCount(s1.getObject(), s2.getObject());
					}
				} else {
					//System.out.println("Props count structural vs literal");
					count++;
				}
				i1++;
				i2++;
				break;
			}
			case -1:{
				count++;
				i1++;
				break;
			}
				
			case 1:{
				count++;
				i2++;
				break;
			}
			}
			

		}
		
		ss1.clear();
		ss2.clear();
		return count;
	}

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