package org.maltparser.parser.algorithm.twoplanar;

import java.util.Stack;

import org.maltparser.core.exception.MaltChainedException;
import org.maltparser.core.syntaxgraph.DependencyStructure;
import org.maltparser.core.syntaxgraph.node.DependencyNode;
import org.maltparser.parser.ParserConfiguration;
import org.maltparser.parser.ParsingException;
/**
 * @author Carlos Gomez Rodriguez
 *
 */
public class TwoPlanarConfig extends ParserConfiguration {

        
        //Connectedness enforcing
        /*
        public static final int NO_CONNECTEDNESS = 1;
        public static final int REDUCE_ONLY = 2; //connectedness enforced on reduce only
        public static final int FULL_CONNECTEDNESS = 3; //connectedness enforced on shift and reduce
        */
        
        // Root Handling
        public static final int NORMAL = 1; //root tokens attached to Root with RightArc
        public static final int RELAXED = 2; //root tokens unattached
        
        //Constraints
        public final boolean SINGLE_HEAD = true; //single-head constraint
        public boolean noCoveredRoots = false; //no-covered-roots constraint
        public boolean acyclicity = true; //acyclicity constraint
        
        //public int connectedness = NO_CONNECTEDNESS; //connectedness constraint
        
        public boolean reduceAfterSwitch = false;
        
        
        private final Stack<DependencyNode> firstStack;
        private final Stack<DependencyNode> secondStack;

        public static final boolean FIRST_STACK = false;
        public static final boolean SECOND_STACK = true;
        
        private boolean activeStack;
        
        private Stack<DependencyNode> input;
        
        private DependencyStructure dependencyGraph;
        
        //root handling: explicitly create links to dummy root or not?
        private int rootHandling;

        //needed to disallow two consecutive switches:
        private int lastAction;
        
        
        public TwoPlanarConfig(String noCoveredRoots , String acyclicity , String reduceAfterSwitch , String rootHandling) throws MaltChainedException {
                super();
                firstStack = new Stack<DependencyNode>();
                secondStack = new Stack<DependencyNode>();
                activeStack = FIRST_STACK;
                input = new Stack<DependencyNode>();
//              dependencyGraph = new DependencyGraph(symbolTableHandler);
                setRootHandling(rootHandling);
                setNoCoveredRoots(Boolean.valueOf(noCoveredRoots));
                setAcyclicity(Boolean.valueOf(acyclicity));
                setReduceAfterSwitch(Boolean.valueOf(reduceAfterSwitch));
        }
        
        public void switchStacks()
        {
                activeStack = !activeStack;
        }
        
        public boolean reduceAfterSwitch ()
        {
                return reduceAfterSwitch;
        }
        
        public void setReduceAfterSwitch ( boolean ras )
        {
                reduceAfterSwitch = ras;
        }
        
        public void setLastAction ( int action )
        {
                lastAction = action;
        }
        
        public int getLastAction ( )
        {
                return lastAction;
        }
        
        public boolean getStackActivityState()
        {
                return activeStack;
        }
        
        private Stack<DependencyNode> getFirstStack() {
                return firstStack;
        }
        
        private Stack<DependencyNode> getSecondStack() {
                return secondStack;
        }
        
        public Stack<DependencyNode> getActiveStack() {
                if ( activeStack == FIRST_STACK ) return getFirstStack();
                else return getSecondStack();
        }
        
        public Stack<DependencyNode> getInactiveStack() {
                if ( activeStack == FIRST_STACK ) return getSecondStack();
                else return getFirstStack();
        }
        
        public Stack<DependencyNode> getInput() {
                return input;
        }
        
        public DependencyStructure getDependencyStructure() {
                return dependencyGraph;
        }
        
        public boolean isTerminalState() {
                return input.isEmpty();
        }
        
        private DependencyNode getStackNode(Stack<DependencyNode> stack , int index) throws MaltChainedException {
                if (index < 0) {
                        throw new ParsingException("Stack index must be non-negative in feature specification. ");
                }
                if (stack.size()-index > 0) {
                        return stack.get(stack.size()-1-index);
                }
                return null;
        }
        
        public DependencyNode getActiveStackNode ( int index ) throws MaltChainedException {
                return getStackNode ( getActiveStack() , index );
        }
        
        public DependencyNode getInactiveStackNode ( int index ) throws MaltChainedException {
                return getStackNode ( getInactiveStack() , index );
        }
        
        public DependencyNode getInputNode(int index) throws MaltChainedException {
                if (index < 0) {
                        throw new ParsingException("Input index must be non-negative in feature specification. ");
                }
                if (input.size()-index > 0) {
                        return input.get(input.size()-1-index);
                }       
                return null;
        }
        
        public void setDependencyGraph(DependencyStructure source) throws MaltChainedException {
                this.dependencyGraph = source;
//              dependencyGraph.clear();
//              for (int index : source.getTokenIndices()) {
//                      DependencyNode gnode = source.getDependencyNode(index);
//                      DependencyNode pnode = dependencyGraph.addDependencyNode(gnode.getIndex());
//                      for (SymbolTable table : gnode.getLabelTypes()) {
//                              pnode.addLabel(table, gnode.getLabelSymbol(table));
//                      }
//                      
//                      if (gnode.hasHead()) {
//                              Edge s = gnode.getHeadEdge();
//                              Edge t = dependencyGraph.addDependencyEdge(s.getSource().getIndex(), s.getTarget().getIndex());
//                              
//                              for (SymbolTable table : s.getLabelTypes()) {
//                                      t.addLabel(table, s.getLabelSymbol(table));
//                              }
//                      }
//              }
        }
        
        public DependencyStructure getDependencyGraph() {
                return dependencyGraph;
        }
        
        public void initialize(ParserConfiguration parserConfiguration) throws MaltChainedException {
                if (parserConfiguration != null) {
                        TwoPlanarConfig planarConfig = (TwoPlanarConfig)parserConfiguration;
                        this.activeStack = planarConfig.activeStack;
                        Stack<DependencyNode> sourceActiveStack = planarConfig.getActiveStack();
                        Stack<DependencyNode> sourceInactiveStack = planarConfig.getInactiveStack();
                        Stack<DependencyNode> sourceInput = planarConfig.getInput();
                        setDependencyGraph(planarConfig.getDependencyGraph());
                        for (int i = 0, n = sourceActiveStack.size(); i < n; i++) {
                                getActiveStack().add(dependencyGraph.getDependencyNode(sourceActiveStack.get(i).getIndex()));
                        }
                        for ( int i =0, n = sourceInactiveStack.size() ; i < n ; i++ ) {
                                getInactiveStack().add(dependencyGraph.getDependencyNode(sourceInactiveStack.get(i).getIndex()));
                        }
                        for (int i = 0, n = sourceInput.size(); i < n; i++) {
                                input.add(dependencyGraph.getDependencyNode(sourceInput.get(i).getIndex()));
                        }
                } else {
                        getActiveStack().push(dependencyGraph.getDependencyRoot());
                        getInactiveStack().push(dependencyGraph.getDependencyRoot());
                        for (int i = dependencyGraph.getHighestTokenIndex(); i > 0; i--) {
                                final DependencyNode node = dependencyGraph.getDependencyNode(i);
                                if (node != null) { 
                                        input.push(node);
                                }
                        }
                }
        }
        
        public void initialize() throws MaltChainedException {
                getActiveStack().push(dependencyGraph.getDependencyRoot());
                getInactiveStack().push(dependencyGraph.getDependencyRoot());
                for (int i = dependencyGraph.getHighestTokenIndex(); i > 0; i--) {
                        final DependencyNode node = dependencyGraph.getDependencyNode(i);
                        if (node != null) { 
                                input.push(node);
                        }
                }
        }
        
        public int getRootHandling() {
                return rootHandling;
        }
        
        protected void setRootHandling(String rh) throws MaltChainedException {
                if (rh.equalsIgnoreCase("relaxed")) {
                        rootHandling = RELAXED;
                } else if (rh.equalsIgnoreCase("normal")) {
                        rootHandling = NORMAL;
                } else {
                        throw new ParsingException("The root handling '"+rh+"' is unknown");
                }
        }
        
        
        public boolean requiresSingleHead()
        {
                return SINGLE_HEAD;
        }
        
        public boolean requiresNoCoveredRoots()
        {
                return noCoveredRoots;
        }
        
        public boolean requiresAcyclicity()
        {
                return acyclicity;
        }
        
        //does not make much sense to enforce the no-covered-roots constraint in 2-planar parsing, it won't capture some 2-planar structures
        public void setNoCoveredRoots ( boolean value ) {noCoveredRoots = value;}
        
        public void setAcyclicity ( boolean value ) {acyclicity = value;}       
        
        public void clear() throws MaltChainedException {
//              dependencyGraph.clear();
                getActiveStack().clear();
                getInactiveStack().clear();
                input.clear();
                historyNode = null;
        }
        
        public boolean equals(Object obj) {
                if (this == obj)
                        return true;
                if (obj == null)
                        return false;
                if (getClass() != obj.getClass())
                        return false;
                TwoPlanarConfig that = (TwoPlanarConfig)obj;
                
                if (getActiveStack().size() != that.getActiveStack().size()) 
                        return false;
                if (getInactiveStack().size() != that.getInactiveStack().size()) 
                        return false;
                if (input.size() != that.getInput().size())
                        return false;
                if (dependencyGraph.nEdges() != that.getDependencyGraph().nEdges())
                        return false;
                for (int i = 0; i < getActiveStack().size(); i++) {
                        if (getActiveStack().get(i).getIndex() != that.getActiveStack().get(i).getIndex()) {
                                return false;
                        }
                }
                for (int i = 0; i < getInactiveStack().size(); i++) {
                        if (getInactiveStack().get(i).getIndex() != that.getInactiveStack().get(i).getIndex()) {
                                return false;
                        }
                }
                for (int i = 0; i < input.size(); i++) {
                        if (input.get(i).getIndex() != that.getInput().get(i).getIndex()) {
                                return false;
                        }
                }               
                return dependencyGraph.getEdges().equals(that.getDependencyGraph().getEdges());
        }
        
        public String toString() {
                final StringBuilder sb = new StringBuilder();
                sb.append(getActiveStack().size());
                sb.append(", ");
                sb.append(getInactiveStack().size());
                sb.append(", ");
                sb.append(input.size());
                sb.append(", ");
                sb.append(dependencyGraph.nEdges());
                return sb.toString();
        }
}