package models.dataConstraintModel;

import models.algebra.Constant;
import models.algebra.Expression;
import models.algebra.Symbol;
import models.algebra.Term;
import parser.Parser;

import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

public class MapTerm extends Term {
	private Map<String, Integer> keyToIndex = new HashMap<>();
	
	public MapTerm() {
		super(new Symbol("map", -1));
		setType(DataConstraintModel.typeMap);
	}
	
	public void insert(String key, Expression value) {
		if (keyToIndex.containsKey(key)) {
			setChild(keyToIndex.get(key), value);
		} else {
			keyToIndex.put(key, getChildren().size());
			addChild(value);
		}
	}
	
	public Set<String> keySet() {
		return keyToIndex.keySet();
	}
	
	public Expression get(String key) {
		return getChild(keyToIndex.get(key));
	}
	
	public Expression get(Constant key) {
		if (keyToIndex.get(key.getValue()) == null) return null;
		return getChild(keyToIndex.get(key.getValue()));
	}
	
	@Override
	public Expression unify(Expression another) {
		if (another instanceof MapTerm) {
			MapTerm anotherTerm = (MapTerm) another;
			MapTerm unifiedTerm = new MapTerm();
			Set<String> keySet = new HashSet<>();
			keySet.addAll(this.keySet());
			keySet.addAll(anotherTerm.keySet());
			for (String key : keySet) {
				if (this.keySet().contains(key)) {
					if (anotherTerm.keySet().contains(key)) {
						unifiedTerm.insert(key, this.get(key).unify(anotherTerm.get(key)));
					} else {
						unifiedTerm.insert(key, this.get(key));
					}
				} else {
					unifiedTerm.insert(key, anotherTerm.get(key));
				}
			}
			return unifiedTerm;
		}
		return this;
	}
	
	@Override
	public Object clone() {
		MapTerm newTerm = new MapTerm();
		for (Expression e : children) {
			newTerm.addChild((Expression) e.clone());
		}
		newTerm.keyToIndex = new HashMap<String, Integer>(keyToIndex);
		return newTerm;
	}
	
	public String toString() {
		String mapStr = "{";
		String delim = "";
		for (String key : keyToIndex.keySet()) {
			mapStr += delim + Parser.DOUBLE_QUOT + key + Parser.DOUBLE_QUOT + ": " + getChild(keyToIndex.get(key)).toString();
			delim = ", ";
		}
		return mapStr + "}";
	}
}