package inference.axioms;

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

import exceptions.SubstituteFailedException;
import inference.EquationAxiom;
import inference.InferenceOrderConstraint;
import models.Position;
import models.algebra.Constant;
import models.algebra.Variable;
import models.formulas.DependencyFormula;
import models.formulas.Formula;
import models.formulas.meta.MetaDependencyFormula;
import models.formulas.meta.MetaEquationFormula;
import models.terms.EvaluatableTerm;
import models.terms.meta.MatchConstraint;
import models.terms.meta.MetaDynamicDependency;
import models.terms.meta.MetaDynamicDependencyTerm;
import models.terms.meta.MetaEvaluatableTermVariable;
import models.terms.meta.MetaRDLTerm;
import models.terms.meta.MetaTermGenerator;
import models.terms.meta.OrderConstraint;

public class PseudoConstantness extends EquationAxiom {

	public PseudoConstantness() {
		super("Pseudo-Constantness");
		assumptions.add(new MetaDependencyFormula(
				new MetaDynamicDependency(
						new MetaTermGenerator() {
							@Override
							public MetaRDLTerm generate(int curIndex, int curDepth, int maxIndex, int maxDepth, Map<Object, Object> context) {
								curIndex -= 1;
								return new MetaEvaluatableTermVariable(new Variable("te" + curIndex), new Variable("n"));
							}
						},
						new MetaEvaluatableTermVariable(new Variable("se"), new Variable("n"))
				)
		));
		defaultOrderConstraint = new InferenceOrderConstraint(new Variable("n"), OrderConstraint.GT, new Constant("0"));
		
		conclusion = new MetaEquationFormula(
				new MetaDynamicDependencyTerm(
						new MetaTermGenerator() {
							@Override
							public MetaRDLTerm generate(int curIndex, int curDepth, int maxIndex, int maxDepth, Map<Object, Object> context) {
								curIndex -= 1;
								return new MetaEvaluatableTermVariable(new Variable("te" + curIndex / 2), new Variable("n"));
							}
						},
						new MetaEvaluatableTermVariable(new Variable("se"), new Variable("n"))
				),
				new MetaEvaluatableTermVariable(new Variable("se"), new Variable("n"))
		);
	}
	
	@Override
	public Set<EvaluatableTerm> apply(List<Formula> assumptions, EvaluatableTerm term, MatchConstraint constraint) {
		Set<EvaluatableTerm> result = new HashSet<>();
		if (assumptions.size() < this.assumptions.size()) {
			return new HashSet<>();
		}
		
		Set<MatchConstraint> matchResult = assumptionMatch(assumptions, constraint);
		
		Set<MatchConstraint> conclusionLeftMatchResult = conclusionLeftSideHandMatch(term, matchResult);
		for (MatchConstraint leftConst: conclusionLeftMatchResult) {
			leftConst.getContext().put("isLeft", true);
		}
		Set<MatchConstraint> conclusionRightMatchResult = conclusionRightSideHandMatch(term, matchResult);
		for (MatchConstraint rightConst: conclusionRightMatchResult) {
			rightConst.getContext().put("isLeft", false);
		}
		Set<MatchConstraint> conclusionMatchResult = new HashSet<>();
		conclusionMatchResult.addAll(conclusionLeftMatchResult);
		conclusionMatchResult.addAll(conclusionRightMatchResult);
		
		MetaEquationFormula metaConclusion = (MetaEquationFormula) this.conclusion;
		for (MatchConstraint matchRes: conclusionMatchResult) {
			boolean isLeft =(Boolean) matchRes.getContext().get("isLeft");
			if (defaultOrderConstraint != null && ! defaultOrderConstraint.check(matchRes.getOrderConstraint())) {
				continue;
			}
			try {
				if (isLeft) {
					result.add((EvaluatableTerm)((MetaRDLTerm) metaConclusion.getRightSideHand()).substitute(matchRes.getBinding(), matchRes.getContext()));
				} else {
					matchRes.getContext().put(new Position(), ((DependencyFormula) assumptions.get(0)).getDependency().getMaxIndex() * 2 - 1);
					result.add((EvaluatableTerm)((MetaRDLTerm) metaConclusion.getLeftSideHand()).substitute(matchRes.getBinding(), matchRes.getContext()));
				}
			} catch (SubstituteFailedException e) {
				continue;
			}
		}
		return result;
	}
	
}