/**
 * #-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=#
 *   This file is part of the LDP4j Project:
 *     http://www.ldp4j.org/
 *
 *   Center for Open Middleware
 *     http://www.centeropenmiddleware.com/
 * #-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=#
 *   Copyright (C) 2014 Center for Open Middleware.
 * #-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=#
 *   Licensed under the Apache License, Version 2.0 (the "License");
 *   you may not use this file except in compliance with the License.
 *   You may obtain a copy of the License at
 *
 *             http://www.apache.org/licenses/LICENSE-2.0
 *
 *   Unless required by applicable law or agreed to in writing, software
 *   distributed under the License is distributed on an "AS IS" BASIS,
 *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *   See the License for the specific language governing permissions and
 *   limitations under the License.
 * #-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=#
 *   Artifact    : org.ldp4j.framework:ldp4j-application-api:0.2.0
 *   Bundle      : ldp4j-application-api-0.2.0.jar
 * #-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=#
 */
package org.ldp4j.application.data.constraints;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;

import java.io.Serializable;
import java.net.URI;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.ldp4j.application.data.DataSet;
import org.ldp4j.application.data.Individual;
import org.ldp4j.application.data.Literal;
import org.ldp4j.application.data.Value;
import org.ldp4j.application.data.ValueVisitor;

import com.google.common.base.MoreObjects;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableList.Builder;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.common.collect.Sets;

public final class Constraints implements Serializable {

  public enum NodeKind {
    NODE("Node"),
    BLANK_NODE_OR_IRI("BlankNodeOrIRI"),
    BLANK_NODE_OR_LITERAL("BlankNodeOrLiteral"),
    LITERAL_OR_IRI("LiteralOrIRI"),
    BLANK_NODE("BlankNode"),
    IRI("IRI"),
    LITERAL("Literal")
    ;

    private final String localName;

    private NodeKind(String localName) {
      this.localName = localName;
    }

    public String localName() {
      return localName;
    }
  }

  public interface Describable {

    String label();
    String comment();
  }

  public static final class Cardinality implements Serializable {

    private static final long serialVersionUID = 7262473645776142538L;

    private int min;
    private int max;

    private Cardinality(int min, int max) {
      this.min = min;
      this.max = max;
    }

    public int min() {
      return this.min;
    }

    public int max() {
      return this.max;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public String toString() {
      return
        MoreObjects.
          toStringHelper(getClass()).
            add("min", this.min).
            add("max", this.max).
            toString();
    }

    public static Cardinality mandatory() {
      return new Cardinality(1,1);
    }

    public static Cardinality atMost(int max) {
      return new Cardinality(0,max);
    }

    public static Cardinality atLeast(int min) {
      return new Cardinality(min,-1);
    }

    public static Cardinality create(int min, int max) {
      return new Cardinality(min,max);
    }

    public static Cardinality optional() {
      return new Cardinality(0,1);
    }

    public static Cardinality unbound() {
      return new Cardinality(0,-1);
    }

  }


  public abstract static class AbstractPropertyConstraint<T extends AbstractPropertyConstraint<T>> implements Serializable {

    private static final long serialVersionUID = 6473281395518369031L;

    private static final class ValueCollector implements ValueVisitor {

      private final Collection<Serializable> individuals;
      private final Collection<Literal<?>> literals;

      private ValueCollector(Collection<Serializable> individuals, Collection<Literal<?>> lLiterals) {
        this.individuals = individuals;
        this.literals = lLiterals;
      }

      @Override
      public void visitLiteral(Literal<?> value) {
        literals.add(value);
      }

      @Override
      public void visitIndividual(Individual<?, ?> value) {
        individuals.add(value.id());
      }

    }

    private final URI predicate;
    private String comment;
    private String label;
    private Set<Serializable> allowedIndividuals;
    private Set<Literal<?>> allowedLiterals;
    private List<Serializable> individuals;
    private List<Literal<?>> literals;
    private URI datatype;
    private NodeKind nodeKind;
    private Shape valueShape;
    private URI valueType;
    private Cardinality cardinality;

    protected AbstractPropertyConstraint(URI predicate) {
      this.predicate=predicate;
    }

    protected abstract T delegate();

    public T withLabel(String label) {
      checkNotNull(label,"Label cannot be null");
      this.label=label;
      return delegate();
    }

    public String label() {
      return this.label;
    }

    public T withComment(String comment) {
      checkNotNull(comment,"Comment cannot be null");
      this.comment=comment;
      return delegate();
    }

    public String comment() {
      return this.comment;
    }

    public URI predicate() {
      return this.predicate;
    }

    public T withCardinality(Cardinality cardinality) {
      checkNotNull(cardinality,"Cardinality cannot be null");
      this.cardinality=cardinality;
      return delegate();
    }

    public Cardinality cardinality() {
      Cardinality result = this.cardinality;
      if(result==null) {
        result=Cardinality.unbound();
      }
      return result;
    }

    public T withAllowedValues(Value... allowedValues) {
      checkNotNull(allowedValues,"Allowed values cannot be null");
      this.allowedLiterals=Sets.newLinkedHashSet();
      this.allowedIndividuals=Sets.newLinkedHashSet();
      ValueCollector valueCollector=new ValueCollector(this.allowedIndividuals,this.allowedLiterals);
      for(Value value:allowedValues) {
        value.accept(valueCollector);
      }
      return delegate();
    }

    public Set<Literal<?>> allowedLiterals() {
      Set<Literal<?>> result=this.allowedLiterals;
      if(result==null) {
        result=Sets.newLinkedHashSet();
      }
      return ImmutableSet.copyOf(result);
    }

    public Set<Individual<?,?>> allowedIndividuals(DataSet dataSet) {
      Set<Serializable> result=this.allowedIndividuals;
      if(result==null) {
        result=Sets.newLinkedHashSet();
      }
      return ConstraintsHelper.getOrCreateIndividuals(dataSet,result);
    }

    public T withDatatype(URI datatype) {
      checkNotNull(datatype,"Datatype cannot be null");
      this.datatype = datatype;
      return delegate();
    }

    public URI datatype() {
      return this.datatype;
    }

    public T withValue(Value... values) {
      checkNotNull(values,"Value cannot be null");
      this.literals=Lists.newArrayList();
      this.individuals=Lists.newArrayList();
      ValueCollector valueCollector=new ValueCollector(this.individuals,this.literals);
      for(Value value:values) {
        value.accept(valueCollector);
      }
      return delegate();
    }

    public List<Literal<?>> literals() {
      List<Literal<?>> result=this.literals;
      if(result==null) {
        result=Lists.newArrayList();
      }
      return ImmutableList.copyOf(result);
    }

    public List<Individual<?,?>> individuals(DataSet dataSet) {
      List<Serializable> result=this.individuals;
      if(result==null) {
        result=Lists.newArrayList();
      }
      return ConstraintsHelper.getOrCreateIndividuals(dataSet,result);
    }

    public T withNodeKind(NodeKind nodeKind) {
      checkNotNull(nodeKind,"Node kind cannot be null");
      this.nodeKind=nodeKind;
      return delegate();
    }

    public NodeKind nodeKind() {
      return this.nodeKind;
    }

    public T withValueShape(Shape valueShape) {
      this.valueShape = valueShape;
      return delegate();
    }

    public Shape valueShape() {
      return this.valueShape;
    }

    public T withValueType(URI valueType) {
      this.valueType = valueType;
      return delegate();
    }

    public URI valueType() {
      return this.valueType;
    }

    @Override
    public String toString() {
      return
        MoreObjects.
          toStringHelper(getClass()).
            omitNullValues().
            add("predicate", this.predicate).
            add("label", this.label).
            add("comment", this.comment).
            add("cardinality", this.cardinality()).
            add("allowedLiterals", this.allowedLiterals).
            add("allowedIndividuals", this.allowedIndividuals).
            add("datatype", this.datatype).
            add("literals", this.literals).
            add("literals", this.individuals).
            add("nodeKind", this.nodeKind).
            add("valueShape", this.valueShape).
            add("valueType", this.valueType).
            toString();
    }

  }

  public static final class PropertyConstraint extends AbstractPropertyConstraint<PropertyConstraint> implements Describable {

    private static final long serialVersionUID = -2646499801130951583L;

    private PropertyConstraint(URI predicate) {
      super(predicate);
    }

    @Override
    protected PropertyConstraint delegate() {
      return this;
    }

  }

  public static final class InversePropertyConstraint extends AbstractPropertyConstraint<InversePropertyConstraint> implements Describable {

    private static final long serialVersionUID = -6328974380403084873L;

    private InversePropertyConstraint(URI predicate) {
      super(predicate);
    }

    @Override
    protected InversePropertyConstraint delegate() {
      return this;
    }

  }

  public static final class Shape implements Describable, Serializable {

    private static final long serialVersionUID = 3966457418001884744L;

    private Map<URI,AbstractPropertyConstraint<?>> constraints; // NOSONAR
    private String label;
    private String comment;

    private Shape() {
      this.constraints=Maps.newLinkedHashMap();
    }

    public Shape withLabel(String label) {
      this.label=label;
      return this;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public String label() {
      return this.label;
    }

    public Shape withComment(String comment) {
      this.comment=comment;
      return this;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public String comment() {
      return this.comment;
    }

    public Shape withPropertyConstraint(PropertyConstraint constraint) {
      checkNotNull(constraint);
      URI predicate = constraint.predicate();
      checkArgument(!this.constraints.containsKey(predicate),"Shape already defines constraints for predicate '"+predicate+"'");
      this.constraints.put(predicate,constraint);
      return this;
    }

    public Shape withPropertyConstraint(InversePropertyConstraint constraint) {
      checkNotNull(constraint);
      URI predicate = constraint.predicate();
      checkArgument(!this.constraints.containsKey(predicate),"Shape already defines constraints for predicate '"+predicate+"'");
      this.constraints.put(predicate,constraint);
      return this;
    }

    public List<PropertyConstraint> propertyConstraints() {
      final Builder<PropertyConstraint> builder=ImmutableList.<PropertyConstraint>builder();
      filter(builder,PropertyConstraint.class);
      return builder.build();
    }

    public List<InversePropertyConstraint> inversePropertyConstraints() {
      final Builder<InversePropertyConstraint> builder=ImmutableList.<InversePropertyConstraint>builder();
      filter(builder,InversePropertyConstraint.class);
      return builder.build();
    }

    private <T extends AbstractPropertyConstraint<?>> void filter(Builder<T> builder, Class<? extends T> clazz) {
      for(AbstractPropertyConstraint<?> c:this.constraints.values()) {
        if(clazz.isInstance(c)) {
          builder.add(clazz.cast(c));
        }
      }
    }

    @Override
    public String toString() {
      return
        MoreObjects.
          toStringHelper(getClass()).
            omitNullValues().
            add("label", this.label).
            add("comment", this.comment).
            add("constraints",this.constraints).
            toString();
    }

  }

  private static final long serialVersionUID = 4368698694568719975L;

  private Map<Serializable,Shape> nodeShapes; // NOSONAR
  private Map<URI,Shape> typeShapes; // NOSONAR

  private Constraints() {
    this.nodeShapes=Maps.newLinkedHashMap();
    this.typeShapes=Maps.newLinkedHashMap();
  }

  public List<Shape> shapes() {
    return
      ImmutableList.
        <Shape>builder().
          addAll(this.typeShapes.values()).
          addAll(this.nodeShapes.values()).
          build();
  }

  public Set<URI> types() {
    return ImmutableSet.copyOf(this.typeShapes.keySet());
  }

  public Set<Individual<?,?>> nodes(DataSet dataSet) {
    checkNotNull(dataSet,"Data set cannot be null");
    return
      ConstraintsHelper.
        getOrCreateIndividuals(
          dataSet,
          this.nodeShapes.keySet());
  }

  public Shape typeShape(URI type) {
    return this.typeShapes.get(type);
  }

  public Shape nodeShape(Individual<?,?> individual) {
    return this.nodeShapes.get(individual.id());
  }

  public Constraints withTypeShape(URI type, Shape shape) {
    checkNotNull(type,"Type URI cannot be null");
    checkNotNull(shape,"Shape cannot be null");
    checkArgument(!this.typeShapes.containsKey(type),"A shape is already defined for type '"+type+"'");
    this.typeShapes.put(type,shape);
    return this;
  }

  public Constraints withNodeShape(Individual<?,?> individual, Shape shape) {
    checkNotNull(individual,"Type URI cannot be null");
    checkNotNull(shape,"Shape cannot be null");
    checkArgument(!this.nodeShapes.containsKey(individual.id()),"A shape is already defined for individual '"+individual.id()+"'");
    this.nodeShapes.put(individual.id(),shape);
    return this;
  }

  @Override
  public String toString() {
    return
      MoreObjects.
        toStringHelper(getClass()).
          add("typeShapes", this.typeShapes).
          add("nodeShapes", this.nodeShapes).
          toString();
  }

  public static Shape shape() {
    return new Shape();
  }

  public static Constraints constraints() {
    return new Constraints();
  }

  public static PropertyConstraint propertyConstraint(URI predicate) {
    return new PropertyConstraint(predicate);
  }

  public static InversePropertyConstraint inversePropertyConstraint(URI predicate) {
    return new InversePropertyConstraint(predicate);
  }

}