// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.searchdefinition;

import com.yahoo.searchdefinition.document.BooleanIndexDefinition;
import com.yahoo.searchdefinition.document.RankType;
import com.yahoo.searchdefinition.document.Stemming;

import java.io.Serializable;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.Set;

/**
 * An index definition in a search definition.
 * Two indices are equal if they have the same name and the same settings, except
 * alias settings (which are excluded).
 *
 * @author  bratseth
 */
public class Index implements Cloneable, Serializable {

    public static enum Type {
        VESPA("vespa");
        private String name;
        private Type(String name) { this.name = name; }
        public String getName() { return name; }

    }

    // Please see hashCode, equals and copy when adding attributes to this

    /** The search definition-unique name of this index */
    private String name;

    /** The rank type of this index */
    private RankType rankType=null;

   /** Whether this index supports prefix search */
    private boolean prefix;

    /** The list of aliases (Strings) to this index name */
    private Set<String> aliases=new java.util.LinkedHashSet<>(1);

    /**
     * The stemming setting of this field, or null to use the default.
     * Default is determined by the owning search definition.
     */
    private Stemming stemming=null;

    /** Whether the content of this index is normalized */
    private boolean normalized=true;

    /** The set of all searchable fields which should be searched with this index. May not null */
    public Set<String> matchGroup=new LinkedHashSet<>();

    private Type type = Type.VESPA;

    /** The boolean index definition, if set */
    private BooleanIndexDefinition boolIndex;

    public Index(String name) {
        this(name, false);
    }

    public Index(String name, boolean prefix) {
        this.name=name;
        this.prefix=prefix;
    }

    public void setName(String name) { this.name=name; }

    public String getName() { return name; }

    /** Sets the rank type of this field */
    public void setRankType(RankType rankType) { this.rankType=rankType; }

    /** Returns the rank type of this field, or null if nothing is set */
    public RankType getRankType() { return rankType; }

    /** Return the stemming setting of this index, may be null */
    public Stemming getStemming() { return stemming; }

    /**
     * Returns the (unmodifiable) set of searchable fields which should be searched
     * when this index is searched. This is useful to specify that some attributes should be
     * searched as well when an index is searched.
     * This set is either empty, or if set contains both the name of this index, and some other
     * indexes.
     */
    public Set<String> getMatchGroup() { return Collections.unmodifiableSet(matchGroup); }

    /** Adds a searchable field name to be searched when this index is searched */
    public void addToMatchGroup(String name) {
        if (name.equals(this.name)) return;
        if (matchGroup.size()==0) matchGroup.add(this.name);
        matchGroup.add(name);
    }

    /**
     * Whether this field should be stemmed in this search definition,
     * this is never null
     */
    public Stemming getStemming(Search search) {
        if (stemming!=null)
            return stemming;
        else
            return search.getStemming();
    }

    /**
     * Sets how this field should be stemmed, or set to null to use the default.
     */
    public void setStemming(Stemming stemming) { this.stemming=stemming; }

    /** Returns whether this index supports prefix search, default is false */
    public boolean isPrefix() { return prefix; }

    /** Sets whether this index supports prefix search */
    public void setPrefix(boolean prefix) { this.prefix=prefix; }

    /** Adds an alias to this index name */
    public void addAlias(String alias) {
        aliases.add(alias);
    }

    /** Returns a read-only iterator of the aliases (Strings) to this index name */
    public Iterator<String> aliasIterator() {
        return Collections.unmodifiableSet(aliases).iterator();
    }

    public int hashCode() {
            return name.hashCode() + ( prefix ? 17 : 0 );
    }

    public boolean equals(Object object) {
            if ( ! (object instanceof Index)) return false;

            Index other=(Index)object;
            return
                this.name.equals(other.name) &&
                this.prefix==other.prefix &&
                this.stemming==other.stemming &&
                this.normalized==other.normalized;
    }

    public String toString() {
        String rankTypeName=rankType==null ? "(none)" : rankType.name();
            return
                "index '" + name +
                "' [ranktype: " + rankTypeName +
                ", prefix: " + prefix + "]";
    }

    /** Makes a deep copy of this index */
    public Object clone() {
        try {
            Index copy=(Index)super.clone();
            copy.aliases=new LinkedHashSet<>(this.aliases);
            return copy;
        }
        catch (CloneNotSupportedException e) {
            throw new RuntimeException("Programming error",e);
        }
    }

    public Index copy() {
        return (Index)clone();
    }

    /**
     * The index engine type
     * @return the type
     */
    public Type getType() {
        return type;
    }

    /**
     * Sets the index engine type
     * @param type a index engine type
     */
    public void setType(Type type) {
        this.type = type;
    }

    /**
     * The boolean index definition
     * @return the boolean index definition
     */
    public BooleanIndexDefinition getBooleanIndexDefiniton() {
        return boolIndex;
    }

    /**
     * Sets the boolean index definition
     * @param def boolean index definition
     */
    public void setBooleanIndexDefiniton(BooleanIndexDefinition def) {
        boolIndex = def;
    }

}