/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */
package org.apache.cassandra.config;

import java.nio.ByteBuffer;
import java.util.*;

import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Function;
import com.google.common.base.MoreObjects;
import com.google.common.base.Objects;
import com.google.common.collect.Collections2;

import org.apache.cassandra.cql3.*;
import org.apache.cassandra.cql3.selection.Selectable;
import org.apache.cassandra.cql3.selection.Selector;
import org.apache.cassandra.cql3.selection.SimpleSelector;
import org.apache.cassandra.db.rows.*;
import org.apache.cassandra.db.marshal.*;
import org.apache.cassandra.exceptions.InvalidRequestException;
import org.apache.cassandra.serializers.MarshalException;
import org.apache.cassandra.utils.ByteBufferUtil;

public class ColumnDefinition extends ColumnSpecification implements Selectable, Comparable<ColumnDefinition>
{
    public static final Comparator<Object> asymmetricColumnDataComparator =
        (a, b) -> ((ColumnData) a).column().compareTo((ColumnDefinition) b);

    public static final int NO_POSITION = -1;

    public enum ClusteringOrder
    {
        ASC, DESC, NONE
    }

    /*
     * The type of CQL3 column this definition represents.
     * There is 4 main type of CQL3 columns: those parts of the partition key,
     * those parts of the clustering columns and amongst the others, regular and
     * static ones.
     *
     * Note that thrift only knows about definitions of type REGULAR (and
     * the ones whose position == NO_POSITION (-1)).
     */
    public enum Kind
    {
        // NOTE: if adding a new type, must modify comparisonOrder
        PARTITION_KEY,
        CLUSTERING,
        REGULAR,
        STATIC;

        public boolean isPrimaryKeyKind()
        {
            return this == PARTITION_KEY || this == CLUSTERING;
        }

    }

    public final Kind kind;

    /*
     * If the column is a partition key or clustering column, its position relative to
     * other columns of the same kind. Otherwise,  NO_POSITION (-1).
     *
     * Note that partition key and clustering columns are numbered separately so
     * the first clustering column is 0.
     */
    private final int position;

    private final Comparator<CellPath> cellPathComparator;
    private final Comparator<Object> asymmetricCellPathComparator;
    private final Comparator<? super Cell> cellComparator;

    private int hash;

    /**
     * These objects are compared frequently, so we encode several of their comparison components
     * into a single long value so that this can be done efficiently
     */
    private final long comparisonOrder;

    private static long comparisonOrder(Kind kind, boolean isComplex, long position, ColumnIdentifier name)
    {
        assert position >= 0 && position < 1 << 12;
        return   (((long) kind.ordinal()) << 61)
               | (isComplex ? 1L << 60 : 0)
               | (position << 48)
               | (name.prefixComparison >>> 16);
    }

    public static ColumnDefinition partitionKeyDef(CFMetaData cfm, ByteBuffer name, AbstractType<?> type, int position)
    {
        return new ColumnDefinition(cfm, name, type, position, Kind.PARTITION_KEY);
    }

    public static ColumnDefinition partitionKeyDef(String ksName, String cfName, String name, AbstractType<?> type, int position)
    {
        return new ColumnDefinition(ksName, cfName, ColumnIdentifier.getInterned(name, true), type, position, Kind.PARTITION_KEY);
    }

    public static ColumnDefinition clusteringDef(CFMetaData cfm, ByteBuffer name, AbstractType<?> type, int position)
    {
        return new ColumnDefinition(cfm, name, type, position, Kind.CLUSTERING);
    }

    public static ColumnDefinition clusteringDef(String ksName, String cfName, String name, AbstractType<?> type, int position)
    {
        return new ColumnDefinition(ksName, cfName, ColumnIdentifier.getInterned(name, true),  type, position, Kind.CLUSTERING);
    }

    public static ColumnDefinition regularDef(CFMetaData cfm, ByteBuffer name, AbstractType<?> type)
    {
        return new ColumnDefinition(cfm, name, type, NO_POSITION, Kind.REGULAR);
    }

    public static ColumnDefinition regularDef(String ksName, String cfName, String name, AbstractType<?> type)
    {
        return new ColumnDefinition(ksName, cfName, ColumnIdentifier.getInterned(name, true), type, NO_POSITION, Kind.REGULAR);
    }

    public static ColumnDefinition staticDef(CFMetaData cfm, ByteBuffer name, AbstractType<?> type)
    {
        return new ColumnDefinition(cfm, name, type, NO_POSITION, Kind.STATIC);
    }

    public ColumnDefinition(CFMetaData cfm, ByteBuffer name, AbstractType<?> type, int position, Kind kind)
    {
        this(cfm.ksName,
             cfm.cfName,
             ColumnIdentifier.getInterned(name, cfm.getColumnDefinitionNameComparator(kind)),
             type,
             position,
             kind);
    }

    @VisibleForTesting
    public ColumnDefinition(String ksName,
                            String cfName,
                            ColumnIdentifier name,
                            AbstractType<?> type,
                            int position,
                            Kind kind)
    {
        super(ksName, cfName, name, type);
        assert name != null && type != null && kind != null;
        assert name.isInterned();
        assert (position == NO_POSITION) == !kind.isPrimaryKeyKind(); // The position really only make sense for partition and clustering columns (and those must have one),
                                                                      // so make sure we don't sneak it for something else since it'd breaks equals()
        this.kind = kind;
        this.position = position;
        this.cellPathComparator = makeCellPathComparator(kind, type);
        this.cellComparator = cellPathComparator == null ? ColumnData.comparator : (a, b) -> cellPathComparator.compare(a.path(), b.path());
        this.asymmetricCellPathComparator = cellPathComparator == null ? null : (a, b) -> cellPathComparator.compare(((Cell)a).path(), (CellPath) b);
        this.comparisonOrder = comparisonOrder(kind, isComplex(), Math.max(0, position), name);
    }

    private static Comparator<CellPath> makeCellPathComparator(Kind kind, AbstractType<?> type)
    {
        if (kind.isPrimaryKeyKind() || !type.isMultiCell())
            return null;

        AbstractType<?> nameComparator = type.isCollection()
                                       ? ((CollectionType) type).nameComparator()
                                       : ((UserType) type).nameComparator();


        return new Comparator<CellPath>()
        {
            public int compare(CellPath path1, CellPath path2)
            {
                if (path1.size() == 0 || path2.size() == 0)
                {
                    if (path1 == CellPath.BOTTOM)
                        return path2 == CellPath.BOTTOM ? 0 : -1;
                    if (path1 == CellPath.TOP)
                        return path2 == CellPath.TOP ? 0 : 1;
                    return path2 == CellPath.BOTTOM ? 1 : -1;
                }

                // This will get more complicated once we have non-frozen UDT and nested collections
                assert path1.size() == 1 && path2.size() == 1;
                return nameComparator.compare(path1.get(0), path2.get(0));
            }
        };
    }

    public ColumnDefinition copy()
    {
        return new ColumnDefinition(ksName, cfName, name, type, position, kind);
    }

    public ColumnDefinition withNewName(ColumnIdentifier newName)
    {
        return new ColumnDefinition(ksName, cfName, newName, type, position, kind);
    }

    public ColumnDefinition withNewType(AbstractType<?> newType)
    {
        return new ColumnDefinition(ksName, cfName, name, newType, position, kind);
    }

    public boolean isPartitionKey()
    {
        return kind == Kind.PARTITION_KEY;
    }

    public boolean isClusteringColumn()
    {
        return kind == Kind.CLUSTERING;
    }

    public boolean isStatic()
    {
        return kind == Kind.STATIC;
    }

    public boolean isRegular()
    {
        return kind == Kind.REGULAR;
    }

    public ClusteringOrder clusteringOrder()
    {
        if (!isClusteringColumn())
            return ClusteringOrder.NONE;

        return type.isReversed() ? ClusteringOrder.DESC : ClusteringOrder.ASC;
    }

    public int position()
    {
        return position;
    }

    @Override
    public boolean equals(Object o)
    {
        if (this == o)
            return true;

        if (!(o instanceof ColumnDefinition))
            return false;

        ColumnDefinition cd = (ColumnDefinition) o;

        return Objects.equal(ksName, cd.ksName)
            && Objects.equal(cfName, cd.cfName)
            && Objects.equal(name, cd.name)
            && Objects.equal(type, cd.type)
            && Objects.equal(kind, cd.kind)
            && Objects.equal(position, cd.position);
    }

    @Override
    public int hashCode()
    {
        // This achieves the same as Objects.hashcode, but avoids the object array allocation
        // which features significantly in the allocation profile and caches the result.
        int result = hash;
        if(result == 0)
        {
            result = 31 + (ksName == null ? 0 : ksName.hashCode());
            result = 31 * result + (cfName == null ? 0 : cfName.hashCode());
            result = 31 * result + (name == null ? 0 : name.hashCode());
            result = 31 * result + (type == null ? 0 : type.hashCode());
            result = 31 * result + (kind == null ? 0 : kind.hashCode());
            result = 31 * result + position;
            hash = result;
        }
        return result;
    }

    @Override
    public String toString()
    {
        return name.toString();
    }

    public String debugString()
    {
        return MoreObjects.toStringHelper(this)
                          .add("name", name)
                          .add("type", type)
                          .add("kind", kind)
                          .add("position", position)
                          .toString();
    }

    public boolean isPrimaryKeyColumn()
    {
        return kind.isPrimaryKeyKind();
    }

    /**
     * Whether the name of this definition is serialized in the cell nane, i.e. whether
     * it's not just a non-stored CQL metadata.
     */
    public boolean isPartOfCellName(boolean isCQL3Table, boolean isSuper)
    {
        // When converting CQL3 tables to thrift, any regular or static column ends up in the cell name.
        // When it's a compact table however, the REGULAR definition is the name for the cell value of "dynamic"
        // column (so it's not part of the cell name) and it's static columns that ends up in the cell name.
        if (isCQL3Table)
            return kind == Kind.REGULAR || kind == Kind.STATIC;
        else if (isSuper)
            return kind == Kind.REGULAR;
        else
            return kind == Kind.STATIC;
    }

    /**
     * Converts the specified column definitions into column identifiers.
     *
     * @param definitions the column definitions to convert.
     * @return the column identifiers corresponding to the specified definitions
     */
    public static Collection<ColumnIdentifier> toIdentifiers(Collection<ColumnDefinition> definitions)
    {
        return Collections2.transform(definitions, new Function<ColumnDefinition, ColumnIdentifier>()
        {
            @Override
            public ColumnIdentifier apply(ColumnDefinition columnDef)
            {
                return columnDef.name;
            }
        });
    }

    public int compareTo(ColumnDefinition other)
    {
        if (this == other)
            return 0;

        if (comparisonOrder != other.comparisonOrder)
            return Long.compare(comparisonOrder, other.comparisonOrder);

        return this.name.compareTo(other.name);
    }

    public Comparator<CellPath> cellPathComparator()
    {
        return cellPathComparator;
    }

    public Comparator<Object> asymmetricCellPathComparator()
    {
        return asymmetricCellPathComparator;
    }

    public Comparator<? super Cell> cellComparator()
    {
        return cellComparator;
    }

    public boolean isComplex()
    {
        return cellPathComparator != null;
    }

    public boolean isSimple()
    {
        return !isComplex();
    }

    public CellPath.Serializer cellPathSerializer()
    {
        // Collections are our only complex so far, so keep it simple
        return CollectionType.cellPathSerializer;
    }

    public void validateCellValue(ByteBuffer value)
    {
        type.validateCellValue(value);
    }

    public void validateCellPath(CellPath path)
    {
        if (!isComplex())
            throw new MarshalException("Only complex cells should have a cell path");

        assert type.isMultiCell();
        if (type.isCollection())
            ((CollectionType)type).nameComparator().validate(path.get(0));
        else
            ((UserType)type).nameComparator().validate(path.get(0));
    }

    public static String toCQLString(Iterable<ColumnDefinition> defs)
    {
        return toCQLString(defs.iterator());
    }

    public static String toCQLString(Iterator<ColumnDefinition> defs)
    {
        if (!defs.hasNext())
            return "";

        StringBuilder sb = new StringBuilder();
        sb.append(defs.next().name);
        while (defs.hasNext())
            sb.append(", ").append(defs.next().name);
        return sb.toString();
    }

    /**
     * The type of the cell values for cell belonging to this column.
     *
     * This is the same than the column type, except for collections where it's the 'valueComparator'
     * of the collection.
     */
    public AbstractType<?> cellValueType()
    {
        return type instanceof CollectionType
             ? ((CollectionType)type).valueComparator()
             : type;
    }

    public Selector.Factory newSelectorFactory(CFMetaData cfm, AbstractType<?> expectedType, List<ColumnDefinition> defs, VariableSpecifications boundNames) throws InvalidRequestException
    {
        return SimpleSelector.newFactory(this, addAndGetIndex(this, defs));
    }

    public AbstractType<?> getExactTypeIfKnown(String keyspace)
    {
        return type;
    }

    /**
     * Because Thrift-created tables may have a non-text comparator, we cannot determine the proper 'key' until
     * we know the comparator. ColumnDefinition.Raw is a placeholder that can be converted to a real ColumnIdentifier
     * once the comparator is known with prepare(). This should only be used with identifiers that are actual
     * column names. See CASSANDRA-8178 for more background.
     */
    public static abstract class Raw extends Selectable.Raw
    {
        /**
         * Creates a {@code ColumnDefinition.Raw} from an unquoted identifier string.
         */
        public static Raw forUnquoted(String text)
        {
            return new Literal(text, false);
        }

        /**
         * Creates a {@code ColumnDefinition.Raw} from a quoted identifier string.
         */
        public static Raw forQuoted(String text)
        {
            return new Literal(text, true);
        }

        /**
         * Creates a {@code ColumnDefinition.Raw} from a pre-existing {@code ColumnDefinition}
         * (useful in the rare cases where we already have the column but need
         * a {@code ColumnDefinition.Raw} for typing purposes).
         */
        public static Raw forColumn(ColumnDefinition column)
        {
            return new ForColumn(column);
        }

        /**
         * Get the identifier corresponding to this raw column, without assuming this is an
         * existing column (unlike {@link #prepare}).
         */
        public abstract ColumnIdentifier getIdentifier(CFMetaData cfm);

        public abstract String rawText();

        @Override
        public abstract ColumnDefinition prepare(CFMetaData cfm);

        @Override
        public boolean processesSelection()
        {
            return false;
        }

        @Override
        public final int hashCode()
        {
            return toString().hashCode();
        }

        @Override
        public final boolean equals(Object o)
        {
            if(!(o instanceof Raw))
                return false;

            Raw that = (Raw)o;
            return this.toString().equals(that.toString());
        }

        private static class Literal extends Raw
        {
            private final String text;

            public Literal(String rawText, boolean keepCase)
            {
                this.text =  keepCase ? rawText : rawText.toLowerCase(Locale.US);
            }

            public ColumnIdentifier getIdentifier(CFMetaData cfm)
            {
                if (!cfm.isStaticCompactTable())
                    return ColumnIdentifier.getInterned(text, true);

                AbstractType<?> thriftColumnNameType = cfm.thriftColumnNameType();
                if (thriftColumnNameType instanceof UTF8Type)
                    return ColumnIdentifier.getInterned(text, true);

                // We have a Thrift-created table with a non-text comparator. Check if we have a match column, otherwise assume we should use
                // thriftColumnNameType
                ByteBuffer bufferName = ByteBufferUtil.bytes(text);
                for (ColumnDefinition def : cfm.allColumns())
                {
                    if (def.name.bytes.equals(bufferName))
                        return def.name;
                }
                return ColumnIdentifier.getInterned(thriftColumnNameType.fromString(text), text);
            }

            public ColumnDefinition prepare(CFMetaData cfm)
            {
                if (!cfm.isStaticCompactTable())
                    return find(cfm);

                AbstractType<?> thriftColumnNameType = cfm.thriftColumnNameType();
                if (thriftColumnNameType instanceof UTF8Type)
                    return find(cfm);

                // We have a Thrift-created table with a non-text comparator. Check if we have a match column, otherwise assume we should use
                // thriftColumnNameType
                ByteBuffer bufferName = ByteBufferUtil.bytes(text);
                for (ColumnDefinition def : cfm.allColumns())
                {
                    if (def.name.bytes.equals(bufferName))
                        return def;
                }
                return find(thriftColumnNameType.fromString(text), cfm);
            }

            private ColumnDefinition find(CFMetaData cfm)
            {
                return find(ByteBufferUtil.bytes(text), cfm);
            }

            private ColumnDefinition find(ByteBuffer id, CFMetaData cfm)
            {
                ColumnDefinition def = cfm.getColumnDefinition(id);
                if (def == null)
                    throw new InvalidRequestException(String.format("Undefined column name %s", toString()));
                return def;
            }

            public String rawText()
            {
                return text;
            }

            @Override
            public String toString()
            {
                return ColumnIdentifier.maybeQuote(text);
            }
        }

        // Use internally in the rare case where we need a ColumnDefinition.Raw for type-checking but
        // actually already have the column itself.
        private static class ForColumn extends Raw
        {
            private final ColumnDefinition column;

            private ForColumn(ColumnDefinition column)
            {
                this.column = column;
            }

            public ColumnIdentifier getIdentifier(CFMetaData cfm)
            {
                return column.name;
            }

            public ColumnDefinition prepare(CFMetaData cfm)
            {
                assert cfm.getColumnDefinition(column.name) != null; // Sanity check that we're not doing something crazy
                return column;
            }

            public String rawText()
            {
                return column.name.toString();
            }

            @Override
            public String toString()
            {
                return column.name.toCQLString();
            }
        }
    }


}