/*
 * 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.
 */

/*
 * Copyright (C) 2015 ScyllaDB
 *
 * Modified by ScyllaDB
 */

/*
 * This file is part of Scylla.
 *
 * Scylla is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Scylla is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Scylla.  If not, see <http://www.gnu.org/licenses/>.
 */

#pragma once

#include "cql3/restrictions/restriction.hh"
#include "cql3/statements/raw/cf_statement.hh"
#include "cql3/column_identifier.hh"
#include "cql3/update_parameters.hh"
#include "cql3/column_condition.hh"
#include "cql3/cql_statement.hh"
#include "cql3/attributes.hh"
#include "cql3/operation.hh"
#include "cql3/relation.hh"

#include "db/consistency_level.hh"

#include "core/shared_ptr.hh"
#include "core/future-util.hh"

#include "unimplemented.hh"
#include "validation.hh"
#include "service/storage_proxy.hh"

#include <memory>
#include <experimental/optional>

namespace cql3 {

namespace statements {


namespace raw { class modification_statement; }

/*
 * Abstract parent class of individual modifications, i.e. INSERT, UPDATE and DELETE.
 */
class modification_statement : public cql_statement_no_metadata {
private:
    static thread_local const ::shared_ptr<column_identifier> CAS_RESULT_COLUMN;

public:
    enum class statement_type { INSERT, UPDATE, DELETE };

    const statement_type type;

private:
    const uint32_t _bound_terms;

public:
    const schema_ptr s;
    const std::unique_ptr<attributes> attrs;

protected:
    std::unordered_map<const column_definition*, ::shared_ptr<restrictions::restriction>> _processed_keys;
    std::vector<::shared_ptr<operation>> _column_operations;
private:
    // Separating normal and static conditions makes things somewhat easier
    std::vector<::shared_ptr<column_condition>> _column_conditions;
    std::vector<::shared_ptr<column_condition>> _static_conditions;

    bool _if_not_exists = false;
    bool _if_exists = false;

    bool _has_no_clustering_columns = true;

    bool _sets_static_columns = false;
    bool _sets_regular_columns = false;
    std::experimental::optional<bool> _is_raw_counter_shard_write;

    const std::function<const column_definition&(::shared_ptr<column_condition>)> get_column_for_condition =
        [](::shared_ptr<column_condition> cond) -> const column_definition& {
            return cond->column;
        };

    uint64_t* _cql_modification_counter_ptr = nullptr;

public:
    modification_statement(statement_type type_, uint32_t bound_terms, schema_ptr schema_, std::unique_ptr<attributes> attrs_, uint64_t* cql_stats_counter_ptr);

    virtual bool uses_function(const sstring& ks_name, const sstring& function_name) const override;

    virtual bool require_full_clustering_key() const = 0;

    virtual void add_update_for_key(mutation& m, const exploded_clustering_prefix& prefix, const update_parameters& params) = 0;

    virtual uint32_t get_bound_terms() override;

    virtual const sstring& keyspace() const;

    virtual const sstring& column_family() const;

    virtual bool is_counter() const;

    virtual bool is_view() const;

    int64_t get_timestamp(int64_t now, const query_options& options) const;

    bool is_timestamp_set() const;

    gc_clock::duration get_time_to_live(const query_options& options) const;

    virtual future<> check_access(const service::client_state& state) override;

    void validate(distributed<service::storage_proxy>&, const service::client_state& state) override;

    virtual bool depends_on_keyspace(const sstring& ks_name) const override;

    virtual bool depends_on_column_family(const sstring& cf_name) const override;

    void add_operation(::shared_ptr<operation> op);

#if 0
    public Iterable<ColumnDefinition> getColumnsWithConditions()
    {
        if (ifNotExists || ifExists)
            return null;

        return Iterables.concat(columnConditions == null ? Collections.<ColumnDefinition>emptyList() : Iterables.transform(columnConditions, getColumnForCondition),
                                staticConditions == null ? Collections.<ColumnDefinition>emptyList() : Iterables.transform(staticConditions, getColumnForCondition));
    }
#endif

    void inc_cql_stats() {
        ++(*_cql_modification_counter_ptr);
    }

public:
    void add_condition(::shared_ptr<column_condition> cond);

    void set_if_not_exist_condition();

    bool has_if_not_exist_condition() const;

    void set_if_exist_condition();

    bool has_if_exist_condition() const;

    bool is_raw_counter_shard_write() const {
        return _is_raw_counter_shard_write.value_or(false);
    }
private:
    void add_key_values(const column_definition& def, ::shared_ptr<restrictions::restriction> values);

public:
    void add_key_value(const column_definition& def, ::shared_ptr<term> value);
    void process_where_clause(database& db, std::vector<relation_ptr> where_clause, ::shared_ptr<variable_specifications> names);
    std::vector<partition_key> build_partition_keys(const query_options& options);

private:
    exploded_clustering_prefix create_exploded_clustering_prefix(const query_options& options);
    exploded_clustering_prefix create_exploded_clustering_prefix_internal(const query_options& options);

protected:
    const column_definition* get_first_empty_key();

public:
    bool requires_read();

protected:
    future<update_parameters::prefetched_rows_type> read_required_rows(
                distributed<service::storage_proxy>& proxy,
                lw_shared_ptr<std::vector<partition_key>> keys,
                lw_shared_ptr<exploded_clustering_prefix> prefix,
                bool local,
                db::consistency_level cl,
                tracing::trace_state_ptr trace_state);
private:
    future<::shared_ptr<transport::messages::result_message>>
    do_execute(distributed<service::storage_proxy>& proxy, service::query_state& qs, const query_options& options);
    friend class modification_statement_executor;
public:
    bool has_conditions();

    virtual future<::shared_ptr<transport::messages::result_message>>
    execute(distributed<service::storage_proxy>& proxy, service::query_state& qs, const query_options& options) override;

    virtual future<::shared_ptr<transport::messages::result_message>>
    execute_internal(distributed<service::storage_proxy>& proxy, service::query_state& qs, const query_options& options) override;

private:
    future<>
    execute_without_condition(distributed<service::storage_proxy>& proxy, service::query_state& qs, const query_options& options);

    future<::shared_ptr<transport::messages::result_message>>
    execute_with_condition(distributed<service::storage_proxy>& proxy, service::query_state& qs, const query_options& options);

#if 0
    public void addConditions(Composite clusteringPrefix, CQL3CasRequest request, QueryOptions options) throws InvalidRequestException
    {
        if (ifNotExists)
        {
            // If we use ifNotExists, if the statement applies to any non static columns, then the condition is on the row of the non-static
            // columns and the prefix should be the clusteringPrefix. But if only static columns are set, then the ifNotExists apply to the existence
            // of any static columns and we should use the prefix for the "static part" of the partition.
            request.addNotExist(clusteringPrefix);
        }
        else if (ifExists)
        {
            request.addExist(clusteringPrefix);
        }
        else
        {
            if (columnConditions != null)
                request.addConditions(clusteringPrefix, columnConditions, options);
            if (staticConditions != null)
                request.addConditions(cfm.comparator.staticPrefix(), staticConditions, options);
        }
    }

    private ResultSet buildCasResultSet(ByteBuffer key, ColumnFamily cf, QueryOptions options) throws InvalidRequestException
    {
        return buildCasResultSet(keyspace(), key, columnFamily(), cf, getColumnsWithConditions(), false, options);
    }

    public static ResultSet buildCasResultSet(String ksName, ByteBuffer key, String cfName, ColumnFamily cf, Iterable<ColumnDefinition> columnsWithConditions, boolean isBatch, QueryOptions options)
    throws InvalidRequestException
    {
        boolean success = cf == null;

        ColumnSpecification spec = new ColumnSpecification(ksName, cfName, CAS_RESULT_COLUMN, BooleanType.instance);
        ResultSet.Metadata metadata = new ResultSet.Metadata(Collections.singletonList(spec));
        List<List<ByteBuffer>> rows = Collections.singletonList(Collections.singletonList(BooleanType.instance.decompose(success)));

        ResultSet rs = new ResultSet(metadata, rows);
        return success ? rs : merge(rs, buildCasFailureResultSet(key, cf, columnsWithConditions, isBatch, options));
    }

    private static ResultSet merge(ResultSet left, ResultSet right)
    {
        if (left.size() == 0)
            return right;
        else if (right.size() == 0)
            return left;

        assert left.size() == 1;
        int size = left.metadata.names.size() + right.metadata.names.size();
        List<ColumnSpecification> specs = new ArrayList<ColumnSpecification>(size);
        specs.addAll(left.metadata.names);
        specs.addAll(right.metadata.names);
        List<List<ByteBuffer>> rows = new ArrayList<>(right.size());
        for (int i = 0; i < right.size(); i++)
        {
            List<ByteBuffer> row = new ArrayList<ByteBuffer>(size);
            row.addAll(left.rows.get(0));
            row.addAll(right.rows.get(i));
            rows.add(row);
        }
        return new ResultSet(new ResultSet.Metadata(specs), rows);
    }

    private static ResultSet buildCasFailureResultSet(ByteBuffer key, ColumnFamily cf, Iterable<ColumnDefinition> columnsWithConditions, boolean isBatch, QueryOptions options)
    throws InvalidRequestException
    {
        CFMetaData cfm = cf.metadata();
        Selection selection;
        if (columnsWithConditions == null)
        {
            selection = Selection.wildcard(cfm);
        }
        else
        {
            // We can have multiple conditions on the same columns (for collections) so use a set
            // to avoid duplicate, but preserve the order just to it follows the order of IF in the query in general
            Set<ColumnDefinition> defs = new LinkedHashSet<>();
            // Adding the partition key for batches to disambiguate if the conditions span multipe rows (we don't add them outside
            // of batches for compatibility sakes).
            if (isBatch)
            {
                defs.addAll(cfm.partitionKeyColumns());
                defs.addAll(cfm.clusteringColumns());
            }
            for (ColumnDefinition def : columnsWithConditions)
                defs.add(def);
            selection = Selection.forColumns(cfm, new ArrayList<>(defs));

        }

        long now = System.currentTimeMillis();
        Selection.ResultSetBuilder builder = selection.resultSetBuilder(now);
        SelectStatement.forSelection(cfm, selection).processColumnFamily(key, cf, options, now, builder);

        return builder.build(options.getProtocolVersion());
    }

    public ResultMessage executeInternal(QueryState queryState, QueryOptions options) throws RequestValidationException, RequestExecutionException
    {
        if (hasConditions())
            throw new UnsupportedOperationException();

        for (IMutation mutation : getMutations(options, true, queryState.getTimestamp()))
        {
            // We don't use counters internally.
            assert mutation instanceof Mutation;

            ((Mutation) mutation).apply();
        }
        return null;
    }
#endif

public:
    /**
     * Convert statement into a list of mutations to apply on the server
     *
     * @param options value for prepared statement markers
     * @param local if true, any requests (for collections) performed by getMutation should be done locally only.
     * @param now the current timestamp in microseconds to use if no timestamp is user provided.
     *
     * @return vector of the mutations
     * @throws invalid_request_exception on invalid requests
     */
    future<std::vector<mutation>> get_mutations(distributed<service::storage_proxy>& proxy, const query_options& options, bool local, int64_t now, tracing::trace_state_ptr trace_state);

public:
    future<std::unique_ptr<update_parameters>> make_update_parameters(
                distributed<service::storage_proxy>& proxy,
                lw_shared_ptr<std::vector<partition_key>> keys,
                lw_shared_ptr<exploded_clustering_prefix> prefix,
                const query_options& options,
                bool local,
                int64_t now,
                tracing::trace_state_ptr trace_state);

protected:
    /**
     * If there are conditions on the statement, this is called after the where clause and conditions have been
     * processed to check that they are compatible.
     * @throws InvalidRequestException
     */
    virtual void validate_where_clause_for_conditions();
    friend class raw::modification_statement;
};

std::ostream& operator<<(std::ostream& out, modification_statement::statement_type t);

}

}