/* -*- Mode: C++; tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/*
 *   Copyright 2023-Present Couchbase, Inc.
 *
 *   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.
 */

#pragma once

#include <couchbase/match_operator.hxx>
#include <couchbase/search_query.hxx>

#include <cstdint>
#include <optional>
#include <stdexcept>
#include <string>

namespace couchbase
{
/**
 * A query that looks for **exact** matches of the term in the index (no analyzer, no stemming). Useful to check what the actual content of
 * the index is. It can also apply fuzziness on the term. Usual better alternative is @ref match_query.
 *
 * @see https://docs.couchbase.com/server/current/fts/fts-supported-queries-term.html server documentation
 * @see https://docs.couchbase.com/server/current/fts/fts-supported-queries-fuzzy.html fuzzy search
 *
 * @since 1.0.0
 * @committed
 */
class term_query : public search_query
{
  public:
    /**
     * Create a new term query.
     *
     * The mandatory term is the exact string that will be searched into the index. Note that the index can (and usually will) contain terms
     * that are derived from the text in documents, as analyzers can apply process like stemming. For example, indexing "programming" could
     * store "program" in the index. As a term query doesn't apply the analyzers, one would need to look for "program" to have a match on
     * that index entry.
     *
     * @param term the input string to be matched against
     *
     * @since 1.0.0
     * @committed
     */
    explicit term_query(std::string term)
      : term_{ std::move(term) }
    {
    }

    /**
     * Require that the term also have the same prefix of the specified length (must be positive).
     *
     * The prefix length only makes sense when fuzziness is enabled. It allows to apply the fuzziness only on the part of the term that is
     * after the `length` character mark.
     *
     * For example, with the term "something" and a prefix length of 4, only the "thing" part of the term will be fuzzy-searched, and hits
     * must start with "some".
     *
     * @param length the length of the term prefix
     *
     * @return this query for chaining purposes.
     *
     * @since 1.0.0
     * @committed
     */
    auto prefix_length(std::uint32_t length) -> term_query&
    {
        if (length <= 0) {
            throw std::invalid_argument("prefix_length must be positive");
        }

        prefix_length_ = length;
        return *this;
    }

    /**
     * If a field is specified, only terms in that field will be matched.
     *
     * @param field_name name of the field to be matched
     *
     * @return this query for chaining purposes.
     *
     * @since 1.0.0
     * @committed
     */
    auto field(std::string field_name) -> term_query&
    {
        field_ = std::move(field_name);
        return *this;
    }

    /**
     * Perform fuzzy matching. If the fuzziness parameter is set to a non-zero integer the analyzed text will be matched with the specified
     * level of fuzziness.
     *
     * @param fuzziness level of fuzziness (the maximum supported fuzziness is 2).
     *
     * @return this query for chaining purposes.
     *
     * @since 1.0.0
     * @committed
     */
    auto fuzziness(std::uint32_t fuzziness) -> term_query&
    {
        fuzziness_ = fuzziness;
        return *this;
    }

    /**
     * Defines how the individual match terms should be logically concatenated
     *
     * @param concatenation_operator operator to be used
     *
     * @return this query for chaining purposes.
     *
     * @since 1.0.0
     * @committed
     */
    auto match_operator(couchbase::match_operator concatenation_operator) -> term_query&
    {
        operator_ = concatenation_operator;
        return *this;
    }

    /**
     * @return encoded representation of the query.
     *
     * @since 1.0.0
     * @internal
     */
    [[nodiscard]] auto encode() const -> encoded_search_query override;

  private:
    std::string term_;
    std::optional<std::uint32_t> prefix_length_{};
    std::optional<std::string> field_{};
    std::optional<std::uint32_t> fuzziness_{};
    std::optional<couchbase::match_operator> operator_{};
};
} // namespace couchbase