/**
 *    Copyright (C) 2018-present MongoDB, Inc.
 *
 *    This program is free software: you can redistribute it and/or modify
 *    it under the terms of the Server Side Public License, version 1,
 *    as published by MongoDB, Inc.
 *
 *    This program 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
 *    Server Side Public License for more details.
 *
 *    You should have received a copy of the Server Side Public License
 *    along with this program. If not, see
 *    <http://www.mongodb.com/licensing/server-side-public-license>.
 *
 *    As a special exception, the copyright holders give permission to link the
 *    code of portions of this program with the OpenSSL library under certain
 *    conditions as described in each individual source file and distribute
 *    linked combinations including the program with the OpenSSL library. You
 *    must comply with the Server Side Public License in all respects for
 *    all of the code used other than as permitted herein. If you modify file(s)
 *    with this exception, you may extend this exception to your version of the
 *    file(s), but you are not obligated to do so. If you do not wish to do so,
 *    delete this exception statement from your version. If you delete this
 *    exception statement from all source files in the program, then also delete
 *    it in the license file.
 */

#include "mongo/platform/basic.h"

#include "mongo/db/matcher/expression_text.h"

#include <memory>

#include "mongo/db/catalog/collection.h"
#include "mongo/db/catalog/index_catalog.h"
#include "mongo/db/db_raii.h"
#include "mongo/db/fts/fts_language.h"
#include "mongo/db/fts/fts_spec.h"
#include "mongo/db/index/fts_access_method.h"

namespace mongo {

TextMatchExpression::TextMatchExpression(fts::FTSQueryImpl ftsQuery)
    : TextMatchExpressionBase("_fts"), _ftsQuery(ftsQuery) {}

TextMatchExpression::TextMatchExpression(OperationContext* opCtx,
                                         const NamespaceString& nss,
                                         TextParams params)
    : TextMatchExpressionBase("_fts") {
    _ftsQuery.setQuery(std::move(params.query));
    _ftsQuery.setLanguage(std::move(params.language));
    _ftsQuery.setCaseSensitive(params.caseSensitive);
    _ftsQuery.setDiacriticSensitive(params.diacriticSensitive);

    fts::TextIndexVersion version;
    {
        // Find text index.
        AutoGetDb autoDb(opCtx, nss.dbName(), MODE_IS);
        Lock::CollectionLock collLock(opCtx, nss, MODE_IS);
        Database* db = autoDb.getDb();

        uassert(ErrorCodes::IndexNotFound,
                str::stream() << "text index required for $text query (no such collection '"
                              << nss.toStringForErrorMsg() << "')",
                db);

        CollectionPtr collection(
            CollectionCatalog::get(opCtx)->lookupCollectionByNamespace(opCtx, nss));

        uassert(ErrorCodes::IndexNotFound,
                str::stream() << "text index required for $text query (no such collection '"
                              << nss.toStringForErrorMsg() << "')",
                collection);

        std::vector<const IndexDescriptor*> idxMatches;
        collection->getIndexCatalog()->findIndexByType(opCtx, IndexNames::TEXT, idxMatches);

        uassert(
            ErrorCodes::IndexNotFound, "text index required for $text query", !idxMatches.empty());
        uassert(ErrorCodes::IndexNotFound,
                "more than one text index found for $text query",
                idxMatches.size() < 2);
        invariant(idxMatches.size() == 1);

        const IndexDescriptor* index = idxMatches[0];
        const FTSAccessMethod* fam = static_cast<const FTSAccessMethod*>(
            collection->getIndexCatalog()->getEntry(index)->accessMethod());
        invariant(fam);

        // Extract version and default language from text index.
        version = fam->getSpec().getTextIndexVersion();
        if (_ftsQuery.getLanguage().empty()) {
            _ftsQuery.setLanguage(fam->getSpec().defaultLanguage().str());
        }
    }

    Status parseStatus = _ftsQuery.parse(version);
    uassertStatusOK(parseStatus);
}

std::unique_ptr<MatchExpression> TextMatchExpression::clone() const {
    auto expr = std::make_unique<TextMatchExpression>(_ftsQuery);
    // We use the query-only constructor here directly rather than using the full constructor, to
    // avoid needing to examine
    // the index catalog.
    if (getTag()) {
        expr->setTag(getTag()->clone());
    }
    return expr;
}

}  // namespace mongo