/**
 *    Copyright (C) 2016 MongoDB Inc.
 *
 *    This program is free software: you can redistribute it and/or  modify
 *    it under the terms of the GNU Affero General Public License, version 3,
 *    as published by the Free Software Foundation.
 *
 *    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
 *    GNU Affero General Public License for more details.
 *
 *    You should have received a copy of the GNU Affero General Public License
 *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 *    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 GNU Affero General 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 <set>
#include <string>

#include "mongo/bson/bsonmisc.h"
#include "mongo/bson/bsonobj.h"
#include "mongo/bson/bsonobjbuilder.h"
#include "mongo/db/pipeline/dependencies.h"
#include "mongo/db/pipeline/document.h"
#include "mongo/unittest/unittest.h"

namespace mongo {
namespace {
using std::set;
using std::string;

static const BSONObj metaTextScore = BSON("$meta"
                                          << "textScore");

template <size_t ArrayLen>
set<string> arrayToSet(const char* (&array)[ArrayLen]) {
    set<string> out;
    for (size_t i = 0; i < ArrayLen; i++)
        out.insert(array[i]);
    return out;
}

TEST(DependenciesToProjectionTest, ShouldIncludeAllFieldsAndExcludeIdIfNotSpecified) {
    const char* array[] = {"a", "b"};
    DepsTracker deps;
    deps.fields = arrayToSet(array);
    ASSERT_BSONOBJ_EQ(deps.toProjection(), BSON("a" << 1 << "b" << 1 << "_id" << 0));
}

TEST(DependenciesToProjectionTest, ShouldIncludeFieldEvenIfSuffixOfAnotherIncludedField) {
    const char* array[] = {"a", "ab"};
    DepsTracker deps;
    deps.fields = arrayToSet(array);
    ASSERT_BSONOBJ_EQ(deps.toProjection(), BSON("a" << 1 << "ab" << 1 << "_id" << 0));
}

TEST(DependenciesToProjectionTest, ShouldNotIncludeSubFieldIfTopLevelAlreadyIncluded) {
    const char* array[] = {"a", "b", "a.b"};  // a.b included by a
    DepsTracker deps;
    deps.fields = arrayToSet(array);
    ASSERT_BSONOBJ_EQ(deps.toProjection(), BSON("a" << 1 << "b" << 1 << "_id" << 0));
}

TEST(DependenciesToProjectionTest, ShouldIncludeIdIfNeeded) {
    const char* array[] = {"a", "_id"};
    DepsTracker deps;
    deps.fields = arrayToSet(array);
    ASSERT_BSONOBJ_EQ(deps.toProjection(), BSON("a" << 1 << "_id" << 1));
}

TEST(DependenciesToProjectionTest, ShouldIncludeEntireIdEvenIfOnlyASubFieldIsNeeded) {
    const char* array[] = {"a", "_id.a"};  // still include whole _id (SERVER-7502)
    DepsTracker deps;
    deps.fields = arrayToSet(array);
    ASSERT_BSONOBJ_EQ(deps.toProjection(), BSON("a" << 1 << "_id" << 1));
}

TEST(DependenciesToProjectionTest, ShouldNotIncludeSubFieldOfIdIfIdIncluded) {
    const char* array[] = {"a", "_id", "_id.a"};  // handle both _id and subfield
    DepsTracker deps;
    deps.fields = arrayToSet(array);
    ASSERT_BSONOBJ_EQ(deps.toProjection(), BSON("a" << 1 << "_id" << 1));
}

TEST(DependenciesToProjectionTest, ShouldIncludeFieldPrefixedById) {
    const char* array[] = {"a", "_id", "_id_a"};  // _id prefixed but non-subfield
    DepsTracker deps;
    deps.fields = arrayToSet(array);
    ASSERT_BSONOBJ_EQ(deps.toProjection(), BSON("_id_a" << 1 << "a" << 1 << "_id" << 1));
}

TEST(DependenciesToProjectionTest, ShouldOutputEmptyObjectIfEntireDocumentNeeded) {
    const char* array[] = {"a"};  // fields ignored with needWholeDocument
    DepsTracker deps;
    deps.fields = arrayToSet(array);
    deps.needWholeDocument = true;
    ASSERT_BSONOBJ_EQ(deps.toProjection(), BSONObj());
}

TEST(DependenciesToProjectionTest, ShouldOnlyRequestTextScoreIfEntireDocumentAndTextScoreNeeded) {
    const char* array[] = {"a"};  // needTextScore with needWholeDocument
    DepsTracker deps(DepsTracker::MetadataAvailable::kTextScore);
    deps.fields = arrayToSet(array);
    deps.needWholeDocument = true;
    deps.setNeedTextScore(true);
    ASSERT_BSONOBJ_EQ(deps.toProjection(), BSON(Document::metaFieldTextScore << metaTextScore));
}

TEST(DependenciesToProjectionTest,
     ShouldRequireFieldsAndTextScoreIfTextScoreNeededWithoutWholeDocument) {
    const char* array[] = {"a"};  // needTextScore without needWholeDocument
    DepsTracker deps(DepsTracker::MetadataAvailable::kTextScore);
    deps.fields = arrayToSet(array);
    deps.setNeedTextScore(true);
    ASSERT_BSONOBJ_EQ(
        deps.toProjection(),
        BSON(Document::metaFieldTextScore << metaTextScore << "a" << 1 << "_id" << 0));
}

TEST(DependenciesToProjectionTest, ShouldProduceEmptyObjectIfThereAreNoDependencies) {
    DepsTracker deps(DepsTracker::MetadataAvailable::kTextScore);
    deps.fields = {};
    deps.needWholeDocument = false;
    deps.setNeedTextScore(false);
    ASSERT_BSONOBJ_EQ(deps.toProjection(), BSONObj());
}

TEST(DependenciesToProjectionTest, ShouldAttemptToExcludeOtherFieldsIfOnlyTextScoreIsNeeded) {
    DepsTracker deps(DepsTracker::MetadataAvailable::kTextScore);
    deps.fields = {};
    deps.needWholeDocument = false;
    deps.setNeedTextScore(true);
    ASSERT_BSONOBJ_EQ(deps.toProjection(),
                      BSON("_id" << 0 << "$noFieldsNeeded" << 1 << Document::metaFieldTextScore
                                 << metaTextScore));
}

TEST(DependenciesToProjectionTest,
     ShouldRequireTextScoreIfNoFieldsPresentButWholeDocumentIsNeeded) {
    DepsTracker deps(DepsTracker::MetadataAvailable::kTextScore);
    deps.fields = {};
    deps.needWholeDocument = true;
    deps.setNeedTextScore(true);
    ASSERT_BSONOBJ_EQ(deps.toProjection(), BSON(Document::metaFieldTextScore << metaTextScore));
}

}  // namespace
}  // namespace mongo