// pipelinetests.cpp : Unit tests for some classes within src/mongo/db/pipeline.

/**
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#include "mongo/platform/basic.h"

#include "mongo/db/pipeline/document.h"
#include "mongo/db/pipeline/expression_context.h"
#include "mongo/db/pipeline/field_path.h"
#include "mongo/db/pipeline/pipeline.h"
#include "mongo/db/operation_context_impl.h"
#include "mongo/dbtests/dbtests.h"

namespace PipelineTests {

    using boost::intrusive_ptr;
    using std::string;

    namespace Optimizations {
        using namespace mongo;

        namespace Local {
            class Base {
            public:
                // These both return json arrays of pipeline operators
                virtual string inputPipeJson() = 0;
                virtual string outputPipeJson() = 0;

                BSONObj pipelineFromJsonArray(const string& array) {
                    return fromjson("{pipeline: " + array + "}");
                }
                virtual void run() {
                    const BSONObj inputBson = pipelineFromJsonArray(inputPipeJson());
                    const BSONObj outputPipeExpected = pipelineFromJsonArray(outputPipeJson());

                    intrusive_ptr<ExpressionContext> ctx =
                        new ExpressionContext(&_opCtx, NamespaceString("a.collection"));
                    string errmsg;
                    intrusive_ptr<Pipeline> outputPipe =
                        Pipeline::parseCommand(errmsg, inputBson, ctx);
                    ASSERT_EQUALS(errmsg, "");
                    ASSERT(outputPipe != NULL);

                    ASSERT_EQUALS(outputPipe->serialize()["pipeline"],
                                  Value(outputPipeExpected["pipeline"]));
                }

                virtual ~Base() {}

            private:
                OperationContextImpl _opCtx;
            };

            class RemoveSkipZero : public Base {
                string inputPipeJson() override {
                    return "[{$skip: 0}]";
                }

                string outputPipeJson() override {
                    return "[]";
                }
            };

            class DoNotRemoveSkipOne : public Base {
                string inputPipeJson() override {
                    return "[{$skip: 1}]";
                }

                string outputPipeJson() override {
                    return "[{$skip: 1}]";
                }
            };

            class RemoveEmptyMatch : public Base {
                string inputPipeJson() override {
                    return "[{$match: {}}]";
                }

                string outputPipeJson() override {
                    return "[]";
                }
            };

            class RemoveMultipleEmptyMatches : public Base {
                string inputPipeJson() override {
                    return "[{$match: {}}, {$match: {}}]";
                }

                string outputPipeJson() override {
                    // TODO: The desired behavior here is to end up with an empty array.
                    return "[{$match: {$and: [{}, {}]}}]";
                }
            };

            class DoNotRemoveNonEmptyMatch : public Base {
                string inputPipeJson() override {
                    return "[{$match: {_id: 1}}]";
                }

                string outputPipeJson() override {
                    return "[{$match: {_id: 1}}]";
                }
            };

        } // namespace Local

        namespace Sharded {
            class Base {
            public:
                // These all return json arrays of pipeline operators
                virtual string inputPipeJson() = 0;
                virtual string shardPipeJson() = 0;
                virtual string mergePipeJson() = 0;

                BSONObj pipelineFromJsonArray(const string& array) {
                    return fromjson("{pipeline: " + array + "}");
                }
                virtual void run() {
                    const BSONObj inputBson = pipelineFromJsonArray(inputPipeJson());
                    const BSONObj shardPipeExpected = pipelineFromJsonArray(shardPipeJson());
                    const BSONObj mergePipeExpected = pipelineFromJsonArray(mergePipeJson());

                    intrusive_ptr<ExpressionContext> ctx =
                        new ExpressionContext(&_opCtx, NamespaceString("a.collection"));
                    string errmsg;
                    intrusive_ptr<Pipeline> mergePipe =
                        Pipeline::parseCommand(errmsg, inputBson, ctx);
                    ASSERT_EQUALS(errmsg, "");
                    ASSERT(mergePipe != NULL);

                    intrusive_ptr<Pipeline> shardPipe = mergePipe->splitForSharded();
                    ASSERT(shardPipe != NULL);

                    ASSERT_EQUALS(shardPipe->serialize()["pipeline"],
                                  Value(shardPipeExpected["pipeline"]));
                    ASSERT_EQUALS(mergePipe->serialize()["pipeline"],
                                  Value(mergePipeExpected["pipeline"]));
                }

                virtual ~Base() {}

            private:
                OperationContextImpl _opCtx;
            };

            // General test to make sure all optimizations support empty pipelines
            class Empty : public Base {
                string inputPipeJson() { return "[]"; }
                string shardPipeJson() { return "[]"; }
                string mergePipeJson() { return "[]"; }
            };

            namespace moveFinalUnwindFromShardsToMerger {

                class OneUnwind : public Base {
                    string inputPipeJson() { return "[{$unwind: '$a'}]}"; }
                    string shardPipeJson() { return "[]}"; }
                    string mergePipeJson() { return "[{$unwind: '$a'}]}"; }
                };

                class TwoUnwind : public Base {
                    string inputPipeJson() { return "[{$unwind: '$a'}, {$unwind: '$b'}]}"; }
                    string shardPipeJson() { return "[]}"; }
                    string mergePipeJson() { return "[{$unwind: '$a'}, {$unwind: '$b'}]}"; }
                };

                class UnwindNotFinal : public Base {
                    string inputPipeJson() { return "[{$unwind: '$a'}, {$match: {a:1}}]}"; }
                    string shardPipeJson() { return "[{$unwind: '$a'}, {$match: {a:1}}]}"; }
                    string mergePipeJson() { return "[]}"; }
                };

                class UnwindWithOther : public Base {
                    string inputPipeJson() { return "[{$match: {a:1}}, {$unwind: '$a'}]}"; }
                    string shardPipeJson() { return "[{$match: {a:1}}]}"; }
                    string mergePipeJson() { return "[{$unwind: '$a'}]}"; }
                };
            } // namespace moveFinalUnwindFromShardsToMerger


            namespace limitFieldsSentFromShardsToMerger {
                // These tests use $limit to split the pipelines between shards and merger as it is
                // always a split point and neutral in terms of needed fields.

                class NeedWholeDoc : public Base {
                    string inputPipeJson() { return "[{$limit:1}]"; }
                    string shardPipeJson() { return "[{$limit:1}]"; }
                    string mergePipeJson() { return "[{$limit:1}]"; }
                };

                class JustNeedsId : public Base {
                    string inputPipeJson() { return "[{$limit:1}, {$group: {_id: '$_id'}}]"; }
                    string shardPipeJson() { return "[{$limit:1}, {$project: {_id:true}}]"; }
                    string mergePipeJson() { return "[{$limit:1}, {$group: {_id: '$_id'}}]"; }
                };

                class JustNeedsNonId : public Base {
                    string inputPipeJson() {
                        return "[{$limit:1}, {$group: {_id: '$a.b'}}]";
                    }
                    string shardPipeJson() {
                        return "[{$limit:1}, {$project: {_id: false, a: {b: true}}}]";
                    }
                    string mergePipeJson() {
                        return "[{$limit:1}, {$group: {_id: '$a.b'}}]";
                    }
                };

                class NothingNeeded : public Base {
                    string inputPipeJson() {
                        return "[{$limit:1}"
                               ",{$group: {_id: {$const: null}, count: {$sum: {$const: 1}}}}"
                               "]";
                    }
                    string shardPipeJson() {
                        return "[{$limit:1}"
                               ",{$project: {_id: true}}"
                               "]";
                    }
                    string mergePipeJson() {
                        return "[{$limit:1}"
                               ",{$group: {_id: {$const: null}, count: {$sum: {$const: 1}}}}"
                               "]";
                    }
                };

                class JustNeedsMetadata : public Base {
                    // Currently this optimization doesn't handle metadata and the shards assume it
                    // needs to be propagated implicitly. Therefore the $project produced should be
                    // the same as in NothingNeeded.
                    string inputPipeJson() {
                        return "[{$limit:1}, {$project: {_id: false, a: {$meta: 'textScore'}}}]";
                    }
                    string shardPipeJson() {
                        return "[{$limit:1}, {$project: {_id: true}}]";
                    }
                    string mergePipeJson() {
                        return "[{$limit:1}, {$project: {_id: false, a: {$meta: 'textScore'}}}]";
                    }
                };

                class ShardAlreadyExhaustive : public Base {
                    // No new project should be added. This test reflects current behavior where the
                    // 'a' field is still sent because it is explicitly asked for, even though it
                    // isn't actually needed. If this changes in the future, this test will need to
                    // change.
                    string inputPipeJson() {
                        return "[{$project: {_id:true, a:true}}"
                               ",{$limit:1}"
                               ",{$group: {_id: '$_id'}}"
                               "]";
                    }
                    string shardPipeJson() {
                        return "[{$project: {_id:true, a:true}}"
                               ",{$limit:1}"
                               "]";
                    }
                    string mergePipeJson() {
                        return "[{$limit:1}"
                               ",{$group: {_id: '$_id'}}"
                               "]";
                    }
                };

            } // namespace limitFieldsSentFromShardsToMerger
        } // namespace Sharded
    } // namespace Optimizations

    class All : public Suite {
    public:
        All() : Suite( "pipeline" ) {
        }
        void setupTests() {
            add<Optimizations::Local::RemoveSkipZero>();
            add<Optimizations::Local::DoNotRemoveSkipOne>();
            add<Optimizations::Local::RemoveEmptyMatch>();
            add<Optimizations::Local::RemoveMultipleEmptyMatches>();
            add<Optimizations::Local::DoNotRemoveNonEmptyMatch>();
            add<Optimizations::Sharded::Empty>();
            add<Optimizations::Sharded::moveFinalUnwindFromShardsToMerger::OneUnwind>();
            add<Optimizations::Sharded::moveFinalUnwindFromShardsToMerger::TwoUnwind>();
            add<Optimizations::Sharded::moveFinalUnwindFromShardsToMerger::UnwindNotFinal>();
            add<Optimizations::Sharded::moveFinalUnwindFromShardsToMerger::UnwindWithOther>();
            add<Optimizations::Sharded::limitFieldsSentFromShardsToMerger::NeedWholeDoc>();
            add<Optimizations::Sharded::limitFieldsSentFromShardsToMerger::JustNeedsId>();
            add<Optimizations::Sharded::limitFieldsSentFromShardsToMerger::JustNeedsNonId>();
            add<Optimizations::Sharded::limitFieldsSentFromShardsToMerger::NothingNeeded>();
            add<Optimizations::Sharded::limitFieldsSentFromShardsToMerger::JustNeedsMetadata>();
            add<Optimizations::Sharded::limitFieldsSentFromShardsToMerger::ShardAlreadyExhaustive>();
        }
    };

    SuiteInstance<All> myall;

} // namespace PipelineTests