// Tests the support for disk storage of intermediate results in aggregation.
//
// Run only when pipeline optimization is enabled, otherwise the type of sorter being used can be
// different (NoLimitSort vs TopKSort) causing an aggregation request to fail with different error
// codes.
// @tags: [requires_pipeline_optimization]
(function() {
    'use strict';

    const coll = db.spill_to_disk;
    coll.drop();

    const memoryLimitMB = 100;

    const bigStr = Array(1024 * 1024 + 1).toString();  // 1MB of ','
    for (let i = 0; i < memoryLimitMB + 1; i++)
        coll.insert({_id: i.toString(), bigStr: i + bigStr, random: Math.random()});

    assert.gt(coll.stats().size, memoryLimitMB * 1024 * 1024);

    function test({pipeline, expectedCodes, canSpillToDisk}) {
        // Test that by default we error out if exceeding memory limit.
        assert.commandFailedWithCode(
            db.runCommand({aggregate: coll.getName(), pipeline: pipeline, cursor: {}}),
            expectedCodes);

        // Test that 'allowDiskUse: false' does indeed prevent spilling to disk.
        assert.commandFailedWithCode(
            db.runCommand(
                {aggregate: coll.getName(), pipeline: pipeline, cursor: {}, allowDiskUse: false}),
            expectedCodes);

        // Test that allowDiskUse only supports bool. In particular, numbers aren't allowed.
        assert.commandFailed(db.runCommand(
            {aggregate: coll.getName(), pipeline: pipeline, cursor: {}, allowDiskUse: 1}));

        // If this command supports spilling to disk, ensure that it will succeed when disk use is
        // allowed.
        let res = db.runCommand(
            {aggregate: coll.getName(), pipeline: pipeline, cursor: {}, allowDiskUse: true});
        if (canSpillToDisk) {
            assert.eq(new DBCommandCursor(coll.getDB(), res).itcount(),
                      coll.count());  // all tests output one doc per input doc
        } else {
            assert.commandFailedWithCode(res, [ErrorCodes.ExceededMemoryLimit, expectedCodes]);
        }
    }

    const groupCode = 16945;
    const sortCode = 16819;
    const sortLimitCode = 16820;

    test({
        pipeline: [{$group: {_id: '$_id', bigStr: {$min: '$bigStr'}}}],
        expectedCodes: groupCode,
        canSpillToDisk: true
    });

    // Sorting with _id would use index which doesn't require external sort, so sort by 'random'
    // instead.
    test({pipeline: [{$sort: {random: 1}}], expectedCodes: sortCode, canSpillToDisk: true});
    test({
        pipeline: [{$sort: {bigStr: 1}}],  // big key and value
        expectedCodes: sortCode,
        canSpillToDisk: true
    });

    // Test that sort + large limit won't crash the server (SERVER-10136)
    test({
        pipeline: [{$sort: {bigStr: 1}}, {$limit: 1000 * 1000 * 1000}],
        expectedCodes: sortLimitCode,
        canSpillToDisk: true
    });

    // Test combining two external sorts in both same and different orders.
    test({
        pipeline: [{$group: {_id: '$_id', bigStr: {$min: '$bigStr'}}}, {$sort: {_id: 1}}],
        expectedCodes: groupCode,
        canSpillToDisk: true
    });
    test({
        pipeline: [{$group: {_id: '$_id', bigStr: {$min: '$bigStr'}}}, {$sort: {_id: -1}}],
        expectedCodes: groupCode,
        canSpillToDisk: true
    });
    test({
        pipeline: [{$group: {_id: '$_id', bigStr: {$min: '$bigStr'}}}, {$sort: {random: 1}}],
        expectedCodes: groupCode,
        canSpillToDisk: true
    });
    test({
        pipeline: [{$sort: {random: 1}}, {$group: {_id: '$_id', bigStr: {$first: '$bigStr'}}}],
        expectedCodes: sortCode,
        canSpillToDisk: true
    });

    // Test accumulating all values into one array. On debug builds we will spill to disk for $group
    // and
    // so may hit the group error code before we hit ExceededMemoryLimit.
    test({
        pipeline: [{$group: {_id: null, bigArray: {$push: '$bigStr'}}}],
        expectedCodes: [groupCode, ErrorCodes.ExceededMemoryLimit],
        canSpillToDisk: false
    });
    test({
        pipeline: [{$group: {_id: null, bigArray: {$addToSet: {$concat: ['$bigStr', "$_id"]}}}}],
        expectedCodes: [groupCode, ErrorCodes.ExceededMemoryLimit],
        canSpillToDisk: false
    });

    // don't leave large collection laying around
    coll.drop();
})();