/**
 * Tests that the cluster collStats command returns timeseries statistics in the expected format.
 *
 * For legacy collStats command:
 * {
 *     ....,
 *     "ns" : ...,
 *     ....,
 *     "timeseries" : {
 *         .... (sums the shards' field values)
 *     }
 *     ....,
 *     "shards" : {
 *         <shardName> {
 *             "timeseries" : {
 *                 .... (single shard's field values)
 *             }
 *             ....
 *         }
 *     }
 *     ....
 * }
 *
 * For aggregate $collStats stage:
 * [
 *  {
 *     ....,
 *     "ns" : ...,
 *     "shard" : ...,
 *     "latencyStats" : {
 *         ....
 *     },
 *     "storageStats" : {
 *         ...,
 *        "timeseries" : {
 *         ...,
 *         },
 *     },
 *     "count" : {
 *         ....
 *     },
 *     "queryExecStats" : {
 *         ....
 *     },
 *  },
 *  {
 *   .... (Other shard's result)
 *  },
 *  ...
 * ]
 *
 * @tags: [
 *   requires_fcv_71
 * ]
 */

(function() {
load("jstests/core/timeseries/libs/timeseries.js");
const numShards = 2;
const st = new ShardingTest({shards: numShards});

if (!TimeseriesTest.shardedtimeseriesCollectionsEnabled(st.shard0)) {
    jsTestLog("Skipping test because the sharded time-series collection feature flag is disabled");
    st.stop();
    return;
}

const dbName = 'testDB';
const collName = 'testColl';
const mongosDB = st.s.getDB(dbName);
const mongosColl = mongosDB.getCollection(collName);
const timeField = 'tm';
const metaField = 'mt';
const viewNs = `${dbName}.${collName}`;
const bucketNs = `${dbName}.system.buckets.${collName}`;

// Create a timeseries collection.
assert.commandWorked(mongosDB.createCollection(
    collName, {timeseries: {timeField: timeField, metaField: metaField}}));

// Populate the timeseries collection with some data. More interesting test case, and populates the
// statistics results.
const numberDoc = 20;
for (let i = 0; i < numberDoc; i++) {
    assert.commandWorked(mongosColl.insert({[timeField]: ISODate(), [metaField]: i}));
}
assert.eq(mongosColl.find().itcount(), numberDoc);

// The cluster collStats command should pull the shard's 'timeseries' data to the top level of the
// command results.
let clusterCollStatsResult = assert.commandWorked(mongosDB.runCommand({collStats: collName}));
jsTestLog("Cluster collStats command result: " + tojson(clusterCollStatsResult));
assert(clusterCollStatsResult.timeseries,
       "Expected a top-level 'timeseries' field but didn't find one: " +
           tojson(clusterCollStatsResult));

// Check that the top-level 'timeseries' fields match the primary shard's, that the stats were
// correctly pulled up.
const primaryShard = st.getPrimaryShard(dbName);
const otherShard = st.getOther(primaryShard);
assert(
    clusterCollStatsResult.shards[primaryShard.shardName].timeseries,
    "Expected a shard 'timeseries' field but didn't find one: " + tojson(clusterCollStatsResult));
assert.docEq(clusterCollStatsResult.timeseries,
             clusterCollStatsResult.shards[primaryShard.shardName].timeseries);

// Shard the timeseries collection
assert.commandWorked(st.s.adminCommand({enableSharding: dbName}));
assert.commandWorked(mongosColl.createIndex({[metaField]: 1}));
assert.commandWorked(st.s.adminCommand({
    shardCollection: viewNs,
    key: {[metaField]: 1},
}));

// Force splitting numShards chunks.
const splitPoint = {
    meta: numberDoc / numShards
};
assert.commandWorked(st.s.adminCommand({split: bucketNs, middle: splitPoint}));
// Ensure that currently both chunks reside on the primary shard.
let counts = st.chunkCounts(`system.buckets.${collName}`, dbName);
assert.eq(numShards, counts[primaryShard.shardName]);
// Move one of the chunks into the second shard.
assert.commandWorked(st.s.adminCommand(
    {movechunk: bucketNs, find: splitPoint, to: otherShard.name, _waitForDelete: true}));
// Ensure that each shard owns one chunk.
counts = st.chunkCounts(`system.buckets.${collName}`, dbName);
assert.eq(1, counts[primaryShard.shardName], counts);
assert.eq(1, counts[otherShard.shardName], counts);

// Do some insertion after moving chunks.
for (let i = 0; i < numberDoc; i++) {
    assert.commandWorked(mongosColl.insert({[timeField]: ISODate(), [metaField]: i}));
}
assert.eq(mongosColl.find().itcount(), numberDoc * 2);

function checkAllFieldsAreInResult(result) {
    assert(result.hasOwnProperty("latencyStats"), result);
    assert(result.hasOwnProperty("storageStats"), result);
    assert(result.hasOwnProperty("count"), result);
    assert(result.hasOwnProperty("queryExecStats"), result);
}

function assertTimeseriesAggregationCorrectness(total, shards) {
    assert(shards.every(x => x.bucketNs === total.bucketNs));
    assert.eq(total.bucketCount,
              shards.map(x => x.bucketCount).reduce((x, y) => x + y, 0 /* initial value */));
    if (total.bucketCount > 0) {
        assert.eq(total.avgBucketSize,
                  Math.floor(shards.map(x => x.avgBucketSize * x.bucketCount)
                                 .reduce((x, y) => x + y, 0 /* initial value */) /
                             total.bucketCount));
    } else {
        assert.eq(total.avgBucketSize, 0);
    }
    assert.eq(total.numBucketInserts,
              shards.map(x => x.numBucketInserts).reduce((x, y) => x + y, 0 /* initial value */));
    assert.eq(total.numBucketUpdates,
              shards.map(x => x.numBucketUpdates).reduce((x, y) => x + y, 0 /* initial value */));
    assert.eq(total.numBucketsOpenedDueToMetadata,
              shards.map(x => x.numBucketsOpenedDueToMetadata)
                  .reduce((x, y) => x + y, 0 /* initial value */));
    assert.eq(total.numBucketsClosedDueToCount,
              shards.map(x => x.numBucketsClosedDueToCount)
                  .reduce((x, y) => x + y, 0 /* initial value */));
    assert.eq(total.numBucketsClosedDueToSize,
              shards.map(x => x.numBucketsClosedDueToSize)
                  .reduce((x, y) => x + y, 0 /* initial value */));
    assert.eq(total.numBucketsClosedDueToTimeForward,
              shards.map(x => x.numBucketsClosedDueToTimeForward)
                  .reduce((x, y) => x + y, 0 /* initial value */));
    assert.eq(total.numBucketsClosedDueToTimeBackward,
              shards.map(x => x.numBucketsClosedDueToTimeBackward)
                  .reduce((x, y) => x + y, 0) /* initial value */);
    assert.eq(total.numBucketsClosedDueToMemoryThreshold,
              shards.map(x => x.numBucketsClosedDueToMemoryThreshold)
                  .reduce((x, y) => x + y, 0 /* initial value */));
    assert.eq(total.numCommits,
              shards.map(x => x.numCommits).reduce((x, y) => x + y, 0 /* initial value */));
    assert.eq(total.numWaits,
              shards.map(x => x.numWaits).reduce((x, y) => x + y, 0 /* initial value */));
    assert.eq(
        total.numMeasurementsCommitted,
        shards.map(x => x.numMeasurementsCommitted).reduce((x, y) => x + y, 0 /* initial value */));
    assert(total.bucketCount > 0);
    assert(total.avgBucketSize > 0);
    assert(total.numBucketInserts > 0);
    assert(total.numCommits > 0);
    assert(total.numMeasurementsCommitted > 0);
}

function verifyClusterCollStatsResult(
    clusterCollStatsResult, sumTimeseriesStatsAcrossShards, isAggregation) {
    if (isAggregation) {
        // $collStats should output one document per shard.
        assert.eq(clusterCollStatsResult.length,
                  numShards,
                  "Expected " + numShards +
                      "documents to be returned: " + tojson(clusterCollStatsResult));

        checkAllFieldsAreInResult(clusterCollStatsResult[0]);
        checkAllFieldsAreInResult(clusterCollStatsResult[1]);
    }

    assert(sumTimeseriesStatsAcrossShards,
           "Expected an aggregated 'timeseries' field but didn't find one: " +
               tojson(clusterCollStatsResult));

    const primaryShardStats = isAggregation
        ? clusterCollStatsResult[0].storageStats.timeseries
        : clusterCollStatsResult.shards[primaryShard.shardName].timeseries;

    const otherShardStats = isAggregation
        ? clusterCollStatsResult[1].storageStats.timeseries
        : clusterCollStatsResult.shards[otherShard.shardName].timeseries;

    // Check that the top-level 'timeseries' fields match the sum of two shard's, that the stats
    // were correctly aggregated.
    assert(primaryShardStats,
           "Expected a shard 'timeseries' field on shard " + primaryShard.shardName +
               " but didn't find one: " + tojson(clusterCollStatsResult));
    assert(otherShardStats,
           "Expected a shard 'timeseries' field on shard " + otherShard.shardName +
               " but didn't find one: " + tojson(clusterCollStatsResult));

    assertTimeseriesAggregationCorrectness(sumTimeseriesStatsAcrossShards,
                                           [primaryShardStats, otherShardStats]);
}

//  Tests that the output of the collStats command returns results from both the shards and
//  includes all the expected fields.
clusterCollStatsResult = assert.commandWorked(mongosDB.runCommand({collStats: collName}));
jsTestLog("Sharded cluster collStats command result: " + tojson(clusterCollStatsResult));
const sumTimeseriesStatsAcrossShards = clusterCollStatsResult.timeseries;
verifyClusterCollStatsResult(
    clusterCollStatsResult, sumTimeseriesStatsAcrossShards, false  // isAggregation
);

// Tests that the output of the $collStats stage returns results from both the shards and includes
// all the expected fields.
clusterCollStatsResult =
    mongosColl
        .aggregate(
            [{$collStats: {latencyStats: {}, storageStats: {}, count: {}, queryExecStats: {}}}])
        .toArray();
jsTestLog("Sharded cluster collStats aggregation result: " + tojson(clusterCollStatsResult));

// Use the same sumTimeseriesStatsAcrossShards value as the collStats command since
// aggregation does not sum up timeseries stats results. This will also verify that the results
// output by collStats in find and aggregation are the same.
verifyClusterCollStatsResult(
    clusterCollStatsResult, sumTimeseriesStatsAcrossShards, true  // isAggregation
);

st.stop();
})();