/**
 * Tests that serverStatus contains an indexStats section. This section reports globally-aggregated
 * statistics about features in use by indexes and how often they are used.
 *
 * @tags: [
 *   requires_persistence,
 *   requires_replication,
 * ]
 */
(function() {
"use strict";

const assertStats = (db, assertFn) => {
    const stats = db.serverStatus().indexStats;
    try {
        assertFn(stats);
    } catch (e) {
        print("result: " + tojson(stats));
        throw e;
    }
};

// If new features are added, they must also be added to this list or the test will fail.
const knownFeatures = [
    "2d",
    "2dsphere",
    "2dsphere_bucket",
    "collation",
    "columnstore",
    "compound",
    "hashed",
    "id",
    "normal",
    "partial",
    "single",
    "sparse",
    "text",
    "ttl",
    "unique",
    "wildcard",
];

const assertZeroCounts = (db) => {
    assertStats(db, (featureStats) => {
        assert.eq(featureStats.count, 0);
        for (const [feature, stats] of Object.entries(featureStats.features)) {
            assert.contains(feature, knownFeatures, "unknown feature reported by indexStats");
            assert.eq(0, stats.count, feature);
        }
    });
};

const assertZeroAccess = (db) => {
    assertStats(db, (featureStats) => {
        for (const [feature, stats] of Object.entries(featureStats.features)) {
            assert.contains(feature, knownFeatures, "unknown feature reported by indexStats");
            assert.eq(0, stats.accesses, feature);
        }
    });
};

const assertCountIncrease = (last, current, inc) => {
    assert.eq(last.count + inc, current.count, "incorrect index count");
};

const assertFeatureCountIncrease = (last, current, feature, inc) => {
    assert.eq(last.features[feature].count + inc,
              current.features[feature].count,
              "incorrect feature count for " + feature);
};

const assertFeatureAccessIncrease = (last, current, feature, inc) => {
    assert.eq(last.features[feature].accesses + inc,
              current.features[feature].accesses,
              "incorrect feature accesses for " + feature);
};

const replSet = new ReplSetTest({nodes: 1});
replSet.startSet();
replSet.initiate();

let primary = replSet.getPrimary();
let db = primary.getDB('test');

assertZeroCounts(db);
assertZeroAccess(db);

let lastStats = db.serverStatus().indexStats;

assert.commandWorked(db.testColl.createIndex({twoD: '2d', b: 1}, {unique: true, sparse: true}));
assert.commandWorked(db.testColl.insert({twoD: [0, 0], b: 1}));
assert.eq(1, db.testColl.find({twoD: {$geoNear: [0, 0]}}).itcount());
assertStats(db, (stats) => {
    assertCountIncrease(lastStats, stats, 2);
    assertFeatureCountIncrease(lastStats, stats, '2d', 1);
    assertFeatureCountIncrease(lastStats, stats, 'compound', 1);
    // The index build implicitly created the collection, which also builds an _id index.
    assertFeatureCountIncrease(lastStats, stats, 'id', 1);
    assertFeatureCountIncrease(lastStats, stats, 'sparse', 1);
    // Note that the _id index is not included in this unique counter. This is due to a quirk in the
    // _id index spec that does not actually have a unique:true property.
    assertFeatureCountIncrease(lastStats, stats, 'unique', 1);

    assertFeatureAccessIncrease(lastStats, stats, '2d', 1);
    assertFeatureAccessIncrease(lastStats, stats, 'compound', 1);
    assertFeatureAccessIncrease(lastStats, stats, 'id', 0);
    assertFeatureAccessIncrease(lastStats, stats, 'sparse', 1);
    assertFeatureAccessIncrease(lastStats, stats, 'unique', 1);
});

lastStats = db.serverStatus().indexStats;

assert.commandWorked(db.testColl.createIndex({sphere: '2dsphere'}));
assert.commandWorked(db.testColl.insert({sphere: {type: "Point", coordinates: [0, 0]}}));
assert.eq(1,
          db.testColl
              .aggregate([{
                  $geoNear: {
                      near: {type: "Point", coordinates: [1, 1]},
                      key: 'sphere',
                      distanceField: 'dist',
                  }
              }])
              .itcount());
assertStats(db, (stats) => {
    assertCountIncrease(lastStats, stats, 1);
    assertFeatureCountIncrease(lastStats, stats, '2dsphere', 1);
    assertFeatureCountIncrease(lastStats, stats, 'single', 1);

    assertFeatureAccessIncrease(lastStats, stats, '2dsphere', 1);
    assertFeatureAccessIncrease(lastStats, stats, 'single', 1);
});

lastStats = db.serverStatus().indexStats;

assert.commandWorked(
    db.testColl.createIndex({hashed: 'hashed', p: 1}, {partialFilterExpression: {p: 1}}));
assert.commandWorked(db.testColl.insert({hashed: 1, p: 1}));
assert.eq(1, db.testColl.find({hashed: 1}).hint({hashed: 'hashed', p: 1}).itcount());
assertStats(db, (stats) => {
    assertCountIncrease(lastStats, stats, 1);
    assertFeatureCountIncrease(lastStats, stats, 'compound', 1);
    assertFeatureCountIncrease(lastStats, stats, 'hashed', 1);
    assertFeatureCountIncrease(lastStats, stats, 'partial', 1);

    assertFeatureAccessIncrease(lastStats, stats, 'compound', 1);
    assertFeatureAccessIncrease(lastStats, stats, 'hashed', 1);
    assertFeatureAccessIncrease(lastStats, stats, 'partial', 1);
});

lastStats = db.serverStatus().indexStats;

assert.commandWorked(
    db.testColl.createIndex({a: 1}, {expireAfterSeconds: 3600, collation: {locale: 'en'}}));
let now = new Date();
assert.commandWorked(db.testColl.insert({a: now}));
assert.eq(1, db.testColl.find({a: now}).itcount());
assertStats(db, (stats) => {
    assertCountIncrease(lastStats, stats, 1);
    assertFeatureCountIncrease(lastStats, stats, 'collation', 1);
    assertFeatureCountIncrease(lastStats, stats, 'normal', 1);
    assertFeatureCountIncrease(lastStats, stats, 'single', 1);
    assertFeatureCountIncrease(lastStats, stats, 'ttl', 1);

    assertFeatureAccessIncrease(lastStats, stats, 'collation', 1);
    assertFeatureAccessIncrease(lastStats, stats, 'normal', 1);
    assertFeatureAccessIncrease(lastStats, stats, 'single', 1);
    assertFeatureAccessIncrease(lastStats, stats, 'ttl', 1);
});

lastStats = db.serverStatus().indexStats;

assert.commandWorked(db.testColl.createIndex({text: 'text'}));
assert.commandWorked(db.testColl.insert({text: "a string"}));
assert.eq(1, db.testColl.find({$text: {$search: "string"}}).itcount());
assertStats(db, (stats) => {
    assertCountIncrease(lastStats, stats, 1);
    // Text indexes are internally compound, but that should not be reflected in the stats.
    assertFeatureCountIncrease(lastStats, stats, 'compound', 0);
    assertFeatureCountIncrease(lastStats, stats, 'text', 1);

    assertFeatureAccessIncrease(lastStats, stats, 'compound', 0);
    assertFeatureAccessIncrease(lastStats, stats, 'text', 1);
});

lastStats = db.serverStatus().indexStats;

assert.commandWorked(db.testColl.createIndex({'wild.$**': 1}));
assert.commandWorked(db.testColl.insert({wild: {a: 1}}));
assert.eq(1, db.testColl.find({'wild.a': 1}).itcount());
assertStats(db, (stats) => {
    assertCountIncrease(lastStats, stats, 1);
    assertFeatureCountIncrease(lastStats, stats, 'single', 1);
    assertFeatureCountIncrease(lastStats, stats, 'wildcard', 1);

    assertFeatureAccessIncrease(lastStats, stats, 'single', 1);
    assertFeatureAccessIncrease(lastStats, stats, 'wildcard', 1);
});

lastStats = db.serverStatus().indexStats;

const timeSeriesMetricIndexesEnabled =
    assert.commandWorked(db.adminCommand({getParameter: 1, featureFlagTimeseriesMetricIndexes: 1}))
        .featureFlagTimeseriesMetricIndexes.value;
if (timeSeriesMetricIndexesEnabled) {
    assert.commandWorked(db.createCollection('ts', {timeseries: {timeField: 't'}}));
    assert.commandWorked(db.ts.createIndex({loc: '2dsphere'}));
    assert.commandWorked(db.ts.insert({t: new Date(), loc: [0, 0]}));
    assert.eq(1,
              db.ts
                  .aggregate([{
                                 $geoNear: {
                                     near: [1, 1],
                                     key: 'loc',
                                     distanceField: 'dist',
                                 }
                             }],
                             {hint: 'loc_2dsphere'})
                  .itcount());
    assertStats(db, (stats) => {
        // Includes _id index built for system.views.
        assertCountIncrease(lastStats, stats, 2);
        assertFeatureCountIncrease(lastStats, stats, 'id', 1);
        assertFeatureCountIncrease(lastStats, stats, 'single', 1);
        assertFeatureCountIncrease(lastStats, stats, '2dsphere_bucket', 1);

        assertFeatureAccessIncrease(lastStats, stats, 'id', 0);
        assertFeatureAccessIncrease(lastStats, stats, 'single', 1);
        assertFeatureAccessIncrease(lastStats, stats, '2dsphere_bucket', 1);
    });
}

lastStats = db.serverStatus().indexStats;

const columnstoreIndexesEnabled =
    assert.commandWorked(db.adminCommand({getParameter: 1, featureFlagColumnstoreIndexes: 1}))
        .featureFlagColumnstoreIndexes.value;
if (columnstoreIndexesEnabled) {
    // TODO SERVER-61644 (or sooner) should support accessing/using index and seeing that reflected.
    assert.commandWorked(db.testColl.createIndex({'$**': 'columnstore'}));
    assertStats(db, (stats) => {
        assertCountIncrease(lastStats, stats, 1);
        assertFeatureCountIncrease(lastStats, stats, 'columnstore', 1);

        assertFeatureAccessIncrease(lastStats, stats, 'id', 0);
        assertFeatureAccessIncrease(lastStats, stats, 'columnstore', 0);
    });
}

lastStats = db.serverStatus().indexStats;

// After restarting the server, we expect all of the access counters to reset to zero, but that the
// feature counters remain the same as before startup.
replSet.stopSet(undefined, /* restart */ true);
replSet.startSet({}, /* restart */ true);
primary = replSet.getPrimary();
db = primary.getDB('test');

assertZeroAccess(db);
assertStats(db, (stats) => {
    assertCountIncrease(lastStats, stats, 0);

    const features = stats.features;
    for (const [feature, _] of Object.entries(features)) {
        assert.contains(feature, knownFeatures);
        assertFeatureCountIncrease(lastStats, stats, feature, 0);
    }
});

assert.commandWorked(db.dropDatabase());
assertZeroCounts(db);

replSet.stopSet();
})();