/**
 * Checks that top removes entries after dropping a collection or database.
 *
 * @tags: [
 *   assumes_against_mongod_not_mongos,
 *   requires_non_retryable_writes,
 * ]
 */
(function() {
"use strict";

let topDB = db.getSiblingDB("topdrop");
assert.commandWorked(topDB.dropDatabase());

// Asserts that the output of top contains exactly these collection entries for topDB.
function checkTopEntries(expectedEntries) {
    let res = topDB.adminCommand("top");
    if (!res.ok) {
        assert.commandFailedWithCode(res, [ErrorCodes.BSONObjectTooLarge, 13548]);
        return;
    }

    let entriesInTop = Object.keys(res.totals).filter(function(ns) {
        // This filter only includes non-system collections in our test database.
        const tenantId = topDB.getName() + ".";
        const systemCollectionPrefix = "system.";
        return ns.startsWith(tenantId) && !ns.startsWith(tenantId + systemCollectionPrefix);
    });
    let expectedEntryNames = expectedEntries.map(function(coll) {
        return coll.getFullName();
    });

    const entriesAreEqual = friendlyEqual(entriesInTop.sort(), expectedEntryNames.sort());
    if (!entriesAreEqual) {
        // TODO(SERVER-26750): This block can be removed once SERVER-26750 is resolved.
        jsTest.log("Warning: expected to see " + tojson(expectedEntryNames) + " in top, but got " +
                   tojson(entriesInTop));

        assert.lt(expectedEntryNames.length,
                  entriesInTop.length,
                  "Fewer entries in top than expected; got " + tojson(entriesInTop) +
                      " but expected " + tojson(expectedEntryNames) + "\nFull top output:\n" +
                      tojson(res.totals));

        // We allow an unexpected entry in top if the insert counter has been cleared. This is
        // probably due to a background job releasing an AutoGetCollectionForReadCommand for
        // that collection.
        entriesInTop.forEach(function(coll) {
            if (expectedEntryNames.includes(coll)) {
                return;
            }

            let topStats = res.totals[coll];
            assert.eq(0,
                      res.totals[coll].insert.count,
                      coll + " has unexpected insert entries in top. Full top output:\n" +
                          tojson(res.totals));
        });
    }
}

// Create a few entries in top.
assert.commandWorked(topDB.coll1.insert({}));
assert.commandWorked(topDB.coll2.insert({}));
assert.commandWorked(topDB.coll3.insert({}));
checkTopEntries([topDB.coll1, topDB.coll2, topDB.coll3]);

// Check that dropping a collection removes that collection but leaves the others.
assert.commandWorked(topDB.runCommand({drop: "coll3"}));
checkTopEntries([topDB.coll1, topDB.coll2]);

// Check that dropping the database removes the remaining collections.
assert.commandWorked(topDB.dropDatabase());
checkTopEntries([]);

// Check that top doesn't keep state about non-existent collections.
assert.commandWorked(topDB.dropDatabase());
topDB.foo.find().itcount();
topDB.baz.update({}, {$set: {a: 1}});
topDB.bar.remove({});

checkTopEntries([]);

assert.commandWorked(topDB.dropDatabase());
}());