/**
 * This test ensures that multiple applyOps commands can run concurrently.
 * Prior to SERVER-29802, applyOps would acquire the global lock regardless of the
 * atomicity of the operations (as a whole) being applied.
 *
 * Every instance of ApplyOpsConcurrentTest is configured with an "options" document
 * with the following format:
 * {
 *     ns1: <string>,
 *     ns1: <string>,
 * }
 *
 * ns1:
 *     Fully qualified namespace of first set of CRUD operations. For simplicity, only insert
 *     operations will be used. The set of documents generated for the inserts into ns1 will have
 *     _id values distinct from those generated for ns2.
 *
 * ns2:
 *     Fully qualified namespace of second set of CRUD operations. This may be the same namespace as
 *     ns1. As with ns1, only insert operations will be used.
 */
import {ReplSetTest} from "jstests/libs/replsettest.js";

export var ApplyOpsConcurrentTest = function (options) {
    if (!(this instanceof ApplyOpsConcurrentTest)) {
        return new ApplyOpsConcurrentTest(options);
    }

    // Capture the 'this' reference
    let self = this;

    self.options = options;

    /**
     * Logs message using test name as prefix.
     */
    function testLog(message) {
        jsTestLog("ApplyOpsConcurrentTest: " + message);
    }

    /**
     * Creates an array of insert operations for applyOps into collection 'coll'.
     */
    function generateInsertOps(coll, numOps, id) {
        const ops = Array(numOps)
            .fill("ignored")
            .map((unused, i) => {
                return {op: "i", ns: coll.getFullName(), o: {_id: id * numOps + i, id: id}};
            });
        return ops;
    }

    /**
     * Runs applyOps to insert 'numOps' documents into collection 'coll'.
     */
    function applyOpsInsert(coll, numOps, id) {
        const ops = generateInsertOps(coll, numOps, id);
        const mydb = coll.getDB();
        assert.commandWorked(mydb.runCommand({applyOps: ops}), "failed to insert documents into " + coll.getFullName());
    }

    /**
     * Parses 'numOps' and collection namespace from 'options' and runs applyOps to inserted
     * generated documents.
     *
     * options format:
     * {
     *     ns: <string>,
     *     numOps: <int>,
     *     id: <int>,
     * }
     *
     * ns:
     *     Fully qualified namespace of collection to insert documents into.
     *
     * numOps:
     *     Number of insert operations to generate for applyOps command.
     *
     * id:
     *     Index of collection for applyOps. Used with 'numOps' to generate _id values that will not
     *     collide with collections with different indexes.
     */
    function insertFunction(options) {
        const coll = db.getMongo().getCollection(options.ns);
        const numOps = options.numOps;
        const id = options.id;

        testLog("Starting to apply " + numOps + " operations in collection " + coll.getFullName());
        applyOpsInsert(coll, numOps, id);
        testLog("Successfully applied " + numOps + " operations in collection " + coll.getFullName());
    }

    /**
     * Creates a function for startParallelShell() to run that will insert documents into
     * collection 'coll' using applyOps.
     */
    function createInsertFunction(coll, numOps, id) {
        const options = {
            ns: coll.getFullName(),
            numOps: numOps,
            id: id,
        };
        const functionName = "insertFunction_" + coll.getFullName().replace(/\./g, "_");
        const s = //
            "\n\n" + //
            "const testLog = " +
            testLog +
            ";\n\n" + //
            "const generateInsertOps = " +
            generateInsertOps +
            ";\n\n" + //
            "const applyOpsInsert = " +
            applyOpsInsert +
            ";\n\n" + //
            "const " +
            functionName +
            " = " +
            insertFunction +
            ";\n\n" + //
            functionName +
            "(" +
            tojson(options) +
            ");"; //
        return s;
    }

    /**
     * Returns number of insert operations recorded on the oplog for the targeted collections.
     */
    function getInsertOpCount(primary, targetedCollections) {
        return primary.getCollection("local.oplog.rs").countDocuments({op: "i", "ns": {$in: targetedCollections}});
    }

    /**
     * Runs the test.
     */
    this.run = function () {
        const options = this.options;

        assert(options.ns1, "collection 1 namespace not provided");
        assert(options.ns2, "collection 2 namespace not provided");

        const replTest = new ReplSetTest({nodes: 1, waitForKeys: true});
        replTest.startSet();
        replTest.initiate();

        const primary = replTest.getPrimary();
        const adminDb = primary.getDB("admin");

        const coll1 = primary.getCollection(options.ns1);
        const db1 = coll1.getDB();
        const coll2 = primary.getCollection(options.ns2);
        const db2 = coll2.getDB();

        assert.commandWorked(db1.createCollection(coll1.getName()));
        if (coll1.getFullName() !== coll2.getFullName()) {
            assert.commandWorked(db2.createCollection(coll2.getName()));
        }

        // Enable fail point to pause applyOps between operations.
        assert.commandWorked(
            primary.adminCommand({configureFailPoint: "applyOpsPauseBetweenOperations", mode: "alwaysOn"}),
        );

        // This logs each operation being applied.
        const previousLogLevel = assert.commandWorked(primary.setLogLevel(3, "replication")).was.replication.verbosity;

        testLog("Applying operations in collections " + coll1.getFullName() + " and " + coll2.getFullName());

        const numOps = 100;
        const insertProcess1 = startParallelShell(createInsertFunction(coll1, numOps, 0), replTest.getPort(0));
        const insertProcess2 = startParallelShell(createInsertFunction(coll2, numOps, 1), replTest.getPort(0));

        // The fail point will prevent applyOps from advancing past the first operation in each
        // batch of operations. If applyOps is applying both sets of operations concurrently without
        // holding the global lock, the insert opcounter will eventually be incremented to 2.
        try {
            let insertOpCount = 0;
            // Expecting two applyOps in-progress.
            let expectedFinalOpCount = 2;

            assert.soon(
                function () {
                    const serverStatus = adminDb.serverStatus();
                    insertOpCount = getInsertOpCount(primary, [coll1.getFullName(), coll2.getFullName()]);
                    // This assertion may fail if the fail point is not implemented correctly within
                    // applyOps. This allows us to fail fast instead of waiting for the
                    // assert.soon() function to time out.
                    assert.lte(
                        insertOpCount,
                        expectedFinalOpCount,
                        "Expected at most " +
                            expectedFinalOpCount +
                            " documents inserted with fail point enabled. " +
                            "Most recent insert operation count = " +
                            insertOpCount,
                    );
                    return insertOpCount == expectedFinalOpCount;
                },
                "Insert operation count did not reach " +
                    expectedFinalOpCount +
                    " as expected with fail point enabled. Most recent insert operation count = " +
                    insertOpCount,
            );
        } finally {
            assert.commandWorked(
                primary.adminCommand({configureFailPoint: "applyOpsPauseBetweenOperations", mode: "off"}),
            );
        }

        insertProcess1();
        insertProcess2();

        testLog(
            "Successfully applied operations in collections " + coll1.getFullName() + " and " + coll2.getFullName(),
        );

        // Reset log level.
        primary.setLogLevel(previousLogLevel, "replication");

        const serverStatus = adminDb.serverStatus();
        let expectedOpCount = 2 * numOps;

        assert.eq(
            expectedOpCount,
            getInsertOpCount(primary, [coll1.getFullName(), coll2.getFullName()]),
            "incorrect number of insert operations in server status after applyOps: " + tojson(serverStatus),
        );

        replTest.stopSet();
    };
};