/**
 * Verifies that the validate hook is able to upgrade the feature compatibility version of the
 * server regardless of what state any previous upgrades or downgrades have left it in (besides
 * the isCleaningServerMetadata state, where we must complete the downgrade before upgrading).
 */

// The global 'db' variable is used by the data consistency hooks.
var db;

(function() {
"use strict";

// We skip doing the data consistency checks while terminating the cluster because they conflict
// with the counts of the number of times the "validate" command is run.
TestData.skipCollectionAndIndexValidation = true;

function makePatternForValidate(dbName, collName) {
    return new RegExp(
        `Slow query.*"ns":"${dbName}\\.\\$cmd","appName":"MongoDB Shell","command":{"validate":"${
            collName}"`,
        "g");
}

function makePatternForSetFCV(targetVersion) {
    return new RegExp(
        `Slow query.*"appName":"MongoDB Shell","command":{"setFeatureCompatibilityVersion":"${
            targetVersion}"`,
        "g");
}

function makePatternForSetParameter(paramName) {
    return new RegExp(
        `Slow query.*"appName":"MongoDB Shell","command":{"setParameter":1,"${paramName}":`, "g");
}

function countMatches(pattern, output) {
    assert(pattern.global, "the 'g' flag must be used to find all matches");

    let numMatches = 0;
    while (pattern.exec(output) !== null) {
        ++numMatches;
    }
    return numMatches;
}

function runValidateHook(testCase) {
    db = testCase.conn.getDB("test");
    TestData.forceValidationWithFeatureCompatibilityVersion = latestFCV;
    try {
        clearRawMongoProgramOutput();

        load("jstests/hooks/run_validate_collections.js");

        // We terminate the processes to ensure that the next call to rawMongoProgramOutput()
        // will return all of their output.
        testCase.teardown();
        return rawMongoProgramOutput();
    } finally {
        db = undefined;
        TestData.forceValidationWithFeatureCompatibilityVersion = undefined;
    }
}

function testStandalone(additionalSetupFn, {
    expectedAtTeardownFCV,
    expectedSetLastLTSFCV: expectedSetLastLTSFCV = 0,
    expectedSetLatestFCV: expectedSetLatestFCV = 0
} = {}) {
    const conn =
        MongoRunner.runMongod({setParameter: {logComponentVerbosity: tojson({command: 1})}});
    assert.neq(conn, "mongod was unable to start up");

    // Insert a document so the "validate" command has some actual work to do.
    assert.commandWorked(conn.getDB("test").mycoll.insert({}));

    // Run the additional setup function to put the server into the desired state.
    additionalSetupFn(conn);

    const output = runValidateHook({
        conn: conn,
        teardown: () => {
            // The validate hook should leave the server with a feature compatibility version of
            // 'expectedAtTeardownFCV' and no targetVersion.
            checkFCV(conn.getDB("admin"), expectedAtTeardownFCV);
            MongoRunner.stopMongod(conn);
        }
    });

    let pattern = makePatternForValidate("test", "mycoll");
    assert.eq(1,
              countMatches(pattern, output),
              "expected to find " + tojson(pattern) + " from mongod in the log output");

    for (let [targetVersion, expectedCount] of [[lastLTSFCV, expectedSetLastLTSFCV],
                                                [latestFCV, expectedSetLatestFCV]]) {
        // Since the additionalSetupFn() function may run the setFeatureCompatibilityVersion
        // command and we don't have a guarantee those log messages were cleared when
        // clearRawMongoProgramOutput() was called, we assert 'expectedSetLastLTSFCV' and
        // 'expectedSetLatestFCV' as lower bounds.
        const pattern = makePatternForSetFCV(targetVersion);
        assert.lte(expectedCount,
                   countMatches(pattern, output),
                   "expected to find " + tojson(pattern) + " from mongod in the log output");
    }

    pattern = makePatternForSetParameter("transactionLifetimeLimitSeconds");
    assert.eq(2,
              countMatches(pattern, output),
              "expected to find " + tojson(pattern) + " from mongod in the log output twice");
}

function forceInterruptedUpgradeOrDowngrade(conn, targetVersion) {
    // We create a separate connection to the server exclusively for running the
    // setFeatureCompatibilityVersion command so only that operation is ever interrupted by
    // the checkForInterruptFail failpoint.
    const setFCVConn = new Mongo(conn.host);
    const myUriRes = assert.commandWorked(setFCVConn.adminCommand({whatsmyuri: 1}));
    const myUri = myUriRes.you;

    const curOpRes = assert.commandWorked(setFCVConn.adminCommand({currentOp: 1, client: myUri}));
    const threadName = curOpRes.inprog[0].desc;

    assert.commandWorked(conn.adminCommand({
        configureFailPoint: "checkForInterruptFail",
        mode: "alwaysOn",
        data: {threadName, chance: 0.05},
    }));

    let attempts = 0;
    assert.soon(
        function() {
            let res = setFCVConn.adminCommand({setFeatureCompatibilityVersion: targetVersion});

            if (res.ok === 1) {
                assert.commandWorked(res);
            } else {
                assert.commandFailedWithCode(res, ErrorCodes.Interrupted);
            }

            ++attempts;

            res = assert.commandWorked(
                conn.adminCommand({getParameter: 1, featureCompatibilityVersion: 1}));

            if (res.featureCompatibilityVersion.hasOwnProperty("targetVersion")) {
                const fcvDoc = conn.getDB("admin")
                                   .system.version.find({_id: "featureCompatibilityVersion"})
                                   .limit(1)
                                   .readConcern("local")
                                   .next();
                if (fcvDoc.isCleaningServerMetadata) {
                    checkFCV(conn.getDB("admin"),
                             lastLTSFCV,
                             targetVersion,
                             true /*isCleaningServerMetadata*/);
                    // If the setFCV command was interrupted while in the isCleaningServerMetadata
                    // state, we must complete the FCV downgrade successfully.
                    assert.commandWorked(
                        conn.adminCommand({setFeatureCompatibilityVersion: lastLTSFCV}));

                } else {
                    checkFCV(conn.getDB("admin"), lastLTSFCV, targetVersion);
                    jsTest.log(`Reached partially downgraded state after ${attempts} attempts`);
                    return true;
                }
            }

            // Either upgrade the feature compatibility version so we can try downgrading again,
            // or downgrade the feature compatibility version so we can try upgrading again.
            // Note that we're using 'conn' rather than 'setFCVConn' to avoid the upgrade being
            // interrupted.
            assert.commandWorked(conn.adminCommand({
                setFeatureCompatibilityVersion: targetVersion === lastLTSFCV ? latestFCV
                                                                             : lastLTSFCV
            }));
        },
        "failed to get featureCompatibilityVersion document into a partially downgraded" +
            " state");

    assert.commandWorked(conn.adminCommand({
        configureFailPoint: "checkForInterruptFail",
        mode: "off",
    }));
}

(function testStandaloneInLatestFCV() {
    testStandalone(conn => {
        checkFCV(conn.getDB("admin"), latestFCV);
    }, {expectedAtTeardownFCV: latestFCV});
})();

(function testStandaloneInLastLTSFCV() {
    testStandalone(conn => {
        assert.commandWorked(conn.adminCommand({setFeatureCompatibilityVersion: lastLTSFCV}));
        checkFCV(conn.getDB("admin"), lastLTSFCV);
    }, {expectedAtTeardownFCV: lastLTSFCV, expectedSetLastLTSFCV: 1, expectedSetLatestFCV: 1});
})();

(function testStandaloneWithInterruptedFCVDowngrade() {
    testStandalone(conn => {
        forceInterruptedUpgradeOrDowngrade(conn, lastLTSFCV);
    }, {expectedAtTeardownFCV: lastLTSFCV, expectedSetLastLTSFCV: 2, expectedSetLatestFCV: 1});
})();

(function testStandaloneWithInterruptedFCVUpgrade() {
    testStandalone(conn => {
        assert.commandWorked(conn.adminCommand({setFeatureCompatibilityVersion: lastLTSFCV}));
        forceInterruptedUpgradeOrDowngrade(conn, latestFCV);
    }, {expectedAtTeardownFCV: lastLTSFCV, expectedSetLastLTSFCV: 1, expectedSetLatestFCV: 1});
})();
})();