/**
 * Tests the idempotency of the 'setFeatureCompatibilityVersion' command.
 * We execute the following steps for both upgrade and downgrade:
 * 1. Enable a failpoint to fail upgrading/downgrading.
 * 2. Issue a setFeatureCompatibilityVersion command, which upgrades/downgrades
 *    the replica set to a kUpgrading/kDowngrading intermediary state.
 * 3. The setFeatureCompatibilityVersion command fails without completing all
 *    upgrade/downgrade behavior.
 * 4. Disable the failpoint, and issue a succesful setFeatureCompatibilityVersion
 *    to finish upgrading/downgrading.
 */
import {configureFailPoint} from "jstests/libs/fail_point_util.js";
import {ReplSetTest} from "jstests/libs/replsettest.js";

function runTest(downgradeVersion) {
    const downgradeFCV = binVersionToFCV(downgradeVersion);
    const replTest = new ReplSetTest({name: jsTestName(), nodes: 2});
    replTest.startSet();
    replTest.initiate();

    let primary = replTest.getPrimary();
    // Enable failpoint to fail downgrading.
    let failpoint = configureFailPoint(primary, "failDowngrading");
    assert.commandFailed(primary.adminCommand({setFeatureCompatibilityVersion: downgradeFCV, confirm: true}));

    // Verify the node is in an intermediary state. If the response object has the 'targetVersion'
    // field, we are in a partially upgraded or downgraded state.
    checkFCV(primary.getDB("admin"), downgradeFCV, downgradeFCV);

    failpoint.off();

    assert.commandWorked(primary.adminCommand({setFeatureCompatibilityVersion: downgradeFCV, confirm: true}));

    // Verify the feature compatibility version transition is complete.
    checkFCV(primary.getDB("admin"), downgradeFCV);

    const latestFCV = binVersionToFCV("latest");
    // Enable failpoint to fail upgrading.
    failpoint = configureFailPoint(primary, "failUpgrading");
    assert.commandFailed(primary.adminCommand({setFeatureCompatibilityVersion: latestFCV, confirm: true}));

    // Verify the node is in an intermediary state. If the response object has the 'targetVersion'
    // field, we are in a partially upgraded or downgraded state.
    checkFCV(primary.getDB("admin"), downgradeFCV, latestFCV);

    failpoint.off();
    assert.commandWorked(primary.adminCommand({setFeatureCompatibilityVersion: latestFCV, confirm: true}));

    // Verify the feature compatibility version transition is complete.
    checkFCV(primary.getDB("admin"), latestFCV);

    replTest.stopSet();
}

runTest("last-lts");
runTest("last-continuous");