/**
 * Verifies that the rollback file for a given database path and namespace exists and contains the
 * 'expectedDocs', in any order. If there are multiple rollback files for the given collection,
 * chooses one of those files arbitrarily to read data from. Note that a rollback file is simply a
 * sequence of concatenated BSON objects, which is a format that can be read by the bsondump tool.
 */
import {extractUUIDFromObject} from "jstests/libs/uuid_util.js";

export function checkRollbackFiles(dbPath, nss, uuid, expectedDocs) {
    // Check the path of the rollback directory.
    const rollbackDir = dbPath + "/rollback";
    assert(pathExists(rollbackDir), "directory for rollback files does not exist: " + rollbackDir);

    // The newer layout, used by recover-to-timestamp (RTT) rollback, places them inside a
    // 'rollback/<db>.<collection>' directory with a file naming scheme of
    // 'removed.<timestamp>.bson'. These file layouts are documented here:
    // https://docs.mongodb.com/manual/core/replica-set-rollbacks/#collect-rollback-data.

    function getRTTRollbackFile() {
        let rollbackFiles = listFiles(rollbackDir + "/" + extractUUIDFromObject(uuid));
        assert.gte(
            rollbackFiles.length,
            1,
            "No RTT rollback files found for namespace: " + nss + " with UUID: " + uuid,
        );
        return rollbackFiles[0].name;
    }

    let rollbackFile;
    print("Assuming rollback files written using the 'RTT' layout.");
    rollbackFile = getRTTRollbackFile();

    print("Found rollback file: " + rollbackFile);

    // If the rollback BSON file is encrypted, don't try to check the data contents. Checking its
    // existence is sufficient.
    if (rollbackFile.endsWith(".enc")) {
        print("Bypassing check of rollback file data since it is encrypted.");
        return;
    }

    // Parse the BSON rollback file and check for the right
    // documents. The documents may be written out in an arbitrary
    // order so we just check the document set.
    //
    // Users are expected to consume these files with
    // bsondump. However, we use a shell builtin do do this testing so
    // that we don't have a dependency on the go tools in order to
    // test the server.
    const rollbackContents = _readDumpFile(rollbackFile);
    assert.sameMembers(rollbackContents, expectedDocs);
}