/**
 * Validate that the 'collMod' command with 'hidden' field will return expected result document for
 * the command and generate expected oplog entries in which hiding a hidden index or un-hiding a
 * visible index will be a no-op if TTL index option is not involved.
 *
 * @tags: [requires_replication]
 */

(function() {
"use strict";
load("jstests/libs/get_index_helpers.js");

const rst = new ReplSetTest({nodes: 2, nodeOpts: {binVersion: "latest"}});
rst.startSet();
rst.initiate();

const dbName = jsTestName();
const collName = "hidden_index";
const primary = rst.getPrimary();
const primaryDB = primary.getDB(dbName);
const primaryColl = primaryDB[collName];
const oplogColl = primary.getDB("local")['oplog.rs'];

// Validate that the generated oplog entries filtered by given filter are what we expect.
function validateCollModOplogEntryCount(hiddenFilter, expectedCount) {
    let filter = {
        "ns": `${dbName}.$cmd`,
        "o.collMod": collName,
    };
    filter = Object.assign(filter, hiddenFilter);
    assert.eq(oplogColl.find(filter).count(), expectedCount);
}

// Validate that the index-related fields in the result document for the 'collMod' command are what
// we expect.
function validateResultForCollMod(result, expectedResult) {
    assert.eq(result.hidden_old, expectedResult.hidden_old, result);
    assert.eq(result.hidden_new, expectedResult.hidden_new, result);
    assert.eq(result.expireAfterSeconds_old, expectedResult.expireAfterSeconds_old, result);
    assert.eq(result.expireAfterSeconds_new, expectedResult.expireAfterSeconds_new, result);
}

primaryColl.drop();
assert.commandWorked(primaryColl.createIndex({a: 1}));
assert.commandWorked(primaryColl.createIndex({b: 1}, {expireAfterSeconds: 5}));

// Hiding a non-hidden index will generate the oplog entry with a 'hidden_old: false'.
let result = assert.commandWorked(primaryColl.hideIndex('a_1'));
validateResultForCollMod(result, {hidden_old: false, hidden_new: true});
validateCollModOplogEntryCount({"o.index.hidden": true, "o2.hidden_old": false}, 1);

// Hiding a hidden index won't generate both 'hidden' and 'hidden_old' field as it's a no-op. The
// result for no-op 'collMod' command shouldn't contain 'hidden' field.
result = assert.commandWorked(primaryColl.hideIndex('a_1'));
validateResultForCollMod(result, {});
validateCollModOplogEntryCount({"o.index.hidden": true, "o2.hidden_old": true}, 0);

// Un-hiding an hidden index will generate the oplog entry with a 'hidden_old: true'.
result = assert.commandWorked(primaryColl.unhideIndex('a_1'));
validateResultForCollMod(result, {hidden_old: true, hidden_new: false});
validateCollModOplogEntryCount({"o.index.hidden": false, "o2.hidden_old": true}, 1);

// Un-hiding a non-hidden index won't generate both 'hidden' and 'hidden_old' field as it's a no-op.
// The result for no-op 'collMod' command shouldn't contain 'hidden' field.
result = assert.commandWorked(primaryColl.unhideIndex('a_1'));
validateResultForCollMod(result, {});
validateCollModOplogEntryCount({"o.index.hidden": false, "o2.hidden_old": false}, 0);

// Validate that if both 'expireAfterSeconds' and 'hidden' options are specified but the 'hidden'
// option is a no-op, the operation as a whole will NOT be a no-op - instead, it will generate an
// oplog entry with only 'expireAfterSeconds'. Ditto for the command result returned to the user.
result = assert.commandWorked(primaryDB.runCommand({
    "collMod": primaryColl.getName(),
    "index": {"name": "b_1", "expireAfterSeconds": 10, "hidden": false},
}));
validateResultForCollMod(result, {expireAfterSeconds_old: 5, expireAfterSeconds_new: 10});
validateCollModOplogEntryCount({
    "o.index.expireAfterSeconds": 10,
    "o2.expireAfterSeconds_old": 5,
},
                               1);

// Test that the index was successfully modified.
const idxSpec = GetIndexHelpers.findByName(primaryColl.getIndexes(), "b_1");
assert.eq(idxSpec.hidden, undefined);
assert.eq(idxSpec.expireAfterSeconds, 10);

rst.stopSet();
})();