(function() {
'use strict';

const t = db.jstests_regex;

const isMaster = db.runCommand("ismaster");
assert.commandWorked(isMaster);
const isMongos = (isMaster.msg === "isdbgrid");

t.drop();
assert.writeOK(t.save({a: "bcd"}));
assert.eq(1, t.count({a: /b/}), "A");
assert.eq(1, t.count({a: /bc/}), "B");
assert.eq(1, t.count({a: /bcd/}), "C");
assert.eq(0, t.count({a: /bcde/}), "D");

t.drop();
assert.writeOK(t.save({a: {b: "cde"}}));
assert.eq(1, t.count({'a.b': /de/}), "E");

t.drop();
assert.writeOK(t.save({a: {b: ["cde"]}}));
assert.eq(1, t.count({'a.b': /de/}), "F");

t.drop();
assert.writeOK(t.save({a: [{b: "cde"}]}));
assert.eq(1, t.count({'a.b': /de/}), "G");

t.drop();
assert.writeOK(t.save({a: [{b: ["cde"]}]}));
assert.eq(1, t.count({'a.b': /de/}), "H");

//
// Confirm match and explain serialization for $elemMatch with $regex.
//
t.drop();
assert.writeOK(t.insert({x: ["abc"]}));

const query = {
    x: {$elemMatch: {$regex: 'ABC', $options: 'i'}}
};
assert.eq(1, t.count(query));

const result = t.find(query).explain();
assert.commandWorked(result);

if (!isMongos) {
    assert(result.hasOwnProperty("queryPlanner"));
    assert(result.queryPlanner.hasOwnProperty("parsedQuery"), tojson(result));
    assert.eq(result.queryPlanner.parsedQuery, query);
}

//
// Disallow embedded null bytes when using $regex syntax.
//
t.drop();
assert.throws(function() {
    t.find({a: {$regex: "a\0b", $options: "i"}}).itcount();
});
assert.throws(function() {
    t.find({a: {$regex: "ab", $options: "i\0"}}).itcount();
});
assert.throws(function() {
    t.find({key: {$regex: 'abcd\0xyz'}}).explain();
});

//
// Confirm $options and mode specified in $regex are not allowed to be specified together.
//
t.drop();
assert.commandWorked(t.insert({x: ["abc"]}));

let regexFirst = assert.throws(() => t.find({x: {$regex: /ab/i, $options: 's'}}).itcount());
assert.commandFailedWithCode(regexFirst, 51075);

let optsFirst = assert.throws(() => t.find({x: {$options: 's', $regex: /ab/i}}).itcount());
assert.commandFailedWithCode(optsFirst, 51074);

t.drop();
assert.commandWorked(t.save({x: ["abc"]}));

assert.eq(1, t.count({x: {$regex: /ABC/i}}));
assert.eq(1, t.count({x: {$regex: /ABC/, $options: 'i'}}));
assert.eq(1, t.count({x: {$options: 'i', $regex: /ABC/}}));
})();