/**
 * Test regexes with various Unicode options.
 */
const coll = db.getCollection("regex_unicode");
coll.drop();

// Populate the collection with strings containing ASCII and non-ASCII characters.
let docAllAscii = {_id: 0, text: "kyle"};
let docNoAscii = {_id: 1, text: "박정수"};
let docMixed = {_id: 2, text: "suárez"};
[docAllAscii, docNoAscii, docMixed].forEach((doc) => assert.commandWorked(coll.insert(doc)));

/**
 * Helper function that asserts that a find command with a filter on the "text" field using
 * 'regex' returns 'expected' when sorting by _id ascending.
 */
function assertFindResultsEq(regex, expected) {
    const res = coll.find({text: {$regex: regex}}).sort({_id: 1}).toArray();
    const errfn = `Regex query "${regex}" returned ${tojson(res)} ` +
        `but expected ${tojson(expected)}`;
    assert.eq(res, expected, errfn);
}

// Sanity check on exact characters.
assertFindResultsEq("y", [docAllAscii]);
assertFindResultsEq("e", [docAllAscii, docMixed]);
assertFindResultsEq("á", [docMixed]);
assertFindResultsEq("정", [docNoAscii]);

// Test that the (*UTF) and (*UTF8) options are accepted.
assertFindResultsEq("(*UTF)e", [docAllAscii, docMixed]);
assertFindResultsEq("(*UTF)á", [docMixed]);
assertFindResultsEq("(*UTF)정", [docNoAscii]);
assertFindResultsEq("(*UTF8)e", [docAllAscii, docMixed]);
assertFindResultsEq("(*UTF8)á", [docMixed]);
assertFindResultsEq("(*UTF8)정", [docNoAscii]);

// Test that regexes support Unicode character properties.
assertFindResultsEq(String.raw`\p{Latin}`, [docAllAscii, docMixed]);
assertFindResultsEq(String.raw`^\p{Latin}+$`, [docAllAscii, docMixed]);
assertFindResultsEq(String.raw`\p{Hangul}`, [docNoAscii]);
assertFindResultsEq(String.raw`^\p{Hangul}+$`, [docNoAscii]);
assertFindResultsEq(String.raw`^\p{L}+$`, [docAllAscii, docNoAscii, docMixed]);
assertFindResultsEq(String.raw`^\p{Xan}+$`, [docAllAscii, docNoAscii, docMixed]);

// Tests for the '\w' character type, which matches any "word" character. In the default mode,
// characters outside of the ASCII code point range are excluded.

// An unanchored regex should match the two documents that contain at least one ASCII character.
assertFindResultsEq(String.raw`\w`, [docAllAscii, docMixed]);

// This anchored regex will only match the document with exclusively ASCII characters, since the
// Unicode character in the mixed document will prevent it from being considered all "word"
// characters.
assertFindResultsEq(String.raw`^\w+$`, [docAllAscii]);

// When the (*UCP) option is specified, Unicode "word" characters are included in the '\w'
// character type, so all three documents should match.
assertFindResultsEq(String.raw`(*UCP)\w`, [docAllAscii, docNoAscii, docMixed]);
assertFindResultsEq(String.raw`(*UCP)^\w+$`, [docAllAscii, docNoAscii, docMixed]);

// By default, the [:alpha:] character class matches ASCII alphabetic characters.
assertFindResultsEq("[[:alpha:]]", [docAllAscii, docMixed]);
assertFindResultsEq("^[[:alpha:]]+$", [docAllAscii]);

// When the (*UCP) option is specified, [:alpha:] becomes \p{L} and matches all Unicode
// alphabetic characters.
assertFindResultsEq("(*UCP)[[:alpha:]]", [docAllAscii, docNoAscii, docMixed]);
assertFindResultsEq("(*UCP)^[[:alpha:]]+$", [docAllAscii, docNoAscii, docMixed]);

// Drop the collection and repopulate it with numerical characters.
coll.drop();
docAllAscii = {
    _id: 0,
    text: "02191996"
};
docNoAscii = {
    _id: 1,
    text: "༢༣༤༥"
};
docMixed = {
    _id: 2,
    text: "9୩୪୬୯6"
};
[docAllAscii, docNoAscii, docMixed].forEach((doc) => assert.commandWorked(coll.insert(doc)));

// Sanity check on exact characters.
assertFindResultsEq("1", [docAllAscii]);
assertFindResultsEq("9", [docAllAscii, docMixed]);
assertFindResultsEq("୪", [docMixed]);
assertFindResultsEq("༣", [docNoAscii]);

// Test that the regexes are matched by the numeric Unicode character property.
assertFindResultsEq(String.raw`^\p{N}+$`, [docAllAscii, docNoAscii, docMixed]);
assertFindResultsEq(String.raw`^\p{Xan}+$`, [docAllAscii, docNoAscii, docMixed]);

// Tests for the '\d' character type, which matches any "digit" character. In the default mode,
// characters outside of the ASCII code point range are excluded.
// An unanchored regex should match the two documents that contain at least one ASCII character.
assertFindResultsEq(String.raw`\d`, [docAllAscii, docMixed]);

// This anchored regex will only match the document with exclusively ASCII characters, since the
// Unicode character in the mixed document will prevent it from being considered all "digit"
// characters.
assertFindResultsEq(String.raw`^\d+$`, [docAllAscii]);

// When the (*UCP) option is specified, Unicode "digit" characters are included in the '\d'
// character type, so all three documents should match.
assertFindResultsEq(String.raw`(*UCP)\d`, [docAllAscii, docNoAscii, docMixed]);
assertFindResultsEq(String.raw`(*UCP)^\d+$`, [docAllAscii, docNoAscii, docMixed]);

// By default, the [:digit:] character class matches ASCII decimal digit characters.
assertFindResultsEq("[[:digit:]]", [docAllAscii, docMixed]);
assertFindResultsEq("^[[:digit:]]+$", [docAllAscii]);

// When the (*UCP) option is specified, [:digit:] becomes \p{N} and matches all Unicode
// decimal digit characters.
assertFindResultsEq("(*UCP)[[:digit:]]", [docAllAscii, docNoAscii, docMixed]);
assertFindResultsEq("(*UCP)^[[:digit:]]+$", [docAllAscii, docNoAscii, docMixed]);