/**
 * Tests that a change stream can take a user-specified collation, does not inherit the collection's
 * default collation, and uses the simple collation if none is provided.
 */
(function() {
"use strict";

load("jstests/libs/collection_drop_recreate.js");  // For assert[Drop|Create]Collection.
load("jstests/libs/change_stream_util.js");        // For 'ChangeStreamTest' and
                                                   // 'runCommandChangeStreamPassthroughAware'.

let cst = new ChangeStreamTest(db);

const caseInsensitive = {
    locale: "en_US",
    strength: 2
};

let caseInsensitiveCollection = "change_stream_case_insensitive";
assertDropCollection(db, caseInsensitiveCollection);

// Test that you can open a change stream before the collection exists, and it will use the
// simple collation. Tag this stream as 'doNotModifyInPassthroughs', since only individual
// collections have the concept of a default collation.
const simpleCollationStream = cst.startWatchingChanges({
    pipeline: [
        {$changeStream: {}},
        {$match: {$or: [{"fullDocument._id": "INSERT_ONE"}, {"fullDocument._id": "INSERT_TWO"}]}},
        {$project: {docId: "$fullDocument._id"}}
    ],
    collection: caseInsensitiveCollection,
    doNotModifyInPassthroughs: true
});

// Create the collection with a non-default collation. The stream should continue to use the
// simple collation.
caseInsensitiveCollection =
    assertCreateCollection(db, caseInsensitiveCollection, {collation: caseInsensitive});
assert.commandWorked(caseInsensitiveCollection.insert([{_id: "insert_one"}, {_id: "INSERT_TWO"}]));
cst.assertNextChangesEqual(
    {cursor: simpleCollationStream, expectedChanges: [{docId: "INSERT_TWO"}]});

const caseInsensitivePipeline = [
    {$changeStream: {}},
    {$match: {"fullDocument.text": "abc"}},
    {$project: {docId: "$documentKey._id"}}
];

// Test that $changeStream will not implicitly adopt the default collation of the collection on
// which it is run. Tag this stream as 'doNotModifyInPassthroughs'; whole-db and cluster-wide
// streams do not have default collations.
const didNotInheritCollationStream = cst.startWatchingChanges({
    pipeline: caseInsensitivePipeline,
    collection: caseInsensitiveCollection,
    doNotModifyInPassthroughs: true
});
// Test that a collation can be explicitly specified for the $changeStream. This does not need
// to be tagged 'doNotModifyInPassthroughs', since whole-db and cluster-wide changeStreams will
// use an explicit collation if present.
let explicitCaseInsensitiveStream = cst.startWatchingChanges({
    pipeline: caseInsensitivePipeline,
    collection: caseInsensitiveCollection,
    aggregateOptions: {collation: caseInsensitive}
});

assert.commandWorked(caseInsensitiveCollection.insert({_id: 0, text: "aBc"}));
assert.commandWorked(caseInsensitiveCollection.insert({_id: 1, text: "abc"}));

// 'didNotInheritCollationStream' should not have inherited the collection's case-insensitive
// default collation, and should only see the second insert.  'explicitCaseInsensitiveStream'
// should see both inserts.
cst.assertNextChangesEqual({cursor: didNotInheritCollationStream, expectedChanges: [{docId: 1}]});
cst.assertNextChangesEqual(
    {cursor: explicitCaseInsensitiveStream, expectedChanges: [{docId: 0}, {docId: 1}]});

// Test that the collation does not apply to the scan over the oplog.
const similarNameCollection = assertDropAndRecreateCollection(
    db, "cHaNgE_sTrEaM_cAsE_iNsEnSiTiVe", {collation: {locale: "en_US"}});

// We must recreate the explicitCaseInsensitiveStream and set 'doNotModifyInPassthroughs'. Whole
// db and cluster-wide streams use the simple collation while scanning the oplog, but they don't
// filter the oplog by collection name. The subsequent $match stage which we inject into the
// pipeline to filter for a specific collection will obey the pipeline's case-insensitive
// collation, meaning that 'cHaNgE_sTrEaM_cAsE_iNsEnSiTiVe' will match
// 'change_stream_case_insensitive'.
explicitCaseInsensitiveStream = cst.startWatchingChanges({
    pipeline: caseInsensitivePipeline,
    collection: caseInsensitiveCollection,
    aggregateOptions: {collation: caseInsensitive},
    doNotModifyInPassthroughs: true
});

assert.commandWorked(similarNameCollection.insert({_id: 0, text: "aBc"}));
assert.commandWorked(caseInsensitiveCollection.insert({_id: 2, text: "ABC"}));

// The case-insensitive stream should not see the first insert (to the other collection), only
// the second. We do not expect to see the insert in 'didNotInheritCollationStream'.
cst.assertNextChangesEqual({cursor: explicitCaseInsensitiveStream, expectedChanges: [{docId: 2}]});

// Test that creating a collection without a collation does not invalidate any change streams
// that were opened before the collection existed.
(function() {
let noCollationCollection = "change_stream_no_collation";
assertDropCollection(db, noCollationCollection);

const streamCreatedBeforeNoCollationCollection = cst.startWatchingChanges({
    pipeline: [{$changeStream: {}}, {$project: {docId: "$documentKey._id"}}],
    collection: noCollationCollection
});

noCollationCollection = assertCreateCollection(db, noCollationCollection);
assert.commandWorked(noCollationCollection.insert({_id: 0}));

cst.assertNextChangesEqual(
    {cursor: streamCreatedBeforeNoCollationCollection, expectedChanges: [{docId: 0}]});
}());

// Test that creating a collection and explicitly specifying the simple collation does not
// invalidate any change streams that were opened before the collection existed.
(function() {
let simpleCollationCollection = "change_stream_simple_collation";
assertDropCollection(db, simpleCollationCollection);

const streamCreatedBeforeSimpleCollationCollection = cst.startWatchingChanges({
    pipeline: [{$changeStream: {}}, {$project: {docId: "$documentKey._id"}}],
    collection: simpleCollationCollection
});

simpleCollationCollection =
    assertCreateCollection(db, simpleCollationCollection, {collation: {locale: "simple"}});
assert.commandWorked(simpleCollationCollection.insert({_id: 0}));

cst.assertNextChangesEqual(
    {cursor: streamCreatedBeforeSimpleCollationCollection, expectedChanges: [{docId: 0}]});
}());

// Test that creating a change stream with a non-default collation, then creating a collection
// with the same collation will not invalidate the change stream.
(function() {
let frenchCollection = "change_stream_french_collation";
assertDropCollection(db, frenchCollection);

const frenchChangeStream = cst.startWatchingChanges({
    pipeline: [{$changeStream: {}}, {$project: {docId: "$documentKey._id"}}],
    aggregateOptions: {collation: {locale: "fr"}},
    collection: frenchCollection
});

frenchCollection = assertCreateCollection(db, frenchCollection, {collation: {locale: "fr"}});
assert.commandWorked(frenchCollection.insert({_id: 0}));

cst.assertNextChangesEqual({cursor: frenchChangeStream, expectedChanges: [{docId: 0}]});
}());

// Test that creating a change stream with a non-default collation, then creating a collection
// with *a different* collation will not invalidate the change stream.
(function() {
let germanCollection = "change_stream_german_collation";
assertDropCollection(db, germanCollection);

const englishCaseInsensitiveStream = cst.startWatchingChanges({
    pipeline: [
        {$changeStream: {}},
        {$match: {"fullDocument.text": "abc"}},
        {$project: {docId: "$documentKey._id"}}
    ],
    aggregateOptions: {collation: caseInsensitive},
    collection: germanCollection
});

germanCollection = assertCreateCollection(db, germanCollection, {collation: {locale: "de"}});
assert.commandWorked(germanCollection.insert({_id: 0, text: "aBc"}));

cst.assertNextChangesEqual({cursor: englishCaseInsensitiveStream, expectedChanges: [{docId: 0}]});
}());

// Test that creating a change stream with a non-default collation against a collection that has
// a non-simple default collation will use the collation specified on the operation.
(function() {
const caseInsensitiveCollection = assertDropAndRecreateCollection(
    db, "change_stream_case_insensitive", {collation: caseInsensitive});

const englishCaseSensitiveStream = cst.startWatchingChanges({
    pipeline: [
        {$changeStream: {}},
        {$match: {"fullDocument.text": "abc"}},
        {$project: {docId: "$documentKey._id"}}
    ],
    aggregateOptions: {collation: {locale: "en_US"}},
    collection: caseInsensitiveCollection
});

assert.commandWorked(caseInsensitiveCollection.insert({_id: 0, text: "aBc"}));
assert.commandWorked(caseInsensitiveCollection.insert({_id: 1, text: "abc"}));

cst.assertNextChangesEqual({cursor: englishCaseSensitiveStream, expectedChanges: [{docId: 1}]});
}());

// Test that collation is supported by the shell helper. Test that creating a change stream with
// a non-default collation against a collection that has a simple default collation will use the
// collation specified on the operation.
(function() {
const noCollationCollection = assertDropAndRecreateCollection(db, "change_stream_no_collation");

const cursor = noCollationCollection.watch(
    [{$match: {"fullDocument.text": "abc"}}, {$project: {docId: "$documentKey._id"}}],
    {collation: caseInsensitive});
assert(!cursor.hasNext());
assert.commandWorked(noCollationCollection.insert({_id: 0, text: "aBc"}));
assert.commandWorked(noCollationCollection.insert({_id: 1, text: "abc"}));
assert.soon(() => cursor.hasNext());
assertChangeStreamEventEq(cursor.next(), {docId: 0});
assert.soon(() => cursor.hasNext());
assertChangeStreamEventEq(cursor.next(), {docId: 1});
assert(!cursor.hasNext());
}());

// Test that we can resume a change stream on a collection that has been dropped without
// requiring the user to explicitly specify the collation.
(function() {
const collName = "change_stream_case_insensitive";
let caseInsensitiveCollection =
    assertDropAndRecreateCollection(db, collName, {collation: caseInsensitive});

let changeStream = caseInsensitiveCollection.watch([{$match: {"fullDocument.text": "abc"}}],
                                                   {collation: caseInsensitive});

assert.commandWorked(caseInsensitiveCollection.insert({_id: 0, text: "abc"}));

assert.soon(() => changeStream.hasNext());
const next = changeStream.next();
assert.docEq(next.documentKey, {_id: 0});
const resumeToken = next._id;

// Insert a second document to see after resuming.
assert.commandWorked(caseInsensitiveCollection.insert({_id: "dropped_coll", text: "ABC"}));

// Drop the collection to invalidate the stream.
assertDropCollection(db, collName);

// Test that a $changeStream is allowed to resume on the dropped collection with an explicit
// collation, even if it doesn't match the original collection's default collation.
changeStream =
    caseInsensitiveCollection.watch([{$match: {"fullDocument.text": "ABC"}}],
                                    {resumeAfter: resumeToken, collation: {locale: "simple"}});

assert.soon(() => changeStream.hasNext());
assert.docEq(changeStream.next().documentKey, {_id: "dropped_coll"});

// Test that a pipeline without an explicit collation is allowed to resume the change stream
// after the collection has been dropped, and it will use the simple collation. Do not
// modify this in the passthrough suite(s) since only individual collections have the
// concept of a default collation.
const doNotModifyInPassthroughs = true;
const cmdRes = assert.commandWorked(runCommandChangeStreamPassthroughAware(
    db,
    {
        aggregate: collName,
        pipeline: [{$changeStream: {resumeAfter: resumeToken}}],
        cursor: {},
    },
    doNotModifyInPassthroughs));

changeStream = new DBCommandCursor(db, cmdRes);
assert.soon(() => changeStream.hasNext());
assert.docEq(changeStream.next().documentKey, {_id: "dropped_coll"});
}());

// Test that the default collation of a new version of the collection is not applied when
// resuming a change stream from before a collection drop.
(function() {
const collName = "change_stream_case_insensitive";
let caseInsensitiveCollection =
    assertDropAndRecreateCollection(db, collName, {collation: caseInsensitive});

let changeStream = caseInsensitiveCollection.watch([{$match: {"fullDocument.text": "abc"}}],
                                                   {collation: caseInsensitive});

assert.commandWorked(caseInsensitiveCollection.insert({_id: 0, text: "abc"}));

assert.soon(() => changeStream.hasNext());
const next = changeStream.next();
assert.docEq(next.documentKey, {_id: 0});
const resumeToken = next._id;

// Insert a second document to see after resuming.
assert.commandWorked(caseInsensitiveCollection.insert({_id: "dropped_coll", text: "ABC"}));

// Recreate the collection with a different collation.
caseInsensitiveCollection = assertDropAndRecreateCollection(
    db, caseInsensitiveCollection.getName(), {collation: {locale: "simple"}});
assert.commandWorked(caseInsensitiveCollection.insert({_id: "new collection", text: "abc"}));

// Verify that the stream sees the insert before the drop and then is exhausted. We won't
// see the invalidate because the pipeline has a $match stage after the $changeStream.
assert.soon(() => changeStream.hasNext());
assert.docEq(changeStream.next().fullDocument, {_id: "dropped_coll", text: "ABC"});
// Only single-collection streams will be exhausted from the drop. Use 'next()' instead of
// 'isExhausted()' to force a getMore since the previous getMore may not include the
// collection drop, which is more likely with sharded collections on slow machines.
if (!isChangeStreamPassthrough()) {
    assert.throws(() => changeStream.next());
}

// Test that a pipeline with an explicit collation is allowed to resume from before the
// collection is dropped and recreated.
changeStream =
    caseInsensitiveCollection.watch([{$match: {"fullDocument.text": "ABC"}}],
                                    {resumeAfter: resumeToken, collation: {locale: "fr"}});

assert.soon(() => changeStream.hasNext());
assert.docEq(changeStream.next().documentKey, {_id: "dropped_coll"});
// Only single-collection streams will be exhausted from the drop. Use 'next()' instead of
// 'isExhausted()' to force a getMore since the previous getMore may not include the
// collection drop, which is more likely with sharded collections on slow machines.
if (!isChangeStreamPassthrough()) {
    assert.throws(() => changeStream.next());
}

// Test that a pipeline without an explicit collation is allowed to resume, even though the
// collection has been recreated with the same default collation as it had previously. Do
// not modify this command in the passthrough suite(s) since only individual collections
// have the concept of a default collation.
const doNotModifyInPassthroughs = true;
const cmdRes = assert.commandWorked(runCommandChangeStreamPassthroughAware(
    db,
    {aggregate: collName, pipeline: [{$changeStream: {resumeAfter: resumeToken}}], cursor: {}},
    doNotModifyInPassthroughs));

changeStream = new DBCommandCursor(db, cmdRes);
assert.soon(() => changeStream.hasNext());
assert.docEq(changeStream.next().documentKey, {_id: "dropped_coll"});
}());
})();