// @tags: [
//   requires_getmore,
//   # Requires a batch size greater than one.
//   does_not_support_config_fuzzer,
// ]

// Ensure that the find and getMore commands can handle documents nearing the 16 MB size limit for
// user-stored BSON documents.
var cmdRes;
var collName = 'find_getmore_bsonsize';
var coll = db[collName];

coll.drop();

var oneKB = 1024;
var oneMB = 1024 * oneKB;

// Build a (1 MB - 1 KB) string.
var smallStr = 'x';
while (smallStr.length < oneMB) {
    smallStr += smallStr;
}
assert.eq(smallStr.length, oneMB);
smallStr = smallStr.substring(0, oneMB - oneKB);

// Build a (16 MB - 1 KB) string.
var bigStr = 'y';
while (bigStr.length < (16 * oneMB)) {
    bigStr += bigStr;
}
assert.eq(bigStr.length, 16 * oneMB);
bigStr = bigStr.substring(0, (16 * oneMB) - oneKB);

// Collection has one ~1 MB doc followed by one ~16 MB doc.
assert.commandWorked(coll.insert({_id: 0, padding: smallStr}));
assert.commandWorked(coll.insert({_id: 1, padding: bigStr}));

// Find command should just return the first doc, as adding the last would create an invalid
// command response document.
cmdRes = db.runCommand({find: collName});
assert.commandWorked(cmdRes);
assert.gt(cmdRes.cursor.id, NumberLong(0));
assert.eq(cmdRes.cursor.ns, coll.getFullName());
assert.eq(cmdRes.cursor.firstBatch.length, 1);

// The 16 MB doc should be returned alone on getMore. This is the last document in the
// collection, so the server should close the cursor.
cmdRes = db.runCommand({getMore: cmdRes.cursor.id, collection: collName});
assert.eq(cmdRes.cursor.id, NumberLong(0));
assert.eq(cmdRes.cursor.ns, coll.getFullName());
assert.eq(cmdRes.cursor.nextBatch.length, 1);

// Setup a cursor without returning any results (batchSize of zero).
cmdRes = db.runCommand({find: collName, batchSize: 0});
assert.commandWorked(cmdRes);
assert.gt(cmdRes.cursor.id, NumberLong(0));
assert.eq(cmdRes.cursor.ns, coll.getFullName());
assert.eq(cmdRes.cursor.firstBatch.length, 0);

// First getMore should only return one doc, since both don't fit in the response.
cmdRes = db.runCommand({getMore: cmdRes.cursor.id, collection: collName});
assert.gt(cmdRes.cursor.id, NumberLong(0));
assert.eq(cmdRes.cursor.ns, coll.getFullName());
assert.eq(cmdRes.cursor.nextBatch.length, 1);

// Second getMore should return the second doc and a third will close the cursor.
cmdRes = db.runCommand({getMore: cmdRes.cursor.id, collection: collName});
assert.eq(cmdRes.cursor.id, NumberLong(0));
assert.eq(cmdRes.cursor.ns, coll.getFullName());
assert.eq(cmdRes.cursor.nextBatch.length, 1);

coll.drop();

// Insert a document of exactly 16MB and make sure the find command can return it.
bigStr = 'y';
while (bigStr.length < (16 * oneMB)) {
    bigStr += bigStr;
}
bigStr = bigStr.substring(0, (16 * oneMB) - 32);
var maxSizeDoc = {_id: 0, padding: bigStr};
assert.eq(Object.bsonsize(maxSizeDoc), 16 * oneMB);
assert.commandWorked(coll.insert(maxSizeDoc));

cmdRes = db.runCommand({find: collName});
assert.commandWorked(cmdRes);
assert.eq(cmdRes.cursor.id, NumberLong(0));
assert.eq(cmdRes.cursor.ns, coll.getFullName());
assert.eq(cmdRes.cursor.firstBatch.length, 1);
