// Tests basic functionality of the $_internalJsEmit expression, which provides capability for the
// map stage of MapReduce.
//
// @tags: [
//   requires_scripting,
// ]
import {resultsEq} from "jstests/aggregation/extras/utils.js";

const coll = db.js_emit_expr;
coll.drop();

function fmap() {
    for (let word of this.text.split(" ")) {
        emit(word, 1);
    }
}

let pipeline = [
    {
        $project: {
            emits: {
                $_internalJsEmit: {
                    "this": "$$ROOT",
                    "eval": fmap,
                },
            },
            _id: 0,
        },
    },
    {$unwind: "$emits"},
    {$replaceRoot: {newRoot: "$emits"}},
];

assert.commandWorked(coll.insert({text: "hello world"}));

let results = coll.aggregate(pipeline, {cursor: {batchSize: 1}}).toArray();
assert(
    resultsEq(results, [
        {k: "hello", v: 1},
        {k: "world", v: 1},
    ]),
    results,
);

assert.commandWorked(coll.insert({text: "mongo db"}));

// Set batchSize to 1 to check that the expression is able to run across getMore's.
results = coll.aggregate(pipeline, {cursor: {batchSize: 1}}).toArray();
assert(
    resultsEq(results, [
        {k: "hello", v: 1},
        {k: "world", v: 1},
        {k: "mongo", v: 1},
        {k: "db", v: 1},
    ]),
    results,
);

// Test that the 'eval' function accepts a string argument.
pipeline[0].$project.emits.$_internalJsEmit.eval = fmap.toString();
results = coll.aggregate(pipeline, {cursor: {batchSize: 1}}).toArray();
assert(
    resultsEq(results, [
        {k: "hello", v: 1},
        {k: "world", v: 1},
        {k: "mongo", v: 1},
        {k: "db", v: 1},
    ]),
    results,
);

// Test that the command correctly fails for an invalid operation within the JS function.
assert.commandWorked(coll.insert({text: 5}));
assert.commandFailedWithCode(
    db.runCommand({aggregate: coll.getName(), pipeline: pipeline, cursor: {}}),
    ErrorCodes.JSInterpreterFailure,
);

// Test that the command correctly fails for invalid arguments.
pipeline = [
    {
        $project: {
            emits: {
                $_internalJsEmit: {
                    "this": "must evaluate to an object",
                    "eval": fmap,
                },
            },
            _id: 0,
        },
    },
];
assert.commandFailedWithCode(db.runCommand({aggregate: coll.getName(), pipeline: pipeline, cursor: {}}), 31225);

pipeline = [
    {
        $project: {
            emits: {
                $_internalJsEmit: {
                    "this": "$$ROOT",
                    "eval": "this is not a valid function!",
                },
            },
            _id: 0,
        },
    },
];
assert.commandFailedWithCode(
    db.runCommand({aggregate: coll.getName(), pipeline: pipeline, cursor: {}}),
    ErrorCodes.JSInterpreterFailure,
);