// In SERVER-10689, the $switch expression was introduced. In this file, we test the functionality
// of the expression.

(function() {
"use strict";

var coll = db.switch;
coll.drop();

// Insert an empty document so that something can flow through the pipeline.
coll.insert({});

// Ensure that a branch is correctly evaluated.
var pipeline = {
    "$project": {
        "_id": 0,
        "output": {
            "$switch": {
                "branches": [{"case": {"$eq": [1, 1]}, "then": "one is equal to one!"}],
            }
        }
    }
};
var res = coll.aggregate(pipeline).toArray();

assert.eq(res.length, 1);
assert.eq(res[0], {"output": "one is equal to one!"});

// Ensure that the first branch which matches is chosen.
pipeline = {
    "$project": {
        "_id": 0,
        "output": {
            "$switch": {
                "branches": [
                    {"case": {"$eq": [1, 1]}, "then": "one is equal to one!"},
                    {"case": {"$eq": [2, 2]}, "then": "two is equal to two!"}
                ],
            }
        }
    }
};
res = coll.aggregate(pipeline).toArray();

assert.eq(res.length, 1);
assert.eq(res[0], {"output": "one is equal to one!"});

// Ensure that the default is chosen if no case matches.
pipeline = {
    "$project": {
        "_id": 0,
        "output": {
            "$switch": {
                "branches": [{"case": {"$eq": [1, 2]}, "then": "one is equal to two!"}],
                "default": "no case matched."
            }
        }
    }
};
res = coll.aggregate(pipeline).toArray();

assert.eq(res.length, 1);
assert.eq(res[0], {"output": "no case matched."});

// Ensure that nullish values are treated as false when they are a "case", and are null
// otherwise.
pipeline = {
    "$project": {
        "_id": 0,
        "output": {
            "$switch": {
                "branches": [{"case": null, "then": "Null was true!"}],
                "default": "No case matched."
            }
        }
    }
};
res = coll.aggregate(pipeline).toArray();

assert.eq(res.length, 1);
assert.eq(res[0], {"output": "No case matched."});

pipeline = {
    "$project": {
        "_id": 0,
        "output": {
            "$switch": {
                "branches": [{"case": "$missingField", "then": "Null was true!"}],
                "default": "No case matched."
            }
        }
    }
};
res = coll.aggregate(pipeline).toArray();

assert.eq(res.length, 1);
assert.eq(res[0], {"output": "No case matched."});

pipeline = {
    "$project": {
        "_id": 0,
        "output": {"$switch": {"branches": [{"case": true, "then": null}], "default": false}}
    }
};
res = coll.aggregate(pipeline).toArray();

assert.eq(res.length, 1);
assert.eq(res[0], {"output": null});

pipeline = {
    "$project": {
        "_id": 0,
        "output":
            {"$switch": {"branches": [{"case": true, "then": "$missingField"}], "default": false}}
    }
};
res = coll.aggregate(pipeline).toArray();

assert.eq(res.length, 1);
assert.eq(res[0], {});

pipeline = {
    "$project": {
        "_id": 0,
        "output": {"$switch": {"branches": [{"case": null, "then": false}], "default": null}}
    }
};
res = coll.aggregate(pipeline).toArray();

assert.eq(res.length, 1);
assert.eq(res[0], {"output": null});

pipeline = {
    "$project": {
        "_id": 0,
        "output":
            {"$switch": {"branches": [{"case": null, "then": false}], "default": "$missingField"}}
    }
};
res = coll.aggregate(pipeline).toArray();

assert.eq(res.length, 1);
assert.eq(res[0], {});
}());