'use strict';

/**
 * explain_aggregate.js
 *
 * Runs explain() and aggregate() on a collection.
 *
 */
load('jstests/concurrency/fsm_libs/extend_workload.js'); // for extendWorkload
load('jstests/concurrency/fsm_workloads/explain.js'); // for $config

var $config = extendWorkload($config, function($config, $super) {

    function assertCursorStages(num, obj) {
        assertAlways(obj.stages, tojson(obj));
        assertAlways.eq(num, obj.stages.length, tojson(obj.stages));
        assertAlways(obj.stages[0].$cursor, tojson(obj.stages[0]));
        assertAlways(obj.stages[0].$cursor.hasOwnProperty('queryPlanner'),
                     tojson(obj.stages[0].$cursor));
    }

    $config.states = Object.extend({
        explainMatch: function explainMatch(db, collName) {
            var res = db[collName].explain().aggregate([{ $match: { i: this.nInserted / 2 } }]);
            assertAlways.commandWorked(res);

            // stages reported: $cursor
            assertCursorStages(1, res);
        },
        explainMatchProject: function explainMatchProject(db, collName) {
            var res = db[collName].explain().aggregate([{ $match: { i: this.nInserted / 3 } },
                                                        { $project: { i: 1 } }]);
            assertAlways.commandWorked(res);

            // stages reported: $cursor, $project
            assertCursorStages(2, res);
        }
    }, $super.states);

    $config.transitions = Object.extend({
        explain: $config.data.assignEqualProbsToTransitions($config.states)
    }, $super.transitions);

    return $config;
});