'use strict';

/**
 * explain_count.js
 *
 * Runs explain() and count() on a collection.
 */
load('jstests/concurrency/fsm_libs/extend_workload.js'); // for extendWorkload
load('jstests/concurrency/fsm_workloads/explain.js'); // for $config
load('jstests/concurrency/fsm_workload_helpers/server_types.js'); // for isMongos
load('jstests/libs/analyze_plan.js'); // for planHasStage

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

    function assertNCounted(num, obj, db) {
        var stage = obj.executionStats.executionStages;
        // get sharded stage(s) if counting on mongos
        if (isMongos(db)) {
            stage = stage.shards[0].executionStages;
        }
        assertWhenOwnColl.eq(num, stage.nCounted);
    }

    $config.states = Object.extend({
        explainBasicCount: function explainBasicCount(db, collName) {
            var res = db[collName].explain().count();
            assertAlways.commandWorked(res);
            assertAlways(planHasStage(res.queryPlanner.winningPlan, 'COUNT'));
        },
        explainCountHint: function explainCountHint(db, collName) {
            assertWhenOwnColl(function() {
                var res = db[collName].explain()
                                      .find({ i: this.nInserted / 2 })
                                      .hint({ i: 1 }).count();
                assertWhenOwnColl.commandWorked(res);
                assertWhenOwnColl(planHasStage(res.queryPlanner.winningPlan, 'COUNT'));
                assertWhenOwnColl(planHasStage(res.queryPlanner.winningPlan, 'COUNT_SCAN'));
            });
        },
        explainCountNoSkipLimit: function explainCountNoSkipLimit(db, collName) {
            var res = db[collName].explain('executionStats')
                                  .find({ i: this.nInserted }).skip(1).count(false);
            assertAlways.commandWorked(res);
            assertNCounted(1, res, db);
        },
        explainCountSkipLimit: function explainCountSkipLimit(db, collName) {
            var res = db[collName].explain('executionStats')
                                  .find({ i: this.nInserted }).skip(1).count(true);
            assertAlways.commandWorked(res);
            assertNCounted(0, res, db);
        }
    }, $super.states);

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

    return $config;
});
