var Mingo = require('mingo');
// or just access *Mingo* global in browser

// setup the key field for your collection
Mingo.setup({
    key: '_id' // default
});

// create a query with criteria
// find all grades for homework with score >= 50
var query = new Mingo.Query({
    type: "homework",
    score: { $gte: 50 }
});

// filter collection with find()
var cursor = query.find(collection);

// shorthand with query criteria
// cursor = Mingo.find(collection, criteria);

// sort, skip and limit by chaining
cursor.sort({student_id: 1, score: -1})
    .skip(100)
    .limit(100);

// count matches
cursor.count();

// iterate cursor
// iteration is forward only
while (cursor.hasNext()) {
    console.log(cursor.next());
}

// use first(), last() and all() to retrieve matched objects
cursor.first();
cursor.last();
cursor.all();

// Filter non-matched objects (
var result = query.remove(collection);

var agg = new Mingo.Aggregator([
    {'$match': { "type": "homework"}},
    {'$group':{'_id':'$student_id', 'score':{$min:'$score'}}},
    {'$sort':{'_id': 1, 'score': 1}}
]);

var result = agg.run(collection);

// shorthand
result = Mingo.aggregate(
    collection,
    [
        {'$match': { "type": "homework"}},
        {'$group':{'_id':'$student_id', 'score':{$min:'$score'}}},
        {'$sort':{'_id': 1, 'score': 1}}
    ]
);

var JSONStream = require('JSONStream'),
    fs = require('fs'),
    Mingo = require('mingo');

var query = new Mingo.Query({
  scores: { $elemMatch: {type: "exam", score: {$gt: 90}} }
}, {name: 1});

file = fs.createReadStream('./students.json');

var qs = query.stream();
qs.on('data', function (data) {
    console.log(data); // log filtered outputs
    // ex. { name: 'Dinah Sauve', _id: 49 }
});

file.pipe(JSONStream.parse("*")).pipe(qs);

// using with Backbone
var Grades = Backbone.Collection.extend(Mingo.CollectionMixin);

var grades = new Grades(collection);

// find students with grades less than 50 in homework or quiz
// sort by score ascending and type descending
cursor = grades.query({
    $or: [{type: "quiz", score: {$lt: 50}}, {type: "homework", score: {$lt: 50}}]
}).sort({score: 1, type: -1}).limit(10);

// print grade with the lowest score
cursor.first();