query.js

var query = {
    $match: {
        "created": {
            $gte: ISODate("2015-08-25T12:15:14-03:00")
        }
    }
}
var group = {
    $group: {
        _id: {
            day: "$dayOfMonth"
        },
        day: {
            $first: "$dayOfMonth"
        },
        "status_aguardando_pagamento": {
            "$sum": { "$cond": [
                { "$eq": [ "$status", 0 ] },
                1,
                0
            ]}
        },
        "status_pago": {
            "$sum": { "$cond": [
                { "$eq": [ "$status", 1 ] },
                1,
                0
            ]}
        },
        count: { 
            $sum: 1
        }
    }
}
var project = {
    $project: {
        "status": 1,
        "items": "$items",
        "year": {
            $year: "$created"
        },
        "month": {
            $month: "$created"
        },
        "dayOfMonth": {
            $dayOfMonth: "$created"
        },
        "created": "$created"
    }
}

db.getCollection('orders').aggregate([
    { $unwind: '$items' },
    { $unwind: '$items.insc' },
    query,
    project,
    group
])