var tz = require('moment-timezone');
var calcMealCOB = require('../determine-basal/cob');

function round(value, digits) {
    if (! digits) { digits = 0; }
    var scale = Math.pow(10, digits);
    return Math.round(value * scale) / scale;
}

function recentCarbs(opts, time) {
    var treatments = opts.treatments;
    var profile_data = opts.profile;
    if (typeof(opts.glucose) !== 'undefined') {
        var glucose_data = opts.glucose;
    }
    var carbs = 0;
    var nsCarbs = 0;
    var bwCarbs = 0;
    var journalCarbs = 0;
    var bwFound = false;
    var mealCarbTime = time.getTime();
    var lastCarbTime = 0;
    if (!treatments) return {};

    //console.error(glucose_data);
    var iob_inputs = {
        profile: profile_data
    ,   history: opts.pumphistory
    };
    var COB_inputs = {
        glucose_data: glucose_data
    ,   iob_inputs: iob_inputs
    ,   basalprofile: opts.basalprofile
    ,   mealTime: mealCarbTime
    };
    var mealCOB = 0;

    // this sorts the treatments collection in order.
    treatments.sort(function (a, b) {
        var aDate = new Date(tz(a.timestamp));
        var bDate = new Date(tz(b.timestamp));
        //console.error(aDate);
        return bDate.getTime() - aDate.getTime();
    });

    var carbsToRemove = 0;
    var nsCarbsToRemove = 0;
    var bwCarbsToRemove = 0;
    var journalCarbsToRemove = 0;
    var maxMealAbsorptionTime = 6;

    if (typeof(profile_data.maxMealAbsorptionTime) === 'number' && ! isNaN(profile_data.maxMealAbsorptionTime)) {
        maxMealAbsorptionTime = profile_data.maxMealAbsorptionTime;
    } else {
        console.error("Bad profile.maxMealAbsorptionTime:",profile_data.maxMealAbsorptionTime);
    }

    treatments.forEach(function(treatment) {
        var now = time.getTime();
        // consider carbs from up to the meal preference maxMealAbsorptionTime hours ago in calculating COB
        var carbWindow = now - maxMealAbsorptionTime * 60*60*1000;
        var treatmentDate = new Date(tz(treatment.timestamp));
        var treatmentTime = treatmentDate.getTime();
        if (treatmentTime > carbWindow && treatmentTime <= now) {
            if (treatment.carbs >= 1) {
                if (treatment.nsCarbs >= 1) {
                    nsCarbs += parseFloat(treatment.nsCarbs);
                } else if (treatment.bwCarbs >= 1) {
                    bwCarbs += parseFloat(treatment.bwCarbs);
                    bwFound = true;
                } else if (treatment.journalCarbs >= 1) {
                    journalCarbs += parseFloat(treatment.journalCarbs);
                } else {
                    console.error("Treatment carbs unclassified:",treatment);
                }
                //console.error(treatment.carbs, maxCarbs, treatmentDate);
                carbs += parseFloat(treatment.carbs);
                COB_inputs.mealTime = treatmentTime;
                lastCarbTime = Math.max(lastCarbTime,treatmentTime);
                var myCarbsAbsorbed = calcMealCOB(COB_inputs).carbsAbsorbed;
                var myMealCOB = Math.max(0, carbs - myCarbsAbsorbed);
                if (typeof(myMealCOB) === 'number' && ! isNaN(myMealCOB)) {
                    mealCOB = Math.max(mealCOB, myMealCOB);
                } else {
                    console.error("Bad myMealCOB:",myMealCOB, "mealCOB:",mealCOB, "carbs:",carbs,"myCarbsAbsorbed:",myCarbsAbsorbed);
                }
                if (myMealCOB < mealCOB) {
                    carbsToRemove += parseFloat(treatment.carbs);
                    if (treatment.nsCarbs >= 1) {
                        nsCarbsToRemove += parseFloat(treatment.nsCarbs);
                    } else if (treatment.bwCarbs >= 1) {
                        bwCarbsToRemove += parseFloat(treatment.bwCarbs);
                    } else if (treatment.journalCarbs >= 1) {
                        journalCarbsToRemove += parseFloat(treatment.journalCarbs);
                    }
                } else {
                    carbsToRemove = 0;
                    nsCarbsToRemove = 0;
                    bwCarbsToRemove = 0;
                }
                //console.error(carbs, carbsToRemove);
                //console.error("COB:",mealCOB);
            }
        }
    });
    // only include carbs actually used in calculating COB
    carbs -= carbsToRemove;
    nsCarbs -= nsCarbsToRemove;
    bwCarbs -= bwCarbsToRemove;
    journalCarbs -= journalCarbsToRemove;

    // calculate the current deviation and steepest deviation downslope over the last hour
    COB_inputs.ciTime = time.getTime();
    // set mealTime to 6h ago for Deviation calculations
    COB_inputs.mealTime = time.getTime() - maxMealAbsorptionTime * 60 * 60 * 1000;
    var c = calcMealCOB(COB_inputs);
    //console.error(c.currentDeviation, c.slopeFromMaxDeviation);

    // set a hard upper limit on COB to mitigate impact of erroneous or malicious carb entry
    if (typeof(profile_data.maxCOB) === 'number' && ! isNaN(profile_data.maxCOB)) {
        mealCOB = Math.min( profile_data.maxCOB, mealCOB );
        console.error("mealCOB: " + round(mealCOB,1) + " with maxCOB " + profile_data.maxCOB + "g and maxMealAbsorptionTime " + maxMealAbsorptionTime + "hrs.");
    } else {
        console.error("Bad profile.maxCOB:",profile_data.maxCOB);
    }

    // if currentDeviation is null or maxDeviation is 0, set mealCOB to 0 for zombie-carb safety
    if (typeof(c.currentDeviation) === 'undefined' || c.currentDeviation === null) {
        console.error("");
        console.error("Warning: setting mealCOB to 0 because currentDeviation is null/undefined");
        mealCOB = 0;
    }
    if (typeof(c.maxDeviation) === 'undefined' || c.maxDeviation === null) {
        console.error("");
        console.error("Warning: setting mealCOB to 0 because maxDeviation is 0 or undefined");
        mealCOB = 0;
    }

    return {
        carbs: Math.round( carbs * 1000 ) / 1000
    ,   nsCarbs: Math.round( nsCarbs * 1000 ) / 1000
    ,   bwCarbs: Math.round( bwCarbs * 1000 ) / 1000
    ,   journalCarbs: Math.round( journalCarbs * 1000 ) / 1000
    ,   mealCOB: Math.round( mealCOB )
    ,   currentDeviation: Math.round( c.currentDeviation * 100 ) / 100
    ,   maxDeviation: Math.round( c.maxDeviation * 100 ) / 100
    ,   minDeviation: Math.round( c.minDeviation * 100 ) / 100
    ,   slopeFromMaxDeviation: Math.round( c.slopeFromMaxDeviation * 1000 ) / 1000
    ,   slopeFromMinDeviation: Math.round( c.slopeFromMinDeviation * 1000 ) / 1000
    ,   allDeviations: c.allDeviations
    ,   lastCarbTime: lastCarbTime
    ,   bwFound: bwFound
    };
}

exports = module.exports = recentCarbs;