function canLoadAd(adType, config, params, isDebug) {
    var debug = strToBool(isDebug);
    var config1 = JSON.parse(config);

    var rules = getAdjustedSuppressionRules(config1, debug);
    prettyPrint(rules, debug);

    var params1 = JSON.parse(params);
    var states = getAdjustedStatesWithDefault(params1);
    prettyPrint(states, debug);

    var results = getLoadSuppressionRulesResults(adType, rules, states);
    prettyPrint(results, debug);

    return andOperation(results);
}

function canShowAd(adType, config, params, isDebug) {
    var debug = strToBool(isDebug);
    var config1 = JSON.parse(config);
    var rules = getAdjustedSuppressionRules(config1, debug);
    prettyPrint(rules, debug);

    var params1 = JSON.parse(params);
    var states = getAdjustedStatesWithDefault(params1);
    prettyPrint(states, debug);

    var loadResults = getLoadSuppressionRulesResults(adType, rules, states);

    if (!andOperation(loadResults)) {
        prettyPrint(loadResults, debug);
        return false;
    }

    var showResults = getShowSuppressionRulesResults(adType, rules, states);
    prettyPrint(showResults, debug);

    return andOperation(showResults);
}

function getLoadSuppressionRulesResults(adType, rules, states) {
    var results = {};

    if (isBanner(adType)) {
        return results;
    }

    if (rules.tutorialCheckEnabled) {
        results.tutorialCheck = states.tutorialComplete;
    }

    if (rules.elapsedTimeSinceAppInstallInSecs) {
        // passed less than elapsedTimeSinceAppInstallInSecs since app is installed
        results.newUserCheck = getTimeDifferenceInSeconds(states.currentTimeInMs, states.appInstallTimeInMs) > rules.elapsedTimeSinceAppInstallInSecs;
    }

    if (rules.minUserLtvInUsd) {
        // paid more than minUserLtvInUsd
        var recentPayerCheck = (states.userLtvInUsd * 100) >= (rules.minUserLtvInUsd * 100);
        if (rules.elapsedTimeSinceLastPurchaseInSecs) {
            // made a purchase within elapsedTimeSinceLastPurchaseInSecs
            recentPayerCheck = recentPayerCheck && (getTimeDifferenceInSeconds(states.currentTimeInMs, states.lastPurchaseTimeInMs) < rules.elapsedTimeSinceLastPurchaseInSecs);
        }
        results.recentPayerCheck = !recentPayerCheck;
    }
    return results;
}

function getShowSuppressionRulesResults(adType, rules, states) {
    var results = getLoadSuppressionRulesResults(adType, rules, states);

    if (isBanner(adType)) {
        if (rules.elapsedTimeSinceAppInstallInDays) {
            // passed less than elapsedTimeSinceAppInstallInDays since app is installed
            results.installedDaysAgoCheck = getTimeDifferenceInDays(states.currentTimeInMs, states.appInstallTimeInMs) > rules.elapsedTimeSinceAppInstallInDays;
        }

        if (rules.minUserLtvInUsd) {
            results.spenderCheck = states.userLtvInUsd < rules.minUserLtvInUsd;
        }
    }
    else {

        if (rules.elapsedTimeSinceCurrentLaunchInSecs) {
            results.currentSessionDurationCheck = getTimeDifferenceInSeconds(states.currentTimeInMs, states.currentLaunchTimeInMs) > rules.elapsedTimeSinceCurrentLaunchInSecs;
        }

        if (rules.elapsedTimeSinceLastAdShownInSecs) {
            results.nextAdShowCheck = getTimeDifferenceInSeconds(states.currentTimeInMs, states.lastAdDismissedTimeInMs) > rules.elapsedTimeSinceLastAdShownInSecs;
        }
    }

    return results;
}

function getAdjustedStatesWithDefault(states) {
    // provide default values for null fields
    states.tutorialComplete = states.tutorialComplete != null ? states.tutorialComplete : true;
    states.appInstallTimeInMs = states.appInstallTimeInMs != null ? states.appInstallTimeInMs : 0;
    states.userLtvInUsd = states.userLtvInUsd != null ? states.userLtvInUsd : 0;
    states.lastPurchaseTimeInMs = states.lastPurchaseTimeInMs != null ? states.lastPurchaseTimeInMs : 0;

    if (!isBoolean(states.tutorialComplete)
        || !isNumber(states.appInstallTimeInMs)
        || !isNumber(states.userLtvInUsd)
        || !isNumber(states.lastPurchaseTimeInMs)) {
        throw new Error("Invalid type of parameter is passed.");
    }

    return states;
}

function getAdjustedSuppressionRules(config, debug) {
    // provide default values for null fields
    var defaultRules = defaultSuppressionRules();
    var minUserLtvInUsd = config.minUserLtvInUsd != null ? config.minUserLtvInUsd : defaultRules.minUserLtvInUsd;
    var elapsedTimeSinceCurrentLaunchInSecs = config.elapsedTimeSinceCurrentLaunchInSecs != null ? config.elapsedTimeSinceCurrentLaunchInSecs : defaultRules.elapsedTimeSinceCurrentLaunchInSecs;
    var elapsedTimeSinceAppInstallInSecs = config.elapsedTimeSinceAppInstallInSecs != null ? config.elapsedTimeSinceAppInstallInSecs : defaultRules.elapsedTimeSinceAppInstallInSecs;
    var elapsedTimeSinceAppInstallInDays = config.elapsedTimeSinceAppInstallInDays != null ? config.elapsedTimeSinceAppInstallInDays : defaultRules.elapsedTimeSinceAppInstallInDays;
    var elapsedTimeSinceLastAdShownInSecs = config.elapsedTimeSinceLastAdShownInSecs != null ? config.elapsedTimeSinceLastAdShownInSecs : defaultRules.elapsedTimeSinceLastAdShownInSecs;
    var elapsedTimeSinceLastPurchaseInSecs = config.elapsedTimeSinceLastPurchaseInSecs != null ? config.elapsedTimeSinceLastPurchaseInSecs : defaultRules.elapsedTimeSinceLastPurchaseInSecs;
    var tutorialCheckEnabled = config.tutorialCheckEnabled != null ? config.tutorialCheckEnabled : defaultRules.tutorialCheckEnabled;

    config.minUserLtvInUsd = minUserLtvInUsd;
    config.elapsedTimeSinceCurrentLaunchInSecs = elapsedTimeSinceCurrentLaunchInSecs;
    config.elapsedTimeSinceAppInstallInSecs = elapsedTimeSinceAppInstallInSecs;
    config.elapsedTimeSinceAppInstallInDays = elapsedTimeSinceAppInstallInDays;
    config.elapsedTimeSinceLastAdShownInSecs = elapsedTimeSinceLastAdShownInSecs;
    config.elapsedTimeSinceLastPurchaseInSecs = elapsedTimeSinceLastPurchaseInSecs;
    config.tutorialCheckEnabled = tutorialCheckEnabled;

    // remove disabled rules from suppression rules. (disabled when set to -1)
    var disabledRules = disabledSuppressionRules(config);
    Object.keys(disabledRules).forEach(function (key) {
        delete config[key];
        prettyPrint(key + " check is disabled", debug);
    });
    return config;
}

function defaultSuppressionRules() {
    return {
        "minUserLtvInUsd": 0.99, // Greater or equal than this value will suppress loading/showing interstitial ads
        "elapsedTimeSinceCurrentLaunchInSecs": 60, // Less than this value will suppress showing interstitial ads
        "elapsedTimeSinceAppInstallInSecs": 600, // Less than this value will suppress loading/showing interstitial ads
        "elapsedTimeSinceAppInstallInDays": 30, // Less that this value will suppress showing banner ads
        "elapsedTimeSinceLastAdShownInSecs": 300, // Less than this value will suppress showing interstitial ads
        "elapsedTimeSinceLastPurchaseInSecs": 2592000, // 30 days - If payer and less than this value will suppress loading/showing interstitial ads
        "tutorialCheckEnabled": true // SDK will ignore the tutorial check if disabled
    };
}

function disabledSuppressionRules(rules) {
    var disabledRules = {};
    Object.keys(rules).forEach(function (key) {
        if (rules[key] == -1 || rules[key] == false) {
            disabledRules[key] = true;
        }
    });
    return disabledRules;
}

/*********************************************************
 * Helper functions
 */
function getTimeDifferenceInSeconds(t1, t2) {
    return (t1 - t2) / 1000;
}

function getTimeDifferenceInDays(t1, t2) {
    return Math.floor((t1 - t2) / (3600*1000*24))
}

function prettyPrint(obj, debug) {
    if (debug) {

        if (typeof console === "undefined") {
            var noop = function() {};
            console = { log: noop, error: noop }
        }

        console.log(JSON.stringify(obj, null, 4));
    }
}

function andOperation(obj) {
    var ret = true;
    Object.keys(obj).forEach(function (key) {
        ret &= obj[key];
    });

    return Boolean(ret);
}

function strToBool(value) {
    return value == 'true';
}

function isNumber(x) {
    return typeof x === 'number';
}

function isBoolean(x) {
    return typeof x === 'boolean' || (typeof x === 'object' && typeof x.valueOf() === 'boolean');
}

function isBanner(adType) {
    return adType === 'banner';
}