// no ES6 here!
/* eslint-disable no-console, no-var */

(function() {
    var abConfigString = '{"name":"ab-2024-04-22","groups":[{"probability":30,"name":"gruppe-a","searchConfig":"\/search\/documents?tuning="},{"probability":30,"name":"gruppe-b","searchConfig":"\/search\/documents?tuning=stopwords:false,type.use.additive:false,compression.use:false,asym.decay:false,time.override.enabled:false,txt.function:true,function.scoremode:avg,function.boostmode:multiply,synthetic.episode.size:7,decay.shape:gauss,weight.decay:128.0,scale:90d,future.scale:7d,boost.category:6.0,boost.brand:9.0,time.override.teilbereich:heute.de,time.override.weight:15.0,time.override.scale:14d,time.override.future.scale:2d,boost.field.newsOverline:0.2,boost.field.title:0.2,boost.field.title2:0.05,boost.field.title3:0.05,boost.field.text:0.1,boost.field.description:0.02,boost.field.editorialTagsFulltext:0.15,compression.target.score:10.0,compression.range:1.0,compression.max.input.score:150.0,boost.ctype.brand:15.0,boost.ctype.news:5.0,boost.ctype.episode:5.0,boost.ctype.clip:4.0,boost.type.page-video:5.0,boost.type.page-index:2.0,weight.type:0.3,weight.category:1.5,weight.brand:1.5,boost.field.category:0.05,boost.field.brand:0.07,weight.txt.function:0.01,decayFunctionOffset:0d,past.decay:0.5,future.decay:0.5"},{"probability":30,"name":"gruppe-c","searchConfig":"\/search\/documents?tuning="},{"probability":5,"name":"gruppe-d","searchConfig":"\/search\/documents?tuning="},{"probability":5,"name":"gruppe-e","searchConfig":"\/search\/documents?tuning="}],"expirationDate":"2024-04-22T08:00:00+02:00"}';

    var abConfig = null;
    var abGroup = null;

    function getConfig() {
        return abConfig;
    }

    function getGroup() {
        if (!abGroup) {
            abGroup = selectGroup(abConfig);
        }

        return abGroup;
    }

    function getConfigName() {
        return abConfig && abConfig.name;
    }

    function getExpirationDate() {
        return abConfig && abConfig.expirationDate;
    }

    function selectGroup(config) {
        var groups = config && config.groups;
        if (!groups || !Array.isArray(groups) || !groups.length) {
            console.warn('cannot select ab group, groups data not valid:', groups);
            return null;
        }

        var sum = groups.reduce(addProbabilities, 0);
        var rand = Math.round(Math.random() * sum);
        var selectedGroup = groups.reduce(findGroupForSelectedProbability, { 'start': 0, 'index': 0, 'probability': rand });
        var groupData = groups[selectedGroup.index];

        return {
            'name': config.name,
            'expirationDate': config.expirationDate,
            'group': groupData.name,
            'searchConfig': groupData.searchConfig,
        }
    }

    function addProbabilities(accumulator, currentValue) {
        return accumulator + currentValue.probability;
    }

    function findGroupForSelectedProbability(accumulator, currentValue, currentIndex) {
        var start = accumulator.start;
        var end = start + currentValue.probability;
        var probability = accumulator.probability;
        return {
            'start': end,
            'index': (probability >= start && probability < end) ? currentIndex : accumulator.index,
            'probability': accumulator.probability,
        };
    }

    /////////////////////////////////////////////////////////////////////////

    try {
        abConfig = JSON.parse(abConfigString);
    }
    catch(e) {
        console.warn('Error parsing abGroup config!', e.message);
    }

    window.abselector = {
        'getConfig': getConfig,
        'getGroup': getGroup,
        'getConfigName': getConfigName,
        'getExpirationDate': getExpirationDate,
    };
}());