/*!
 * SAPUI5
 * Copyright (c) 2025 SAP SE or an SAP affiliate company. All rights reserved.
 */
import { SearchResultSetItem } from "../../sina/SearchResultSetItem";

export interface IFederationMethod {
    sort: (resultSetItemList: Array<SearchResultSetItem>) => Array<SearchResultSetItem>;
}

export class Ranking implements IFederationMethod {
    //sorting method according ranking
    sort(resultSetItemList) {
        let results = [];
        for (let j = 0; j < resultSetItemList.length; j++) {
            results = results.concat(resultSetItemList[j]);
        }
        results.sort(function (a, b) {
            const ret = b.score - a.score; //high score is first
            return ret;
        });
        return results;
    }
}

export class RoundRobin implements IFederationMethod {
    //simple round robin method
    sort(resultSetItemList) {
        let sortedResults = [];
        for (let i = 0; i < resultSetItemList.length; i++) {
            sortedResults = this.mergeMultiResults(sortedResults, resultSetItemList[i], i + 1);
        }
        return sortedResults;
    }

    mergeMultiResults(firstResults, secondResults, mergeIndex) {
        if (mergeIndex < 1) {
            return [];
        }
        if (mergeIndex === 1) {
            return secondResults;
        }
        const firstLength = firstResults.length;
        const secondLength = secondResults.length;
        let results = [];
        for (let k = 0; k < firstLength; k++) {
            results.push(firstResults[k]);
        }
        for (let i = 0; i < firstLength; i++) {
            if (i >= secondLength) {
                break;
            }
            results.splice(mergeIndex * (i + 1) - 1, 0, secondResults[i]);
        }
        if (secondLength > firstLength) {
            results = results.concat(secondResults.slice(firstLength - secondLength));
        }
        return results;
    }
}

export class AdvancedRoundRobin implements IFederationMethod {
    //advanced round robin method
    sort(resultSetItemList) {
        let results = [];
        for (let j = 0; j < resultSetItemList.length; j++) {
            results = results.concat(resultSetItemList[j]);
        }

        let dataSourceId;

        //result list map, key: dataSourceId, value: array list of resultlist
        const dataSourceIdMap = {};
        for (let i = 0; i < results.length; i++) {
            dataSourceId = results[i].dataSource.id;
            if (!dataSourceIdMap[dataSourceId]) {
                dataSourceIdMap[dataSourceId] = [];
            }
            dataSourceIdMap[dataSourceId].push(results[i]);
        }

        //array of objects: dataSouceId, high score, original index
        const dataSourceScoreArray = [];
        let index = 0;
        for (const key in dataSourceIdMap) {
            const item = dataSourceIdMap[key][0];
            dataSourceId = item.dataSource.id;
            const score = item.score;
            dataSourceScoreArray.push({
                dataSourceId: dataSourceId,
                score: score,
                index: index,
            });
            index++;
        }

        //sort dataSourceScoreArray
        dataSourceScoreArray.sort(function (a, b) {
            let ret = b.score - a.score; //high score is first
            if (ret === 0) {
                ret = a.index - b.index; //low index is first
            }
            return ret;
        });

        //rebuild the results
        const sortedResults = [];
        let dsIndex = 0;
        for (let r = 0; r < results.length; ) {
            const selectDs = dataSourceScoreArray[dsIndex];
            const selectRs = dataSourceIdMap[selectDs.dataSourceId];
            if (selectRs.length > 0) {
                sortedResults.push(selectRs.shift());
                r++;
            }
            dsIndex = (dsIndex + 1) % dataSourceScoreArray.length;
        }

        return sortedResults;
    }
}