(function () {

    
    const metaElementsSelector = ".entry-footer .entry-meta";
    const dataAttr = "data-poemid";

    const dbNameFav = "PtryLndDB_favorites"
    const storeNameFav = "favorites";

    const dbNameAudio = "PtryLndDB_audioRecords";
    const storeNameAudio = "audioStore";
    const indexNameAudio = "poemId";


    function checkRecordExists(storeName, dbName, key, indexName) {
        return new Promise((resolve, reject) => {

            const openRequest = indexedDB.open(dbName);

            openRequest.onupgradeneeded = function (event) {

                db = event.target.result;
                if (storeName === storeNameFav) {
                    if (!db.objectStoreNames.contains("favorites")) {
                        var objectStore = db.createObjectStore("favorites", { keyPath: "poemId" });
                    }
                }
                if (storeName === storeNameAudio) {

                    if (!db.objectStoreNames.contains('audioStore')) {
                        var objectStore = db.createObjectStore('audioStore', { keyPath: 'id', autoIncrement: true });
                        // Создаём индекс для поля 'poemId'
                        objectStore.createIndex('poemId', 'poemId', { unique: false });
                    }
                }
            };

            openRequest.onsuccess = function (event) {
                const db = event.target.result;
                const transaction = db.transaction([storeName], "readonly");
                const store = transaction.objectStore(storeName);

                let request;

                if (indexName) {
                    const index = store.index(indexName);
                    request = index.get(key);
                }
                else {
                    request = store.get(key)
                }

                request.onsuccess = function () {
                    if (request.result === undefined)
                        resolve(false); // не найдена
                    else
                        resolve(true); // запись найдена

                };
                request.onerror = function () {
                    resolve(new Error( "Ошибка при поиске записи: ", event.target.error));
                };
            };

            openRequest.onerror = function (event) {
                reject(new Error("Ошибка при открытии базы данных: ", event.target.error));
            };
        })
    }



    async function processMetaEntries() {

        const metaElements = document.querySelectorAll(metaElementsSelector);

        for (const element of metaElements) {
            const poemId = element.getAttribute(dataAttr);
            const ulElement = element.querySelector('ul');

            if (poemId != null && ulElement != null) {

                // .. esrt Favorite
                try {
                    const existsFav = await checkRecordExists(storeNameFav, dbNameFav, poemId, null);
                    if (existsFav) {
                        // создаем элемент
                        const liElement = document.createElement('li');
                        liElement.innerHTML = '<a><i class="bi bi-heart-fill"></i><span class="d-none d-sm-inline">Избранное</span></a>';
                        // add to parent element
                        ulElement.appendChild(liElement);
                    }
                }
                catch (error) {
                    console.error("Ошибка в " + storeNameFav, error);
                }

                // dann Audio ..
                try {
                    const existsAudio = await checkRecordExists(storeNameAudio, dbNameAudio, poemId, indexNameAudio);
                    if (existsAudio) {
                        // создаем элемент
                        const liElement = document.createElement('li');
                        liElement.innerHTML = '<a><i class="bi bi-soundwave"></i><span class="d-none d-sm-inline">Аудиозапись</span></a>';
                        // add to parent element
                        ulElement.appendChild(liElement);
                    }
                }
                catch (error) {
                    console.error("Ошибка в " + storeNameAudio, error);
                }
            }
        }
    }

    processMetaEntries();

})()