// ==UserScript==
// @name              X Timeline Manager
// @description       Tracks and syncs your last reading position on Twitter/X, with manual and automatic options.
// @description:de    Verfolgt und synchronisiert Ihre letzte Leseposition auf Twitter/X, mit manuellen und automatischen Optionen.
// @description:es    Rastrea y sincroniza tu última posición de lectura en Twitter/X, con opciones manuales y automáticas.
// @description:fr    Suit et synchronise votre dernière position de lecture sur Twitter/X, avec des options manuelles et automatiques.
// @description:zh-CN 跟踪并同步您在 Twitter/X 上的最后阅读位置，提供手动和自动选项。
// @description:ru    Отслеживает и синхронизирует вашу последнюю позицию чтения на Twitter/X с ручными и автоматическими опциями.
// @description:ja    Twitter/X での最後の読み取り位置を追跡して同期します。手動および自動オプションを提供します。
// @description:pt-BR Rastrea e sincroniza sua última posição de leitura no Twitter/X, com opções manuais e automáticas.
// @description:hi    Twitter/X पर आपकी अंतिम पठन स्थिति को ट्रैक और सिंक करता है, मैनुअल और स्वचालित विकल्पों के साथ।
// @description:ar    يتتبع ويزامن آخر موضع قراءة لك على Twitter/X، مع خيارات يدوية وتلقائية.
// @description:it    Traccia e sincronizza la tua ultima posizione di lettura su Twitter/X, con opzioni manuali e automatiche.
// @description:ko    Twitter/X에서 마지막 읽기 위치를 추적하고 동기화합니다. 수동 및 자동 옵션 포함.
// @icon              https://x.com/favicon.ico
// @namespace         http://tampermonkey.net/
// @version           2024.12.3
// @author            Copiis
// @license           MIT
// @match             https://x.com/home
// @grant             GM_setValue
// @grant             GM_getValue
// @downloadURL none
// ==/UserScript==

/*
If you find this script useful and would like to support my work, consider making a small donation! 
Your generosity helps me maintain and improve projects like this one. 😊

Bitcoin (BTC): bc1quc5mkudlwwkktzhvzw5u2nruxyepef957p68r7
PayPal: https://www.paypal.com/paypalme/Coopiis?country.x=DE&locale.x=de_DE

Thank you for your support! ❤️
*/

(function () {
    let lastReadPost = null; // Letzte Leseposition
    let isAutoScrolling = false;
    let isSearching = false;

    window.onload = async () => {
        console.log("🚀 Seite vollständig geladen. Initialisiere Skript...");
        await initializeScript();
        createButtons();
    };

    async function initializeScript() {
        console.log("🔧 Lade Leseposition...");
        await loadLastReadPostFromFile();

        observeForNewPosts(); // Beobachtung für neue Beiträge aktivieren
        window.addEventListener("scroll", () => {
            if (!isAutoScrolling && !isSearching) {
                markCentralVisiblePost(true);
            }
        });
    }

    async function loadLastReadPostFromFile() {
        try {
            const data = GM_getValue("lastReadPost", null);
            if (data) {
                lastReadPost = JSON.parse(data);
                console.log("✅ Leseposition erfolgreich geladen:", lastReadPost);
            } else {
                console.warn("⚠️ Keine gespeicherte Leseposition gefunden.");
                lastReadPost = null;
            }
        } catch (err) {
            console.error("⚠️ Fehler beim Laden der Leseposition:", err);
            lastReadPost = null;
        }
    }

    async function saveLastReadPostToFile() {
        try {
            if (!lastReadPost || !lastReadPost.timestamp || !lastReadPost.authorHandler) {
                console.warn("⚠️ Keine gültige Leseposition vorhanden. Speichern übersprungen.");
                return;
            }

            GM_setValue("lastReadPost", JSON.stringify(lastReadPost));
            console.log("💾 Leseposition erfolgreich gespeichert:", lastReadPost);
        } catch (err) {
            console.error("❌ Fehler beim Speichern der Leseposition:", err);
        }
    }

    async function exportLastReadPost() {
    if (!lastReadPost || !lastReadPost.timestamp || !lastReadPost.authorHandler) {
        console.warn("⚠️ Keine gültige Leseposition zum Exportieren.");
        showPopup("⚠️ Keine gültige Leseposition verfügbar.");
        return;
    }

    try {
        const data = JSON.stringify(lastReadPost, null, 2);
        const sanitizedHandler = lastReadPost.authorHandler.replace(/[^a-zA-Z0-9-_]/g, ""); // Sonderzeichen entfernen
        const timestamp = new Date(lastReadPost.timestamp).toISOString().replace(/[:.-]/g, "_");
        const fileName = `${sanitizedHandler}_${timestamp}.json`;

        const blob = new Blob([data], { type: "application/json" });

        const a = document.createElement("a");
        a.href = URL.createObjectURL(blob);
        a.download = fileName;
        a.style.display = "none";
        document.body.appendChild(a);
        a.click();
        document.body.removeChild(a);

        showPopup(`✅ Datei "${fileName}" wurde erfolgreich generiert und heruntergeladen.`);
    } catch (error) {
        console.error("❌ Fehler beim Exportieren der Leseposition:", error);
        showPopup("❌ Fehler: Leseposition konnte nicht exportiert werden.");
    }
}

    function createButtons() {
        const buttonContainer = document.createElement("div");
        buttonContainer.style.position = "fixed";
        buttonContainer.style.top = "10px";
        buttonContainer.style.left = "10px";
        buttonContainer.style.display = "flex";
        buttonContainer.style.gap = "10px";
        buttonContainer.style.zIndex = "10000";

        const saveButton = createButton("💾", "Leseposition exportieren", exportLastReadPost);
        const importButton = createButton("📂", "Gespeicherte Leseposition importieren", importLastReadPost);
        const searchButton = createButton("🔍", "Suche manuell starten", startSearchForLastReadPost);

        buttonContainer.appendChild(saveButton);
        buttonContainer.appendChild(importButton);
        buttonContainer.appendChild(searchButton);

        document.body.appendChild(buttonContainer);
    }

    function createButton(icon, title, onClick) {
        const button = document.createElement("div");
        button.style.width = "30px";
        button.style.height = "30px";
        button.style.backgroundColor = "rgba(0, 0, 0, 0.9)";
        button.style.color = "#ffffff";
        button.style.borderRadius = "50%";
        button.style.display = "flex";
        button.style.justifyContent = "center";
        button.style.alignItems = "center";
        button.style.cursor = "pointer";
        button.style.fontSize = "16px";
        button.style.boxShadow = "0 0 8px rgba(255, 255, 255, 0.8)";
        button.textContent = icon;
        button.title = title;

        button.addEventListener("click", onClick);
        return button;
    }

    async function importLastReadPost() {
        const input = document.createElement("input");
        input.type = "file";
        input.accept = "application/json";
        input.style.display = "none";

        input.addEventListener("change", async (event) => {
            const file = event.target.files[0];
            if (file) {
                const reader = new FileReader();
                reader.onload = async () => {
                    try {
                        const importedData = JSON.parse(reader.result);
                        if (importedData.timestamp && importedData.authorHandler) {
                            lastReadPost = importedData;
                            await saveLastReadPostToFile();
                            showPopup("✅ Leseposition erfolgreich importiert.");
                            console.log("✅ Importierte Leseposition:", lastReadPost);
                            await startSearchForLastReadPost();
                        } else {
                            throw new Error("Ungültige Leseposition");
                        }
                    } catch (error) {
                        console.error("❌ Fehler beim Importieren der Leseposition:", error);
                        showPopup("❌ Fehler: Ungültige Leseposition.");
                    }
                };
                reader.readAsText(file);
            }
        });

        document.body.appendChild(input);
        input.click();
        document.body.removeChild(input);
    }

    function observeForNewPosts() {
        const observer = new MutationObserver(() => {
            const newPostsIndicator = getNewPostsIndicator();

            if (newPostsIndicator) {
                console.log("🆕 Neue Beiträge erkannt. Automatische Suche wird gestartet...");
                clickNewPostsIndicator(newPostsIndicator);
            }
        });

        observer.observe(document.body, { childList: true, subtree: true });
    }

    function getNewPostsIndicator() {
        return document.querySelector('div[aria-label*="ungelesene Elemente"]');
    }

    function clickNewPostsIndicator(indicator) {
        if (!indicator) {
            console.warn("⚠️ Kein Indikator für neue Beiträge gefunden.");
            return;
        }

        indicator.scrollIntoView({ behavior: "smooth", block: "center" });
        setTimeout(() => {
            indicator.click();
            console.log("✅ Indikator für neue Beiträge geklickt.");
            startSearchForLastReadPost();
        }, 500);
    }

    function startSearchForLastReadPost() {
        if (!lastReadPost || !lastReadPost.timestamp || !lastReadPost.authorHandler) {
            console.log("❌ Keine gültige Leseposition verfügbar. Suche übersprungen.");
            return;
        }

        isSearching = true;
        isAutoScrolling = true;

        const popup = document.createElement("div");
        popup.id = "search-popup";
        popup.style.position = "fixed";
        popup.style.bottom = "20px";
        popup.style.left = "50%";
        popup.style.transform = "translateX(-50%)";
        popup.style.backgroundColor = "rgba(0, 0, 0, 0.9)";
        popup.style.color = "#ffffff";
        popup.style.padding = "10px 20px";
        popup.style.borderRadius = "8px";
        popup.style.fontSize = "14px";
        popup.style.boxShadow = "0 0 10px rgba(255, 255, 255, 0.8)";
        popup.style.zIndex = "10000";
        popup.textContent = "🔍 Suche läuft... Drücke SPACE, um abzubrechen.";
        document.body.appendChild(popup);

        console.log("🔍 Suche gestartet.");

        function handleSpaceKey(event) {
            if (event.code === "Space") {
                console.log("⏹️ Suche manuell abgebrochen.");
                isSearching = false;
                isAutoScrolling = false;
                clearInterval(searchInterval);
                popup.remove();
                window.removeEventListener("keydown", handleSpaceKey);
            }
        }

        window.addEventListener("keydown", handleSpaceKey);

        const searchInterval = setInterval(() => {
            const matchedPost = findPostByData(lastReadPost);
            if (matchedPost) {
                clearInterval(searchInterval);
                isSearching = false;
                isAutoScrolling = false;
                scrollToPost(matchedPost);
                console.log(`🎯 Zuletzt gelesenen Beitrag gefunden: ${lastReadPost.timestamp}, @${lastReadPost.authorHandler}`);
                popup.remove();
                window.removeEventListener("keydown", handleSpaceKey);
            } else {
                console.log("🔄 Beitrag nicht direkt gefunden. Suche weiter unten.");
                window.scrollBy({ top: 500, behavior: "smooth" });
            }
        }, 1000);
    }

    function findPostByData(data) {
        const posts = Array.from(document.querySelectorAll("article"));
        return posts.find(post => {
            const postTimestamp = getPostTimestamp(post);
            const authorHandler = getPostAuthorHandler(post);
            return postTimestamp === data.timestamp && authorHandler === data.authorHandler;
        });
    }

    function markCentralVisiblePost(save = true) {
        const centralPost = getCentralVisiblePost();
        if (!centralPost) {
            console.log("❌ Kein zentral sichtbarer Beitrag gefunden.");
            return;
        }

        const postTimestamp = getPostTimestamp(centralPost);
        const authorHandler = getPostAuthorHandler(centralPost);

        if (!postTimestamp || !authorHandler) {
            console.log("❌ Zentral sichtbarer Beitrag hat keine gültigen Daten.");
            return;
        }

        if (!lastReadPost || new Date(postTimestamp) > new Date(lastReadPost.timestamp)) {
            lastReadPost = { timestamp: postTimestamp, authorHandler };
            console.log(`💾 Neuste Leseposition aktualisiert: ${postTimestamp}, @${authorHandler}`);
            if (save) saveLastReadPostToFile();
        }
    }

    function getCentralVisiblePost() {
        const posts = Array.from(document.querySelectorAll("article"));
        const centerY = window.innerHeight / 2;

        return posts.reduce((closestPost, currentPost) => {
            const rect = currentPost.getBoundingClientRect();
            const distanceToCenter = Math.abs(centerY - (rect.top + rect.bottom) / 2);

            if (!closestPost) return currentPost;

            const closestRect = closestPost.getBoundingClientRect();
            const closestDistance = Math.abs(centerY - (closestRect.top + closestRect.bottom) / 2);

            return distanceToCenter < closestDistance ? currentPost : closestPost;
        }, null);
    }

    function getPostTimestamp(post) {
        const timeElement = post.querySelector("time");
        return timeElement ? timeElement.getAttribute("datetime") : null;
    }

    function getPostAuthorHandler(post) {
        const handlerElement = post.querySelector('[role="link"][href*="/"]');
        if (handlerElement) {
            const handler = handlerElement.getAttribute("href");
            return handler && handler.startsWith("/") ? handler.slice(1) : null;
        }
        return null;
    }

    function scrollToPost(post) {
        if (!post) {
            console.log("❌ Kein Beitrag zum Scrollen gefunden.");
            return;
        }

        isAutoScrolling = true;
        post.scrollIntoView({ behavior: "smooth", block: "center" });
        setTimeout(() => {
            isAutoScrolling = false;
            console.log("✅ Beitrag wurde erfolgreich zentriert!");
        }, 1000);
    }

    function showPopup(message) {
        const popup = document.createElement("div");
        popup.style.position = "fixed";
        popup.style.bottom = "20px";
        popup.style.right = "20px";
        popup.style.backgroundColor = "rgba(0, 0, 0, 0.9)";
        popup.style.color = "#ffffff";
        popup.style.padding = "10px 20px";
        popup.style.borderRadius = "8px";
        popup.style.fontSize = "14px";
        popup.style.boxShadow = "0 0 10px rgba(255, 255, 255, 0.8)";
        popup.style.zIndex = "10000";
        popup.textContent = message;

        document.body.appendChild(popup);

        setTimeout(() => {
            popup.remove();
        }, 3000);
    }
})();