// ==UserScript==
// @name         YouTube History Backspace Remover
// @namespace    http://tampermonkey.net/
// @version      2.0
// @description  Hover over a video in YouTube watch history and press Backspace to remove it
// @author       You
// @match        https://www.youtube.com/feed/history
// @match        https://www.youtube.com/feed/history/*
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    // videoId → feedbackToken, populated from ytInitialData
    let tokenMap = {};
    let hoveredLink = null;
    let isProcessing = false;

    // --- Token extraction from ytInitialData ---

    function extractTokens(data) {
        const tokens = {};
        (function walk(obj) {
            if (!obj || typeof obj !== 'object') return;
            if (Array.isArray(obj)) { obj.forEach(walk); return; }
            if (obj.listItemViewModel) {
                const lv = obj.listItemViewModel;
                const title = lv.title?.content || '';
                if (title.toLowerCase().includes('remove from watch history')) {
                    const ep = lv.rendererContext?.commandContext?.onTap?.innertubeCommand?.feedbackEndpoint;
                    if (ep?.feedbackToken && ep?.contentId) {
                        tokens[ep.contentId] = ep.feedbackToken;
                    }
                }
            }
            for (const v of Object.values(obj)) walk(v);
        })(data);
        return tokens;
    }

    function refreshTokens() {
        if (!window.ytInitialData) return;
        const found = extractTokens(window.ytInitialData);
        const n = Object.keys(found).length;
        if (n > 0) {
            tokenMap = Object.assign(tokenMap, found);
            console.log(`[YT History Remover] ${n} tokens loaded (total: ${Object.keys(tokenMap).length})`);
        }
    }

    // --- SAPISIDHASH for Authorization header ---

    async function buildAuthHeader() {
        const sapisid = document.cookie.match(/(?:^|;\s*)SAPISID=([^;]+)/)?.[1];
        if (!sapisid) return null;
        const ts = Math.floor(Date.now() / 1000);
        const buf = await crypto.subtle.digest('SHA-1', new TextEncoder().encode(`${ts} ${sapisid} https://www.youtube.com`));
        const hex = [...new Uint8Array(buf)].map(b => b.toString(16).padStart(2, '0')).join('');
        return `SAPISIDHASH ${ts}_${hex}`;
    }

    // --- API call to remove from history ---

    async function callFeedbackApi(feedbackToken) {
        const ctx = window.ytcfg?.data_?.INNERTUBE_CONTEXT;
        if (!ctx) { console.log('[YT History Remover] No INNERTUBE_CONTEXT'); return false; }

        const auth = await buildAuthHeader();
        const headers = {
            'Content-Type': 'application/json',
            'X-YouTube-Client-Name': '1',
            'X-YouTube-Client-Version': window.ytcfg?.data_?.INNERTUBE_CLIENT_VERSION || '',
            'X-Origin': 'https://www.youtube.com',
        };
        if (auth) headers['Authorization'] = auth;

        const res = await fetch('/youtubei/v1/feedback?prettyPrint=false', {
            method: 'POST',
            headers,
            credentials: 'include',
            body: JSON.stringify({ context: ctx, feedbackTokens: [feedbackToken] }),
        });
        if (!res.ok) { console.log(`[YT History Remover] HTTP ${res.status}`); return false; }
        const json = await res.json();
        return json.feedbackResponses?.[0]?.isProcessed === true;
    }

    // --- DOM helpers ---

    function getVideoId(href) {
        try {
            const url = new URL(href);
            if (url.pathname.startsWith('/shorts/')) return url.pathname.split('/')[2] || null;
            return url.searchParams.get('v');
        } catch { return null; }
    }

    function findVideoLink(el) {
        while (el && el !== document.body) {
            if (el.tagName === 'A' && el.href && (el.href.includes('/watch?') || el.href.includes('/shorts/')))
                return el;
            el = el.parentElement;
        }
        return null;
    }

    function hideInDOM(videoId) {
        for (const sel of [`a[href*="v=${videoId}"]`, `a[href*="/shorts/${videoId}"]`]) {
            const link = document.querySelector(sel);
            if (!link) continue;
            const row = link.closest('yt-lockup-view-model')
                || link.closest('ytm-shorts-lockup-view-model')
                || link.closest('ytd-item-section-renderer');
            if (row) { row.style.display = 'none'; return; }
        }
    }

    // --- Main remove action ---

    async function tryRemove() {
        if (isProcessing || !hoveredLink) return;
        isProcessing = true;
        try {
            const videoId = getVideoId(hoveredLink.href);
            if (!videoId) return;
            const token = tokenMap[videoId];
            if (!token) {
                console.log(`[YT History Remover] No token for ${videoId}. Tokens available: ${Object.keys(tokenMap).length}`);
                return;
            }
            const ok = await callFeedbackApi(token);
            if (ok) {
                hideInDOM(videoId);
                delete tokenMap[videoId];
                hoveredLink = null;
                console.log(`[YT History Remover] Removed ${videoId}`);
            } else {
                console.log(`[YT History Remover] API returned not-processed for ${videoId}`);
            }
        } catch (e) {
            console.error('[YT History Remover]', e);
        } finally {
            isProcessing = false;
        }
    }

    // --- Event listeners ---

    document.addEventListener('mouseover', e => {
        if (isProcessing) return;
        const link = findVideoLink(e.target);
        if (link) hoveredLink = link;
    });

    document.addEventListener('keydown', e => {
        if (e.key !== 'Backspace' || !hoveredLink || isProcessing) return;
        const ae = document.activeElement;
        if (ae && (ae.tagName === 'INPUT' || ae.tagName === 'TEXTAREA' || ae.isContentEditable)) return;
        e.preventDefault();
        tryRemove();
    });

    document.addEventListener('mouseout', e => {
        if (isProcessing || !hoveredLink) return;
        const rt = e.relatedTarget;
        if (!rt || !hoveredLink.contains(rt)) hoveredLink = null;
    });

    // Re-extract when YouTube finishes a SPA navigation
    document.addEventListener('yt-navigate-finish', () => setTimeout(refreshTokens, 500));

    // Polling: re-read ytInitialData (updated by YouTube on SPA nav) and clean stale refs
    setInterval(() => {
        refreshTokens();
        if (hoveredLink && !document.contains(hoveredLink)) hoveredLink = null;
    }, 2000);

    // Initial extraction
    refreshTokens();
    console.log(`[YT History Remover] Ready. Tokens loaded: ${Object.keys(tokenMap).length}`);
})();