// ==UserScript==
// @name         TL;DR Summarizer (Facebook & Articles)
// @namespace    https://github.com/tldr-summarizer
// @version      1.1.0
// @description  Adds TL;DR buttons to Facebook posts and web articles. Summarizes using DeepSeek via Replicate API.
// @author       User
// @match        https://www.facebook.com/*
// @match        https://*/*
// @exclude      https://api.replicate.com/*
// @grant        GM_xmlhttpRequest
// @grant        GM_addStyle
// @grant        GM_getValue
// @grant        GM_setValue
// @grant        GM_registerMenuCommand
// @connect      api.replicate.com
// @run-at       document-idle
// ==/UserScript==

(function () {
    'use strict';

    // ── Config ────────────────────────────────────────────────────────────────
    const API_KEY_STORAGE = 'tldr_replicate_api_key';
    const DEEPSEEK_MODEL  = 'deepseek-ai/deepseek-r1';

    let apiKey = GM_getValue(API_KEY_STORAGE, '');

    GM_registerMenuCommand('⚙️ Set Replicate API Key', () => {
        const key = prompt('Enter your Replicate API key (get one at replicate.com):', apiKey);
        if (key !== null) {
            GM_setValue(API_KEY_STORAGE, key.trim());
            apiKey = key.trim();
            alert('✅ API key saved!');
        }
    });

    // ── Styles ────────────────────────────────────────────────────────────────
    GM_addStyle(`
        .tldr-btn {
            display: inline-flex;
            align-items: center;
            gap: 5px;
            padding: 5px 12px;
            margin: 4px 6px;
            background: #1877f2;
            color: #fff !important;
            border: none;
            border-radius: 6px;
            font-size: 12px;
            font-weight: 600;
            cursor: pointer;
            transition: background 0.15s, opacity 0.15s;
            font-family: inherit;
            line-height: 1.4;
            text-decoration: none;
            vertical-align: middle;
        }
        .tldr-btn:hover { background: #1464d0; }
        .tldr-btn:disabled { background: #999; cursor: not-allowed; opacity: 0.7; }
        .tldr-btn.article-btn {
            position: fixed;
            bottom: 28px;
            right: 28px;
            padding: 10px 20px;
            font-size: 13px;
            border-radius: 999px;
            box-shadow: 0 4px 18px rgba(0,0,0,0.28);
            z-index: 2147483646;
        }
        .tldr-modal-overlay {
            position: fixed;
            inset: 0;
            background: rgba(0, 0, 0, 0.55);
            z-index: 2147483647;
            display: flex;
            align-items: center;
            justify-content: center;
            animation: tldr-fade-in 0.15s ease;
        }
        @keyframes tldr-fade-in { from { opacity: 0; } to { opacity: 1; } }
        .tldr-modal {
            background: #fff;
            border-radius: 14px;
            padding: 26px 30px 22px;
            max-width: 580px;
            width: 92vw;
            max-height: 72vh;
            overflow-y: auto;
            box-shadow: 0 12px 50px rgba(0,0,0,0.35);
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            position: relative;
            animation: tldr-slide-in 0.15s ease;
        }
        @keyframes tldr-slide-in { from { transform: translateY(12px); opacity: 0; } to { transform: none; opacity: 1; } }
        .tldr-modal-header {
            display: flex;
            align-items: flex-start;
            justify-content: space-between;
            gap: 12px;
            margin-bottom: 14px;
        }
        .tldr-modal-title {
            margin: 0;
            font-size: 15px;
            font-weight: 700;
            color: #1877f2;
            line-height: 1.3;
        }
        .tldr-modal-close {
            flex-shrink: 0;
            background: #f0f2f5;
            border: none;
            border-radius: 50%;
            width: 28px;
            height: 28px;
            font-size: 16px;
            cursor: pointer;
            color: #444;
            display: flex;
            align-items: center;
            justify-content: center;
            line-height: 1;
            transition: background 0.15s;
            margin-top: -2px;
        }
        .tldr-modal-close:hover { background: #dde1e7; }
        .tldr-modal-body {
            margin: 0;
            font-size: 14px;
            line-height: 1.65;
            color: #1c1e21;
            white-space: pre-wrap;
            word-break: break-word;
        }
        .tldr-modal-body ul { padding-left: 20px; margin: 6px 0; }
        .tldr-modal-body li { margin-bottom: 4px; }
        .tldr-spinner {
            display: inline-block;
            width: 13px;
            height: 13px;
            border: 2px solid rgba(255,255,255,0.35);
            border-top-color: #fff;
            border-radius: 50%;
            animation: tldr-spin 0.65s linear infinite;
        }
        @keyframes tldr-spin { to { transform: rotate(360deg); } }
    `);

    // ── UI helpers ────────────────────────────────────────────────────────────
    function showModal(titleText, bodyText) {
        const overlay = document.createElement('div');
        overlay.className = 'tldr-modal-overlay';

        // Render bullet points nicely if body uses "- " or "• " lines
        let formattedBody = bodyText;

        overlay.innerHTML = `
            <div class="tldr-modal">
                <div class="tldr-modal-header">
                    <h3 class="tldr-modal-title">📋 TL;DR — ${titleText}</h3>
                    <button class="tldr-modal-close" title="Close">✕</button>
                </div>
                <div class="tldr-modal-body">${escapeHtml(formattedBody)}</div>
            </div>
        `;

        overlay.querySelector('.tldr-modal-close').onclick = () => overlay.remove();
        overlay.addEventListener('click', (e) => { if (e.target === overlay) overlay.remove(); });
        document.addEventListener('keydown', function esc(e) {
            if (e.key === 'Escape') { overlay.remove(); document.removeEventListener('keydown', esc); }
        });
        document.body.appendChild(overlay);
    }

    function escapeHtml(str) {
        return str
            .replace(/&/g, '&amp;')
            .replace(/</g, '&lt;')
            .replace(/>/g, '&gt;')
            .replace(/"/g, '&quot;');
    }

    // ── API call ──────────────────────────────────────────────────────────────
    function summarize(rawText, btn, label) {
        if (!apiKey) {
            alert('⚠️ No API key set.\nClick the TL;DR Summarizer menu in your userscript manager and choose "Set Replicate API Key".');
            return;
        }

        const origHTML = btn.innerHTML;
        btn.innerHTML = '<span class="tldr-spinner"></span> Summarizing…';
        btn.disabled = true;

        // Trim text to keep API costs low; ~4000 chars ≈ ~1000 tokens
        const text = rawText.trim().slice(0, 4500);

        const prompt = `Summarize the following text in 2-3 sentences in English.

Rules:
- You MUST use the full name of every person mentioned — never say "the subject", "he", "she", or "an unnamed figure" without first stating their name.
- Include what they did, when, and why it matters historically or contextually.
- If the source text is in another language, still write the summary in English.
- Do not use bullet points. Write a single flowing paragraph.
- Start directly with the person's name or the topic — no preamble.

Text:
${text}

Summary:`;

        GM_xmlhttpRequest({
            method: 'POST',
            url: `https://api.replicate.com/v1/models/${DEEPSEEK_MODEL}/predictions`,
            headers: {
                'Authorization': `Bearer ${apiKey}`,
                'Content-Type': 'application/json',
                'Prefer': 'wait'   // Block until prediction completes (up to 60s)
            },
            data: JSON.stringify({
                input: {
                    prompt,
                    max_tokens: 600,
                    temperature: 0.2,
                    top_p: 0.9
                }
            }),
            timeout: 90000,
            onload(resp) {
                btn.innerHTML = origHTML;
                btn.disabled = false;

                let summary = '';
                try {
                    const data = JSON.parse(resp.responseText);

                    if (data.error) {
                        showModal('Error', `Replicate error: ${data.error}`);
                        return;
                    }

                    // Output is typically an array of token strings; join them
                    if (Array.isArray(data.output)) {
                        summary = data.output.join('');
                    } else if (typeof data.output === 'string') {
                        summary = data.output;
                    } else if (data.status && data.status !== 'succeeded') {
                        // Prediction didn't finish in time — fall back to polling
                        pollForResult(data.id, label, btn, origHTML);
                        return;
                    }

                    // Strip DeepSeek R1 <think>…</think> reasoning blocks
                    summary = summary.replace(/<think>[\s\S]*?<\/think>/gi, '').trim();

                    showModal(label, summary || '(No summary returned — the content may be too short or ambiguous.)');
                } catch (e) {
                    showModal('Parse Error', `Could not parse Replicate response.\n\nRaw: ${resp.responseText.slice(0, 300)}`);
                }
            },
            onerror() {
                btn.innerHTML = origHTML;
                btn.disabled = false;
                showModal('Network Error', 'Could not reach api.replicate.com. Check your internet connection and API key.');
            },
            ontimeout() {
                btn.innerHTML = origHTML;
                btn.disabled = false;
                showModal('Timeout', 'The request timed out (>90s). Try again or summarize a shorter snippet.');
            }
        });
    }

    // Fallback polling when Prefer:wait doesn't return a completed prediction
    function pollForResult(predictionId, label, btn, origHTML) {
        const maxPolls = 20;
        let polls = 0;

        function poll() {
            if (polls++ > maxPolls) {
                btn.innerHTML = origHTML;
                btn.disabled = false;
                showModal('Timeout', 'Prediction is taking too long. Try again in a moment.');
                return;
            }
            GM_xmlhttpRequest({
                method: 'GET',
                url: `https://api.replicate.com/v1/predictions/${predictionId}`,
                headers: { 'Authorization': `Bearer ${apiKey}` },
                onload(resp) {
                    const data = JSON.parse(resp.responseText);
                    if (data.status === 'succeeded') {
                        btn.innerHTML = origHTML;
                        btn.disabled = false;
                        let summary = Array.isArray(data.output) ? data.output.join('') : (data.output || '');
                        summary = summary.replace(/<think>[\s\S]*?<\/think>/gi, '').trim();
                        showModal(label, summary || '(Empty response)');
                    } else if (data.status === 'failed' || data.status === 'canceled') {
                        btn.innerHTML = origHTML;
                        btn.disabled = false;
                        showModal('Error', `Prediction ${data.status}: ${data.error || 'unknown reason'}`);
                    } else {
                        setTimeout(poll, 2500); // still processing
                    }
                },
                onerror() {
                    btn.innerHTML = origHTML;
                    btn.disabled = false;
                    showModal('Polling Error', 'Failed while checking prediction status.');
                }
            });
        }
        setTimeout(poll, 2500);
    }

    // ── Button factory ────────────────────────────────────────────────────────
    function makeBtn(label, text, extraClass = '') {
        const btn = document.createElement('button');
        btn.className = `tldr-btn${extraClass ? ' ' + extraClass : ''}`;
        btn.innerHTML = '📋 TL;DR';
        btn.title = 'Summarize with DeepSeek via Replicate';
        btn.addEventListener('click', (e) => {
            e.stopPropagation();
            e.preventDefault();
            summarize(text, btn, label);
        });
        return btn;
    }

    // ── Facebook ──────────────────────────────────────────────────────────────
    const isFacebook = location.hostname.includes('facebook.com');

    function extractFBText(article) {
        // Ordered list of selectors from most specific to most generic
        const selectors = [
            '[data-ad-preview="message"]',
            '[data-testid="post_message"]',
            '[class*="userContent"]',
            'div[dir="auto"]',
            'span[dir="auto"]'
        ];
        for (const sel of selectors) {
            const nodes = article.querySelectorAll(sel);
            const combined = [...nodes]
                .map(n => n.innerText.trim())
                .filter(t => t.length > 25)
                .join('\n');
            if (combined.length > 30) return combined;
        }
        return article.innerText.trim();
    }

    function injectFBBtn(article) {
        if (article.dataset.tldrDone) return;

        // Skip comments — they are articles nested inside another article
        if (article.parentElement && article.parentElement.closest('[role="article"]')) return;

        article.dataset.tldrDone = '1';

        const text = extractFBText(article);
        if (!text || text.length < 40) return;

        const btn = makeBtn('Facebook Post', text);

        // Try to place the button near the reaction/action bar
        const actionRow = article.querySelector(
            '[aria-label*="React"], [aria-label*="Comment"], [aria-label*="Share"], ' +
            '[data-testid*="UFI"], div[role="toolbar"]'
        );
        if (actionRow) {
            const parent = actionRow.closest('div') || actionRow.parentNode;
            parent.insertAdjacentElement('afterend', btn);
        } else {
            article.appendChild(btn);
        }
    }

    // Debounced scan — runs at most once per 600ms to avoid hammering the DOM
    let scanTimer = null;
    function scanFB() {
        clearTimeout(scanTimer);
        scanTimer = setTimeout(() => {
            document.querySelectorAll('div[role="article"]').forEach(injectFBBtn);
        }, 600);
    }

    // ── General articles / pages ──────────────────────────────────────────────
    function extractPageText() {
        const candidates = [
            'article',
            '[role="article"]',
            'main article',
            '.article-body',
            '.article-content',
            '.post-body',
            '.post-content',
            '.entry-content',
            '.story-body',
            '#article-body',
            '#main-content',
            'main'
        ];
        for (const sel of candidates) {
            const el = document.querySelector(sel);
            if (el && el.innerText.trim().length > 150) {
                return el.innerText.trim();
            }
        }
        return document.body.innerText.trim();
    }

    function injectPageBtn() {
        if (document.querySelector('.tldr-btn.article-btn')) return;
        const text = extractPageText();
        if (!text || text.length < 100) return;

        const label = (document.title || location.hostname).slice(0, 60);
        const btn = makeBtn(label, text, 'article-btn');
        btn.innerHTML = '📋 TL;DR this page';
        document.body.appendChild(btn);
    }

    // ── Bootstrap ─────────────────────────────────────────────────────────────
    if (isFacebook) {
        scanFB();
        // Re-scan when FB dynamically injects new posts
        new MutationObserver(scanFB).observe(document.body, { childList: true, subtree: true });
    } else {
        injectPageBtn();
        // Some SPAs replace content after load
        window.addEventListener('load', injectPageBtn);
    }

})();