feat(analytics): add writing analytics with readability scores and vocabulary analysis

Amit Haridas

src/analytics/analytics-panel.js

@@ -0,0 +1,112 @@
+/**
+ * Writing Analytics Panel — modal overlay displaying analytics dashboard
+ */
+
+const { analyze } = require('./writing-analytics');
+
+function showAnalyticsModal(tabManager) {
+    const existing = document.getElementById('analytics-modal');
+    if (existing) existing.remove();
+
+    const content = tabManager.getEditorContent();
+    const metrics = analyze(content);
+
+    const overlay = document.createElement('div');
+    overlay.id = 'analytics-modal';
+    overlay.className = 'analytics-overlay';
+
+    const maxCount = metrics.topWords.length > 0 ? metrics.topWords[0].count : 1;
+
+    overlay.innerHTML = `
+        <div class="analytics-modal">
+            <div class="analytics-header">
+                <h2>Writing Analytics</h2>
+                <button class="analytics-close" title="Close">&times;</button>
+            </div>
+            <div class="analytics-body">
+                <div class="analytics-section">
+                    <h3>Readability</h3>
+                    <div class="analytics-row">
+                        <span class="analytics-label">Flesch Reading Ease</span>
+                        <span class="analytics-value">${metrics.fleschEase}<small>${metrics.readabilityLabel}</small></span>
+                    </div>
+                    <div class="analytics-row">
+                        <span class="analytics-label">Grade Level</span>
+                        <span class="analytics-value">${metrics.fleschGrade}</span>
+                    </div>
+                    <div class="readability-meter">
+                        <div class="readability-fill" style="width: ${Math.max(0, Math.min(100, metrics.fleschEase))}%"></div>
+                    </div>
+                </div>
+
+                <div class="analytics-section">
+                    <h3>Timing</h3>
+                    <div class="analytics-row">
+                        <span class="analytics-label">Reading Time</span>
+                        <span class="analytics-value">~${metrics.readingTime} min</span>
+                    </div>
+                    <div class="analytics-row">
+                        <span class="analytics-label">Speaking Time</span>
+                        <span class="analytics-value">~${metrics.speakingTime} min</span>
+                    </div>
+                </div>
+
+                <div class="analytics-section">
+                    <h3>Structure</h3>
+                    <div class="analytics-row">
+                        <span class="analytics-label">Sentences</span>
+                        <span class="analytics-value">${metrics.sentenceCount} &bull; Paragraphs: ${metrics.paragraphCount}</span>
+                    </div>
+                    <div class="analytics-row">
+                        <span class="analytics-label">Avg Sentence</span>
+                        <span class="analytics-value">${metrics.avgSentenceLength} words</span>
+                    </div>
+                    ${metrics.longestSentenceLength > 0 ? `
+                    <div class="analytics-row analytics-longest">
+                        <span class="analytics-label">Longest (${metrics.longestSentenceLength} words)</span>
+                        <span class="analytics-value analytics-sentence-preview">${escapeHtml(metrics.longestSentence)}</span>
+                    </div>` : ''}
+                </div>
+
+                <div class="analytics-section">
+                    <h3>Vocabulary</h3>
+                    <div class="analytics-row">
+                        <span class="analytics-label">Unique</span>
+                        <span class="analytics-value">${metrics.uniqueWordCount} / ${metrics.wordCount}<small>${metrics.lexicalDiversity}%</small></span>
+                    </div>
+                    ${metrics.topWords.length > 0 ? `
+                    <div class="word-cloud">
+                        ${metrics.topWords.map(w => {
+                            const scale = 13 + Math.round((w.count / maxCount) * 3);
+                            return `<span class="word-tag" style="font-size:${scale}px">${escapeHtml(w.word)}<small>${w.count}</small></span>`;
+                        }).join('')}
+                    </div>` : ''}
+                </div>
+            </div>
+        </div>
+    `;
+
+    const closeBtn = overlay.querySelector('.analytics-close');
+    closeBtn.addEventListener('click', () => overlay.remove());
+    overlay.addEventListener('click', (e) => {
+        if (e.target === overlay) overlay.remove();
+    });
+
+    const escHandler = (e) => {
+        if (e.key === 'Escape') {
+            overlay.remove();
+            document.removeEventListener('keydown', escHandler);
+        }
+    };
+    document.addEventListener('keydown', escHandler);
+
+    document.body.appendChild(overlay);
+}
+
+function escapeHtml(str) {
+    const div = document.createElement('div');
+    div.textContent = str;
+    return div.innerHTML;
+}
+
+module.exports = { showAnalyticsModal };

src/analytics/writing-analytics.js

@@ -0,0 +1,127 @@
+/**
+ * Writing Analytics — pure computation engine
+ * No DOM dependencies. Exported analyze(text) returns a metrics object.
+ */
+
+const STOP_WORDS = new Set([
+    'the', 'a', 'an', 'is', 'are', 'was', 'were', 'be', 'been',
+    'have', 'has', 'had', 'do', 'does', 'did', 'will', 'would',
+    'could', 'should', 'to', 'of', 'in', 'for', 'on', 'with',
+    'at', 'by', 'from', 'as', 'and', 'or', 'but', 'if', 'it',
+    'its', 'this', 'that', 'these', 'those', 'i', 'me', 'my',
+    'we', 'our', 'you', 'your', 'he', 'him', 'his', 'she', 'her',
+    'they', 'them', 'their', 'not', 'no', 'so', 'than', 'too',
+    'very', 'also', 'just', 'about', 'up', 'out', 'what', 'which', 'who'
+]);
+
+function countSyllables(word) {
+    word = word.toLowerCase().replace(/(?:[^laeiouy]es|ed|[^laeiouy]e)$/, '');
+    word = word.replace(/^y/, '');
+    return word.match(/[aeiouy]{1,2}/gi)?.length || 1;
+}
+
+function extractWords(text) {
+    return text.match(/[a-zA-Z]+(?:['-][a-zA-Z]+)*/g) || [];
+}
+
+function getReadabilityLabel(score) {
+    if (score >= 90) return 'Very Easy';
+    if (score >= 70) return 'Easy';
+    if (score >= 50) return 'Standard';
+    if (score >= 30) return 'Difficult';
+    return 'Very Difficult';
+}
+
+function analyze(text) {
+    if (!text || !text.trim()) {
+        return {
+            wordCount: 0,
+            sentenceCount: 0,
+            paragraphCount: 0,
+            fleschEase: 0,
+            fleschGrade: 0,
+            readabilityLabel: 'N/A',
+            readingTime: 0,
+            speakingTime: 0,
+            uniqueWordCount: 0,
+            lexicalDiversity: 0,
+            avgSentenceLength: 0,
+            longestSentence: '',
+            longestSentenceLength: 0,
+            topWords: []
+        };
+    }
+
+    const words = extractWords(text);
+    const wordCount = words.length;
+
+    const sentences = text.split(/[.!?]+/).map(s => s.trim()).filter(Boolean);
+    const sentenceCount = Math.max(sentences.length, 1);
+
+    const paragraphs = text.split(/\n\s*\n/).map(p => p.trim()).filter(Boolean);
+    const paragraphCount = Math.max(paragraphs.length, 1);
+
+    let totalSyllables = 0;
+    for (const w of words) {
+        totalSyllables += countSyllables(w);
+    }
+
+    const fleschEase = Math.round((206.835 - 1.015 * (wordCount / sentenceCount) - 84.6 * (totalSyllables / wordCount)) * 10) / 10;
+    const fleschGrade = Math.round((0.39 * (wordCount / sentenceCount) + 11.8 * (totalSyllables / wordCount) - 15.59) * 10) / 10;
+    const readabilityLabel = getReadabilityLabel(fleschEase);
+
+    const readingTime = Math.ceil(wordCount / 200);
+    const speakingTime = Math.ceil(wordCount / 130);
+
+    const uniqueWords = new Set(words.map(w => w.toLowerCase()));
+    const uniqueWordCount = uniqueWords.size;
+    const lexicalDiversity = wordCount > 0 ? Math.round((uniqueWordCount / wordCount) * 1000) / 10 : 0;
+
+    const avgSentenceLength = Math.round((wordCount / sentenceCount) * 10) / 10;
+
+    let longestSentence = '';
+    let longestSentenceLength = 0;
+    for (const s of sentences) {
+        const sWords = extractWords(s);
+        if (sWords.length > longestSentenceLength) {
+            longestSentenceLength = sWords.length;
+            longestSentence = s.trim();
+        }
+    }
+
+    if (longestSentence.length > 80) {
+        longestSentence = longestSentence.substring(0, 80) + '...';
+    }
+
+    const wordFreq = {};
+    for (const w of words) {
+        const lower = w.toLowerCase();
+        if (!STOP_WORDS.has(lower) && lower.length > 1) {
+            wordFreq[lower] = (wordFreq[lower] || 0) + 1;
+        }
+    }
+
+    const topWords = Object.entries(wordFreq)
+        .sort((a, b) => b[1] - a[1])
+        .slice(0, 10)
+        .map(([word, count]) => ({ word, count }));
+
+    return {
+        wordCount,
+        sentenceCount,
+        paragraphCount,
+        fleschEase,
+        fleschGrade,
+        readabilityLabel,
+        readingTime,
+        speakingTime,
+        uniqueWordCount,
+        lexicalDiversity,
+        avgSentenceLength,
+        longestSentence,
+        longestSentenceLength,
+        topWords
+    };
+}
+
+module.exports = { analyze };

src/renderer.js

@@ -28,6 +28,8 @@ function getPrintPreview() { if (!_PrintPreview) _PrintPreview = require('./prin
 function getCreateWelcomeContent() { if (!_createWelcomeContent) _createWelcomeContent = require('./welcome').createWelcomeContent; return _createWelcomeContent; }
 let _ZenMode;
 function getZenMode() { if (!_ZenMode) _ZenMode = require('./zen-mode').ZenMode; return _ZenMode; }
+let _showAnalyticsModal;
+function getShowAnalyticsModal() { if (!_showAnalyticsModal) _showAnalyticsModal = require('./analytics/analytics-panel').showAnalyticsModal; return _showAnalyticsModal; }
 
 // Configure marked with highlight extension
 marked.use(markedHighlight({
@@ -1663,6 +1665,7 @@ document.addEventListener('DOMContentLoaded', () => {
     commandPalette.register('Insert Link', '', () => tabManager.wrapSelection('[', '](url)'));
     commandPalette.register('Insert Image', '', () => tabManager.wrapSelection('![', '](image.jpg)'));
     commandPalette.register('Toggle Zen Mode', 'F11', () => zenMode.toggle());
+    commandPalette.register('Writing Analytics', 'Ctrl+Shift+A', () => getShowAnalyticsModal()(tabManager));
 
     // Keyboard shortcuts
     document.addEventListener('keydown', (e) => {
@@ -1676,6 +1679,11 @@ document.addEventListener('DOMContentLoaded', () => {
             e.preventDefault();
             zenMode.toggle();
         }
+        // Ctrl+Shift+A — Writing Analytics
+        if (e.ctrlKey && e.shiftKey && e.key === 'A') {
+            e.preventDefault();
+            getShowAnalyticsModal()(tabManager);
+        }
         // Escape — Exit Zen Mode
         if (e.key === 'Escape' && zenMode.active) {
             zenMode.deactivate();

src/styles-modern.css

@@ -2346,3 +2346,29 @@ body[class*="dark"] .breadcrumb-bar {
     font-size: 14px;
     cursor: pointer;
 }
+
+/* Writing Analytics Modal */
+.analytics-overlay { position:fixed; inset:0; background:rgba(0,0,0,0.5); backdrop-filter:blur(4px); display:flex; align-items:center; justify-content:center; z-index:10000; animation:analyticsFadeIn 0.2s ease; }
+.analytics-modal { background:var(--bg-primary,#fff); border-radius:12px; width:520px; max-height:80vh; overflow-y:auto; box-shadow:0 20px 60px rgba(0,0,0,0.3); animation:analyticsSlideUp 0.3s ease; }
+.analytics-header { display:flex; justify-content:space-between; align-items:center; padding:20px 24px; border-bottom:1px solid var(--border-color,#e5e7eb); }
+.analytics-header h2 { margin:0; font-size:18px; font-weight:600; color:var(--text-primary); }
+.analytics-close { background:none; border:none; font-size:24px; cursor:pointer; color:var(--text-muted); padding:4px 8px; border-radius:4px; }
+.analytics-close:hover { background:var(--bg-tertiary); color:var(--text-primary); }
+.analytics-body { padding:16px 24px 24px; }
+.analytics-section { margin-bottom:20px; }
+.analytics-section h3 { font-size:12px; font-weight:600; text-transform:uppercase; letter-spacing:0.05em; color:var(--text-muted,#9ca3af); margin:0 0 10px; }
+.analytics-row { display:flex; justify-content:space-between; align-items:baseline; padding:6px 0; font-size:14px; }
+.analytics-label { color:var(--text-secondary,#6b7280); }
+.analytics-value { font-weight:500; color:var(--text-primary); }
+.analytics-value small { color:var(--text-muted); font-weight:400; margin-left:6px; }
+.readability-meter { height:4px; background:var(--bg-tertiary,#f3f4f6); border-radius:2px; margin-top:8px; overflow:hidden; }
+.readability-fill { height:100%; background:linear-gradient(90deg,#ef4444,#f59e0b,#10b981); border-radius:2px; transition:width 0.5s ease; }
+.word-cloud { display:flex; flex-wrap:wrap; gap:8px; margin-top:8px; }
+.word-tag { background:var(--bg-tertiary,#f3f4f6); padding:4px 10px; border-radius:12px; font-size:13px; color:var(--text-secondary); }
+.word-tag small { opacity:0.5; font-size:10px; margin-left:2px; }
+.analytics-longest { flex-direction:column; gap:4px; }
+.analytics-sentence-preview { font-style:italic; font-size:13px; color:var(--text-secondary); font-weight:400; }
+@keyframes analyticsFadeIn { from{opacity:0} to{opacity:1} }
+@keyframes analyticsSlideUp { from{transform:translateY(16px);opacity:0} to{transform:translateY(0);opacity:1} }
+body[class*="dark"] .analytics-modal { background:var(--gray-800,#1f2937); }
+body[class*="dark"] .word-tag { background:var(--gray-700,#374151); }