async function correctText() {
    const inputText = document.getElementById("inputText").value;
    const outputTextElem = document.getElementById("outputText");
    const btn = document.getElementById("submitBtn");
    const loading = document.getElementById("loading");
    const analysisSection = document.getElementById("analysisSection");
    
    const mode = document.querySelector('input[name="modelType"]:checked').value;

    analysisSection.style.display = "none";
    outputTextElem.value = "";

    if (!inputText.trim()) {
        document.getElementById("inputText").focus();
        return;
    }

    btn.disabled = true;
    loading.style.display = "flex";

    try {
        const response = await fetch('/correct', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({ 
                text: inputText,
                mode: mode 
            })
        });

        const data = await response.json();

        if (data.error) {
            outputTextElem.value = "Lỗi: " + data.error;
        } else {
            outputTextElem.value = data.result;
            
            const alignmentData = data.alignment || [];
            renderAnalysis(alignmentData);

            analysisSection.style.display = "block";
            setTimeout(() => {
                analysisSection.scrollIntoView({ behavior: 'smooth', block: 'start' });
            }, 100);
        }
    } catch (error) {
        outputTextElem.value = "Lỗi kết nối: " + error;
        console.error(error);
    } finally {
        btn.disabled = false;
        loading.style.display = "none";
    }
}

function handleModeChange() {
    document.getElementById("analysisSection").style.display = "none";
    document.getElementById("outputText").value = "";
    document.getElementById("inputText").focus();
}

function renderAnalysis(alignmentData) {
    const highlightContainer = document.getElementById("highlightedText");
    const tableBody = document.getElementById("comparisonTableBody");

    highlightContainer.innerHTML = "";
    tableBody.innerHTML = "";

    let htmlHighlight = "";
    let hasChange = false;

    alignmentData.forEach(item => {
        const original = item.original;
        const corrected = item.corrected;
        const confidence = item.confidence;
        const type = item.type; 

        let scoreText = confidence.toFixed(1) + "%";
        let scoreColor = "#999";

        if (confidence >= 90) scoreColor = "#2e7d32";
        else if (confidence >= 70) scoreColor = "#f57f17";
        else scoreColor = "#c62828";

        if (type === 'equal') {
            htmlHighlight += `<span>${original}</span> `;
        } 
        else if (type === 'replace') {
            hasChange = true;
            htmlHighlight += `<span class="highlight-word" title="Sửa thành: ${corrected} (${scoreText})">${original}</span> `;
            
            addTableRow(tableBody, original, corrected, scoreText, scoreColor);
        }
        else if (type === 'delete') {
            hasChange = true;
            htmlHighlight += `<span class="highlight-word" style="text-decoration: line-through; opacity: 0.7;" title="Đã xóa">${original}</span> `;
            
            addTableRow(tableBody, original, "(Xóa)", "-", "#c62828");
        }
        else if (type === 'insert') {
            hasChange = true;
            htmlHighlight += `<span class="highlight-word" style="border-bottom: 2px solid #2e7d32;" title="Thêm mới">[+${corrected}]</span> `;
            
            addTableRow(tableBody, "(Thêm)", corrected, scoreText, scoreColor);
        }
    });

    highlightContainer.innerHTML = htmlHighlight.trim();

    if (!hasChange) {
        tableBody.innerHTML = `<tr><td colspan="3" style="color:#888; text-align:center; padding: 20px;">Văn bản không có thay đổi nào.</td></tr>`;
    }
}

function addTableRow(tbody, col1, col2, score, color) {
    const row = document.createElement("tr");
    row.innerHTML = `
        <td style="color: #d32f2f;">${col1}</td>
        <td style="color: #2e7d32; font-weight:bold;">${col2}</td>
        <td style="color: ${color}; font-weight:600;">${score}</td>
    `;
    tbody.appendChild(row);
}