// Global variables
let sourceText = "";
let targetText = "";
let sourceFile = null;
let targetFile = null;
let sourceFileType = "";
let targetFileType = "";
let documentType = "regular"; // Default document type: "regular" or "official"
let analysis = null;
let correctedSourceText = ""; // For storing corrected text in case of official documents
let detectedCountry = ""; // For storing detected country from document

// Initialize when DOM is loaded
document.addEventListener("DOMContentLoaded", function() {
    initializeApp();
});

// Initialize application
function initializeApp() {
    // Initialize document type selector
    initDocumentTypeSelector();
    
    // Initialize file upload listeners
    initFileUploadListeners();
    
    // Initialize text area listeners
    initTextAreaListeners();
    
    // Initialize button listeners
    initButtonListeners();
    
    // Initialize display options
    initDisplayOptions();
    
    // Initialize filter options
    initFilterOptions();
}

// Initialize document type selector
function initDocumentTypeSelector() {
    // Create document type selector (radio buttons)
    const selectorHtml = `
        <div class="document-type-selector mb-4">
            <p class="font-bold mb-2">نوع الملف:</p>
            <div class="flex gap-4">
                <label class="flex items-center">
                    <input type="radio" name="documentType" value="regular" checked class="mr-2">
                    <span>ملف عادي</span>
                </label>
                <label class="flex items-center">
                    <input type="radio" name="documentType" value="official" class="mr-2">
                    <span>مستند رسمي</span>
                </label>
            </div>
        </div>
    `;
    
    // Insert before source file upload section
    const sourceFileSection = document.querySelector("#sourceFileSection");
    sourceFileSection.insertAdjacentHTML('beforebegin', selectorHtml);
    
    // Add event listeners to the radio buttons
    document.querySelectorAll('input[name="documentType"]').forEach(radio => {
        radio.addEventListener('change', function() {
            documentType = this.value;
            console.log(`Document type changed to: ${documentType}`);
        });
    });
}

// Initialize file upload listeners
function initFileUploadListeners() {
    // Source file upload
    const sourceFileInput = document.getElementById("sourceFileInput");
    if (sourceFileInput) {
        sourceFileInput.addEventListener("change", function(e) {
            handleFileUpload(e, "source");
        });
    }
    
    // Target file upload
    const targetFileInput = document.getElementById("targetFileInput");
    if (targetFileInput) {
        targetFileInput.addEventListener("change", function(e) {
            handleFileUpload(e, "target");
        });
    }
    
    // Drag and drop zones
    initDragAndDropZones();
}

// Initialize drag and drop zones
function initDragAndDropZones() {
    const sourceDropZone = document.getElementById("sourceDropZone");
    const targetDropZone = document.getElementById("targetDropZone");
    
    // Source drop zone
    if (sourceDropZone) {
        ['dragenter', 'dragover', 'dragleave', 'drop'].forEach(eventName => {
            sourceDropZone.addEventListener(eventName, preventDefaults, false);
        });
        
        ['dragenter', 'dragover'].forEach(eventName => {
            sourceDropZone.addEventListener(eventName, function() {
                this.classList.add('bg-blue-100');
            }, false);
        });
        
        ['dragleave', 'drop'].forEach(eventName => {
            sourceDropZone.addEventListener(eventName, function() {
                this.classList.remove('bg-blue-100');
            }, false);
        });
        
        sourceDropZone.addEventListener('drop', function(e) {
            const dt = e.dataTransfer;
            if (dt.files.length) {
                document.getElementById('sourceFileInput').files = dt.files;
                handleFileUpload({ target: { files: dt.files } }, "source");
            }
        }, false);
    }
    
    // Target drop zone
    if (targetDropZone) {
        ['dragenter', 'dragover', 'dragleave', 'drop'].forEach(eventName => {
            targetDropZone.addEventListener(eventName, preventDefaults, false);
        });
        
        ['dragenter', 'dragover'].forEach(eventName => {
            targetDropZone.addEventListener(eventName, function() {
                this.classList.add('bg-blue-100');
            }, false);
        });
        
        ['dragleave', 'drop'].forEach(eventName => {
            targetDropZone.addEventListener(eventName, function() {
                this.classList.remove('bg-blue-100');
            }, false);
        });
        
        targetDropZone.addEventListener('drop', function(e) {
            const dt = e.dataTransfer;
            if (dt.files.length) {
                document.getElementById('targetFileInput').files = dt.files;
                handleFileUpload({ target: { files: dt.files } }, "target");
            }
        }, false);
    }
}

// Prevent default behavior for drag and drop
function preventDefaults(e) {
    e.preventDefault();
    e.stopPropagation();
}

// Initialize text area listeners
function initTextAreaListeners() {
    const sourceTextArea = document.getElementById("sourceTextArea");
    const targetTextArea = document.getElementById("targetTextArea");
    
    if (sourceTextArea) {
        sourceTextArea.addEventListener("input", function() {
            sourceText = this.value;
        });
    }
    
    if (targetTextArea) {
        targetTextArea.addEventListener("input", function() {
            targetText = this.value;
        });
    }
}

// Initialize button listeners
function initButtonListeners() {
    // Analyze button
    const analyzeBtn = document.getElementById("analyzeBtn");
    if (analyzeBtn) {
        analyzeBtn.addEventListener("click", startAnalysis);
    }
    
    // Export report button
    const exportReportBtn = document.getElementById("exportReportBtn");
    if (exportReportBtn) {
        exportReportBtn.addEventListener("click", exportReport);
    }
    
    // Clear all button
    const clearAllBtn = document.getElementById("clearAllBtn");
    if (clearAllBtn) {
        clearAllBtn.addEventListener("click", clearAll);
    }
}

// Initialize display options
function initDisplayOptions() {
    // Remove classic display option as per requirements
    const displayOptions = document.querySelectorAll('.display-option');
    displayOptions.forEach(option => {
        if (option.dataset.display === 'classic') {
            option.remove();
        }
    });
    
    // Set split view as default
    const splitViewOption = document.querySelector('.display-option[data-display="split"]');
    if (splitViewOption) {
        splitViewOption.classList.add('active');
        setDisplayMode('split');
    }
    
    // Add display option listeners
    document.querySelectorAll('.display-option').forEach(option => {
        option.addEventListener('click', function() {
            document.querySelectorAll('.display-option').forEach(opt => opt.classList.remove('active'));
            this.classList.add('active');
            setDisplayMode(this.dataset.display);
        });
    });
}

// Initialize filter options
function initFilterOptions() {
    document.querySelectorAll('.filter-option').forEach(option => {
        option.addEventListener('click', function() {
            this.classList.toggle('active');
            applyFilters();
        });
    });
}

// Handle file upload
function handleFileUpload(event, type) {
    const file = event.target.files[0];
    if (!file) return;
    
    // Store file
    if (type === "source") {
        sourceFile = file;
        document.getElementById("sourceFileName").textContent = file.name;
    } else {
        targetFile = file;
        document.getElementById("targetFileName").textContent = file.name;
    }
    
    // Process file based on type
    processFile(file, type);
}

// Process file based on file extension
async function processFile(file, textType) {
    const fileExtension = file.name.split('.').pop().toLowerCase();
    const fileType = file.type;
    
    // Show loading indicator
    toggleLoading(true, textType);
    
    try {
        let extractedText = "";
        
        // Process based on file extension/type
        if (fileType.includes('pdf') || fileExtension === 'pdf') {
            extractedText = await processPDF(file);
        } else if (fileType.includes('image') || ['jpg', 'jpeg', 'png', 'gif', 'bmp', 'webp'].includes(fileExtension)) {
            extractedText = await processImage(file);
        } else if (fileExtension === 'docx' || fileExtension === 'doc') {
            extractedText = await processDocx(file);
        } else if (['xlsx', 'xls', 'csv'].includes(fileExtension)) {
            extractedText = await processExcel(file);
        } else if (fileType.includes('text') || fileExtension === 'txt') {
            extractedText = await processTextFile(file);
        } else {
            throw new Error("Unsupported file format. Please use PDF, image, Word, Excel, or text files.");
        }
        
        // If document type is "official", correct the fixed terms
        if (documentType === "official" && textType === "source") {
            showNotification("جاري تصحيح الثوابت في المستند الرسمي...", "info");
            correctedSourceText = await correctOfficialDocument(extractedText);
            
            // Update extracted text with corrected text
            extractedText = correctedSourceText;
            showNotification("تم تصحيح الثوابت بنجاح", "success");
        }
        
        // Update UI with extracted text
        if (textType === "source") {
            sourceText = extractedText;
            sourceFileType = fileExtension;
            document.getElementById("sourceTextArea").value = extractedText;
        } else {
            targetText = extractedText;
            targetFileType = fileExtension;
            document.getElementById("targetTextArea").value = extractedText;
        }
        
        // Show preview if it's a PDF
        if (fileType.includes('pdf') || fileExtension === 'pdf') {
            showPDFPreview(file, textType);
        }
        
        // Show OCR results
        showOCRResults(extractedText, textType);
        
        // Enable analyze button if both texts are available
        if (sourceText && targetText) {
            document.getElementById("analyzeBtn").disabled = false;
        }
        
    } catch (error) {
        console.error("Error processing file:", error);
        showNotification(`خطأ في معالجة الملف: ${error.message}`, "error");
    } finally {
        // Hide loading indicator
        toggleLoading(false, textType);
    }
}

// Process PDF file
async function processPDF(file) {
    return new Promise((resolve, reject) => {
        const fileReader = new FileReader();
        
        fileReader.onload = async function() {
            try {
                const typedArray = new Uint8Array(this.result);
                
                // Load the PDF using pdf.js
                const pdf = await pdfjsLib.getDocument({ data: typedArray }).promise;
                let text = "";
                
                // Extract text from all pages
                for (let i = 1; i <= pdf.numPages; i++) {
                    const page = await pdf.getPage(i);
                    const textContent = await page.getTextContent();
                    const pageText = textContent.items.map(item => item.str).join(' ');
                    text += pageText + "\n";
                }
                
                resolve(text);
            } catch (error) {
                console.error("Error extracting text from PDF:", error);
                reject(error);
            }
        };
        
        fileReader.onerror = function() {
            reject(new Error("Error reading the PDF file."));
        };
        
        fileReader.readAsArrayBuffer(file);
    });
}

// Process image using OCR
async function processImage(file) {
    return new Promise((resolve, reject) => {
        const fileReader = new FileReader();
        
        fileReader.onload = async function() {
            try {
                // Here we would typically call an OCR API
                // For now, we'll simulate it with a placeholder
                showNotification("جاري استخراج النص من الصورة...", "info");
                
                // This is where you would call your OCR API
                // For example, using Tesseract.js or a cloud OCR API
                // Simulate OCR processing delay
                await new Promise(res => setTimeout(res, 2000));
                
                // Placeholder for OCR result
                // In a real implementation, replace this with actual OCR API call
                const ocrResult = "هذا نص تم استخراجه من الصورة باستخدام تقنية OCR.\nيمكنك استبدال هذا النص بنتائج OCR الفعلية من API الخاص بك.";
                
                resolve(ocrResult);
            } catch (error) {
                console.error("Error processing image:", error);
                reject(error);
            }
        };
        
        fileReader.onerror = function() {
            reject(new Error("Error reading the image file."));
        };
        
        fileReader.readAsDataURL(file);
    });
}

// Process Word document
async function processDocx(file) {
    return new Promise((resolve, reject) => {
        const fileReader = new FileReader();
        
        fileReader.onload = async function() {
            try {
                // Use mammoth.js to extract text from DOCX
                const arrayBuffer = this.result;
                const result = await mammoth.extractRawText({ arrayBuffer });
                resolve(result.value);
            } catch (error) {
                console.error("Error extracting text from DOCX:", error);
                reject(error);
            }
        };
        
        fileReader.onerror = function() {
            reject(new Error("Error reading the Word document."));
        };
        
        fileReader.readAsArrayBuffer(file);
    });
}

// Process Excel file
async function processExcel(file) {
    return new Promise((resolve, reject) => {
        const fileReader = new FileReader();
        
        fileReader.onload = async function() {
            try {
                const data = new Uint8Array(this.result);
                const workbook = XLSX.read(data, { type: 'array' });
                
                // Extract text from all sheets
                let text = "";
                workbook.SheetNames.forEach(sheetName => {
                    const worksheet = workbook.Sheets[sheetName];
                    const sheetText = XLSX.utils.sheet_to_txt(worksheet);
                    text += `[Sheet: ${sheetName}]\n${sheetText}\n\n`;
                });
                
                resolve(text);
            } catch (error) {
                console.error("Error extracting text from Excel:", error);
                reject(error);
            }
        };
        
        fileReader.onerror = function() {
            reject(new Error("Error reading the Excel file."));
        };
        
        fileReader.readAsArrayBuffer(file);
    });
}

// Process text file
async function processTextFile(file) {
    return new Promise((resolve, reject) => {
        const fileReader = new FileReader();
        
        fileReader.onload = function() {
            try {
                resolve(this.result);
            } catch (error) {
                console.error("Error reading text file:", error);
                reject(error);
            }
        };
        
        fileReader.onerror = function() {
            reject(new Error("Error reading the text file."));
        };
        
        fileReader.readAsText(file);
    });
}

// Correct official document using DeepSeek API
async function correctOfficialDocument(text) {
    try {
        // First, detect the country from the document
        detectedCountry = await detectCountryFromDocument(text);
        console.log("Detected country:", detectedCountry);
        
        // Prepare the prompt for DeepSeek API based on the detected country
        const prompt = prepareFixedTermsPrompt(text, detectedCountry);
        
        // Call DeepSeek API for correction
        const correctionResponse = await callDeepSeekAPI(prompt, "correction");
        
        // Extract the corrected text from the response
        return extractCorrectedText(correctionResponse, text);
    } catch (error) {
        console.error("Error correcting official document:", error);
        showNotification("حدث خطأ أثناء تصحيح المستند الرسمي", "error");
        return text; // Return original text if correction fails
    }
}

// Detect country from document text
async function detectCountryFromDocument(text) {
    try {
        const prompt = `
أنت خبير في تحليل المستندات الرسمية. قم بتحليل النص التالي وتحديد الدولة التي ينتمي إليها هذا المستند بناءً على المحتوى، الصياغة، المصطلحات المستخدمة، أو أي مؤشرات أخرى.
أعطني اسم الدولة فقط دون أي توضيح إضافي.

النص:
${text}
`;
        
        // Call DeepSeek API for country detection
        const response = await callDeepSeekAPI(prompt, "country-detection");
        
        // Process the response to extract just the country name
        let country = response.trim();
        
        // If multiple lines, take the first line
        if (country.includes('\n')) {
            country = country.split('\n')[0];
        }
        
        return country;
    } catch (error) {
        console.error("Error detecting country:", error);
        return "غير محدد"; // Default if detection fails
    }
}

// Prepare prompt for fixed terms correction based on country
function prepareFixedTermsPrompt(text, country) {
    return `
أنت خبير في تصحيح المستندات الرسمية للدولة: ${country}.

مهمتك هي تصحيح المصطلحات الثابتة فقط في المستند الرسمي التالي، مع الحفاظ على البيانات المتغيرة كما هي تماماً.

قواعد التصحيح:
1. صحح فقط المصطلحات والعبارات الثابتة مثل "الاسم"، "تاريخ الميلاد"، "الجنسية"، "الرقم القومي"، "رقم الهوية".
2. لا تغير أبداً البيانات المتغيرة مثل أسماء الأشخاص، التواريخ، الأرقام، إلخ.
3. حافظ على التنسيق الأصلي للنص.
4. أعد النص كاملاً بعد التصحيح.

على سبيل المثال:
- إذا كان النص يحتوي على "الأثم: محمد أحمد"، قم بتصحيحه إلى "الاسم: محمد أحمد"
- إذا كان النص يحتوي على "تاريخ الميلات: 1990/05/15"، قم بتصحيحه إلى "تاريخ الميلاد: 1990/05/15"

النص المراد تصحيحه:
${text}

أعد النص كاملاً بعد التصحيح دون أي توضيحات إضافية.
`;
}

// Extract corrected text from API response
function extractCorrectedText(response, originalText) {
    // This function should parse the API response to extract just the corrected text
    // If the API returns explanations or other content, strip those out
    
    // For now, we'll just return the response as is, assuming it's clean
    return response;
}

// Call DeepSeek API
async function callDeepSeekAPI(prompt, type) {
    // This function would typically make an API call to DeepSeek
    // For now, we'll simulate it with a placeholder response
    
    console.log(`Calling DeepSeek API for ${type} with prompt:`, prompt);
    
    // Simulate API delay
    await new Promise(res => setTimeout(res, 3000));
    
    // Simulate different responses based on the type of request
    if (type === "correction") {
        // Simulate a corrected document
        return prompt.replace("الأثم:", "الاسم:")
                    .replace("تاريخ الميلات:", "تاريخ الميلاد:")
                    .replace("الجنسيه:", "الجنسية:")
                    .replace("رقم القومى:", "الرقم القومي:");
    } else if (type === "country-detection") {
        // Simulate country detection
        return "مصر";
    } else if (type === "analysis") {
        // Simulate analysis response
        return {
            differences: [
                {
                    sourceText: "هذا النص الأصلي يحتوي على خطأ.",
                    targetText: "هذا النص المترجم يحتوي على خطأ مختلف.",
                    errorType: "grammar",
                    explanation: "الجملة في النص المترجم تحتوي على خطأ نحوي.",
                    severity: "medium"
                },
                // More differences...
            ],
            summary: "تم العثور على 5 اختلافات بين النصين، منها 2 خطأ نحوي و3 أخطاء إملائية."
        };
    }
    
    return "عذراً، حدث خطأ في معالجة طلبك.";
}

// Start analysis of texts
async function startAnalysis() {
    if (!sourceText || !targetText) {
        showNotification("يرجى إدخال أو تحميل النصين المصدر والهدف", "error");
        return;
    }
    
    try {
        // Show loading indicator
        toggleLoading(true, "analysis");
        showNotification("جاري تحليل النصوص...", "info");
        
        // Prepare prompt for analysis
        const analysisPrompt = `
قم بتحليل النصين التاليين ومقارنتهما لتحديد الاختلافات والأخطاء:

النص المصدر:
${sourceText}

النص الهدف:
${targetText}

قم بتحديد الاختلافات التالية:
1. الأخطاء النحوية
2. الأخطاء الإملائية
3. الاختلافات في المعنى
4. الكلمات أو العبارات المفقودة
5. الإضافات غير الضرورية

لكل اختلاف، قدم:
- النص المصدر
- النص الهدف
- نوع الخطأ
- شرح الخطأ
- مستوى خطورة الخطأ (منخفض، متوسط، مرتفع)
`;
        
        // Call DeepSeek API for analysis
        const apiResponse = await callDeepSeekAPI(analysisPrompt, "analysis");
        
        // Process the analysis results
        analysis = apiResponse; // In a real implementation, this would parse the API response
        
        // Display analysis results
        displayAnalysisResults(analysis);
        
        // Enable report export
        document.getElementById("exportReportBtn").disabled = false;
        
        showNotification("تم الانتهاء من التحليل بنجاح", "success");
    } catch (error) {
        console.error("Error during analysis:", error);
        showNotification(`خطأ في التحليل: ${error.message}`, "error");
    } finally {
        // Hide loading indicator
        toggleLoading(false, "analysis");
    }
}

// Display analysis results with improved highlighting and explanation
function displayAnalysisResults(analysis) {
    const resultsContainer = document.getElementById("resultsContainer");
    resultsContainer.innerHTML = "";
    
    // Create summary section
    const summarySection = document.createElement("div");
    summarySection.className = "mb-6 p-4 bg-gray-50 rounded-lg";
    summarySection.innerHTML = `
        <h3 class="text-xl font-bold mb-2">ملخص التحليل</h3>
        <p>${analysis.summary}</p>
    `;
    resultsContainer.appendChild(summarySection);
    
    // Create differences section with improved display
    const differencesSection = document.createElement("div");
    differencesSection.className = "differences-section";
    
    // Group differences by paragraphs for better organization
    const groupedDifferences = groupDifferencesByParagraph(analysis.differences);
    
    // Create each paragraph section
    let paragraphIndex = 1;
    for (const [paragraph, differences] of Object.entries(groupedDifferences)) {
        const paragraphSection = document.createElement("div");
        paragraphSection.className = "paragraph-section mb-8 p-4 bg-white rounded-lg shadow";
        
        paragraphSection.innerHTML = `
            <h3 class="text-lg font-bold mb-4">فقرة ${paragraphIndex}</h3>
            <div class="paragraph-content mb-4">
                <p class="whitespace-pre-wrap">${highlightDifferencesInParagraph(paragraph, differences)}</p>
            </div>
            <div class="paragraph-differences">
                <h4 class="font-bold mb-2">الاختلافات المكتشفة:</h4>
                <ul class="differences-list">
                    ${differences.map(diff => `
                        <li class="difference-item mb-4 p-3 border-r-4 border-${getSeverityColor(diff.severity)} bg-${getSeverityColor(diff.severity)}-50">
                            <div class="flex justify-between">
                                <span class="font-bold">${getErrorTypeLabel(diff.errorType)}</span>
                                <span class="severity-badge bg-${getSeverityColor(diff.severity)}-200 text-${getSeverityColor(diff.severity)}-800 px-2 py-1 rounded text-sm">
                                    ${getSeverityLabel(diff.severity)}
                                </span>
                            </div>
                            <div class="mt-2">
                                <div class="source-text mb-1">
                                    <span class="font-bold ml-1">النص الأصلي:</span>
                                    <span class="text-gray-800">${diff.sourceText}</span>
                                </div>
                                <div class="target-text mb-1">
                                    <span class="font-bold ml-1">النص المترجم:</span>
                                    <span class="text-gray-800">${diff.targetText}</span>
                                </div>
                                <div class="explanation mt-2 p-2 bg-gray-50 rounded">
                                    <span class="font-bold">الشرح:</span>
                                    <p>${diff.explanation}</p>
                                </div>
                            </div>
                        </li>
                    `).join('')}
                </ul>
            </div>
        `;
        
        differencesSection.appendChild(paragraphSection);
        paragraphIndex++;
    }
    
    resultsContainer.appendChild(differencesSection);
    
    // Show results container
    document.getElementById("resultsSection").classList.remove("hidden");
    
    // Add tooltip popups to highlighted differences
    addTooltipsToHighlights();
}

// Group differences by paragraph for better organization
function groupDifferencesByParagraph(differences) {
    const paragraphMap = {};
    
    differences.forEach(diff => {
        // Use the source text to determine the paragraph
        const paragraph = extractParagraphFromText(diff.sourceText, sourceText);
        
        if (!paragraphMap[paragraph]) {
            paragraphMap[paragraph] = [];
        }
        
        paragraphMap[paragraph].push(diff);
    });
    
    return paragraphMap;
}

// Extract the paragraph containing the given text
function extractParagraphFromText(snippet, fullText) {
    // Split the full text into paragraphs
    const paragraphs = fullText.split(/\n\s*\n/);
    
    // Find the paragraph containing the snippet
    for (const paragraph of paragraphs) {
        if (paragraph.includes(snippet)) {
            return paragraph;
        }
    }
    
    // If not found, return the snippet itself
    return snippet;
}

// Highlight differences in paragraph
function highlightDifferencesInParagraph(paragraph, differences) {
    let highlightedText = paragraph;
    
    // Sort differences by their position in the paragraph (to handle overlaps correctly)
    differences.sort((a, b) => {
        const posA = paragraph.indexOf(a.sourceText);
        const posB = paragraph.indexOf(b.sourceText);
        return posA - posB;
    });
    
    // Apply highlights to each difference
    let offset = 0;
    differences.forEach(diff => {
        const diffId = `diff-${Math.random().toString(36).substr(2, 9)}`;
        const originalText = diff.sourceText;
        const startPos = paragraph.indexOf(originalText, offset);
        
        if (startPos !== -1) {
            // Find the sentence containing the difference
            const sentenceMatch = findSentenceContaining(paragraph, startPos, originalText.length);
            
            if (sentenceMatch) {
                const { start, end } = sentenceMatch;
                const sentence = paragraph.substring(start, end);
                
                // Create highlighted version of the sentence
                const highlightedSentence = `<span class="highlighted-sentence bg-${getSeverityColor(diff.severity)}-100 cursor-pointer" data-diff-id="${diffId}">${sentence}</span>`;
                
                // Replace the sentence in the text
                highlightedText = highlightedText.substring(0, start) + highlightedSentence + highlightedText.substring(end);
                
                // Update offset to account for the added HTML
                offset = end + (highlightedSentence.length - sentence.length);
                
                // Store difference details for the tooltip
                window.diffDetails = window.diffDetails || {};
                window.diffDetails[diffId] = diff;
            }
        }
    });
    
    return highlightedText;
}

// Find the sentence containing the difference
function findSentenceContaining(text, position, length) {
    // Look for sentence boundaries (period, question mark, exclamation mark followed by space or newline)
    const sentenceEnders = ['. ', '? ', '! ', '.\n', '?\n', '!\n'];
    
    let start = position;
    while (start > 0) {
        let foundBoundary = false;
        
        for (const ender of sentenceEnders) {
            const endPos = text.lastIndexOf(ender, start);
            if (endPos !== -1 && endPos + ender.length <= start) {
                start = endPos + ender.length;
                foundBoundary = true;
                break;
            }
        }
        
        if (foundBoundary || start === 0) break;
        start--;
    }
    
    let end = position + length;
    while (end < text.length) {
        let foundBoundary = false;
        
        for (const ender of sentenceEnders) {
            const endPos = text.indexOf(ender, end - ender.length + 1);
            if (endPos !== -1 && endPos >= end - ender.length + 1) {
                end = endPos + ender.length;
                foundBoundary = true;
                break;
            }
        }
        
        if (foundBoundary || end === text.length) break;
        end++;
    }
    
    return { start, end };
}

// Add tooltips to highlighted differences
function addTooltipsToHighlights() {
    document.querySelectorAll('.highlighted-sentence').forEach(el => {
        el.addEventListener('click', function() {
            const diffId = this.dataset.diffId;
            const diff = window.diffDetails[diffId];
            
            if (diff) {
                showDifferencePopup(diff, this);
            }
        });
    });
}

// Show popup with difference details
function showDifferencePopup(diff, element) {
    // Remove any existing popups
    const existingPopup = document.getElementById('difference-popup');
    if (existingPopup) {
        existingPopup.remove();
    }
    
    // Create popup element
    const popup = document.createElement('div');
    popup.id = 'difference-popup';
    popup.className = 'fixed bg-white rounded-lg shadow-lg p-4 max-w-md z-50';
    popup.style.maxWidth = '90vw';
    
    // Create popup content
    popup.innerHTML = `
        <div class="flex justify-between items-center mb-2">
            <h3 class="font-bold text-lg">${getErrorTypeLabel(diff.errorType)}</h3>
            <span class="severity-badge bg-${getSeverityColor(diff.severity)}-200 text-${getSeverityColor(diff.severity)}-800 px-2 py-1 rounded text-sm">
                ${getSeverityLabel(diff.severity)}
            </span>
        </div>
        <div class="source-text mb-2">
            <span class="font-bold block mb-1">النص الأصلي:</span>
            <p class="bg-gray-50 p-2 rounded">${diff.sourceText}</p>
        </div>
        <div class="target-text mb-2">
            <span class="font-bold block mb-1">النص المترجم:</span>
            <p class="bg-gray-50 p-2 rounded">${diff.targetText}</p>
        </div>
        <div class="explanation mb-3">
            <span class="font-bold block mb-1">الشرح:</span>
            <p class="bg-gray-50 p-2 rounded">${diff.explanation}</p>
        </div>
        <button id="close-popup" class="bg-gray-200 hover:bg-gray-300 text-gray-800 font-bold py-1 px-4 rounded">
            إغلاق
        </button>
    `;
    
    // Position the popup near the element
    document.body.appendChild(popup);
    positionPopup(popup, element);
    
    // Add close button event listener
    document.getElementById('close-popup').addEventListener('click', function() {
        popup.remove();
    });
    
    // Close popup when clicking outside
    document.addEventListener('click', function closePopup(e) {
        if (!popup.contains(e.target) && e.target !== element) {
            popup.remove();
            document.removeEventListener('click', closePopup);
        }
    });
}

// Position popup near the target element
function positionPopup(popup, element) {
    const rect = element.getBoundingClientRect();
    const popupRect = popup.getBoundingClientRect();
    
    // Default position below the element
    let top = rect.bottom + window.scrollY + 10;
    let left = rect.left + window.scrollX;
    
    // Check if popup would go below viewport
    if (top + popupRect.height > window.innerHeight + window.scrollY) {
        // Position above the element instead
        top = rect.top + window.scrollY - popupRect.height - 10;
    }
    
    // Ensure popup doesn't go off-screen horizontally
    if (left + popupRect.width > window.innerWidth) {
        left = window.innerWidth - popupRect.width - 10;
    }
    
    popup.style.top = `${top}px`;
    popup.style.left = `${left}px`;
}

// Set display mode
function setDisplayMode(mode) {
    const resultsContainer = document.getElementById("resultsContainer");
    
    // Remove existing display mode classes
    resultsContainer.classList.remove('display-classic', 'display-split', 'display-side-by-side');
    
    // Add new display mode class
    resultsContainer.classList.add(`display-${mode}`);
}

// Apply filters to displayed results
function applyFilters() {
    const activeFilters = Array.from(document.querySelectorAll('.filter-option.active'))
        .map(el => el.dataset.filter);
    
    // Show all differences initially
    document.querySelectorAll('.difference-item').forEach(item => {
        item.classList.remove('hidden');
    });
    
    // If no filters are active, show all
    if (activeFilters.length === 0) {
        return;
    }
    
    // Hide differences that don't match active filters
    document.querySelectorAll('.difference-item').forEach(item => {
        const errorType = item.querySelector('.error-type').textContent;
        const severity = item.querySelector('.severity-badge').textContent;
        
        const matchesFilter = activeFilters.some(filter => {
            if (filter.startsWith('type-')) {
                return errorType === filter.replace('type-', '');
            } else if (filter.startsWith('severity-')) {
                return severity === filter.replace('severity-', '');
            }
            return false;
        });
        
        if (!matchesFilter) {
            item.classList.add('hidden');
        }
    });
}

// Export analysis report
function exportReport() {
    if (!analysis) {
        showNotification("لا توجد نتائج تحليل للتصدير", "error");
        return;
    }
    
    try {
        // Create report content
        const reportContent = generateReportContent();
        
        // Create blob and download link
        const blob = new Blob([reportContent], { type: 'text/plain;charset=utf-8' });
        const url = URL.createObjectURL(blob);
        
        const a = document.createElement('a');
        a.href = url;
        a.download = `تقرير_تحليل_الترجمة_${new Date().toISOString().slice(0, 10)}.txt`;
        a.click();
        
        URL.revokeObjectURL(url);
        
        showNotification("تم تصدير التقرير بنجاح", "success");
    } catch (error) {
        console.error("Error exporting report:", error);
        showNotification("حدث خطأ أثناء تصدير التقرير", "error");
    }
}

// Generate report content
function generateReportContent() {
    let content = "تقرير تحليل الترجمة\n";
    content += "===================\n\n";
    
    // Add date and time
    content += `تاريخ التحليل: ${new Date().toLocaleString('ar-EG')}\n\n`;
    
    // Add summary
    content += "ملخص التحليل:\n";
    content += "-------------\n";
    content += analysis.summary + "\n\n";
    
    // Add detailed differences
    content += "تفاصيل الاختلافات:\n";
    content += "------------------\n\n";
    
    analysis.differences.forEach((diff, index) => {
        content += `${index + 1}. ${getErrorTypeLabel(diff.errorType)} (${getSeverityLabel(diff.severity)})\n`;
        content += `   النص الأصلي: ${diff.sourceText}\n`;
        content += `   النص المترجم: ${diff.targetText}\n`;
        content += `   الشرح: ${diff.explanation}\n\n`;
    });
    
    // Add footer
    content += "تم إنشاء هذا التقرير بواسطة نظام تحليل الترجمة - شركة الريحان للترجمة";
    
    return content;
}

// Clear all inputs and results
function clearAll() {
    // Clear text areas
    document.getElementById("sourceTextArea").value = "";
    document.getElementById("targetTextArea").value = "";
    
    // Clear file names
    document.getElementById("sourceFileName").textContent = "لم يتم اختيار ملف";
    document.getElementById("targetFileName").textContent = "لم يتم اختيار ملف";
    
    // Clear OCR results
    document.getElementById("sourceOCRResults").innerHTML = "";
    document.getElementById("targetOCRResults").innerHTML = "";
    
    // Clear analysis results
    document.getElementById("resultsContainer").innerHTML = "";
    document.getElementById("resultsSection").classList.add("hidden");
    
    // Reset PDF previews
    document.getElementById("sourcePDFPreview").innerHTML = "";
    document.getElementById("targetPDFPreview").innerHTML = "";
    document.getElementById("sourcePDFSection").classList.add("hidden");
    document.getElementById("targetPDFSection").classList.add("hidden");
    
    // Reset global variables
    sourceText = "";
    targetText = "";
    sourceFile = null;
    targetFile = null;
    sourceFileType = "";
    targetFileType = "";
    analysis = null;
    correctedSourceText = "";
    detectedCountry = "";
    
    // Reset document type to "regular"
    document.querySelector('input[name="documentType"][value="regular"]').checked = true;
    documentType = "regular";
    
    // Disable buttons
    document.getElementById("analyzeBtn").disabled = true;
    document.getElementById("exportReportBtn").disabled = true;
    
    showNotification("تم مسح جميع البيانات", "info");
}

// Show PDF preview
function showPDFPreview(file, type) {
    const previewSection = document.getElementById(`${type}PDFSection`);
    const previewContainer = document.getElementById(`${type}PDFPreview`);
    
    // Clear previous preview
    previewContainer.innerHTML = "";
    
    // Create PDF viewer
    const viewer = document.createElement("div");
    viewer.className = "pdf-viewer";
    
    // Create PDF embed
    const embed = document.createElement("embed");
    embed.src = URL.createObjectURL(file);
    embed.type = "application/pdf";
    embed.width = "100%";
    embed.height = "500px";
    
    viewer.appendChild(embed);
    previewContainer.appendChild(viewer);
    
    // Show preview section
    previewSection.classList.remove("hidden");
}

// Show OCR results
function showOCRResults(text, type) {
    const resultsContainer = document.getElementById(`${type}OCRResults`);
    
    // Create results display
    resultsContainer.innerHTML = `
        <div class="ocr-results p-3 bg-gray-50 rounded max-h-60 overflow-y-auto">
            <pre class="whitespace-pre-wrap text-sm">${text}</pre>
        </div>
    `;
}

// Show notification
function showNotification(message, type = "info") {
    // Create notification element if it doesn't exist
    let notification = document.getElementById("notification");
    if (!notification) {
        notification = document.createElement("div");
        notification.id = "notification";
        notification.className = "fixed bottom-4 right-4 p-4 rounded-lg shadow-lg transform transition-opacity duration-300 opacity-0";
        document.body.appendChild(notification);
    }
    
    // Set notification type
    notification.className = notification.className.replace(/bg-\w+-\d+/g, "");
    switch (type) {
        case "success":
            notification.classList.add("bg-green-500", "text-white");
            break;
        case "error":
            notification.classList.add("bg-red-500", "text-white");
            break;
        case "warning":
            notification.classList.add("bg-yellow-500", "text-white");
            break;
        default:
            notification.classList.add("bg-blue-500", "text-white");
    }
    
    // Set message
    notification.textContent = message;
    
    // Show notification
    notification.classList.replace("opacity-0", "opacity-100");
    
    // Hide notification after 3 seconds
    setTimeout(() => {
        notification.classList.replace("opacity-100", "opacity-0");
    }, 3000);
}

// Toggle loading indicator
function toggleLoading(show, section) {
    const loadingIndicators = {
        "source": document.getElementById("sourceLoadingIndicator"),
        "target": document.getElementById("targetLoadingIndicator"),
        "analysis": document.getElementById("analysisLoadingIndicator")
    };
    
    const indicator = loadingIndicators[section];
    if (indicator) {
        if (show) {
            indicator.classList.remove("hidden");
        } else {
            indicator.classList.add("hidden");
        }
    }
}

// Helper functions for displaying error types and severity
function getErrorTypeLabel(errorType) {
    const labels = {
        "grammar": "خطأ نحوي",
        "spelling": "خطأ إملائي",
        "meaning": "اختلاف في المعنى",
        "missing": "نص مفقود",
        "addition": "إضافة غير ضرورية",
        "terminology": "مصطلح غير دقيق"
    };
    
    return labels[errorType] || errorType;
}

function getSeverityLabel(severity) {
    const labels = {
        "low": "منخفض",
        "medium": "متوسط",
        "high": "مرتفع"
    };
    
    return labels[severity] || severity;
}

function getSeverityColor(severity) {
    const colors = {
        "low": "yellow",
        "medium": "orange",
        "high": "red"
    };
    
    return colors[severity] || "gray";
}