/**
 * pdf-generator.js
 * Generates High-Resolution Image PDF using html2canvas 
 * to preserve exact Devanagari ligatures and fonts,
 * optimized for 2-5MB file sizes via JPEG compression.
 */

async function generateAadhaarPDF(isFree = false) {
    const { jsPDF } = window.jspdf;

    // 1. Inject Base64 Fonts into Main Document for absolute reliability
    if (!document.getElementById('injected-fonts')) {
        const style = document.createElement('style');
        style.id = 'injected-fonts';
        style.innerHTML = `
            @font-face {
                font-family: 'AadhaarEnglish';
                src: url('data:font/ttf;base64,${FONT_ENGLISH_B64}') format('truetype');
                font-display: block;
            }
            @font-face {
                font-family: 'AadhaarHindi';
                src: url('data:font/ttf;base64,${FONT_HINDI_B64}') format('truetype');
                font-display: block;
            }
            @font-face {
                font-family: 'AadhaarDigits';
                src: url('data:font/ttf;base64,${FONT_DIGITS_B64}') format('truetype');
                font-display: block;
            }
        `;
        document.head.appendChild(style);
    }

    // 2. Wait for fonts to be ready before proceeding
    try {
        await document.fonts.ready;
        // Force load specific fonts
        await Promise.all([
            document.fonts.load('12px AadhaarEnglish'),
            document.fonts.load('12px AadhaarHindi'),
            document.fonts.load('12px AadhaarDigits')
        ]);
        console.log("All fonts loaded successfully");
    } catch (e) {
        console.warn("Font loading wait failed, proceeding anyway:", e);
    }
    
    // UI Elements for status updates
    const popupMessage = document.getElementById('popup-message');
    const popup = document.getElementById('validation-popup');
    const closeBtn = document.getElementById('popup-close-btn');
    const iconContainer = document.getElementById('popup-icon-container');
    const popupTitle = document.getElementById('popup-title');
    const popupSvg = document.getElementById('popup-svg');
    
    // Initial UI State
    if (popup && !popup.classList.contains('active')) {
        popup.classList.add('active');
    }
    if (closeBtn) closeBtn.style.display = 'none';

    // If it's a free reprint (from history), skip the wallet deduction
    if (isFree) {
        if (popupMessage) popupMessage.innerText = "Reprinting from History...";
        startPDFGenerationFlow();
        return;
    }

    // Otherwise, check and deduct wallet balance
    const cost = 10;
    if (popupMessage) popupMessage.innerText = "Checking wallet balance...";

    // Call deduction API with Aadhaar Number in description
    const adharNo = document.getElementById('in-aadhaar')?.value || "Unknown";
    const serviceDesc = `Aadhaar Advance: ${adharNo}`;

    fetch('/api/wallet/deduct', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ amount: cost, service: serviceDesc })
    })
    .then(async res => {
        const data = await res.json();
        if (!res.ok) {
            throw new Error(data.error || "Failed to deduct balance");
        }
        
        // Success: Deduction done, now proceed with PDF generation
        if (popupMessage) popupMessage.innerText = "Processing Aadhaar PDF... Please wait.";
        startPDFGenerationFlow();
    })
    .catch(err => {
        console.error("Deduction failed:", err);
        const isBalanceError = err.message.toLowerCase().includes('balance');
        
        if (popupMessage) {
            popupMessage.innerHTML = isBalanceError 
                ? "<span style='color:#ff4757; font-weight:600;'>Insufficient Balance!</span><br>Redirecting to Wallet page in 2s..."
                : "System Error: " + err.message;
        }
        
        // Reset popup to Error State
        if (iconContainer) {
            iconContainer.style.background = '#fff0f0';
            iconContainer.style.color = '#ff4757';
            iconContainer.style.boxShadow = '0 0 0 10px rgba(255, 71, 87, 0.1)';
        }
        if (popupTitle) popupTitle.innerText = isBalanceError ? "Low Balance" : "Payment Error";
        if (popupSvg) {
            popupSvg.innerHTML = '<circle cx="12" cy="12" r="10"></circle><line x1="12" y1="8" x2="12" y2="12"></line><line x1="12" y1="16" x2="12.01" y2="16"></line>';
            popupSvg.classList.remove('spinner-animation');
        }
        
        // Final Action: Hide close button for balance errors (since it's automated)
        if (closeBtn) closeBtn.style.display = isBalanceError ? 'none' : 'block';
        
        if (isBalanceError) {
            setTimeout(() => {
                if (popup) popup.classList.remove('active');
                window.location.href = '/wallet';
            }, 2000);
        }
        
        // Refresh balance in case of sync issues
        if (typeof updateWalletPill === 'function') updateWalletPill();
    });
}

function startPDFGenerationFlow() {
    const { jsPDF } = window.jspdf;
    
    // Re-fetch UI Elements for the flow (avoiding scope issues)
    const popupMessage = document.getElementById('popup-message');
    const popup = document.getElementById('validation-popup');
    const closeBtn = document.getElementById('popup-close-btn');
    const iconContainer = document.getElementById('popup-icon-container');
    const popupTitle = document.getElementById('popup-title');
    const popupSvg = document.getElementById('popup-svg');

    const now = new Date();
    const timeStamp = `${String(now.getHours()).padStart(2, '0')}${String(now.getMinutes()).padStart(2, '0')}${String(now.getSeconds()).padStart(2, '0')}`;
    
    const nameInput = document.getElementById('in-name-en');
    const nameVal = nameInput && nameInput.value ? nameInput.value.trim().replace(/\s+/g, '_') : 'Applicant';
    const fileName = `${nameVal}_Aadhaar_${timeStamp}.pdf`;

    const ws = document.getElementById('workspace');
    const previewArea = document.querySelector('.preview-area');
    
    // Update Popup to "Processing" State (variables are already defined in outer scope)
    if (iconContainer) {
        iconContainer.style.background = '#e7f3ff';
        iconContainer.style.color = '#007bff';
        iconContainer.style.boxShadow = '0 0 0 10px rgba(0, 123, 255, 0.1)';
    }
    if (popupTitle) popupTitle.innerText = "Processing";
    if (popupSvg) {
        popupSvg.innerHTML = '<path d="M12 2v4M12 18v4M4.93 4.93l2.83 2.83M16.24 16.24l2.83 2.83M2 12h4M18 12h4M4.93 19.07l2.83-2.83M16.24 7.76l2.83-2.83"></path>';
        popupSvg.classList.add('spinner-animation');
    }

    // Show preview area off-screen so html2canvas can capture it
    const originalPreviewDisplay = previewArea ? previewArea.style.display : '';
    const originalPreviewPosition = previewArea ? previewArea.style.position : '';
    const originalPreviewLeft = previewArea ? previewArea.style.left : '';
    const originalPreviewVisibility = previewArea ? previewArea.style.visibility : '';
    if (previewArea) {
        previewArea.style.setProperty('display', 'flex', 'important');
        previewArea.style.position = 'fixed';
        previewArea.style.left = '-9999px';
        previewArea.style.visibility = 'visible';
        previewArea.style.top = '0';
    }

    // Temporarily remove scale transforms so html2canvas captures full A4 layout
    const originalTransform = ws.style.transform;
    const originalShadow = ws.style.boxShadow;
    ws.style.transform = 'none';
    ws.style.boxShadow = 'none';

    // FIX: html2canvas blurs "background-size: cover" CSS images and misaligns them
    // Calculate precise mathematical dimensions mirroring 'cover' logic in mm natively
    const bgImgNative = new Image();

    bgImgNative.onload = () => {
        const pageRatio = 210 / 297;
        const imgRatio = bgImgNative.naturalWidth / bgImgNative.naturalHeight;
        let drawW, drawH, drawX, drawY;

        if (imgRatio > pageRatio) {
            drawH = 297;
            drawW = (297 / bgImgNative.naturalHeight) * bgImgNative.naturalWidth;
            drawX = (210 - drawW) / 2;
            drawY = 0;
        } else {
            drawW = 210;
            drawH = (210 / bgImgNative.naturalWidth) * bgImgNative.naturalHeight;
            drawX = 0;
            drawY = (297 - drawH) / 2;
        }

        bgImgNative.style.position = 'absolute';
        bgImgNative.style.width = drawW + 'mm';
        bgImgNative.style.height = drawH + 'mm';
        bgImgNative.style.left = drawX + 'mm';
        bgImgNative.style.top = drawY + 'mm';
        bgImgNative.style.objectFit = 'fill';
        bgImgNative.style.zIndex = '0';
        bgImgNative.id = 'temp-bg-native';

        const originalBgLayer = document.querySelector('.bg-layer');
        const oldDisplay = originalBgLayer ? originalBgLayer.style.display : '';
        if (originalBgLayer) originalBgLayer.style.display = 'none';
        ws.prepend(bgImgNative);

        // Timeout ensures DOM repaints and font loading before capture
        setTimeout(() => {
            html2canvas(ws, {
                scale: 4, // High-res capture
                useCORS: true,
                allowTaint: true,
                backgroundColor: '#ffffff',
                logging: false,
                onclone: (clonedDoc) => {
                    // 1. Inject Base64 Fonts into Cloned Document for absolute reliability
                    const style = clonedDoc.createElement('style');
                    style.innerHTML = `
                        @font-face {
                            font-family: 'AadhaarEnglish';
                            src: url('data:font/ttf;base64,${FONT_ENGLISH_B64}') format('truetype');
                        }
                        @font-face {
                            font-family: 'AadhaarHindi';
                            src: url('data:font/ttf;base64,${FONT_HINDI_B64}') format('truetype');
                        }
                        @font-face {
                            font-family: 'AadhaarDigits';
                            src: url('data:font/ttf;base64,${FONT_DIGITS_B64}') format('truetype');
                        }
                    `;
                    clonedDoc.head.appendChild(style);

                    const clonedWs = clonedDoc.getElementById('workspace');
                    if (clonedWs) {
                        clonedWs.style.transform = 'none';
                        clonedWs.style.boxShadow = 'none';
                    }

                    // 2. Force exact font-family and sizes on requested text elements
                    const englishEls = clonedDoc.querySelectorAll('.inroltext, .english-name, .address-en-text, .address-en-label, .enrolment-no, .inrol-date, .download-date');
                    englishEls.forEach(el => {
                        el.style.fontFamily = "'AadhaarEnglish', Arial, sans-serif";
                        if (!el.classList.contains('enrolment-no')) {
                             el.style.fontSize = '8.4px';
                        }
                    });

                    const hindiEls = clonedDoc.querySelectorAll('.hindi-name, .address-hi-text, .address-hi-label, .gender-text');
                    hindiEls.forEach(el => {
                        el.style.fontFamily = "'AadhaarHindi', Arial, sans-serif";
                        el.style.fontSize = '8.4px';
                    });

                    const digitEls = clonedDoc.querySelectorAll('.aadhar-no-top, .aadhar-no-middle, .aadhar-no-bottom, .dob-text, .enrolment-no');
                    digitEls.forEach(el => {
                        el.style.fontFamily = "'AadhaarDigits', Arial, sans-serif";
                    });

                    // 3. Fix Rotation and Visibility for Dates
                    const rotatedEls = clonedDoc.querySelectorAll('.inrol-date, .download-date');
                    rotatedEls.forEach(el => {
                        el.style.display = 'block';
                        el.style.visibility = 'visible';
                        el.style.opacity = '1';
                        el.style.color = '#000000';
                        el.style.whiteSpace = 'nowrap';
                        el.style.fontFamily = "'AadhaarEnglish', Arial, sans-serif";
                        el.style.fontSize = '7.5px';
                        el.style.zIndex = '100';
                        el.style.letterSpacing = '0.2px'; // Increased spacing to prevent mixing
                        
                        // Force layout properties that html2canvas likes for rotated elements
                        el.style.transformOrigin = 'center center';
                        el.style.transform = 'rotate(-90deg)';
                        el.style.width = '200px'; // Increased width
                        el.style.textAlign = 'center';
                    });
                }
            }).then(canvas => {
                // Restore UI immediately
                ws.style.transform = originalTransform;
                ws.style.boxShadow = originalShadow;
                if (originalBgLayer) originalBgLayer.style.display = oldDisplay;
                const tempBg = document.getElementById('temp-bg-native');
                if (tempBg) tempBg.remove();

                // Restore preview area state
                if (previewArea) {
                    previewArea.style.removeProperty('display');
                    previewArea.style.position = originalPreviewPosition;
                    previewArea.style.left = originalPreviewLeft;
                    previewArea.style.visibility = originalPreviewVisibility;
                    previewArea.style.top = '';
                }

                // JPEG encoding at 1.0 provides the absolute maximum fidelity
                // resulting in a beautiful 5-7MB file size as requested
                const imgData = canvas.toDataURL('image/jpeg', 1.0);

                const doc = new jsPDF({
                    orientation: 'portrait',
                    unit: 'pt',
                    format: 'letter'
                });

                // Aspect Ratio Calculation to prevent stretching
                // Workspace: 794x1123, PDF: 612x792
                // To keep ratio, Width = (794 / 1123) * 792 = ~560pt
                // (612 - 560) / 2 = 26pt margin on each side to center it
                doc.addImage(imgData, 'JPEG', 26, 0, 560, 792);

                if (popupMessage) popupMessage.innerText = `PDF Saved: ${fileName}`;
                
                // Update Popup to "Success" State
                if (iconContainer) {
                    iconContainer.style.background = '#e6ffed';
                    iconContainer.style.color = '#28a745';
                    iconContainer.style.boxShadow = '0 0 0 10px rgba(40, 167, 69, 0.1)';
                }
                if (popupTitle) popupTitle.innerText = "Success!";
                if (popupSvg) {
                    popupSvg.innerHTML = '<polyline points="20 6 9 17 4 12"></polyline>';
                    popupSvg.classList.remove('spinner-animation');
                }

                setTimeout(() => {
                    if (popup) popup.classList.remove('active');
                }, 1500);

                doc.save(fileName);

                // Save to History
                saveToHistory();
                if (typeof updateWalletPill === 'function') updateWalletPill();

            }).catch(err => {
                console.error("PDF Generation Error:", err);
                ws.style.transform = originalTransform;
                ws.style.boxShadow = originalShadow;
                if (originalBgLayer) originalBgLayer.style.display = oldDisplay;
                const tempBg = document.getElementById('temp-bg-native');
                if (tempBg) tempBg.remove();

                if (previewArea) {
                    previewArea.style.removeProperty('display');
                    previewArea.style.position = originalPreviewPosition;
                    previewArea.style.left = originalPreviewLeft;
                    previewArea.style.top = '';
                }
                if (popupMessage) popupMessage.innerText = "Error generating PDF. Check console.";
                
                // Show close button so user can exit error state
                if (closeBtn) closeBtn.style.display = 'block';

                // Reset to Error State
                if (iconContainer) {
                    iconContainer.style.background = '#fff0f0';
                    iconContainer.style.color = '#ff4757';
                    iconContainer.style.boxShadow = '0 0 0 10px rgba(255, 71, 87, 0.1)';
                }
                if (popupTitle) popupTitle.innerText = "Error";
                if (popupSvg) {
                    popupSvg.innerHTML = '<circle cx="12" cy="12" r="10"></circle><line x1="12" y1="8" x2="12" y2="12"></line><line x1="12" y1="16" x2="12.01" y2="16"></line>';
                    popupSvg.classList.remove('spinner-animation');
                }

                setTimeout(() => { if (popup) popup.classList.remove('active'); }, 2000);
            });
        }, 1000);
    };
    bgImgNative.src = EMBEDDED_BG;
}

/**
 * Collects form data and saves it to the backend history API
 */
async function saveToHistory() {
    const data = {
        id: (typeof crypto !== 'undefined' && crypto.randomUUID) ? crypto.randomUUID() : Math.random().toString(36).substring(2, 11),
        timestamp: new Date().toISOString()
    };

    // Collect all in-* inputs and radio buttons
    const inputs = document.querySelectorAll('input[id^="in-"], textarea[id^="in-"]');
    inputs.forEach(input => {
        if (input.type === 'radio') {
            if (input.checked) data[input.id] = input.value;
        } else if (input.type === 'file') {
            // Skip file input's fakepath, we'll handle the base64 photo separately
        } else {
            data[input.id] = input.value;
        }
    });

    // Also save the photo data if it exists in the preview
    const photoPreview = document.getElementById('out-photo');
    if (photoPreview && photoPreview.src && photoPreview.src.startsWith('data:image')) {
        data['photo_data'] = photoPreview.src;
    }

    try {
        const response = await fetch('/api/history', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify(data)
        });
        
        const result = await response.json();
        
        if (response.ok) {
            console.log("History saved successfully, ID:", result.id || data.id);
            // Update local ID if backend returned a different one (e.g. for duplicates)
            if (result.id) data.id = result.id;
            
            // Refresh badge if function exists in generate.js
            if (typeof fetchHistoryCount === 'function') fetchHistoryCount();
        }
    } catch (err) {
        console.error("Failed to save history:", err);
    }
}