Dear ${recipientName || 'Recipient'},
${letterBody.replace(/\n/g, '
')}
Sincerely,
${senderName}
`;
const pdfHtml = `
${senderName}
${senderTitle}
${senderCompany}
${senderAddress}
${senderCityStateZip}
${senderEmail}
${senderPhone}
${recipientName}
${recipientTitle}
${recipientCompany}
${recipientAddress}
${recipientCityStateZip}
Dear ${recipientName || 'Recipient'},
${letterBody}
`;
if (letterPreview) letterPreview.innerHTML = html;
if (letterPreviewPdf) letterPreviewPdf.innerHTML = pdfHtml;
}
// --- AI Content Generation ---
if (generateContentBtn) {
generateContentBtn.addEventListener('click', async () => {
const purpose = inputs.letterPurpose ? inputs.letterPurpose.value : '';
const tone = inputs.letterTone ? inputs.letterTone.value : 'Formal';
const senderName = inputs.senderName ? inputs.senderName.value : 'the sender';
const recipientName = inputs.recipientName ? inputs.recipientName.value : 'the recipient';
if (!purpose) {
alert('Please specify the purpose of the letter.');
return;
}
const prompt = `Write a professional business letter from ${senderName} to ${recipientName}. The purpose of the letter is: "${purpose}". The desired tone is ${tone}. Write only the body of the letter, starting after the salutation "Dear ${recipientName}," and ending before "Sincerely,". Do not include the salutation or the closing.`;
const spinner = document.getElementById('generateSpinner');
const btnText = document.getElementById('generateBtnText');
if (spinner) spinner.classList.remove('hidden');
if (btnText) btnText.textContent = 'Generating...';
generateContentBtn.disabled = true;
try {
let chatHistory = [{ role: "user", parts: [{ text: prompt }] }];
const payload = { contents: chatHistory };
const apiKey = ""; // API key will be handled by the environment
const apiUrl = `https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash-preview-05-20:generateContent?key=${apiKey}`;
const response = await fetch(apiUrl, {
method: 'POST',
headers: { 'Content-Type': 'application/json' },
body: JSON.stringify(payload)
});
if (!response.ok) {
throw new Error(`API request failed with status ${response.status}`);
}
const result = await response.json();
if (result.candidates && result.candidates.length > 0 &&
result.candidates[0].content && result.candidates[0].content.parts &&
result.candidates[0].content.parts.length > 0) {
const text = result.candidates[0].content.parts[0].text;
if (inputs.letterBody) {
inputs.letterBody.value = text.trim();
updatePreview(); // Update preview after generating content
}
} else {
throw new Error('Unexpected API response structure.');
}
} catch (error) {
console.error('Error generating letter content:', error);
if (inputs.letterBody) {
inputs.letterBody.value = 'Sorry, there was an error generating the content. Please try again.';
}
} finally {
if (spinner) spinner.classList.add('hidden');
if (btnText) btnText.textContent = 'Generate Letter Content with AI';
generateContentBtn.disabled = false;
}
});
}
// --- PDF Download Logic ---
if (downloadPdfBtn) {
downloadPdfBtn.addEventListener('click', () => {
updatePreview(); // Ensure PDF content is up-to-date
const { jsPDF } = window.jspdf;
const pdfElement = document.getElementById('letter-preview-pdf');
if (!pdfElement) {
console.error("PDF preview element not found.");
return;
}
html2canvas(pdfElement, {
scale: 2, // Higher scale for better quality
useCORS: true
}).then(canvas => {
const imgData = canvas.toDataURL('image/png');
// A4 size: 210mm x 297mm. In points (1pt = 1/72 inch): ~595 x 842
const pdf = new jsPDF({
orientation: 'portrait',
unit: 'pt',
format: 'a4'
});
const pdfWidth = pdf.internal.pageSize.getWidth();
const pdfHeight = pdf.internal.pageSize.getHeight();
const canvasWidth = canvas.width;
const canvasHeight = canvas.height;
const canvasAspectRatio = canvasWidth / canvasHeight;
const pdfAspectRatio = pdfWidth / pdfHeight;
let finalCanvasWidth, finalCanvasHeight;
// Fit canvas content to PDF page width
finalCanvasWidth = pdfWidth;
finalCanvasHeight = finalCanvasWidth / canvasAspectRatio;
pdf.addImage(imgData, 'PNG', 0, 0, finalCanvasWidth, finalCanvasHeight);
pdf.save("business-letter.pdf");
}).catch(error => {
console.error("Error generating PDF:", error);
});
});
}
// --- Initial Setup ---
updateTabUI();
updatePreview();
});
