Message Attachments

Check out our latest case study: https://yoursite.com/case-study

See what our customers are saying: https://twitter.com/customer/status/123

Here's your proposal: https://drive.google.com/file/d/abc123/view

Hi {{firstName}},

Thanks for your interest in {{serviceType}}! 

I've attached some samples of our work with similar {{industryType}} clients. The {{attachmentDescription}} should give you a good sense of our capabilities.

I'd love to discuss how we could create something similar for {{companyName}}.

Available for a quick call this week?

Best,
{{agentName}}

function selectPortfolioSamples(industry, budget) {
  const samples = portfolioLibrary[industry] || [];
  
  // Filter by budget tier
  if (budget < 5000) {
    return samples.filter(s => s.tier === 'basic');
  } else if (budget > 20000) {
    return samples.filter(s => s.tier === 'premium');
  }
  
  return samples.filter(s => s.tier === 'standard');
}

Hi {{firstName}},

I've prepared a custom proposal for your {{projectType}} project.

The attached document includes:
• Project timeline and milestones
• Detailed pricing breakdown
• Team member profiles
• Similar client case studies

Please review and let me know if you have any questions. I'm available to discuss any aspects of the proposal.

Looking forward to working together!

{{agentName}}

function selectCaseStudies(contactData) {
  const relevant = caseStudyLibrary.filter(study => 
    study.industry === contactData.industry ||
    study.projectType === contactData.serviceType ||
    study.companySize === contactData.companySize
  );
  
  // Return top 2-3 most relevant
  return relevant
    .sort((a, b) => b.relevanceScore - a.relevanceScore)
    .slice(0, 3);
}

Hi {{firstName}},

Welcome to {{productName}}! 

I've attached a quick video tutorial that will help you get started with {{specificFeature}}.

The video is just {{videoDuration}} and covers:
• Initial setup steps
• Key features for your {{useCase}}
• Pro tips for maximum efficiency

Watch when convenient, and feel free to reach out with any questions!

{{supportTeamName}}

function generateTroubleshootingGuide(issueType, userPlatform) {
  const guide = {
    steps: getTroubleshootingSteps(issueType),
    screenshots: getScreenshots(issueType, userPlatform),
    additionalInfo: getAdditionalResources(issueType)
  };
  
  return generatePDF(guide);
}

Hi {{firstName}},

Your order #{{orderNumber}} has shipped! 🎉

I've attached photos of your {{productName}} being carefully packaged. Your order includes:

{{#orderItems}}
• {{itemName}} ({{quantity}}x)
{{/orderItems}}

Tracking: {{trackingUrl}}
Expected delivery: {{deliveryDate}}

Thanks for choosing {{companyName}}!

function attachSizeGuide(productCategory, customerData) {
  const sizeChart = getSizeChart(productCategory);
  const personalizedGuide = generatePersonalizedGuide(
    sizeChart, 
    customerData.previousOrders
  );
  
  return {
    type: 'image',
    url: personalizedGuide.url,
    caption: `Size guide for ${productCategory}`
  };
}

class AttachmentManager {
  async uploadFile(file, metadata) {
    const storageKey = `attachments/${metadata.campaignId}/${file.name}`;
    
    const uploadResult = await this.cloudStorage.upload({
      key: storageKey,
      body: file.buffer,
      contentType: file.mimeType,
      metadata: {
        originalName: file.name,
        uploadedBy: metadata.userId,
        campaignId: metadata.campaignId,
        expiresAt: metadata.expiresAt
      }
    });
    
    return {
      url: uploadResult.publicUrl,
      storageKey: storageKey,
      size: file.size,
      contentType: file.mimeType
    };
  }
}

function generateCDNUrl(attachmentKey, transformations = {}) {
  const baseUrl = 'https://cdn.yoursite.com';
  const params = new URLSearchParams();
  
  // Image transformations
  if (transformations.width) params.set('w', transformations.width);
  if (transformations.height) params.set('h', transformations.height);
  if (transformations.quality) params.set('q', transformations.quality);
  
  return `${baseUrl}/${attachmentKey}?${params.toString()}`;
}

function generateTemporaryUrl(attachmentKey, expirationHours = 24) {
  const expiresAt = Date.now() + (expirationHours * 60 * 60 * 1000);
  const signature = generateSignature(attachmentKey, expiresAt);
  
  return `https://secure.yoursite.com/attachments/${attachmentKey}?expires=${expiresAt}&sig=${signature}`;
}

const sizeLimits = {
  image: 10 * 1024 * 1024,    // 10 MB
  video: 100 * 1024 * 1024,  // 100 MB
  document: 50 * 1024 * 1024, // 50 MB
  audio: 25 * 1024 * 1024     // 25 MB
};

function validateFileSize(attachment) {
  const limit = sizeLimits[attachment.type];
  if (attachment.size > limit) {
    throw new Error(`File too large: ${attachment.type} limit is ${limit} bytes`);
  }
}

async function downloadWithRetry(url, maxRetries = 3) {
  for (let attempt = 1; attempt <= maxRetries; attempt++) {
    try {
      const response = await fetch(url, { timeout: 30000 });
      if (response.ok) {
        return await response.buffer();
      }
    } catch (error) {
      if (attempt === maxRetries) {
        throw new Error(`Failed to download after ${maxRetries} attempts: ${error.message}`);
      }
      
      // Wait before retry
      await new Promise(resolve => setTimeout(resolve, attempt * 1000));
    }
  }
}

function handleAttachmentFailure(message, failedAttachment) {
  // Remove failed attachment
  message.attachments = message.attachments.filter(a => a !== failedAttachment);
  
  // Add fallback text
  message.content += `\n\n📎 Attachment unavailable. View online: ${failedAttachment.fallbackUrl}`;
  
  // Log for manual review
  this.logAttachmentFailure(message.id, failedAttachment);
  
  return message;
}

// Only download attachments when message is being sent
async function prepareMessageForSending(message) {
  const attachments = await Promise.all(
    message.attachmentUrls.map(url => this.downloadAttachment(url))
  );
  
  return {
    ...message,
    attachments: attachments.filter(a => a !== null) // Remove failed downloads
  };
}

class AttachmentCache {
  constructor() {
    this.cache = new Map();
    this.maxSize = 100 * 1024 * 1024; // 100 MB cache
  }
  
  async getAttachment(url) {
    if (this.cache.has(url)) {
      return this.cache.get(url);
    }
    
    const attachment = await this.downloadAttachment(url);
    
    if (this.getCacheSize() + attachment.size <= this.maxSize) {
      this.cache.set(url, attachment);
    }
    
    return attachment;
  }
}