Incremental Static Regeneration

// pages/articles/[slug].js - NewsWave article page with ISR
export async function getStaticProps({ params }) {
  // Fetch article data exactly like normal SSG
  const article = await fetch(`https://api.newswave.com/articles/${params.slug}`)
    .then(res => res.json())

  return {
    props: {
      article
    },
    revalidate: 60 // Regenerate every 60 seconds maximum
  }
}

// The article component receives fresh data automatically
export default function Article({ article }) {
  return (
    <div style={{ maxWidth: '800px', margin: '0 auto', padding: '20px' }}>
      <h1>{article.title}</h1>
      <p>Views: {article.viewCount}</p>
      <p>Last updated: {new Date().toLocaleTimeString()}</p>
    </div>
  )
}

// pages/api/revalidate.js - Trigger regeneration on demand
export default async function handler(req, res) {
  // Verify this request came from your CMS or admin panel
  if (req.query.secret !== process.env.REVALIDATE_TOKEN) {
    return res.status(401).json({ message: 'Invalid token' })
  }

  try {
    // Regenerate the specific article page that was updated
    await res.revalidate(`/articles/${req.query.slug}`)
    return res.json({ revalidated: true })
  } catch (err) {
    return res.status(500).send('Error revalidating')
  }
}

// Your CMS webhook calls this after content updates
// POST /api/revalidate?secret=your-token&slug=breaking-ai-news
// This immediately regenerates /articles/breaking-ai-news

// Multiple pages can be revalidated in one request
export default async function handler(req, res) {
  if (req.query.secret !== process.env.REVALIDATE_TOKEN) {
    return res.status(401).json({ message: 'Invalid token' })
  }

  try {
    // Regenerate article page and category page
    await res.revalidate(`/articles/${req.query.slug}`)
    await res.revalidate(`/category/tech`) // If it was a tech article
    return res.json({ revalidated: true, pages: 2 })
  } catch (err) {
    return res.status(500).send('Error revalidating')
  }
}

// pages/articles/[slug].js - Complete ISR with error handling
export async function getStaticPaths() {
  // Pre-build only popular articles at build time
  const popularSlugs = ['breaking-news', 'tech-update', 'market-report']
  
  const paths = popularSlugs.map(slug => ({
    params: { slug }
  }))

  return {
    paths,
    fallback: 'blocking' // Generate missing pages on first request
  }
}

export async function getStaticProps({ params }) {
  try {
    // Attempt to fetch article data
    const response = await fetch(`https://api.newswave.com/articles/${params.slug}`)
    
    if (!response.ok) {
      // Article doesn't exist or API is down
      return {
        notFound: true // Shows 404 page instead of broken page
      }
    }

    const article = await response.json()

    return {
      props: { article },
      revalidate: 300 // 5 minutes - balance freshness with API load
    }
  } catch (error) {
    // Network error, API timeout, etc.
    console.error('ISR generation failed:', error)
    
    return {
      notFound: true // Fail gracefully rather than show broken page
    }
  }
}

// Different revalidation strategies for NewsWave content types
export async function getStaticProps({ params }) {
  const { contentType, slug } = params
  let revalidateTime

  // Match revalidation to content update frequency
  switch (contentType) {
    case 'breaking':
      revalidateTime = 30 // Breaking news updates every 30 seconds
      break
    case 'articles':
      revalidateTime = 600 // Regular articles every 10 minutes
      break
    case 'authors':
      revalidateTime = 86400 // Author pages daily
      break
    default:
      revalidateTime = 3600 // Default to hourly
  }

  const content = await fetchContent(contentType, slug)
  
  return {
    props: { content },
    revalidate: revalidateTime
  }
}

// pages/api/revalidate-with-logging.js - Monitor ISR health
export default async function handler(req, res) {
  const startTime = Date.now()
  
  try {
    await res.revalidate(`/articles/${req.query.slug}`)
    
    // Log successful revalidation
    console.log({
      type: 'revalidation_success',
      slug: req.query.slug,
      duration: Date.now() - startTime,
      timestamp: new Date().toISOString()
    })
    
    return res.json({ revalidated: true })
  } catch (error) {
    // Log failed revalidation for monitoring
    console.error({
      type: 'revalidation_error',
      slug: req.query.slug,
      error: error.message,
      duration: Date.now() - startTime,
      timestamp: new Date().toISOString()
    })
    
    return res.status(500).json({ error: 'Revalidation failed' })
  }
}