/**
 * Email Routes
 * Email account management and sorting
 */

import express from 'express'
import { asyncHandler, NotFoundError, AuthorizationError, ValidationError } from '../middleware/errorHandler.mjs'
import { validate, rules } from '../middleware/validate.mjs'
import { limiters } from '../middleware/rateLimit.mjs'
import { respond } from '../utils/response.mjs'
import { emailAccounts, emailStats, emailDigests, userPreferences } from '../services/database.mjs'
import { config, features } from '../config/index.mjs'
import { log } from '../middleware/logger.mjs'

const router = express.Router()

// Lazy load heavy services
let gmailServiceClass = null
let outlookServiceClass = null
let aiSorterInstance = null

async function getGmailService(accessToken, refreshToken) {
  if (!gmailServiceClass) {
    const { GmailService } = await import('../services/gmail.mjs')
    gmailServiceClass = GmailService
  }
  return new gmailServiceClass(accessToken, refreshToken)
}

async function getOutlookService(accessToken) {
  if (!outlookServiceClass) {
    const { OutlookService } = await import('../services/outlook.mjs')
    outlookServiceClass = OutlookService
  }
  return new outlookServiceClass(accessToken)
}

async function getAISorter() {
  if (!aiSorterInstance) {
    const { AISorterService } = await import('../services/ai-sorter.mjs')
    aiSorterInstance = new AISorterService()
  }
  return aiSorterInstance
}

// ═══════════════════════════════════════════════════════════════════════════
// DEMO DATA - Realistic Test Emails
// ═══════════════════════════════════════════════════════════════════════════

const DEMO_EMAILS = [
  { from: 'boss@company.com', subject: 'Urgent: Meeting tomorrow 9 AM', snippet: 'Hi, we need to discuss the new project urgently...' },
  { from: 'billing@amazon.com', subject: 'Your invoice for Order #US123456', snippet: 'Thank you for your order. Please find your invoice attached...' },
  { from: 'newsletter@techcrunch.com', subject: 'TechCrunch Weekly: AI Revolution 2026', snippet: 'This week in Tech: OpenAI announces new model...' },
  { from: 'noreply@linkedin.com', subject: '5 new connection requests', snippet: 'You have new connection requests from: John Smith, Jane Doe...' },
  { from: 'support@stripe.com', subject: 'Payment confirmation: $49.00', snippet: 'Your payment was successfully processed...' },
  { from: 'client@acme-corp.com', subject: 'RE: Web development proposal', snippet: 'Thank you for your proposal. We have a few questions...' },
  { from: 'noreply@google.com', subject: 'Security alert: New sign-in detected', snippet: 'We detected a new sign-in from Windows Chrome...' },
  { from: 'marketing@shopify.com', subject: '50% off today only!', snippet: 'Exclusive offer for our premium customers...' },
  { from: 'team@slack.com', subject: 'New message in #general', snippet: '@Max posted a message: Hey team, how\'s it going...' },
  { from: 'calendar@gmail.com', subject: 'Invitation: Project meeting (Monday 2 PM)', snippet: 'You have been invited to a meeting...' },
  { from: 'john.doe@gmail.com', subject: 'Important: Documents needed by tomorrow', snippet: 'Hi, could you please send the documents by tomorrow morning...' },
  { from: 'billing@verizon.com', subject: 'Your phone bill January 2026', snippet: 'Dear customer, your bill is ready for download...' },
  { from: 'deals@ebay.com', subject: 'Your Watchlist: Price drops!', snippet: '3 items on your watchlist are now cheaper...' },
  { from: 'no-reply@github.com', subject: '[GitHub] Security alert: Dependabot', snippet: 'We found a potential security vulnerability in...' },
  { from: 'newsletter@wired.com', subject: 'Wired Weekly: Cloud Computing Trends', snippet: 'The most important tech news of the week...' },
  { from: 'support@bank.com', subject: 'Account statement January 2026', snippet: 'Your monthly account statement is ready...' },
  { from: 'noreply@twitter.com', subject: '@TechNews replied to your tweet', snippet: 'TechNews: "That\'s an interesting perspective..."' },
  { from: 'info@ups.com', subject: 'Your package is on the way!', snippet: 'Tracking number: 1Z999AA10123456784, Expected delivery...' },
  { from: 'team@notion.so', subject: 'New comments in your workspace', snippet: 'Anna added a comment to "Project Plan"...' },
  { from: 'service@insurance.com', subject: 'Your policy has been updated', snippet: 'Dear customer, we have made changes to your policy...' },
]

/**
 * POST /api/email/connect
 * Connect a new email account
 */
router.post('/connect',
  validate({
    body: {
      userId: [rules.required('userId')],
      provider: [rules.required('provider'), rules.isIn('provider', ['gmail', 'outlook', 'demo'])],
      email: [rules.required('email'), rules.email()],
    },
  }),
  asyncHandler(async (req, res) => {
    const { userId, provider, email, accessToken, refreshToken, expiresAt } = req.body

    // Check if account already exists
    const existingAccounts = await emailAccounts.getByUser(userId)
    const alreadyConnected = existingAccounts.find(a => a.email === email)

    if (alreadyConnected) {
      throw new ValidationError('This email account is already connected', {
        email: ['Already connected'],
      })
    }

    // Create account
    const account = await emailAccounts.create({
      userId,
      provider,
      email,
      accessToken: accessToken || '',
      refreshToken: refreshToken || '',
      expiresAt: expiresAt || 0,
      isActive: true,
      lastSync: null,
    })

    log.success(`Email account connected: ${email} (${provider})`)

    respond.created(res, {
      accountId: account.$id,
      email: account.email,
      provider: account.provider,
    })
  })
)

/**
 * POST /api/email/connect-demo
 * Connect a demo email account for testing
 */
router.post('/connect-demo',
  validate({
    body: {
      userId: [rules.required('userId')],
    },
  }),
  asyncHandler(async (req, res) => {
    const { userId } = req.body
    const demoEmail = `demo-${userId.slice(0, 8)}@emailsorter.demo`

    // Check if demo account already exists
    const existingAccounts = await emailAccounts.getByUser(userId)
    const alreadyConnected = existingAccounts.find(a => a.provider === 'demo')

    if (alreadyConnected) {
      return respond.success(res, {
        accountId: alreadyConnected.$id,
        email: alreadyConnected.email,
        provider: 'demo',
        message: 'Demo account already connected',
      })
    }

    // Create demo account
    const account = await emailAccounts.create({
      userId,
      provider: 'demo',
      email: demoEmail,
      accessToken: 'demo-token',
      refreshToken: '',
      expiresAt: 0,
      isActive: true,
      lastSync: null,
    })

    log.success(`Demo account created for user ${userId}`)

    respond.created(res, {
      accountId: account.$id,
      email: account.email,
      provider: 'demo',
      message: 'Demo account successfully created',
    })
  })
)

/**
 * GET /api/email/accounts
 * Get user's connected email accounts
 */
router.get('/accounts', asyncHandler(async (req, res) => {
  const { userId } = req.query

  if (!userId) {
    throw new ValidationError('userId is required')
  }

  const accounts = await emailAccounts.getByUser(userId)

  // Don't expose tokens
  const safeAccounts = accounts.map(acc => ({
    id: acc.$id,
    email: acc.email,
    provider: acc.provider,
    connected: true,
    lastSync: acc.lastSync,
    isDemo: acc.provider === 'demo',
  }))

  respond.success(res, safeAccounts)
}))

/**
 * DELETE /api/email/accounts/:accountId
 * Disconnect an email account
 */
router.delete('/accounts/:accountId', asyncHandler(async (req, res) => {
  const { accountId } = req.params
  const { userId } = req.query

  if (!userId) {
    throw new ValidationError('userId is required')
  }

  // Verify ownership
  const account = await emailAccounts.get(accountId)

  if (account.userId !== userId) {
    throw new AuthorizationError('No permission for this account')
  }

  await emailAccounts.deactivate(accountId)

  log.info(`Email account disconnected: ${account.email}`)

  respond.success(res, null, 'Account successfully disconnected')
}))

/**
 * GET /api/email/stats
 * Get email sorting statistics
 */
router.get('/stats', asyncHandler(async (req, res) => {
  const { userId } = req.query

  if (!userId) {
    throw new ValidationError('userId is required')
  }

  const stats = await emailStats.getByUser(userId)

  if (!stats) {
    // Return empty stats for new users
    return respond.success(res, {
      totalSorted: 0,
      todaySorted: 0,
      weekSorted: 0,
      categories: {},
      timeSaved: 0,
    })
  }

  respond.success(res, {
    totalSorted: stats.totalSorted || 0,
    todaySorted: stats.todaySorted || 0,
    weekSorted: stats.weekSorted || 0,
    categories: stats.categoriesJson ? JSON.parse(stats.categoriesJson) : {},
    timeSaved: stats.timeSavedMinutes || 0,
  })
}))

/**
 * POST /api/email/sort
 * Trigger email sorting for an account
 * 
 * Options:
 * - maxEmails: Maximum emails to process (default: 500, max: 2000)
 * - processAll: If true, process entire inbox with pagination
 */
router.post('/sort',
  limiters.emailSort,
  validate({
    body: {
      userId: [rules.required('userId')],
      accountId: [rules.required('accountId')],
    },
  }),
  asyncHandler(async (req, res) => {
    const { userId, accountId, maxEmails = 500, processAll = true } = req.body
    const effectiveMax = Math.min(maxEmails, 2000) // Cap at 2000 emails

    // Get account
    const account = await emailAccounts.get(accountId)

    if (account.userId !== userId) {
      throw new AuthorizationError('No permission for this account')
    }

    // Get user preferences
    const prefs = await userPreferences.getByUser(userId)
    const preferences = prefs?.preferences || {}

    // Get AI sorter
    const sorter = await getAISorter()
    let sortedCount = 0
    const results = { byCategory: {} }

    // ═══════════════════════════════════════════════════════════════════════
    // DEMO MODE - Sorting with simulated emails
    // ═══════════════════════════════════════════════════════════════════════
    if (account.provider === 'demo') {
      log.info(`Demo sorting started for user ${userId}`)

      // Select random emails from the demo pool
      const emailCount = Math.min(maxEmails, DEMO_EMAILS.length)
      const shuffled = [...DEMO_EMAILS].sort(() => Math.random() - 0.5)
      const emailsToSort = shuffled.slice(0, emailCount)

      // Check if AI is available
      if (features.ai()) {
        // Real AI sorting with demo data
        const classified = await sorter.batchCategorize(emailsToSort, preferences)

        for (const { classification } of classified) {
          const category = classification.category
          sortedCount++
          results.byCategory[category] = (results.byCategory[category] || 0) + 1
        }

        log.success(`AI sorting completed: ${sortedCount} demo emails`)
      } else {
        // Fallback without AI - simulated categorization
        const categoryDistribution = {
          vip: 0.1,
          customers: 0.15,
          invoices: 0.15,
          newsletters: 0.2,
          social: 0.15,
          promotions: 0.1,
          security: 0.05,
          calendar: 0.05,
          review: 0.05,
        }

        for (const email of emailsToSort) {
          // Simple rule-based categorization
          let category = 'review'
          const from = email.from.toLowerCase()
          const subject = email.subject.toLowerCase()

          if (from.includes('boss') || from.includes('john.doe')) {
            category = 'vip'
          } else if (from.includes('billing') || subject.includes('invoice') || subject.includes('bill')) {
            category = 'invoices'
          } else if (from.includes('newsletter') || subject.includes('weekly') || subject.includes('news')) {
            category = 'newsletters'
          } else if (from.includes('linkedin') || from.includes('twitter') || from.includes('slack')) {
            category = 'social'
          } else if (from.includes('client') || subject.includes('proposal') || subject.includes('project')) {
            category = 'customers'
          } else if (from.includes('security') || subject.includes('security') || subject.includes('sign-in')) {
            category = 'security'
          } else if (subject.includes('off') || subject.includes('deal') || from.includes('marketing')) {
            category = 'promotions'
          } else if (subject.includes('invitation') || subject.includes('meeting') || subject.includes('calendar')) {
            category = 'calendar'
          }

          sortedCount++
          results.byCategory[category] = (results.byCategory[category] || 0) + 1
        }

        log.success(`Rule-based sorting completed: ${sortedCount} demo emails`)
      }
    }
    // ═══════════════════════════════════════════════════════════════════════
    // GMAIL - Real Gmail sorting with native categories
    // ═══════════════════════════════════════════════════════════════════════
    else if (account.provider === 'gmail') {
      if (!features.ai()) {
        throw new ValidationError('AI sorting is not configured. Please set MISTRAL_API_KEY.')
      }

      if (!account.accessToken) {
        throw new ValidationError('Gmail account needs to be reconnected')
      }

      log.info(`Gmail sorting started for ${account.email}`)

      try {
        const gmail = await getGmailService(account.accessToken, account.refreshToken)

        // FIRST: Clean up old "EmailSorter/..." labels
        const deletedLabels = await gmail.cleanupOldLabels()
        if (deletedLabels > 0) {
          log.success(`${deletedLabels} old labels cleaned up`)
        }

        // Create labels only for categories without native Gmail category
        const categories = sorter.getCategories()
        const labelMap = {}

        for (const [key, cat] of Object.entries(categories)) {
          // Wenn Gmail-Kategorie existiert, diese verwenden
          const gmailCat = sorter.getGmailCategory(key)
          if (gmailCat) {
            labelMap[key] = gmailCat // z.B. CATEGORY_SOCIAL
          } else {
            // Create custom label (clean name without prefix)
            try {
              const label = await gmail.createLabel(cat.name, cat.color)
              if (label) {
                labelMap[key] = label.id
              }
            } catch (err) {
              log.warn(`Failed to create label: ${cat.name}`)
            }
          }
        }

        // Fetch and process ALL emails with pagination
        let pageToken = null
        let totalProcessed = 0
        const batchSize = 100 // Gmail API batch size

        do {
          // Fetch batch of messages
          const { messages, nextPageToken } = await gmail.listEmails(
            batchSize, 
            pageToken, 
            'in:inbox' // All inbox emails
          )
          pageToken = nextPageToken

          if (!messages?.length) break

          // Get full email details
          const emails = await gmail.batchGetEmails(messages.map(m => m.id))

          // Classify emails with AI
          const classified = await sorter.batchCategorize(
            emails.map(e => ({
              from: e.headers?.from || '',
              subject: e.headers?.subject || '',
              snippet: e.snippet || '',
            })),
            preferences
          )

          // Apply labels/categories and actions
          for (let i = 0; i < classified.length; i++) {
            const email = emails[i]
            const { category } = classified[i].classification
            const action = sorter.getCategoryAction(category)

            try {
              const labelsToAdd = []
              const labelsToRemove = []
              
              // Add label/category
              if (labelMap[category]) {
                labelsToAdd.push(labelMap[category])
              }

              // Handle different actions
              switch (action) {
                case 'star':
                  // Keep in inbox + add star
                  labelsToAdd.push('STARRED')
                  break

                case 'archive_read':
                  // Archive + mark as read (clean inbox)
                  labelsToRemove.push('INBOX', 'UNREAD')
                  break

                case 'archive':
                  // Just archive (legacy)
                  labelsToRemove.push('INBOX')
                  break

                case 'inbox':
                default:
                  // Keep in inbox, no changes needed
                  break
              }

              // Apply label changes
              if (labelsToAdd.length > 0) {
                await gmail.addLabels(email.id, labelsToAdd)
              }
              if (labelsToRemove.length > 0) {
                await gmail.removeLabels(email.id, labelsToRemove)
              }

              sortedCount++
              results.byCategory[category] = (results.byCategory[category] || 0) + 1
            } catch (err) {
              log.warn(`Email sorting failed: ${email.id}`, { error: err.message })
            }
          }

          totalProcessed += emails.length
          log.info(`Processed ${totalProcessed} emails so far...`)

          // Stop if we've hit the limit or there's no more pages
          if (totalProcessed >= effectiveMax) {
            log.info(`Reached limit of ${effectiveMax} emails`)
            break
          }

          // Small delay between batches to avoid rate limiting
          if (pageToken) {
            await new Promise(r => setTimeout(r, 200))
          }
        } while (pageToken && processAll)

        log.success(`Gmail sorting completed: ${sortedCount} emails processed`)
      } catch (err) {
        log.error('Gmail sorting failed', { error: err.message })
        throw new ValidationError(`Gmail error: ${err.message}. Please reconnect account.`)
      }
    }
    // ═══════════════════════════════════════════════════════════════════════
    // OUTLOOK - Real Outlook sorting
    // ═══════════════════════════════════════════════════════════════════════
    else if (account.provider === 'outlook') {
      if (!features.ai()) {
        throw new ValidationError('AI sorting is not configured. Please set MISTRAL_API_KEY.')
      }

      if (!account.accessToken) {
        throw new ValidationError('Outlook account needs to be reconnected')
      }

      log.info(`Outlook sorting started for ${account.email}`)

      try {
        const outlook = await getOutlookService(account.accessToken)

        // Fetch and process ALL emails with pagination
        let skipToken = null
        let totalProcessed = 0
        const batchSize = 100

        do {
          // Fetch batch of messages
          const { messages, nextLink } = await outlook.listEmails(batchSize, skipToken)
          skipToken = nextLink

          if (!messages?.length) break

          // Classify emails with AI
          const classified = await sorter.batchCategorize(
            messages.map(e => ({
              from: e.from?.emailAddress?.address || '',
              subject: e.subject || '',
              snippet: e.bodyPreview || '',
            })),
            preferences
          )

          // Apply categories and actions
          for (let i = 0; i < classified.length; i++) {
            const email = messages[i]
            const { category } = classified[i].classification
            const action = sorter.getCategoryAction(category)
            const catName = sorter.getLabelName(category)

            try {
              await outlook.addCategories(email.id, [catName])

              // Handle different actions
              switch (action) {
                case 'archive_read':
                  // Archive + mark as read
                  await outlook.archiveEmail(email.id)
                  await outlook.markAsRead(email.id)
                  break

                case 'archive':
                  await outlook.archiveEmail(email.id)
                  break

                case 'star':
                  await outlook.flagEmail(email.id)
                  break
              }

              sortedCount++
              results.byCategory[category] = (results.byCategory[category] || 0) + 1
            } catch (err) {
              log.warn(`Email sorting failed: ${email.id}`)
            }
          }

          totalProcessed += messages.length
          log.info(`Processed ${totalProcessed} emails so far...`)

          // Stop if we've hit the limit
          if (totalProcessed >= effectiveMax) {
            log.info(`Reached limit of ${effectiveMax} emails`)
            break
          }

          // Small delay between batches
          if (skipToken) {
            await new Promise(r => setTimeout(r, 200))
          }
        } while (skipToken && processAll)

        log.success(`Outlook sorting completed: ${sortedCount} emails processed`)
      } catch (err) {
        log.error('Outlook sorting failed', { error: err.message })
        throw new ValidationError(`Outlook error: ${err.message}. Please reconnect account.`)
      }
    }

    // Update last sync
    await emailAccounts.updateLastSync(accountId)

    // Update stats
    const timeSaved = Math.round(sortedCount * 0.25) // 15 seconds per email
    await emailStats.increment(userId, {
      total: sortedCount,
      today: sortedCount,
      week: sortedCount,
      timeSaved,
    })

    // Update categories in stats
    try {
      const currentStats = await emailStats.getByUser(userId)
      if (currentStats) {
        const existingCategories = currentStats.categoriesJson 
          ? JSON.parse(currentStats.categoriesJson) 
          : {}
        
        for (const [cat, count] of Object.entries(results.byCategory)) {
          existingCategories[cat] = (existingCategories[cat] || 0) + count
        }

        await emailStats.updateCategories(userId, existingCategories)
      }
    } catch (err) {
      log.warn('Category update failed', { error: err.message })
    }

    // Calculate inbox cleared (archived emails)
    const archivedCategories = ['newsletters', 'promotions', 'social']
    const inboxCleared = archivedCategories.reduce((sum, cat) => 
      sum + (results.byCategory[cat] || 0), 0
    )

    // Generate digest highlights (important emails)
    const highlights = []
    if (results.byCategory.vip > 0) {
      highlights.push({ type: 'vip', count: results.byCategory.vip, message: `${results.byCategory.vip} important emails need attention` })
    }
    if (results.byCategory.security > 0) {
      highlights.push({ type: 'security', count: results.byCategory.security, message: `${results.byCategory.security} security notifications` })
    }
    if (results.byCategory.invoices > 0) {
      highlights.push({ type: 'invoices', count: results.byCategory.invoices, message: `${results.byCategory.invoices} invoices received` })
    }

    // Generate suggestions (potential unsubscribes)
    const suggestions = []
    if (results.byCategory.newsletters > 5) {
      suggestions.push({ type: 'unsubscribe', message: 'Consider unsubscribing from some newsletters to reduce inbox clutter' })
    }
    if (results.byCategory.promotions > 10) {
      suggestions.push({ type: 'unsubscribe', message: 'High volume of promotional emails - review subscriptions' })
    }

    // Update daily digest
    try {
      await emailDigests.updateToday(userId, {
        stats: results.byCategory,
        highlights,
        suggestions,
        totalSorted: sortedCount,
        inboxCleared,
        timeSavedMinutes: timeSaved,
      })
    } catch (err) {
      log.warn('Digest update failed', { error: err.message })
    }

    log.success(`Sorting completed: ${sortedCount} emails for ${account.email}`)

    respond.success(res, {
      sorted: sortedCount,
      inboxCleared,
      categories: results.byCategory,
      timeSaved: {
        minutes: timeSaved,
        formatted: timeSaved > 0 ? `${timeSaved} minutes` : '< 1 minute',
      },
      highlights,
      suggestions,
      provider: account.provider,
      isDemo: account.provider === 'demo',
    })
  })
)

/**
 * POST /api/email/sort-demo
 * Quick demo sorting without account (for testing)
 */
router.post('/sort-demo', asyncHandler(async (req, res) => {
  const { count = 10 } = req.body

  log.info(`Quick demo sorting: ${count} emails`)

  // Get AI sorter
  const sorter = await getAISorter()
  const results = { byCategory: {} }

  // Select random emails
  const emailCount = Math.min(count, DEMO_EMAILS.length)
  const shuffled = [...DEMO_EMAILS].sort(() => Math.random() - 0.5)
  const emailsToSort = shuffled.slice(0, emailCount)

  if (features.ai()) {
    // Real AI sorting
    const classified = await sorter.batchCategorize(emailsToSort, {})

    const sortedEmails = emailsToSort.map((email, i) => ({
      ...email,
      category: classified[i].classification.category,
      categoryName: sorter.getLabelName(classified[i].classification.category),
      confidence: classified[i].classification.confidence,
      reason: classified[i].classification.reason,
    }))

    for (const email of sortedEmails) {
      results.byCategory[email.category] = (results.byCategory[email.category] || 0) + 1
    }

    respond.success(res, {
      sorted: emailCount,
      emails: sortedEmails,
      categories: results.byCategory,
      aiEnabled: true,
    })
  } else {
    // Rule-based sorting
    const sortedEmails = emailsToSort.map(email => {
      let category = 'review'
      const from = email.from.toLowerCase()
      const subject = email.subject.toLowerCase()

      if (from.includes('boss') || from.includes('john.doe')) {
        category = 'vip'
      } else if (from.includes('billing') || subject.includes('invoice')) {
        category = 'invoices'
      } else if (from.includes('newsletter') || subject.includes('weekly')) {
        category = 'newsletters'
      } else if (from.includes('linkedin') || from.includes('twitter')) {
        category = 'social'
      } else if (from.includes('client') || subject.includes('proposal')) {
        category = 'customers'
      } else if (subject.includes('security') || subject.includes('sign-in')) {
        category = 'security'
      } else if (subject.includes('off') || from.includes('marketing')) {
        category = 'promotions'
      } else if (subject.includes('invitation') || subject.includes('meeting')) {
        category = 'calendar'
      }

      results.byCategory[category] = (results.byCategory[category] || 0) + 1

      return {
        ...email,
        category,
        categoryName: sorter.getLabelName(category),
      }
    })

    respond.success(res, {
      sorted: emailCount,
      emails: sortedEmails,
      categories: results.byCategory,
      aiEnabled: false,
      message: 'AI not configured - rule-based sorting used',
    })
  }
}))

/**
 * POST /api/email/cleanup
 * Cleanup old EmailSorter labels from Gmail
 */
router.post('/cleanup',
  validate({
    body: {
      userId: [rules.required('userId')],
      accountId: [rules.required('accountId')],
    },
  }),
  asyncHandler(async (req, res) => {
    const { userId, accountId } = req.body

    const account = await emailAccounts.get(accountId)

    if (account.userId !== userId) {
      throw new AuthorizationError('No permission for this account')
    }

    if (account.provider !== 'gmail') {
      return respond.success(res, { deleted: 0, message: 'Cleanup only available for Gmail' })
    }

    log.info(`Label cleanup started for ${account.email}`)

    const gmail = await getGmailService(account.accessToken, account.refreshToken)
    const deleted = await gmail.cleanupOldLabels()

    log.success(`${deleted} old labels deleted`)

    respond.success(res, { 
      deleted, 
      message: deleted > 0 
        ? `${deleted} old "EmailSorter/..." labels were deleted` 
        : 'No old labels found' 
    })
  })
)

/**
 * GET /api/email/digest
 * Get today's sorting digest summary
 */
router.get('/digest', asyncHandler(async (req, res) => {
  const { userId } = req.query

  if (!userId) {
    throw new ValidationError('userId is required')
  }

  const digest = await emailDigests.getByUserToday(userId)

  if (!digest) {
    // Return empty digest for new users
    return respond.success(res, {
      date: new Date().toISOString().split('T')[0],
      totalSorted: 0,
      inboxCleared: 0,
      timeSavedMinutes: 0,
      stats: {},
      highlights: [],
      suggestions: [],
      hasData: false,
    })
  }

  respond.success(res, {
    date: digest.date,
    totalSorted: digest.totalSorted,
    inboxCleared: digest.inboxCleared,
    timeSavedMinutes: digest.timeSavedMinutes,
    stats: digest.stats,
    highlights: digest.highlights,
    suggestions: digest.suggestions,
    hasData: true,
  })
}))

/**
 * GET /api/email/digest/history
 * Get digest history for the last N days
 */
router.get('/digest/history', asyncHandler(async (req, res) => {
  const { userId, days = 7 } = req.query

  if (!userId) {
    throw new ValidationError('userId is required')
  }

  const digests = await emailDigests.getByUserRecent(userId, parseInt(days))

  // Calculate totals
  const totals = {
    totalSorted: digests.reduce((sum, d) => sum + (d.totalSorted || 0), 0),
    inboxCleared: digests.reduce((sum, d) => sum + (d.inboxCleared || 0), 0),
    timeSavedMinutes: digests.reduce((sum, d) => sum + (d.timeSavedMinutes || 0), 0),
  }

  respond.success(res, {
    days: parseInt(days),
    digests: digests.map(d => ({
      date: d.date,
      totalSorted: d.totalSorted,
      inboxCleared: d.inboxCleared,
      timeSavedMinutes: d.timeSavedMinutes,
      stats: d.stats,
    })),
    totals,
  })
}))

/**
 * GET /api/email/categories
 * Get all available categories
 */
router.get('/categories', asyncHandler(async (req, res) => {
  const sorter = await getAISorter()
  const categories = sorter.getCategories()

  const formattedCategories = Object.entries(categories).map(([key, cat]) => ({
    id: key,
    name: cat.name,
    description: cat.description,
    color: cat.color,
    action: cat.action,
    priority: cat.priority,
  }))

  respond.success(res, formattedCategories)
}))

/**
 * POST /api/email/webhook/gmail
 * Gmail push notification webhook
 */
router.post('/webhook/gmail', asyncHandler(async (req, res) => {
  // Acknowledge immediately
  res.status(200).send()

  const { message } = req.body
  if (!message?.data) return

  try {
    const data = JSON.parse(Buffer.from(message.data, 'base64').toString())
    log.info(`Gmail Webhook: ${data.emailAddress}`, { historyId: data.historyId })
    // Queue processing in production
  } catch (err) {
    log.error('Gmail Webhook Error', { error: err.message })
  }
}))

/**
 * POST /api/email/webhook/outlook
 * Microsoft Graph webhook
 */
router.post('/webhook/outlook', asyncHandler(async (req, res) => {
  // Handle validation request
  if (req.query.validationToken) {
    return res.status(200).send(req.query.validationToken)
  }

  res.status(202).send()

  const { value } = req.body
  if (!value?.length) return

  for (const notification of value) {
    log.info(`Outlook Webhook: ${notification.changeType}`, { resource: notification.resource })
    // Queue processing in production
  }
}))

export default router