'use strict'
// ─────────────────────────────────────────────────────────────────────────────
// Gift campaigns — backend for the ops UI.
//
// One campaign = one Mailjet blast of personalized French emails containing a
// Giftbit shortlink. Two CSVs come in (raw Map export + Giftbit shortlinks),
// we match each contact to an ERPNext Customer (email / phone / civic address),
// store the send list as JSON, and run the send in the background with live
// progress over SSE.
//
// Storage layout:
//   data/campaigns/<campaign-id>.json
//     {
//       id, name, created_at, status: draft|sending|completed|failed,
//       params: { amount, expiry, commitment_months, subject, from, template,
//                 throttle_ms, smtp_host, smtp_port },
//       counters: { total, sent, failed, queued, opened, clicked, bounced },
//       recipients: [{
//         firstname, lastname, email, phone, civic_address, postal_code,
//         gift_url, giftbit_uuid, gift_value_cents,
//         customer_id,           # null if unmatched
//         customer_name,         # display name from ERPNext
//         match_method,          # 'email' | 'phone' | 'civic' | null
//         match_confidence,      # 1.0 (exact) | 0.8 (postal+civic) | 0 (none)
//         status,                # pending | queued | sent | failed | clicked | bounced
//         mailjet_uuid,          # set when sent (used by webhook to update)
//         error, sent_at, opened_at, clicked_at,
//         excluded               # true = skip on send
//       }]
//     }
//
// SSE topic: 'campaign:<id>' — emits 'recipient-update' on every status change
// and 'campaign-done' when send finishes.
// ─────────────────────────────────────────────────────────────────────────────

const fs    = require('fs')
const path  = require('path')
const crypto = require('crypto')
const cfg   = require('./config')
const { log, json, parseBody } = require('./helpers')
const erp   = require('./erp')
const email = require('./email')
const sse   = require('./sse')

const DATA_DIR = path.join(__dirname, '..', 'data', 'campaigns')
if (!fs.existsSync(DATA_DIR)) fs.mkdirSync(DATA_DIR, { recursive: true })

// ── CSV utilities ────────────────────────────────────────────────────────────
// Same RFC-4180-ish parser as the CLI scripts. Handles quoted fields with
// embedded delimiters and escaped double-quotes. Delimiter auto-detect
// (comma / tab / pipe) based on the first line.
function parseCsv (text, opts = {}) {
  const skipPreamble = !!opts.skipPreamble
  let work = text.replace(/^/, '')               // strip BOM
  if (skipPreamble) work = work.replace(/^[^\n]*\n/, '') // drop title line

  const sample = work.split(/\r?\n/, 1)[0] || ''
  const delim = sample.includes('|') ? '|'
              : sample.includes('\t') ? '\t'
              : ','
  const rows = []; let row = [], field = '', inQ = false
  for (let i = 0; i < work.length; i++) {
    const c = work[i]
    if (inQ) {
      if (c === '"' && work[i + 1] === '"') { field += '"'; i++ }
      else if (c === '"') inQ = false
      else field += c
    } else {
      if (c === '"') inQ = true
      else if (c === delim) { row.push(field); field = '' }
      else if (c === '\n' || c === '\r') {
        if (field !== '' || row.length) { row.push(field); rows.push(row); row = []; field = '' }
        if (c === '\r' && work[i + 1] === '\n') i++
      } else field += c
    }
  }
  if (field !== '' || row.length) { row.push(field); rows.push(row) }
  if (!rows.length) return []
  const header = rows[0].map(h => h.trim())
  return rows.slice(1).filter(r => r.some(c => c !== '')).map(r => {
    const o = {}; header.forEach((h, i) => { o[h] = (r[i] || '').trim() }); return o
  })
}

// ── Address / name normalization (mirrors contacts_from_legacy.py) ──────────
const LOWER_WORDS = new Set(['de','du','des','la','le','les','au','aux','à',
                             'et','sur','en'])
const EMAIL_SPLIT = /\s*[;,]\s*/

function titleAddress (addr) {
  if (!addr) return ''
  return addr.split(/\s+/).map((word, i) => {
    const lw = word.toLowerCase()
    if (i > 0 && LOWER_WORDS.has(lw)) return lw
    if (word.includes('-')) {
      return word.split('-').map(c => {
        const cl = c.toLowerCase()
        return LOWER_WORDS.has(cl) ? cl : (c[0] || '').toUpperCase() + c.slice(1).toLowerCase()
      }).join('-')
    }
    return (word[0] || '').toUpperCase() + word.slice(1).toLowerCase()
  }).join(' ')
}

function normalizeEmail (raw) {
  return (raw || '').trim().toLowerCase()
}

// Strip non-digit chars; treat as Canadian 10-digit if longer than 10
function normalizePhone (raw) {
  const digits = (raw || '').replace(/\D/g, '')
  if (digits.length === 11 && digits.startsWith('1')) return digits.slice(1)
  if (digits.length === 10) return digits
  return digits || null
}

// Canadian postal H1A 1B1 — uppercase, no internal space
function normalizePostal (raw) {
  return (raw || '').replace(/\s+/g, '').toUpperCase().replace(/^([A-Z]\d[A-Z])(\d[A-Z]\d)$/, '$1 $2')
}

// Civic = numeric prefix + first non-empty street word. We compare prefix +
// first 5 chars of street to avoid false-positives from "Rue" vs "Route".
function normalizeCivic (addr) {
  if (!addr) return null
  const m = addr.trim().match(/^(\d+[A-Za-z]?)\s+(.+)$/)
  if (!m) return null
  const num = m[1].toUpperCase()
  // Strip "Rue", "Route", "Boulevard" etc. — they're noise for matching
  const street = m[2].replace(/^(rue|route|boulevard|boul\.?|avenue|av\.?|chemin|ch\.?|place|pl\.?)\s+/i, '').trim()
  return num + '|' + street.toLowerCase().slice(0, 12)
}

// ── Map CSV parsing — port of contacts_from_legacy.py ────────────────────────
// The legacy export has a 1-line title preamble + pipe-delimited columns.
// Columns we care about:
//   "nom au compte"           — billing contact name (preferred)
//   "nom à l'adresse"         — service-address name (fallback)
//   "email au compte"         — billing email (preferred)
//   "email à l'adresse"       — service-address email (fallback)
//   "telephone au compte" or "telephone à l'adresse" — phone for matching
//   "adresse dans F"          — street address
//   "code postal au compte" or "code postal à l'adresse" — postal
//   "id emplacement"          — legacy_delivery_id (note: only 25% resolves)
function parseMapCsv (text, multi = 'first') {
  const rows = parseCsv(text, { skipPreamble: true })
  const contacts = []
  const seen = new Set()
  let skippedNoEmail = 0, skippedNoName = 0

  for (const r of rows) {
    // Pull emails from either source column
    let rawEmails = (r['email au compte'] || r["email à l'adresse"] || '').trim()
    if (!rawEmails) { skippedNoEmail++; continue }
    const emails = rawEmails.split(EMAIL_SPLIT)
                            .map(e => normalizeEmail(e))
                            .filter(e => e.includes('@') && e.split('@')[1]?.includes('.'))
    if (!emails.length) { skippedNoEmail++; continue }

    const sendEmails = multi === 'split' ? emails
                     : multi === 'skip'  ? (emails.length > 1 ? [] : emails)
                     : emails.slice(0, 1)
    if (!sendEmails.length) continue

    const full = (r['nom au compte'] || r["nom à l'adresse"] || '').trim()
    if (!full) { skippedNoName++; continue }
    const parts = full.split(/\s+/, 2)
    const firstname = parts[0] || ''
    const lastname  = parts.length > 1 ? full.slice(parts[0].length).trim() : ''

    const civic_address = titleAddress(r['adresse dans F'] || '')
    const postal_code   = normalizePostal(r['code postal au compte'] || r["code postal à l'adresse"] || '')
    const phone         = normalizePhone(r['telephone au compte'] || r["telephone à l'adresse"] || '')

    for (const em of sendEmails) {
      if (seen.has(em)) continue
      seen.add(em)
      contacts.push({
        firstname, lastname,
        email: em,
        phone,
        civic_address,
        postal_code,
      })
    }
  }
  return { contacts, skipped: { no_email: skippedNoEmail, no_name: skippedNoName, total_rows: rows.length } }
}

// ── Giftbit CSV parsing ──────────────────────────────────────────────────────
function parseGiftbitCsv (text) {
  const rows = parseCsv(text)
  if (!rows.length) return []
  // Detect URL column from common names
  const keys = Object.keys(rows[0])
  const urlCandidates = ['gift_url','gift link','gift_link','url','link','shortlink',
                         'redemption_url','gift','giftbit_link','campaign_link']
  let urlCol = null
  for (const c of urlCandidates) {
    const hit = keys.find(k => k.toLowerCase().replace(/\s+/g, '_') === c)
    if (hit) { urlCol = hit; break }
  }
  // Fallback: any column with http(s)://
  if (!urlCol) {
    for (const k of keys) {
      if ((rows[0][k] || '').match(/^https?:\/\//)) { urlCol = k; break }
    }
  }
  if (!urlCol) return []

  return rows.map(r => ({
    gift_url:          r[urlCol],
    giftbit_uuid:      r.giftbit_uuid || r.uuid || r.gift_id || '',
    gift_value_cents:  parseInt(r.gift_value_cents || r.value_cents || r.amount || '0', 10) || 0,
    email:             normalizeEmail(r.email || ''),
    firstname:         r.firstname || '',
    lastname:          r.lastname || '',
    internal_id:       r.internal_id || '',
  }))
}

// ── Customer matching against ERPNext ────────────────────────────────────────
// Strategy: email → phone → civic+postal. First hit wins. Confidence:
//   1.0 = exact email match
//   0.9 = exact phone match
//   0.8 = civic + postal_code on a Service Location (then customer link)
//   0   = unmatched
async function matchCustomer (recipient) {
  // 1) Email match on Customer.email_id (most reliable)
  if (recipient.email) {
    try {
      const r = await erp.list('Customer', {
        fields: ['name', 'customer_name', 'email_id', 'mobile_no'],
        filters: [['email_id', '=', recipient.email]],
        limit: 1,
      })
      if (r && r.length) {
        return { customer_id: r[0].name, customer_name: r[0].customer_name,
                 match_method: 'email', match_confidence: 1.0 }
      }
    } catch (e) { log('match email error:', e.message) }
  }

  // 2) Phone match
  if (recipient.phone) {
    try {
      // Try both mobile_no (with various formattings) and the canonical 10-digit form
      const r = await erp.list('Customer', {
        fields: ['name', 'customer_name', 'mobile_no'],
        filters: [['mobile_no', 'like', '%' + recipient.phone.slice(-7) + '%']],
        limit: 5,
      })
      // Filter to exact digit match
      const hit = (r || []).find(c => normalizePhone(c.mobile_no) === recipient.phone)
      if (hit) {
        return { customer_id: hit.name, customer_name: hit.customer_name,
                 match_method: 'phone', match_confidence: 0.9 }
      }
    } catch (e) { log('match phone error:', e.message) }
  }

  // 3) Civic + postal on Service Location → Customer
  if (recipient.civic_address && recipient.postal_code) {
    try {
      const civic = normalizeCivic(recipient.civic_address)
      if (civic) {
        const [num, streetPrefix] = civic.split('|')
        const r = await erp.list('Service Location', {
          fields: ['name', 'address_line', 'postal_code', 'customer', 'customer_name'],
          filters: [
            ['postal_code', '=', recipient.postal_code],
            ['address_line', 'like', num + '%'],
          ],
          limit: 10,
        })
        const hit = (r || []).find(sl => {
          const slCivic = normalizeCivic(sl.address_line)
          return slCivic && slCivic.startsWith(num + '|') &&
                 slCivic.split('|')[1]?.startsWith(streetPrefix.slice(0, 5))
        })
        if (hit && hit.customer) {
          return { customer_id: hit.customer, customer_name: hit.customer_name || hit.customer,
                   match_method: 'civic', match_confidence: 0.8 }
        }
      }
    } catch (e) { log('match civic error:', e.message) }
  }

  return { customer_id: null, customer_name: null, match_method: null, match_confidence: 0 }
}

// ── Storage helpers ──────────────────────────────────────────────────────────
function campaignPath (id) {
  // Defensive: prevent path traversal — IDs are uuid-like; reject anything else
  if (!/^[a-zA-Z0-9_-]+$/.test(id)) throw new Error('invalid campaign id')
  return path.join(DATA_DIR, id + '.json')
}

function listCampaigns () {
  if (!fs.existsSync(DATA_DIR)) return []
  return fs.readdirSync(DATA_DIR)
    .filter(f => f.endsWith('.json'))
    .map(f => {
      try {
        const c = JSON.parse(fs.readFileSync(path.join(DATA_DIR, f), 'utf8'))
        return { id: c.id, name: c.name, created_at: c.created_at,
                 status: c.status, counters: c.counters,
                 total: (c.recipients || []).length }
      } catch { return null }
    })
    .filter(Boolean)
    .sort((a, b) => (b.created_at || '').localeCompare(a.created_at || ''))
}

function loadCampaign (id) {
  const p = campaignPath(id)
  if (!fs.existsSync(p)) return null
  return JSON.parse(fs.readFileSync(p, 'utf8'))
}

function saveCampaign (campaign) {
  // Recompute counters from recipients every save — single source of truth
  const c = { ...campaign }
  c.counters = (c.recipients || []).reduce((acc, r) => {
    acc[r.status] = (acc[r.status] || 0) + 1
    return acc
  }, { total: (c.recipients || []).length })
  fs.writeFileSync(campaignPath(c.id), JSON.stringify(c, null, 2))
  return c
}

function newCampaignId () {
  const stamp = new Date().toISOString().slice(0, 10).replace(/-/g, '')
  const slug = crypto.randomBytes(3).toString('hex')
  return `cmp-${stamp}-${slug}`
}

// ── Template rendering (mirrors send_gift_campaign.js) ───────────────────────
function renderTemplate (tpl, vars) {
  // Section blocks first: {{#var}}...{{/var}} kept if var truthy
  tpl = tpl.replace(/\{\{\s*#\s*(\w+)\s*\}\}([\s\S]*?)\{\{\s*\/\s*\1\s*\}\}/g,
                    (_, k, body) => (vars[k] ? body : ''))
  return tpl.replace(/\{\{\s*(\w+)\s*\}\}/g, (_, k) => {
    const v = vars[k]
    return v == null ? '' : String(v)
  })
}

// Default template path — bundled inside the hub at services/targo-hub/templates/.
// Can be overridden per campaign via params.template_path (e.g. for A/B testing).
// Keep the file in sync with scripts/campaigns/templates/gift-email-fr.html
// (the CLI uses that copy for one-off batch sends outside the hub).
const TEMPLATES_DIR  = path.resolve(__dirname, '..', 'templates')
const DEFAULT_TEMPLATE = path.join(TEMPLATES_DIR, 'gift-email-fr.html')

// Allow-list templates that can be edited via the API. Anything outside this
// list is rejected (path-traversal defence + intent: only campaign-related
// templates are exposed; contract-residential.html etc. are NOT editable here).
const EDITABLE_TEMPLATES = ['gift-email-fr']

function templatePath (name) {
  if (!EDITABLE_TEMPLATES.includes(name)) {
    throw new Error(`template not editable: ${name}`)
  }
  return path.join(TEMPLATES_DIR, name + '.html')
}

function listEditableTemplates () {
  return EDITABLE_TEMPLATES.map(name => {
    const p = path.join(TEMPLATES_DIR, name + '.html')
    let size = 0, modified = null
    try {
      const stat = fs.statSync(p)
      size = stat.size
      modified = stat.mtime.toISOString()
    } catch {}
    return { name, size, modified }
  })
}

function readTemplate (tplPath) {
  const p = tplPath || DEFAULT_TEMPLATE
  if (!fs.existsSync(p)) {
    throw new Error(`Template not found: ${p}`)
  }
  return fs.readFileSync(p, 'utf8')
}

// ── Send-async worker ────────────────────────────────────────────────────────
// Iterates recipients (not excluded, status=pending), sends each via the
// existing email lib, broadcasts each status change over SSE. Throttle is
// configurable. Failures stop only that recipient — the loop continues.
//
// Runs in the background — caller fires this and returns immediately.
const activeWorkers = new Set()

async function sendCampaignAsync (id) {
  if (activeWorkers.has(id)) {
    log(`campaign ${id} already sending`)
    return
  }
  activeWorkers.add(id)
  const topic = `campaign:${id}`

  try {
    let campaign = loadCampaign(id)
    if (!campaign) throw new Error(`campaign ${id} not found`)
    campaign.status = 'sending'
    campaign.send_started_at = new Date().toISOString()
    campaign = saveCampaign(campaign)
    sse.broadcast(topic, 'campaign-status', { id, status: 'sending' })

    const p = campaign.params || {}
    const tplText = readTemplate(p.template_path)
    const throttle = parseInt(p.throttle_ms || 600, 10)

    for (let i = 0; i < campaign.recipients.length; i++) {
      const r = campaign.recipients[i]
      if (r.excluded || r.status !== 'pending') continue

      // Mark queued so the UI shows movement immediately
      r.status = 'queued'
      saveCampaign(campaign)
      sse.broadcast(topic, 'recipient-update', { i, recipient: r })

      const vars = {
        firstname:         r.firstname || 'cher client',
        lastname:          r.lastname  || '',
        email:             r.email,
        description:       r.civic_address || '',
        gift_url:          r.gift_url,
        amount:            p.amount || '50 $',
        expiry:            p.expiry || '',
        commitment_months: p.commitment_months || '3',
      }
      const html = renderTemplate(tplText, vars)
      const toName = `${r.firstname || ''} ${r.lastname || ''}`.trim()
      const to = toName ? `"${toName}" <${r.email}>` : r.email

      // Set Mailjet CustomID = campaign_id:recipient_index so the Event API
      // webhook events can be matched back to a specific recipient row.
      // Mailjet echoes this value in every event under the CustomID field;
      // SMTP messageId alone is not a reliable join key (different ID space).
      const customId = `${id}:${i}`
      r.mailjet_custom_id = customId

      // email.sendEmail returns the nodemailer info object on success
      // (truthy, with .messageId), or `false` on failure (error logged in
      // lib/email.js). It doesn't throw. We treat falsy = failed.
      let sendRes
      try {
        sendRes = await email.sendEmail({
          to,
          subject: p.subject || 'Un cadeau pour vous, de la part de TARGO',
          html,
          from: p.from || cfg.MAIL_FROM,
          headers: { 'X-MJ-CustomID': customId },
        })
      } catch (e) {
        sendRes = false
        r.error = String(e.message || e).slice(0, 500)
      }
      if (sendRes && sendRes.messageId !== undefined) {
        r.mailjet_uuid = sendRes.messageId || null   // SMTP Message-ID for reference
        r.status = 'sent'
        r.sent_at = new Date().toISOString()
        r.error = null
      } else {
        r.status = 'failed'
        if (!r.error) r.error = 'SMTP send returned false (see hub logs)'
        log(`campaign ${id} recipient ${i} failed:`, r.error)
      }

      saveCampaign(campaign)
      sse.broadcast(topic, 'recipient-update', { i, recipient: r })

      if (throttle > 0) await new Promise(rs => setTimeout(rs, throttle))
    }

    campaign = loadCampaign(id)
    campaign.status = 'completed'
    campaign.send_completed_at = new Date().toISOString()
    campaign = saveCampaign(campaign)
    sse.broadcast(topic, 'campaign-done', { id, counters: campaign.counters })
    log(`campaign ${id} done — ${campaign.counters.sent || 0} sent, ${campaign.counters.failed || 0} failed`)
  } catch (e) {
    log(`campaign ${id} worker failed:`, e.message)
    try {
      const c = loadCampaign(id)
      if (c) {
        c.status = 'failed'
        c.error = String(e.message || e)
        saveCampaign(c)
        sse.broadcast(topic, 'campaign-done', { id, error: c.error })
      }
    } catch {}
  } finally {
    activeWorkers.delete(id)
  }
}

// ── Mailjet webhook receiver ─────────────────────────────────────────────────
// Mailjet's Event API posts a JSON array of events:
//   [{"event": "sent"|"open"|"click"|"bounce"|"blocked"|"spam"|"unsub",
//     "MessageID": 1234, "CustomID": "<our reference>",
//     "time": 1234567890, "email": "...", "Payload": "..."}, ...]
// We match by mailjet_uuid (== MessageID) and update status across all
// campaigns. We don't know which campaign a given event belongs to without
// scanning, but for the volumes we're dealing with (a few campaigns × ~200
// recipients each) scanning all open JSON files per webhook is fine.
function mailjetEventToStatus (event) {
  switch ((event || '').toLowerCase()) {
    case 'sent':    return null   // already 'sent' from SMTP — informational
    case 'open':    return 'opened'
    case 'click':   return 'clicked'
    case 'bounce':
    case 'hardbounce':
    case 'softbounce': return 'bounced'
    case 'blocked':
    case 'spam':
    case 'unsub':   return 'failed'
    default:        return null
  }
}

function applyWebhookEvent (ev) {
  const newStatus = mailjetEventToStatus(ev.event)
  if (!newStatus) return false
  // Primary join key: CustomID = "<campaign-id>:<recipient-index>" which we
  // injected on send via X-MJ-CustomID. Falling back to MessageID for events
  // that might predate the CustomID rollout.
  const customId = String(ev.CustomID || ev.custom_id || '')
  const msgId    = String(ev.MessageID || ev.message_id || '')

  // Fast path: parse CustomID to skip the campaign scan entirely
  if (customId && customId.includes(':')) {
    const [campId, idxStr] = customId.split(':')
    const idx = parseInt(idxStr, 10)
    const c = loadCampaign(campId)
    if (c && c.recipients && c.recipients[idx]) {
      const r = c.recipients[idx]
      r.status = newStatus
      if (newStatus === 'opened')  r.opened_at  = new Date((ev.time || 0) * 1000).toISOString()
      if (newStatus === 'clicked') r.clicked_at = new Date((ev.time || 0) * 1000).toISOString()
      if (newStatus === 'bounced' || newStatus === 'failed') {
        r.error = ev.error || ev.error_related_to || ev.event
      }
      saveCampaign(c)
      sse.broadcast(`campaign:${c.id}`, 'recipient-update', { i: idx, recipient: r })
      return true
    }
  }

  // Fallback: scan all campaigns for a recipient matching msgId (slower)
  if (!msgId) return false
  for (const meta of listCampaigns()) {
    const c = loadCampaign(meta.id)
    if (!c) continue
    for (let i = 0; i < (c.recipients || []).length; i++) {
      const r = c.recipients[i]
      if (String(r.mailjet_uuid) !== msgId) continue
      r.status = newStatus
      if (newStatus === 'opened')  r.opened_at  = new Date((ev.time || 0) * 1000).toISOString()
      if (newStatus === 'clicked') r.clicked_at = new Date((ev.time || 0) * 1000).toISOString()
      if (newStatus === 'bounced' || newStatus === 'failed') {
        r.error = ev.error || ev.error_related_to || ev.event
      }
      saveCampaign(c)
      sse.broadcast(`campaign:${c.id}`, 'recipient-update', { i, recipient: r })
      return true
    }
  }
  return false
}

// ── HTTP routing ─────────────────────────────────────────────────────────────
async function handle (req, res, method, path) {
  // POST /campaigns/parse — preview matched send list (no save)
  if (path === '/campaigns/parse' && method === 'POST') {
    const body = await parseBody(req)
    const { map_csv, giftbit_csv, multi } = body || {}
    if (!map_csv || !giftbit_csv) {
      return json(res, 400, { error: 'map_csv and giftbit_csv required' })
    }
    const { contacts, skipped } = parseMapCsv(map_csv, multi || 'first')
    const gifts = parseGiftbitCsv(giftbit_csv)

    // Match contacts ↔ gifts (by row order, fallback to email)
    const recipients = []
    const n = Math.min(contacts.length, gifts.length)
    for (let i = 0; i < n; i++) {
      const c = contacts[i]; const g = gifts[i]
      // If Giftbit echoed back our email, prefer that match for robustness
      const giftByEmail = gifts.find(gg => normalizeEmail(gg.email) === c.email)
      const gift = giftByEmail || g
      const match = await matchCustomer(c)
      recipients.push({
        ...c,
        gift_url:          gift.gift_url,
        giftbit_uuid:      gift.giftbit_uuid,
        gift_value_cents:  gift.gift_value_cents,
        ...match,
        status: 'pending',
        excluded: false,
      })
    }
    return json(res, 200, {
      recipients,
      leftover_gifts:    gifts.length    - n,
      leftover_contacts: contacts.length - n,
      skipped,
    })
  }

  // POST /campaigns — create from a parsed send list
  if (path === '/campaigns' && method === 'POST') {
    const body = await parseBody(req)
    const { name, params, recipients } = body || {}
    if (!Array.isArray(recipients) || !recipients.length) {
      return json(res, 400, { error: 'recipients[] required' })
    }
    const id = newCampaignId()
    const campaign = {
      id,
      name: name || `Campagne ${id}`,
      created_at: new Date().toISOString(),
      status: 'draft',
      params: params || {},
      recipients: recipients.map(r => ({ ...r, status: r.status || 'pending' })),
    }
    const saved = saveCampaign(campaign)
    return json(res, 200, saved)
  }

  // GET /campaigns — list summaries
  if (path === '/campaigns' && method === 'GET') {
    return json(res, 200, { campaigns: listCampaigns() })
  }

  // ── Template CRUD (for the GrapesJS editor in the ops UI) ─────────────────
  // ORDER MATTERS: these template routes must be BEFORE the /campaigns/:id
  // wildcard below, otherwise paths like /campaigns/templates get matched
  // by the wildcard as if "templates" were a campaign ID.

  // GET /campaigns/templates — list editable templates with metadata
  if (path === '/campaigns/templates' && method === 'GET') {
    return json(res, 200, { templates: listEditableTemplates() })
  }

  // GET /campaigns/templates/:name — return current HTML content
  const tplGet = path.match(/^\/campaigns\/templates\/([a-zA-Z0-9_-]+)$/)
  if (tplGet && method === 'GET') {
    try {
      const html = fs.readFileSync(templatePath(tplGet[1]), 'utf8')
      return json(res, 200, { name: tplGet[1], html })
    } catch (e) {
      return json(res, 404, { error: 'template not found', detail: e.message })
    }
  }

  // PUT /campaigns/templates/:name — save new HTML
  // Keeps the previous version as <name>.bak-<ts>.html so a bad edit can
  // be rolled back without git access.
  if (tplGet && method === 'PUT') {
    const body = await parseBody(req)
    if (typeof body.html !== 'string' || !body.html) {
      return json(res, 400, { error: 'html string required' })
    }
    try {
      const p = templatePath(tplGet[1])
      // Backup current version (if any) — best effort, don't fail save on backup error
      try {
        if (fs.existsSync(p)) {
          const ts = new Date().toISOString().replace(/[:.]/g, '-').slice(0, 19)
          fs.copyFileSync(p, p.replace(/\.html$/, `.bak-${ts}.html`))
        }
      } catch (e) { log('template backup failed:', e.message) }
      fs.writeFileSync(p, body.html, 'utf8')
      log(`template ${tplGet[1]} updated by ops (${body.html.length} bytes)`)
      return json(res, 200, { name: tplGet[1], saved: true, size: body.html.length })
    } catch (e) {
      return json(res, 400, { error: e.message })
    }
  }

  // POST /campaigns/templates/:name/preview — render with sample data
  // Useful for the editor's "Preview" pane to see what {{vars}} resolve to.
  const tplPreview = path.match(/^\/campaigns\/templates\/([a-zA-Z0-9_-]+)\/preview$/)
  if (tplPreview && method === 'POST') {
    const body = await parseBody(req)
    const html = body.html || fs.readFileSync(templatePath(tplPreview[1]), 'utf8')
    const vars = {
      firstname: 'Louis', lastname: 'Paul', email: 'louis@targo.ca',
      description: '123 Rue de Test', gift_url: 'http://gtbt.co/PREVIEW',
      amount: '60 $', expiry: '31 décembre 2026', commitment_months: '3',
      ...(body.vars || {}),
    }
    return json(res, 200, { rendered: renderTemplate(html, vars) })
  }

  // POST /campaigns/webhook — Mailjet Event API receiver
  // Mailjet sends an array of events; we process all of them.
  if (path === '/campaigns/webhook' && method === 'POST') {
    const body = await parseBody(req)
    const events = Array.isArray(body) ? body : [body]
    let applied = 0
    for (const ev of events) {
      if (applyWebhookEvent(ev)) applied++
    }
    log(`mailjet webhook: ${events.length} events, ${applied} applied`)
    return json(res, 200, { received: events.length, applied })
  }

  // ── Per-campaign wildcard routes (MUST stay below the /templates and
  //    /webhook fixed paths above, otherwise the wildcard captures them) ─────

  // GET /campaigns/:id — full detail
  const detailMatch = path.match(/^\/campaigns\/([^/]+)$/)
  if (detailMatch && method === 'GET') {
    const c = loadCampaign(detailMatch[1])
    if (!c) return json(res, 404, { error: 'not found' })
    return json(res, 200, c)
  }

  // PATCH /campaigns/:id — update recipients (e.g. exclude rows, edit email)
  if (detailMatch && method === 'PATCH') {
    const body = await parseBody(req)
    const c = loadCampaign(detailMatch[1])
    if (!c) return json(res, 404, { error: 'not found' })
    if (body.name) c.name = body.name
    if (body.params) c.params = { ...c.params, ...body.params }
    if (Array.isArray(body.recipients)) c.recipients = body.recipients
    return json(res, 200, saveCampaign(c))
  }

  // POST /campaigns/:id/send — fire background worker
  const sendMatch = path.match(/^\/campaigns\/([^/]+)\/send$/)
  if (sendMatch && method === 'POST') {
    const id = sendMatch[1]
    const c = loadCampaign(id)
    if (!c) return json(res, 404, { error: 'not found' })
    if (activeWorkers.has(id)) return json(res, 409, { error: 'already sending' })
    // Fire and forget
    setImmediate(() => sendCampaignAsync(id))
    return json(res, 202, { id, status: 'sending' })
  }

  return json(res, 404, { error: 'campaigns endpoint not found' })
}

module.exports = {
  handle,
  // Exposed for testing
  parseCsv, parseMapCsv, parseGiftbitCsv,
  matchCustomer, normalizeCivic, normalizePhone, normalizePostal,
  renderTemplate,
}