/*
|--------------------------------------------------------------------------
| Agência PSI — Edge Function: process-sms-queue
|--------------------------------------------------------------------------
| Processa a notification_queue para channel = 'sms' via Twilio.
|
| Modelo: Créditos da plataforma
|   - Credenciais Twilio são da plataforma (env vars)
|   - Antes de enviar, debita 1 crédito do tenant via RPC
|   - Sem crédito → marca como 'sem_credito'
|
| Fluxo:
|   1. Busca pendentes (channel='sms', status='pendente', scheduled_at <= now)
|   2. Lock otimista (status → processando)
|   3. Debita crédito SMS do tenant (addon_credits)
|   4. Resolve template (tenant → global fallback)
|   5. Renderiza variáveis {{var}}
|   6. Envia via Twilio REST API (credenciais da plataforma)
|   7. Atualiza queue + insere notification_logs
|   8. Retry com backoff em caso de erro
|--------------------------------------------------------------------------
*/

import { createClient } from 'https://esm.sh/@supabase/supabase-js@2'

const corsHeaders = {
  'Access-Control-Allow-Origin':  '*',
  'Access-Control-Allow-Headers': 'authorization, x-client-info, apikey, content-type',
  'Access-Control-Allow-Methods': 'POST, OPTIONS',
}

// ── Template renderer ──────────────────────────────────────────

function renderTemplate(template: string, variables: Record<string, unknown>): string {
  if (!template) return ''
  return template.replace(/\{\{([\w.]+)\}\}/g, (_, key) => {
    const val = variables[key]
    return val !== undefined && val !== null ? String(val) : ''
  })
}

// ── Twilio SMS sender (credenciais da plataforma) ──────────────

async function sendViaTwilio(
  to: string,
  body: string,
  fromOverride?: string | null
): Promise<{ sid: string; status: string }> {
  const accountSid = Deno.env.get('TWILIO_ACCOUNT_SID')!
  const authToken  = Deno.env.get('TWILIO_AUTH_TOKEN')!
  const fromNumber = fromOverride || Deno.env.get('TWILIO_FROM_NUMBER')!

  const url = `https://api.twilio.com/2010-04-01/Accounts/${accountSid}/Messages.json`
  const auth = btoa(`${accountSid}:${authToken}`)

  const params = new URLSearchParams()
  params.set('From', fromNumber)
  params.set('To', to)
  params.set('Body', body)

  const res = await fetch(url, {
    method: 'POST',
    headers: {
      'Authorization': `Basic ${auth}`,
      'Content-Type': 'application/x-www-form-urlencoded',
    },
    body: params.toString(),
  })

  const data = await res.json()

  if (!res.ok) {
    throw new Error(data.message || `Twilio error ${res.status}: ${data.code}`)
  }

  return { sid: data.sid, status: data.status }
}

// ── Mock sender (dev/test) ─────────────────────────────────────

function isMockMode(): boolean {
  const sid = Deno.env.get('TWILIO_ACCOUNT_SID') || ''
  return sid.startsWith('AC_TEST') || Deno.env.get('DEV') === 'true'
}

function mockSend(_to: string, _body: string): { sid: string; status: string } {
  const sid = `mock_${crypto.randomUUID().slice(0, 8)}`
  console.log(`[SMS MOCK] To: ${_to} | Body: ${_body} | SID: ${sid}`)
  return { sid, status: 'sent' }
}

// ── Main handler ───────────────────────────────────────────────

Deno.serve(async (req: Request) => {
  if (req.method === 'OPTIONS') {
    return new Response('ok', { headers: corsHeaders })
  }

  const supabase = createClient(
    Deno.env.get('SUPABASE_URL')!,
    Deno.env.get('SUPABASE_SERVICE_ROLE_KEY')!
  )

  const now = new Date().toISOString()

  // 1. Busca itens pendentes
  const { data: items, error: fetchErr } = await supabase
    .from('notification_queue')
    .select('*')
    .eq('channel', 'sms')
    .eq('status', 'pendente')
    .lte('scheduled_at', now)
    .order('scheduled_at', { ascending: true })
    .limit(20)

  if (fetchErr) {
    return new Response(
      JSON.stringify({ error: fetchErr.message }),
      { status: 500, headers: { ...corsHeaders, 'Content-Type': 'application/json' } }
    )
  }

  if (!items?.length) {
    return new Response(
      JSON.stringify({ message: 'Nenhum SMS na fila', processed: 0 }),
      { status: 200, headers: { ...corsHeaders, 'Content-Type': 'application/json' } }
    )
  }

  const results: Array<{ id: string; status: string; error?: string }> = []

  for (const item of items) {
    // Filtra por max_attempts
    if (item.attempts >= (item.max_attempts || 5)) continue

    // 2. Lock otimista
    const { error: lockErr } = await supabase
      .from('notification_queue')
      .update({ status: 'processando', attempts: item.attempts + 1 })
      .eq('id', item.id)
      .eq('status', 'pendente')

    if (lockErr) {
      results.push({ id: item.id, status: 'skip', error: 'lock failed' })
      continue
    }

    try {
      // 3. Debita crédito SMS do tenant
      const { data: debitResult, error: debitErr } = await supabase
        .rpc('debit_addon_credit', {
          p_tenant_id:   item.tenant_id,
          p_addon_type:  'sms',
          p_queue_id:    item.id,
          p_description: `SMS para ${item.recipient_address}`,
        })

      if (debitErr) {
        throw new Error(`Erro ao debitar crédito: ${debitErr.message}`)
      }

      if (!debitResult?.success) {
        // Sem crédito — não envia, marca como sem_credito
        await supabase
          .from('notification_queue')
          .update({ status: 'sem_credito', last_error: debitResult?.reason || 'Sem créditos SMS' })
          .eq('id', item.id)

        await supabase.from('notification_logs').insert({
          tenant_id:         item.tenant_id,
          owner_id:          item.owner_id,
          queue_id:          item.id,
          agenda_evento_id:  item.agenda_evento_id,
          patient_id:        item.patient_id,
          channel:           'sms',
          template_key:      item.template_key,
          schedule_key:      item.schedule_key,
          recipient_address: item.recipient_address,
          status:            'failed',
          failure_reason:    `Sem créditos SMS: ${debitResult?.reason || 'balance=0'}`,
          failed_at:         new Date().toISOString(),
        })

        results.push({ id: item.id, status: 'sem_credito', error: debitResult?.reason })
        continue
      }

      // 4. Resolve template: tenant → global fallback
      let template: { body_text: string } | null = null

      const { data: tenantTpl } = await supabase
        .from('notification_templates')
        .select('body_text, is_active')
        .eq('tenant_id', item.tenant_id)
        .eq('key', item.template_key)
        .eq('channel', 'sms')
        .eq('is_active', true)
        .is('deleted_at', null)
        .maybeSingle()

      if (tenantTpl) {
        template = tenantTpl
      } else {
        const { data: globalTpl } = await supabase
          .from('notification_templates')
          .select('body_text')
          .is('tenant_id', null)
          .eq('key', item.template_key)
          .eq('channel', 'sms')
          .eq('is_default', true)
          .eq('is_active', true)
          .is('deleted_at', null)
          .maybeSingle()

        template = globalTpl
      }

      if (!template) {
        throw new Error(`Template SMS não encontrado: ${item.template_key}`)
      }

      // 5. Renderiza variáveis
      const vars = item.resolved_vars || {}
      const message = renderTemplate(template.body_text, vars)

      // 6. Busca from_number override do tenant (se tiver)
      const { data: creditRow } = await supabase
        .from('addon_credits')
        .select('from_number_override')
        .eq('tenant_id', item.tenant_id)
        .eq('addon_type', 'sms')
        .maybeSingle()

      const fromOverride = creditRow?.from_number_override || null

      // 7. Envia via Twilio (ou mock)
      let sendResult: { sid: string; status: string }

      if (isMockMode()) {
        sendResult = mockSend(item.recipient_address, message)
      } else {
        sendResult = await sendViaTwilio(item.recipient_address, message, fromOverride)
      }

      // 8. Sucesso
      await supabase
        .from('notification_queue')
        .update({
          status:              'enviado',
          sent_at:             new Date().toISOString(),
          provider_message_id: sendResult.sid,
        })
        .eq('id', item.id)

      await supabase.from('notification_logs').insert({
        tenant_id:           item.tenant_id,
        owner_id:            item.owner_id,
        queue_id:            item.id,
        agenda_evento_id:    item.agenda_evento_id,
        patient_id:          item.patient_id,
        channel:             'sms',
        template_key:        item.template_key,
        schedule_key:        item.schedule_key,
        recipient_address:   item.recipient_address,
        resolved_message:    message,
        resolved_vars:       vars,
        status:              'sent',
        provider:            'twilio',
        provider_message_id: sendResult.sid,
        sent_at:             new Date().toISOString(),
      })

      results.push({ id: item.id, status: 'enviado' })

    } catch (err) {
      // 9. Erro — retry com backoff
      const attempts = item.attempts + 1
      const maxAttempts = item.max_attempts || 5
      const isExhausted = attempts >= maxAttempts
      const retryMs = attempts * 2 * 60 * 1000

      await supabase
        .from('notification_queue')
        .update({
          status:        isExhausted ? 'falhou' : 'pendente',
          last_error:    err.message,
          next_retry_at: isExhausted ? null : new Date(Date.now() + retryMs).toISOString(),
        })
        .eq('id', item.id)

      await supabase.from('notification_logs').insert({
        tenant_id:         item.tenant_id,
        owner_id:          item.owner_id,
        queue_id:          item.id,
        agenda_evento_id:  item.agenda_evento_id,
        patient_id:        item.patient_id,
        channel:           'sms',
        template_key:      item.template_key,
        schedule_key:      item.schedule_key,
        recipient_address: item.recipient_address,
        status:            'failed',
        failure_reason:    err.message,
        failed_at:         new Date().toISOString(),
      })

      results.push({ id: item.id, status: isExhausted ? 'falhou' : 'retry', error: err.message })
    }
  }

  const sent      = results.filter(r => r.status === 'enviado').length
  const failed    = results.filter(r => r.status === 'falhou').length
  const noCredit  = results.filter(r => r.status === 'sem_credito').length

  return new Response(
    JSON.stringify({ processed: results.length, sent, failed, no_credit: noCredit, details: results }),
    { status: 200, headers: { ...corsHeaders, 'Content-Type': 'application/json' } }
  )
})