import { NextResponse } from 'next/server'
import { createClient } from '@/lib/supabase/server'
import { decrypt } from '@/lib/whatsapp/encryption'
import { submitMessageTemplate } from '@/lib/whatsapp/meta-api'
import {
  validateTemplatePayload,
  type TemplatePayload,
} from '@/lib/whatsapp/template-validators'
import { buildMetaTemplatePayload } from '@/lib/whatsapp/template-components'
import { normalizeStatus } from '@/lib/whatsapp/template-status-normalize'

/**
 * Submit a template to Meta for approval AND persist it locally.
 *
 * Auth → fetch whatsapp_config → validate → (DRY_RUN short-circuit) →
 * POST to Meta → upsert local row by (user_id, name, language) with
 * status, meta_template_id, sample_values, last_submitted_at.
 *
 * When WHATSAPP_TEMPLATES_DRY_RUN=true, we skip the network call and
 * insert a row with a synthetic `dry-run-<uuid>` meta_template_id so
 * CI / local dev can exercise the full UI without a real Meta App.
 *
 * On the Meta side this is a one-way trip — a row can only be
 * submitted; editing or deleting requires hsm_id and lives in PR 4.
 */
export async function POST(request: Request) {
  try {
    const supabase = await createClient()
    const {
      data: { user },
      error: authError,
    } = await supabase.auth.getUser()
    if (authError || !user) {
      return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
    }

    let payload: TemplatePayload
    try {
      payload = (await request.json()) as TemplatePayload
    } catch {
      return NextResponse.json({ error: 'Invalid JSON body.' }, { status: 400 })
    }

    if (payload.category === 'Authentication') {
      return NextResponse.json(
        {
          error:
            'AUTHENTICATION templates are not yet supported here — create them in Meta WhatsApp Manager and use "Sync from Meta".',
        },
        { status: 400 },
      )
    }

    try {
      validateTemplatePayload(payload)
    } catch (e) {
      return NextResponse.json(
        { error: e instanceof Error ? e.message : 'Validation failed.' },
        { status: 400 },
      )
    }

    const metaPayload = buildMetaTemplatePayload(payload)

    const dryRun =
      process.env.WHATSAPP_TEMPLATES_DRY_RUN === 'true' ||
      process.env.WHATSAPP_TEMPLATES_DRY_RUN === '1'

    let metaTemplateId: string
    let metaStatus: string

    if (dryRun) {
      metaTemplateId = `dry-run-${crypto.randomUUID()}`
      metaStatus = 'PENDING'
    } else {
      const { data: config, error: configError } = await supabase
        .from('whatsapp_config')
        .select('*')
        .eq('user_id', user.id)
        .single()
      if (configError || !config) {
        return NextResponse.json(
          {
            error:
              'WhatsApp not configured. Connect your WhatsApp Business account in Settings first.',
          },
          { status: 400 },
        )
      }
      if (!config.waba_id) {
        return NextResponse.json(
          {
            error:
              'WABA (WhatsApp Business Account) ID missing. Re-connect your account in Settings.',
          },
          { status: 400 },
        )
      }

      const accessToken = decrypt(config.access_token)
      try {
        const meta = await submitMessageTemplate({
          wabaId: config.waba_id,
          accessToken,
          payload: metaPayload,
        })
        metaTemplateId = meta.id
        metaStatus = meta.status
      } catch (e) {
        const message = e instanceof Error ? e.message : 'Meta submit failed.'
        // Persist the failure so the user can retry; tag with a 429
        // hint if Meta's rate-limit response leaked through.
        await supabase
          .from('message_templates')
          .upsert(
            {
              user_id: user.id,
              name: payload.name,
              category: payload.category,
              language: payload.language,
              header_type: payload.header_type ?? null,
              header_content: payload.header_content ?? null,
              header_media_url: payload.header_media_url ?? null,
              header_handle: payload.header_handle ?? null,
              body_text: payload.body_text,
              footer_text: payload.footer_text ?? null,
              buttons: payload.buttons ?? null,
              sample_values: payload.sample_values ?? null,
              status: 'DRAFT',
              submission_error: message,
              last_submitted_at: new Date().toISOString(),
            },
            { onConflict: 'user_id,name,language' },
          )
        const isRateLimit = /\b429\b/.test(message)
        return NextResponse.json(
          {
            error: isRateLimit
              ? 'Meta rate limit hit (100 template creates per hour). Try again later.'
              : message,
          },
          { status: isRateLimit ? 429 : 502 },
        )
      }
    }

    const { data: row, error: upsertErr } = await supabase
      .from('message_templates')
      .upsert(
        {
          user_id: user.id,
          name: payload.name,
          category: payload.category,
          language: payload.language,
          header_type: payload.header_type ?? null,
          header_content: payload.header_content ?? null,
          header_media_url: payload.header_media_url ?? null,
          header_handle: payload.header_handle ?? null,
          body_text: payload.body_text,
          footer_text: payload.footer_text ?? null,
          buttons: payload.buttons ?? null,
          sample_values: payload.sample_values ?? null,
          status: normalizeStatus(metaStatus),
          meta_template_id: metaTemplateId,
          submission_error: null,
          rejection_reason: null,
          last_submitted_at: new Date().toISOString(),
        },
        { onConflict: 'user_id,name,language' },
      )
      .select()
      .single()

    if (upsertErr) {
      // The submit succeeded on Meta's side but we failed to persist
      // locally. That's a data-drift state — surface the meta_template_id
      // so the user can recover via "Sync from Meta".
      return NextResponse.json(
        {
          error: `Submitted to Meta but failed to save locally: ${upsertErr.message}. Run "Sync from Meta" to recover.`,
          meta_template_id: metaTemplateId,
        },
        { status: 500 },
      )
    }

    return NextResponse.json({
      success: true,
      template: row,
      dry_run: dryRun,
    })
  } catch (error) {
    console.error('Error submitting template:', error)
    return NextResponse.json(
      {
        error:
          error instanceof Error ? error.message : 'Failed to submit template.',
      },
      { status: 500 },
    )
  }
}