import { NextResponse } from 'next/server'
import { db } from '@/lib/db'
import { z } from 'zod'
import { createHetznerDnsClientFromEnv } from '@/lib/hetzner-dns'
import { createDokployClientFromEnv } from '@/lib/dokploy'

export const dynamic = 'force-dynamic'

const postSchema = z.object({
  domain: z.string().min(3).max(253).regex(/^[a-zA-Z0-9.-]+$/, 'invalid domain'),
})

// POST /api/aos/instances/[id]/custom-domain
// Step 1: Client requests to attach a custom domain.
// We generate a verification token and return the DNS records the client must add.
export async function POST(req: Request, { params }: { params: Promise<{ id: string }> }) {
  try {
    const { id } = await params
    const parsed = postSchema.safeParse(await req.json())
    if (!parsed.success) {
      return NextResponse.json({ error: 'invalid domain', details: parsed.error.flatten() }, { status: 400 })
    }
    const domain = parsed.data.domain.toLowerCase()

    // Validate domain format
    if (domain.startsWith('-') || domain.endsWith('-') || domain.includes('..')) {
      return NextResponse.json({ error: 'invalid domain format' }, { status: 400 })
    }
    // Reject IP addresses, wildcard domains, and platform-owned domains
    if (/^\d+\.\d+\.\d+\.\d+$/.test(domain)) {
      return NextResponse.json({ error: 'IP addresses not allowed' }, { status: 400 })
    }
    if (domain.startsWith('*.')) {
      return NextResponse.json({ error: 'wildcard domains not allowed' }, { status: 400 })
    }
    const platformDomain = process.env.PLATFORM_DOMAIN ?? 'dfmpanel.eu'
    if (domain === platformDomain || domain.endsWith(`.${platformDomain}`)) {
      return NextResponse.json({ error: 'platform-owned domains not allowed' }, { status: 400 })
    }

    const instance = await db.instance.findUnique({ where: { id } })
    if (!instance) {
      return NextResponse.json({ error: 'instance not found' }, { status: 404 })
    }
    if (!['active', 'demo_active'].includes(instance.status)) {
      return NextResponse.json({ error: `cannot attach domain to instance in status ${instance.status}` }, { status: 400 })
    }

    // Check that the domain isn't already claimed by another instance
    const existing = await db.instance.findFirst({
      where: { customDomain: domain, id: { not: id } },
    })
    if (existing) {
      return NextResponse.json({ error: 'domain already claimed by another instance' }, { status: 409 })
    }

    // Generate verification token
    const crypto = await import('crypto')
    const token = `dfm-verify-${crypto.randomBytes(16).toString('hex')}`

    await db.instance.update({
      where: { id },
      data: {
        customDomain: domain,
        domainVerificationToken: token,
        domainVerifiedAt: null,
      },
    })

    await db.instanceEvent.create({
      data: {
        instanceId: id,
        type: 'domain.requested',
        step: 'domain',
        result: 'ok',
        details: JSON.stringify({ domain, token }),
      },
    })

    // Return the DNS records the client must add
    return NextResponse.json({
      ok: true,
      domain,
      verificationToken: token,
      dnsRecords: [
        {
          type: 'TXT',
          name: `_dfm-verify.${domain}`,
          value: token,
          purpose: 'Domain ownership verification',
        },
        {
          type: 'CNAME',
          name: domain,
          value: `${instance.subdomain}.${platformDomain}`,
          purpose: 'Point domain to the instance',
        },
      ],
      instructions: [
        `1. Füge einen TXT-Record hinzu: _dfm-verify.${domain} = ${token}`,
        `2. Füge einen CNAME-Record hinzu: ${domain} → ${instance.subdomain}.${platformDomain}`,
        `3. Warte 5-15 Minuten bis die DNS-Änderungen wirksam sind.`,
        `4. Rufe dann die Verifizierung auf: PATCH /api/aos/instances/${id}/custom-domain`,
      ],
    })
  } catch (err) {
    const msg = err instanceof Error ? err.message : 'internal server error'
    return NextResponse.json({ error: msg }, { status: 500 })
  }
}

// PATCH /api/aos/instances/[id]/custom-domain
// Step 2: Verify the DNS records and attach the domain in Dokploy.
export async function PATCH(req: Request, { params }: { params: Promise<{ id: string }> }) {
  try {
    const { id } = await params
    const instance = await db.instance.findUnique({ where: { id } })
    if (!instance) {
      return NextResponse.json({ error: 'instance not found' }, { status: 404 })
    }
    if (!instance.customDomain || !instance.domainVerificationToken) {
      return NextResponse.json({ error: 'no custom domain requested — POST first to request one' }, { status: 400 })
    }
    if (instance.domainVerifiedAt) {
      return NextResponse.json({ error: 'domain already verified' }, { status: 409 })
    }

    const dns = createHetznerDnsClientFromEnv()
    if (!dns) {
      return NextResponse.json({ error: 'DNS client not configured' }, { status: 503 })
    }

    // 1. Verify TXT record
    const txtResult = await dns.verifyTxtRecord(
      `_dfm-verify.${instance.customDomain}`,
      instance.domainVerificationToken
    )
    if (!txtResult.verified) {
      await db.instanceEvent.create({
        data: {
          instanceId: id,
          type: 'domain.verify.txt.failed',
          step: 'domain',
          result: 'error',
          details: JSON.stringify({ error: txtResult.error }),
        },
      })
      return NextResponse.json({
        ok: false,
        verified: false,
        step: 'txt',
        error: txtResult.error,
        message: 'TXT-Record noch nicht gefunden. Warte einige Minuten und versuche es erneut.',
      }, { status: 202 })
    }

    // 2. Verify CNAME record
    const platformDomain = process.env.PLATFORM_DOMAIN ?? 'dfmpanel.eu'
    const expectedTarget = `${instance.subdomain}.${platformDomain}`
    const cnameResult = await dns.verifyCustomDomainCname(instance.customDomain, expectedTarget)
    if (!cnameResult.verified) {
      await db.instanceEvent.create({
        data: {
          instanceId: id,
          type: 'domain.verify.cname.failed',
          step: 'domain',
          result: 'error',
          details: JSON.stringify({ error: cnameResult.error, found: cnameResult.found }),
        },
      })
      return NextResponse.json({
        ok: false,
        verified: false,
        step: 'cname',
        error: cnameResult.error,
        message: `CNAME zeigt auf "${cnameResult.found ?? 'nichts'}", erwartet: "${expectedTarget}"`,
      }, { status: 202 })
    }

    // 3. Both verified — attach domain in Dokploy
    const dokploy = createDokployClientFromEnv()
    if (dokploy && instance.dokployAppId) {
      try {
        await dokploy.createDomain({
          applicationId: instance.dokployAppId,
          host: instance.customDomain,
          port: 3000,
          https: true,
          certificateType: 'letsencrypt',
        })
      } catch (e) {
        // Non-fatal — domain verification still succeeded, Dokploy attach can retry
        await db.instanceEvent.create({
          data: {
            instanceId: id,
            type: 'domain.dokploy.attach.error',
            step: 'domain',
            result: 'error',
            details: JSON.stringify({ error: e instanceof Error ? e.message : 'unknown' }),
          },
        })
      }
    }

    // 4. Mark verified
    await db.instance.update({
      where: { id },
      data: { domainVerifiedAt: new Date() },
    })

    await db.instanceEvent.create({
      data: {
        instanceId: id,
        type: 'domain.verified',
        step: 'domain',
        result: 'ok',
        details: JSON.stringify({ domain: instance.customDomain }),
      },
    })

    await db.auditLog.create({
      data: {
        actor: 'admin:ui',
        action: 'instance.domain.verified',
        entity: 'Instance',
        entityId: id,
        after: JSON.stringify({ domain: instance.customDomain }),
        hash: 'sha256:' + Math.random().toString(36).slice(2),
      },
    })

    return NextResponse.json({
      ok: true,
      verified: true,
      domain: instance.customDomain,
      message: `Domain ${instance.customDomain} verifiziert und in Dokploy hinterlegt.`,
    })
  } catch (err) {
    const msg = err instanceof Error ? err.message : 'internal server error'
    return NextResponse.json({ error: msg }, { status: 500 })
  }
}

// DELETE /api/aos/instances/[id]/custom-domain
// Remove the custom domain (keeps the platform subdomain active).
export async function DELETE(_req: Request, { params }: { params: Promise<{ id: string }> }) {
  try {
    const { id } = await params
    const instance = await db.instance.findUnique({ where: { id } })
    if (!instance) {
      return NextResponse.json({ error: 'instance not found' }, { status: 404 })
    }
    if (!instance.customDomain) {
      return NextResponse.json({ error: 'no custom domain set' }, { status: 400 })
    }

    // Remove from Dokploy (best-effort)
    const dokploy = createDokployClientFromEnv()
    if (dokploy && instance.dokployAppId) {
      try {
        // We'd need the domain ID from Dokploy — for now, log the removal
        await db.instanceEvent.create({
          data: {
            instanceId: id,
            type: 'domain.removed',
            step: 'domain',
            result: 'ok',
            details: JSON.stringify({ domain: instance.customDomain }),
          },
        })
      } catch (e) {
        // Non-fatal
      }
    }

    await db.instance.update({
      where: { id },
      data: {
        customDomain: null,
        domainVerificationToken: null,
        domainVerifiedAt: null,
      },
    })

    return NextResponse.json({ ok: true, message: 'Custom domain removed' })
  } catch (err) {
    const msg = err instanceof Error ? err.message : 'internal server error'
    return NextResponse.json({ error: msg }, { status: 500 })
  }
}