import { NextResponse } from "next/server"
import { prisma } from "@/lib/db"
import { randomUUID } from "crypto"

export async function POST(request: Request) {
  try {
    const { deviceFingerprint, pairingCode, childId, action } = await request.json()

    if (action === "generate") {
      if (!childId) {
        return NextResponse.json({ error: "childId required" }, { status: 400 })
      }
      const code = randomUUID().slice(0, 8).toUpperCase()
      await prisma.pendingPairing.create({
        data: {
          code,
          childId,
          expiresAt: new Date(Date.now() + 10 * 60 * 1000),
        },
      })
      return NextResponse.json({ pairingCode: code })
    }

    if (pairingCode) {
      const pending = await prisma.pendingPairing.findUnique({
        where: { code: pairingCode },
      })
      if (!pending || pending.expiresAt < new Date()) {
        return NextResponse.json({ error: "Código inválido o expirado" }, { status: 404 })
      }

      const targetChildId = childId || pending.childId
      if (!targetChildId) {
        return NextResponse.json({ error: "Sin niño asociado" }, { status: 400 })
      }

      if (childId && !pending.childId) {
        await prisma.pendingPairing.update({
          where: { id: pending.id },
          data: { childId },
        })
      }

      const fp = deviceFingerprint || pending.deviceFingerprint
      if (!fp) {
        return NextResponse.json({ error: "Se requiere deviceFingerprint" }, { status: 400 })
      }

      const device = await prisma.device.create({
        data: {
          childId: targetChildId,
          deviceFingerprint: fp,
          role: "child",
        },
        include: { child: true },
      })

      await prisma.pendingPairing.delete({ where: { id: pending.id } })

      return NextResponse.json({
        success: true,
        childId: device.childId,
        childName: device.child.name,
      })
    }

    if (deviceFingerprint) {
      const existingDevice = await prisma.device.findFirst({
        where: { deviceFingerprint },
      })
      if (existingDevice) {
        return NextResponse.json({
          paired: true,
          childId: existingDevice.childId,
          role: existingDevice.role,
        })
      }

      const code = randomUUID().slice(0, 8).toUpperCase()
      await prisma.pendingPairing.create({
        data: {
          code,
          deviceFingerprint,
          expiresAt: new Date(Date.now() + 10 * 60 * 1000),
        },
      })
      return NextResponse.json({
        paired: false,
        pairingCode: code,
      })
    }

    return NextResponse.json({ error: "Invalid request" }, { status: 400 })
  } catch (error) {
    console.error("Pairing error:", error)
    return NextResponse.json({ error: "Internal error" }, { status: 500 })
  }
}