import { cookies } from "next/headers"
import { redirect } from "next/navigation"

import { auth } from "@/auth"
import { prisma } from "@/lib/prisma"
import { verifyJoinLinkToken } from "@/lib/join-link"
import { guestIdentityCookieName } from "@/lib/participant-identity"
import { AppShell } from "@/components/shell/app-shell"
import {
  Card,
  CardDescription,
  CardHeader,
  CardTitle,
} from "@/components/ui/card"
import { JoinFlow } from "@/components/join/join-flow"

// Reads the session/cookies and queries the DB on every request to
// resolve "who is this visitor and what's their access state" — same
// reasoning as the dashboard page (see its own comment) for opting out
// of Cache Components' static-shell validation.
export const instant = false

function JoinShell({
  title,
  children,
}: {
  title?: string
  children: React.ReactNode
}) {
  return (
    <AppShell className="flex min-h-[80vh] items-center justify-center">
      <div className="w-full max-w-md">
        {title ? (
          <h1 className="mb-4 text-center text-lg font-semibold text-foreground">
            {title}
          </h1>
        ) : null}
        {children}
      </div>
    </AppShell>
  )
}

function JoinMessage({
  title,
  description,
}: {
  title: string
  description: string
}) {
  return (
    <JoinShell>
      <Card>
        <CardHeader>
          <CardTitle>{title}</CardTitle>
          <CardDescription>{description}</CardDescription>
        </CardHeader>
      </Card>
    </JoinShell>
  )
}

export default async function JoinPage({
  params,
  searchParams,
}: {
  params: Promise<{ meetingUuid: string }>
  searchParams: Promise<{ token?: string }>
}) {
  const { meetingUuid } = await params
  const { token } = await searchParams

  if (!token) {
    return (
      <JoinMessage
        title="Enlace inválido"
        description="Falta el token de invitación en el enlace. Pide al anfitrión que te comparta el enlace completo."
      />
    )
  }

  const verified = await verifyJoinLinkToken(token)
  if (!verified || verified.meetingUuid !== meetingUuid) {
    return (
      <JoinMessage
        title="Enlace inválido o expirado"
        description="Este enlace de invitación ya no es válido. Pide al anfitrión un nuevo enlace."
      />
    )
  }

  const meeting = await prisma.meeting.findUnique({
    where: { uuid: meetingUuid },
  })

  if (!meeting) {
    return (
      <JoinMessage
        title="Reunión no encontrada"
        description="No encontramos esta reunión. Verifica el enlace."
      />
    )
  }

  if (meeting.status === "ended") {
    return (
      <JoinMessage
        title="Esta reunión ha finalizado"
        description="El anfitrión ya terminó esta reunión. No es posible unirse."
      />
    )
  }

  const session = await auth()

  if (session?.user?.id) {
    const userId = Number(session.user.id)
    const identity = `user-${userId}`

    if (meeting.hostUserId === userId) {
      await prisma.meetingParticipant.upsert({
        where: {
          meetingId_identity: { meetingId: meeting.id, identity },
        },
        update: {},
        create: {
          meetingId: meeting.id,
          userId,
          identity,
          role: "host",
          status: "admitted",
          admittedAt: new Date(),
        },
      })

      redirect(`/room/${meetingUuid}`)
    }

    const participant = await prisma.meetingParticipant.findUnique({
      where: {
        meetingId_identity: { meetingId: meeting.id, identity },
      },
    })

    if (participant) {
      if (participant.status === "admitted") {
        redirect(`/room/${meetingUuid}`)
      }

      if (participant.status === "denied") {
        return (
          <JoinShell>
            <JoinFlow meetingUuid={meetingUuid} token={token} mode="denied" />
          </JoinShell>
        )
      }

      return (
        <JoinShell>
          <JoinFlow meetingUuid={meetingUuid} token={token} mode="waiting" />
        </JoinShell>
      )
    }

    return (
      <JoinShell>
        <JoinFlow
          meetingUuid={meetingUuid}
          token={token}
          mode="confirm"
          displayName={session.user.displayName}
        />
      </JoinShell>
    )
  }

  // Anonymous visitor: recognize a returning guest via cookie before
  // falling back to the name-entry form.
  const cookieStore = await cookies()
  const guestIdentity = cookieStore.get(
    guestIdentityCookieName(meetingUuid)
  )?.value

  if (guestIdentity) {
    const participant = await prisma.meetingParticipant.findUnique({
      where: {
        meetingId_identity: { meetingId: meeting.id, identity: guestIdentity },
      },
    })

    if (participant) {
      if (participant.status === "admitted") {
        redirect(`/room/${meetingUuid}`)
      }

      if (participant.status === "denied") {
        return (
          <JoinShell>
            <JoinFlow meetingUuid={meetingUuid} token={token} mode="denied" />
          </JoinShell>
        )
      }

      return (
        <JoinShell>
          <JoinFlow meetingUuid={meetingUuid} token={token} mode="waiting" />
        </JoinShell>
      )
    }
  }

  return (
    <JoinShell>
      <JoinFlow meetingUuid={meetingUuid} token={token} mode="name-entry" />
    </JoinShell>
  )
}