import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query"
import { Bot } from "lucide-react"
import { useState } from "react"

import { OauthService, type RegisteredClient } from "@/client"
import { Badge } from "@/components/ui/badge"
import { Button } from "@/components/ui/button"
import {
  Dialog,
  DialogContent,
  DialogDescription,
  DialogFooter,
  DialogHeader,
  DialogTitle,
} from "@/components/ui/dialog"
import useCustomToast from "@/hooks/useCustomToast"
import { handleError } from "@/utils"

const clientsKey = ["oauth", "clients"]

function when(value: string): string {
  return new Date(value).toLocaleString()
}

/** The agents that registered themselves for the MCP endpoint, and the way to
 *  withdraw one — the alternative being to rotate the signing key, which cuts
 *  off every agent at once. */
export function OAuthClients() {
  const { data } = useQuery({
    queryKey: clientsKey,
    queryFn: () => OauthService.readClients(),
  })
  const queryClient = useQueryClient()
  const { showSuccessToast, showErrorToast } = useCustomToast()
  const [pending, setPending] = useState<RegisteredClient | null>(null)

  const revoke = useMutation({
    mutationFn: (clientId: string) => OauthService.revokeClient({ clientId }),
    onSuccess: (message) => {
      showSuccessToast(message.message)
      setPending(null)
    },
    onError: handleError.bind(showErrorToast),
    onSettled: () => {
      queryClient.invalidateQueries({ queryKey: clientsKey })
    },
  })

  const clients = data?.data ?? []

  return (
    <div className="flex flex-col gap-6">
      <div>
        <h1 className="text-2xl font-bold tracking-tight">Agents</h1>
        <p className="text-muted-foreground">
          Clients that registered themselves to reach the MCP endpoint. Each one
          still needed a person to approve it before it could do anything.
        </p>
      </div>

      {clients.length === 0 ? (
        <p className="text-sm text-muted-foreground">
          Nothing has registered yet. An agent adds itself here the first time
          it asks for access.
        </p>
      ) : (
        <div className="grid gap-2">
          {clients.map((client) => (
            <div
              key={client.id}
              className="flex flex-wrap items-center justify-between gap-3 rounded-lg border border-border bg-card p-4 shadow-e1"
              data-testid="oauth-client"
            >
              <div className="grid gap-1">
                <span className="flex items-center gap-2 text-sm font-medium">
                  <Bot className="size-4 text-muted-foreground" />
                  {client.client_name}
                </span>
                <span className="font-mono text-xs text-muted-foreground">
                  {client.redirect_uris.join(" ")}
                </span>
                <span className="text-xs text-muted-foreground">
                  Registered {when(client.created_at)}
                  {client.last_authorized_at
                    ? ` · approved ${when(client.last_authorized_at)}`
                    : ""}
                </span>
              </div>
              <div className="flex items-center gap-3">
                <Badge
                  variant={client.active_tokens > 0 ? "default" : "secondary"}
                >
                  {client.active_tokens > 0
                    ? `${client.active_tokens} live token${
                        client.active_tokens === 1 ? "" : "s"
                      }`
                    : "Never approved"}
                </Badge>
                <Button
                  variant="ghost"
                  size="sm"
                  className="text-destructive hover:text-destructive"
                  data-testid="revoke-client"
                  onClick={() => setPending(client)}
                >
                  Revoke
                </Button>
              </div>
            </div>
          ))}
        </div>
      )}

      <Dialog
        open={pending !== null}
        onOpenChange={(open) => !open && setPending(null)}
      >
        <DialogContent>
          <DialogHeader>
            <DialogTitle>Revoke '{pending?.client_name}'?</DialogTitle>
            <DialogDescription>
              It loses its refresh tokens, so it can get nothing new and has to
              be approved again from scratch. An access token already in its
              hands keeps working until it expires. Every other agent is left
              alone.
            </DialogDescription>
          </DialogHeader>
          <DialogFooter>
            <Button variant="outline" onClick={() => setPending(null)}>
              Keep it
            </Button>
            <Button
              variant="destructive"
              disabled={revoke.isPending}
              data-testid="confirm-revoke-client"
              onClick={() => pending && revoke.mutate(pending.id)}
            >
              Revoke
            </Button>
          </DialogFooter>
        </DialogContent>
      </Dialog>
    </div>
  )
}

export default OAuthClients