"use client";

import { useState } from "react";
import { useQuery, useMutation, useQueryClient } from "@tanstack/react-query";
import { useParams, useRouter } from "next/navigation";
import Link from "next/link";
import { api, ServerStatus } from "@/lib/api";
import { Badge, Button, Card, CardHeader, CardTitle } from "@/components/ui";
import { Table, Thead, Tbody, Tr, Th, Td } from "@/components/ui";

function statusVariant(status: ServerStatus) {
  switch (status) {
    case "active": return "success";
    case "pending": return "warning";
    case "offline": return "danger";
  }
}

function formatDate(dateStr: string) {
  return new Date(dateStr).toLocaleString();
}

export default function ServerDetailPage() {
  const params = useParams();
  const router = useRouter();
  const queryClient = useQueryClient();
  const serverId = params.id as string;
  const [confirmDelete, setConfirmDelete] = useState(false);

  const { data: server, isLoading, error } = useQuery({
    queryKey: ["servers", serverId],
    queryFn: () => api.getServer(serverId),
    refetchInterval: 30_000,
  });

  const { mutate: generateKey, isPending: isGenerating } = useMutation({
    mutationFn: () => api.generateKeyForServer(serverId),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ["servers", serverId] });
      queryClient.invalidateQueries({ queryKey: ["keys"] });
    },
  });

  const { mutate: deleteServer, isPending: isDeleting } = useMutation({
    mutationFn: () => api.deleteServer(serverId),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ["servers"] });
      router.push("/servers");
    },
  });

  if (isLoading) {
    return (
      <div className="flex h-full items-center justify-center">
        <div className="h-8 w-8 animate-spin rounded-full border-2 border-border border-t-accent" />
      </div>
    );
  }

  if (error || !server) {
    return (
      <div className="p-8">
        <div className="rounded-lg border border-danger/30 bg-danger/10 p-4 text-danger">
          Server not found or failed to load.
        </div>
      </div>
    );
  }

  return (
    <div className="p-8">
      <div className="mb-6 flex items-start justify-between">
        <div>
          <div className="flex items-center gap-3">
            <Link href="/servers" className="text-text-secondary hover:text-text-primary text-sm">
              ← Servers
            </Link>
          </div>
          <div className="mt-2 flex items-center gap-3">
            <h1 className="text-2xl font-bold text-text-primary">{server.hostname}</h1>
            <Badge variant={statusVariant(server.status)}>{server.status}</Badge>
          </div>
          <p className="mt-1 font-mono text-sm text-text-secondary">{server.ip_address}</p>
        </div>
        <div className="flex gap-2">
          <Button
            variant="secondary"
            loading={isGenerating}
            onClick={() => generateKey()}
          >
            <svg className="h-4 w-4" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={1.5}>
              <path strokeLinecap="round" strokeLinejoin="round" d="M15.75 5.25a3 3 0 013 3m3 0a6 6 0 01-7.029 5.912c-.563-.097-1.159.026-1.563.43L10.5 17.25H8.25v2.25H6v2.25H2.25v-2.818c0-.597.237-1.17.659-1.591l6.499-6.499c.404-.404.527-1 .43-1.563A6 6 0 1121.75 8.25z" />
            </svg>
            Generate SSH Key
          </Button>
          {!confirmDelete ? (
            <Button variant="danger" onClick={() => setConfirmDelete(true)}>
              Remove Server
            </Button>
          ) : (
            <div className="flex items-center gap-2">
              <span className="text-sm text-danger">Are you sure?</span>
              <Button
                variant="danger"
                loading={isDeleting}
                onClick={() => deleteServer()}
              >
                Confirm
              </Button>
              <Button variant="ghost" onClick={() => setConfirmDelete(false)}>
                Cancel
              </Button>
            </div>
          )}
        </div>
      </div>

      <div className="grid grid-cols-1 gap-6 lg:grid-cols-3">
        <Card className="lg:col-span-1">
          <CardHeader>
            <CardTitle>Details</CardTitle>
          </CardHeader>
          <dl className="space-y-3 text-sm">
            <div>
              <dt className="text-text-secondary">Server ID</dt>
              <dd className="mt-0.5 font-mono text-xs text-text-primary break-all">{server.server_id}</dd>
            </div>
            <div className="border-t border-border pt-3">
              <dt className="text-text-secondary">OS</dt>
              <dd className="mt-0.5 text-text-primary">{server.os_info}</dd>
            </div>
            <div className="border-t border-border pt-3">
              <dt className="text-text-secondary">Last Seen</dt>
              <dd className="mt-0.5 text-text-primary">{server.last_seen ? formatDate(server.last_seen) : "Never"}</dd>
            </div>
            <div className="border-t border-border pt-3">
              <dt className="text-text-secondary">Registered</dt>
              <dd className="mt-0.5 text-text-primary">{formatDate(server.created_at)}</dd>
            </div>
          </dl>
        </Card>

        <div className="lg:col-span-2">
          <Card padding={false}>
            <div className="flex items-center justify-between border-b border-border px-6 py-4">
              <h2 className="text-lg font-semibold text-text-primary">
                Installed Keys
                <span className="ml-2 rounded-full bg-surface-2 px-2 py-0.5 text-xs text-text-secondary">
                  {server.keys?.filter(k => !k.revoked_at).length ?? 0} active
                </span>
              </h2>
              <Link href="/keys">
                <Button variant="ghost" size="sm">Manage Keys →</Button>
              </Link>
            </div>

            {!server.keys || server.keys.length === 0 ? (
              <div className="py-16 text-center">
                <p className="text-text-secondary text-sm">No keys assigned to this server.</p>
                <Link href="/keys">
                  <Button variant="secondary" size="sm" className="mt-3">
                    Assign a key
                  </Button>
                </Link>
              </div>
            ) : (
              <Table>
                <Thead>
                  <Tr>
                    <Th>Label</Th>
                    <Th>Fingerprint</Th>
                    <Th>Source</Th>
                    <Th>Status</Th>
                    <Th>Assigned</Th>
                    <Th />
                  </Tr>
                </Thead>
                <Tbody>
                  {server.keys.map((assignment) => (
                    <Tr key={assignment.key_id}>
                      <Td>
                        <span className="font-medium">{assignment.key.label}</span>
                      </Td>
                      <Td>
                        <span className="font-mono text-xs text-text-secondary">
                          {assignment.key.fingerprint}
                        </span>
                      </Td>
                      <Td>
                        <Badge variant={assignment.key.source === "generated" ? "accent" : "neutral"}>
                          {assignment.key.source}
                        </Badge>
                      </Td>
                      <Td>
                        <Badge variant={assignment.revoked_at ? "danger" : "success"}>
                          {assignment.revoked_at ? "revoked" : "active"}
                        </Badge>
                      </Td>
                      <Td>
                        <span className="text-text-secondary text-xs">
                          {formatDate(assignment.assigned_at)}
                        </span>
                      </Td>
                      <Td>
                        <Link href={`/keys/${assignment.key_id}`}>
                          <Button variant="ghost" size="sm">View</Button>
                        </Link>
                      </Td>
                    </Tr>
                  ))}
                </Tbody>
              </Table>
            )}
          </Card>
        </div>
      </div>
    </div>
  );
}