import { Fragment, useState } from "react";
import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
import {
  Network as NetworkIcon,
  Plus,
  Trash2,
  Eraser,
  ChevronRight,
  ChevronDown,
  Link2,
  Unplug,
} from "lucide-react";
import { toast } from "sonner";
import { Badge, Button, Card, Input, Spinner } from "@/components/ui";
import { ConfirmDialog } from "@/components/ui/ConfirmDialog";
import { HostHeader } from "@/components/hosts/HostHeader";
import { networksApi, type NetworkInfo } from "@/api/networks";
import { agentsApi } from "@/api/agents";
import { apiErrorMessage } from "@/api/client";
import { useAuthStore } from "@/store/auth";
import type { Agent } from "@/types";

const selectClass =
  "w-full rounded-lg border border-slate-300 bg-white px-3 py-2 text-sm dark:border-slate-600 dark:bg-slate-800";

export function Networks() {
  const isAdmin = useAuthStore((s) => s.user?.role === "admin");
  const agents = useQuery({
    queryKey: ["agents"],
    queryFn: () => agentsApi.list(),
    refetchInterval: 15000,
  });
  const hasAgents = (agents.data?.length ?? 0) > 0;

  return (
    <div className="space-y-8">
      <NetworksSection isAdmin={isAdmin} showHostLabel={hasAgents} />
      {agents.data?.map((agent) => (
        <NetworksSection key={agent.id} agent={agent} isAdmin={isAdmin} showHostLabel />
      ))}
    </div>
  );
}

function NetworksSection({
  agent,
  isAdmin,
  showHostLabel,
}: {
  agent?: Agent;
  isAdmin: boolean;
  showHostLabel: boolean;
}) {
  const agentId = agent?.id;
  const online = !agent || agent.status === "online";
  const qc = useQueryClient();
  const { data, isLoading } = useQuery({
    queryKey: ["networks", agentId ?? "local"],
    queryFn: () => networksApi.list(agentId),
    refetchInterval: 10000,
    enabled: online,
  });
  const [creating, setCreating] = useState(false);
  const [toDelete, setToDelete] = useState<NetworkInfo | null>(null);
  const [expanded, setExpanded] = useState<string | null>(null);
  const invalidate = () => qc.invalidateQueries({ queryKey: ["networks", agentId ?? "local"] });
  const colSpan = isAdmin ? 6 : 5;

  const prune = useMutation({
    mutationFn: () => networksApi.prune(agentId),
    onSuccess: (r) => {
      const n = r.NetworksDeleted?.length ?? 0;
      toast.success(n ? `Pruned ${n} network(s)` : "No unused networks");
      invalidate();
    },
    onError: (e) => toast.error(apiErrorMessage(e)),
  });
  const remove = useMutation({
    mutationFn: (id: string) => networksApi.remove(id, agentId),
    onSuccess: () => {
      toast.success("Network deleted");
      setToDelete(null);
      invalidate();
    },
    onError: (e) => toast.error(apiErrorMessage(e)),
  });

  const header = (
    <HostHeader agent={agent}>
      {isAdmin && online && (
        <>
          <Button variant="outline" onClick={() => prune.mutate()} loading={prune.isPending}>
            <Eraser className="h-4 w-4" /> Prune unused
          </Button>
          <Button onClick={() => setCreating(true)}>
            <Plus className="h-4 w-4" /> Create network
          </Button>
        </>
      )}
    </HostHeader>
  );

  return (
    <section>
      {(showHostLabel || (isAdmin && online)) && header}

      {!online ? (
        <Card>
          <p className="text-sm text-slate-500">
            Host is {agent?.status}. Check it under Settings → Remote hosts.
          </p>
        </Card>
      ) : isLoading ? (
        <Spinner />
      ) : (
        <Card className="overflow-x-auto p-0">
          <table className="w-full text-left text-sm">
            <thead className="border-b border-slate-200 text-xs uppercase text-slate-500 dark:border-slate-700">
              <tr>
                <th className="px-4 py-2">Name</th>
                <th className="px-4 py-2">Driver</th>
                <th className="px-4 py-2">Scope</th>
                <th className="px-4 py-2">Subnet</th>
                <th className="px-4 py-2">In use</th>
                {isAdmin && <th className="px-4 py-2"></th>}
              </tr>
            </thead>
            <tbody className="divide-y divide-slate-100 dark:divide-slate-700">
              {data?.map((n) => (
                <Fragment key={n.id}>
                  <tr
                    onClick={() => setExpanded((e) => (e === n.id ? null : n.id))}
                    className="cursor-pointer hover:bg-slate-50 dark:hover:bg-slate-800/50"
                  >
                    <td className="px-4 py-2">
                      <div className="flex items-center gap-2">
                        {expanded === n.id ? (
                          <ChevronDown className="h-4 w-4 text-slate-400" />
                        ) : (
                          <ChevronRight className="h-4 w-4 text-slate-400" />
                        )}
                        <NetworkIcon className="h-4 w-4 text-slate-400" />
                        <span className="font-medium">{n.name}</span>
                        {n.is_default && <Badge>default</Badge>}
                        {n.stack && <Badge>{n.stack}</Badge>}
                        {n.internal && <span className="text-xs text-slate-400">internal</span>}
                      </div>
                    </td>
                    <td className="px-4 py-2 text-slate-500">{n.driver}</td>
                    <td className="px-4 py-2 text-slate-500">{n.scope}</td>
                    <td className="px-4 py-2 font-mono text-xs text-slate-500">{n.subnet ?? "—"}</td>
                    <td className="px-4 py-2">
                      {n.in_use ? (
                        <span title={n.containers.join(", ")} className="text-slate-600 dark:text-slate-300">
                          {n.containers.length} container{n.containers.length > 1 ? "s" : ""}
                        </span>
                      ) : (
                        <span className="text-slate-400">—</span>
                      )}
                    </td>
                    {isAdmin && (
                      <td className="px-4 py-2 text-right">
                        {!n.is_default && (
                          <button
                            title={n.in_use ? "In use — disconnect containers first" : "Delete"}
                            onClick={(e) => { e.stopPropagation(); setToDelete(n); }}
                            className="rounded-lg p-1.5 hover:bg-slate-100 dark:hover:bg-slate-700"
                          >
                            <Trash2 className="h-4 w-4 text-red-500" />
                          </button>
                        )}
                      </td>
                    )}
                  </tr>
                  {expanded === n.id && (
                    <tr>
                      <td colSpan={colSpan} className="bg-slate-50 px-4 py-3 dark:bg-slate-800/40">
                        <NetworkDetail network={n} isAdmin={isAdmin} agentId={agentId} />
                      </td>
                    </tr>
                  )}
                </Fragment>
              ))}
              {data?.length === 0 && (
                <tr>
                  <td colSpan={colSpan} className="px-4 py-8 text-center text-sm text-slate-500">
                    No networks.
                  </td>
                </tr>
              )}
            </tbody>
          </table>
        </Card>
      )}

      {creating && (
        <CreateNetworkDialog
          agentId={agentId}
          onDone={() => { setCreating(false); invalidate(); }}
          onCancel={() => setCreating(false)}
        />
      )}
      {toDelete && (
        <ConfirmDialog
          title={`Delete network “${toDelete.name}”?`}
          message={
            toDelete.in_use
              ? "This network is in use; Docker will refuse unless containers are disconnected first."
              : "This cannot be undone."
          }
          confirmLabel="Delete network"
          danger
          busy={remove.isPending}
          onConfirm={() => remove.mutate(toDelete.id)}
          onCancel={() => setToDelete(null)}
        />
      )}
    </section>
  );
}

function NetworkDetail({
  network,
  isAdmin,
  agentId,
}: {
  network: NetworkInfo;
  isAdmin: boolean;
  agentId?: number;
}) {
  const qc = useQueryClient();
  const [pick, setPick] = useState("");
  const { data, isLoading } = useQuery({
    queryKey: ["network-containers", agentId ?? "local", network.id],
    queryFn: () => networksApi.containers(network.id, agentId),
    refetchInterval: 10000,
  });
  const refresh = () => {
    qc.invalidateQueries({ queryKey: ["network-containers", agentId ?? "local", network.id] });
    qc.invalidateQueries({ queryKey: ["networks", agentId ?? "local"] });
  };

  const connect = useMutation({
    mutationFn: (container: string) => networksApi.connect(network.id, container, undefined, agentId),
    onSuccess: () => { toast.success("Container connected"); setPick(""); refresh(); },
    onError: (e) => toast.error(apiErrorMessage(e)),
  });
  const disconnect = useMutation({
    mutationFn: (container: string) => networksApi.disconnect(network.id, container, false, agentId),
    onSuccess: () => { toast.success("Container disconnected"); refresh(); },
    onError: (e) => toast.error(apiErrorMessage(e)),
  });

  const connected = (data ?? []).filter((c) => c.connected);
  const available = (data ?? []).filter((c) => !c.connected);

  return (
    <div className="space-y-3 text-sm">
      <div className="grid grid-cols-2 gap-x-6 gap-y-1 sm:grid-cols-4">
        <Meta label="Driver" value={network.driver} />
        <Meta label="Scope" value={network.scope} />
        <Meta label="Subnet" value={network.subnet ?? "—"} mono />
        <Meta label="Gateway" value={network.gateway ?? "—"} mono />
        <Meta label="Attachable" value={network.attachable ? "yes" : "no"} />
        <Meta label="Internal" value={network.internal ? "yes" : "no"} />
        <Meta label="ID" value={network.id} mono />
      </div>

      <div>
        <p className="mb-1 text-xs font-semibold uppercase tracking-wide text-slate-500">
          Connected containers
        </p>
        {isLoading ? (
          <Spinner />
        ) : connected.length === 0 ? (
          <p className="text-slate-400">No containers connected.</p>
        ) : (
          <ul className="space-y-1">
            {connected.map((c) => (
              <li key={c.id} className="flex items-center gap-2">
                <span className="font-medium">{c.name}</span>
                {c.stack && <Badge>{c.stack}</Badge>}
                <span className="text-xs text-slate-400">{c.state}</span>
                {isAdmin && !network.is_default && (
                  <button
                    title="Disconnect"
                    onClick={() => disconnect.mutate(c.name)}
                    disabled={disconnect.isPending}
                    className="ml-1 rounded p-1 hover:bg-slate-200 dark:hover:bg-slate-700"
                  >
                    <Unplug className="h-3.5 w-3.5 text-red-500" />
                  </button>
                )}
              </li>
            ))}
          </ul>
        )}
      </div>

      {isAdmin && (
        <div className="flex items-center gap-2">
          <select
            className={selectClass + " max-w-xs"}
            value={pick}
            onChange={(e) => setPick(e.target.value)}
          >
            <option value="">Connect a container…</option>
            {available.map((c) => (
              <option key={c.id} value={c.name}>
                {c.name}
                {c.stack ? ` (${c.stack})` : ""}
              </option>
            ))}
          </select>
          <Button
            variant="outline"
            disabled={!pick || connect.isPending}
            loading={connect.isPending}
            onClick={() => connect.mutate(pick)}
          >
            <Link2 className="h-4 w-4" /> Connect
          </Button>
        </div>
      )}
    </div>
  );
}

function Meta({ label, value, mono }: { label: string; value: string; mono?: boolean }) {
  return (
    <div>
      <span className="text-xs text-slate-400">{label}</span>
      <p className={mono ? "font-mono text-xs" : ""}>{value}</p>
    </div>
  );
}

function CreateNetworkDialog({
  agentId,
  onDone,
  onCancel,
}: {
  agentId?: number;
  onDone: () => void;
  onCancel: () => void;
}) {
  const [form, setForm] = useState({
    name: "",
    driver: "bridge",
    subnet: "",
    gateway: "",
    internal: false,
    attachable: true,
  });
  const set = (k: string, v: unknown) => setForm((f) => ({ ...f, [k]: v }));

  const create = useMutation({
    mutationFn: () =>
      networksApi.create(
        {
          name: form.name,
          driver: form.driver,
          subnet: form.subnet.trim() || null,
          gateway: form.gateway.trim() || null,
          internal: form.internal,
          attachable: form.attachable,
        },
        agentId
      ),
    onSuccess: () => { toast.success("Network created"); onDone(); },
    onError: (e) => toast.error(apiErrorMessage(e)),
  });

  return (
    <div className="fixed inset-0 z-50 flex items-center justify-center bg-black/50 p-4" onClick={onCancel}>
      <div
        className="w-full max-w-md rounded-xl border border-slate-200 bg-card p-5 shadow-xl dark:border-slate-700 dark:bg-card-dark"
        onClick={(e) => e.stopPropagation()}
      >
        <h2 className="mb-3 text-lg font-semibold">Create network</h2>
        <div className="space-y-3">
          <label className="block space-y-1">
            <span className="text-xs font-medium text-slate-500">Name</span>
            <Input value={form.name} onChange={(e) => set("name", e.target.value)} placeholder="my-net" />
          </label>
          <label className="block space-y-1">
            <span className="text-xs font-medium text-slate-500">Driver</span>
            <select className={selectClass} value={form.driver} onChange={(e) => set("driver", e.target.value)}>
              <option value="bridge">bridge</option>
              <option value="macvlan">macvlan</option>
              <option value="ipvlan">ipvlan</option>
              <option value="overlay">overlay</option>
            </select>
          </label>
          <div className="grid grid-cols-2 gap-3">
            <label className="space-y-1">
              <span className="text-xs font-medium text-slate-500">Subnet (optional)</span>
              <Input value={form.subnet} onChange={(e) => set("subnet", e.target.value)} placeholder="172.20.0.0/16" />
            </label>
            <label className="space-y-1">
              <span className="text-xs font-medium text-slate-500">Gateway (optional)</span>
              <Input value={form.gateway} onChange={(e) => set("gateway", e.target.value)} placeholder="172.20.0.1" />
            </label>
          </div>
          <div className="flex gap-4">
            <label className="flex items-center gap-2 text-sm">
              <input type="checkbox" checked={form.internal} onChange={(e) => set("internal", e.target.checked)} className="h-4 w-4" />
              Internal (no external access)
            </label>
            <label className="flex items-center gap-2 text-sm">
              <input type="checkbox" checked={form.attachable} onChange={(e) => set("attachable", e.target.checked)} className="h-4 w-4" />
              Attachable
            </label>
          </div>
        </div>
        <div className="mt-4 flex justify-end gap-2">
          <Button variant="outline" onClick={onCancel}>Cancel</Button>
          <Button onClick={() => create.mutate()} loading={create.isPending} disabled={!form.name.trim()}>
            Create
          </Button>
        </div>
      </div>
    </div>
  );
}