import { useCallback, useEffect, useState } from "react";
import { Check, Copy, FolderOpen, KeyRound, MessageSquare, RotateCcw, Trash2, UserPlus, Users } from "lucide-react";
import { Button } from "@/components/ui/button";
import {
  AlertDialog,
  AlertDialogAction,
  AlertDialogCancel,
  AlertDialogContent,
  AlertDialogDescription,
  AlertDialogFooter,
  AlertDialogHeader,
  AlertDialogTitle,
} from "@/components/ui/alert-dialog";
import { Badge } from "@/components/ui/badge";
import { Dialog, DialogContent, DialogDescription, DialogHeader, DialogTitle } from "@/components/ui/dialog";
import { Input } from "@/components/ui/input";
import { Label } from "@/components/ui/label";
import {
  Table,
  TableBody,
  TableCell,
  TableHead,
  TableHeader,
  TableRow,
} from "@/components/ui/table";
import {
  createUser,
  deleteUser,
  listUsers,
  resetPassword,
  roleLabel,
  statusLabel,
  type StoredUser,
} from "@/lib/auth-service";
import {
  countProjectsByOwner,
  formatStamp,
  listProjects,
  removeProjectsOfOwner,
  type StoredProject,
} from "@/lib/studio-storage";
import { listFeedback, markFeedbackRead, removeFeedback, type FeedbackItem } from "@/lib/feedback-service";

type Props = {
  open: boolean;
  onOpenChange: (v: boolean) => void;
};

export default function AdminPanel({ open, onOpenChange }: Props) {
  const [users, setUsers] = useState<StoredUser[]>([]);
  const [counts, setCounts] = useState<Record<string, number>>({});
  const [createOpen, setCreateOpen] = useState(false);
  const [newLogin, setNewLogin] = useState("");
  const [createError, setCreateError] = useState<string | null>(null);
  const [credentials, setCredentials] = useState<{ username: string; password: string } | null>(null);
  const [toDelete, setToDelete] = useState<StoredUser | null>(null);
  const [viewing, setViewing] = useState<{ user: StoredUser; items: StoredProject[] } | null>(null);
  const [feedback, setFeedback] = useState<FeedbackItem[]>([]);

  const refresh = useCallback(() => {
    setUsers(listUsers());
    setCounts(countProjectsByOwner());
    setFeedback(listFeedback());
  }, []);

  useEffect(() => {
    if (open) refresh();
  }, [open, refresh]);

  const totalProjects = Object.values(counts).reduce((a, b) => a + b, 0);
  const activeUsers = users.filter((u) => u.status === "active").length;
  const pendingUsers = users.length - activeUsers;

  const copy = (value: string) => {
    void navigator.clipboard?.writeText(value);
  };

  const submitCreate = () => {
    const result = createUser(newLogin);
    if (!result.ok) {
      setCreateError(result.error);
      return;
    }
    setCreateError(null);
    setCreateOpen(false);
    setNewLogin("");
    setCredentials({ username: result.user.username, password: result.tempPassword });
    refresh();
  };

  return (
    <>
      <Dialog open={open} onOpenChange={onOpenChange}>
        <DialogContent className="max-h-[88vh] max-w-5xl overflow-y-auto">
          <DialogHeader>
            <DialogTitle className="flex items-center gap-2 font-display text-2xl">
              <Users className="h-6 w-6 text-accent" /> Панель админа
            </DialogTitle>
            <DialogDescription>Управление пользователями студии и обзор сохранённых схем.</DialogDescription>
          </DialogHeader>

          <div className="grid gap-3 sm:grid-cols-5">
            {[
              { label: "Пользователей", value: users.length },
              { label: "Активных", value: activeUsers },
              { label: "Ожидают входа", value: pendingUsers },
              { label: "Всего схем", value: totalProjects },
              { label: "Новых пожеланий", value: feedback.filter((f) => !f.read).length },
            ].map((s) => (
              <div key={s.label} className="rounded-2xl border border-border bg-secondary p-4">
                <p className="text-xs text-muted-foreground">{s.label}</p>
                <p className="font-display text-3xl leading-tight">{s.value}</p>
              </div>
            ))}
          </div>

          <section className="rounded-2xl border border-border">
            <h3 className="flex items-center gap-2 border-b border-border px-4 py-2 font-display text-lg">
              <MessageSquare className="h-5 w-5 text-accent" /> Пожелания пользователей
            </h3>
            {feedback.length === 0 ? (
              <p className="px-4 py-6 text-center text-sm text-muted-foreground">Пока нет сообщений.</p>
            ) : (
              <ul className="max-h-64 divide-y divide-border overflow-y-auto">
                {feedback.map((f) => (
                  <li key={f.id} className="flex items-start gap-3 px-4 py-2.5">
                    <div className="min-w-0 flex-1">
                      <p className="text-xs text-muted-foreground">
                        {f.username} · {formatStamp(f.createdAt)}
                        {!f.read && <Badge className="ml-2 align-middle">новое</Badge>}
                      </p>
                      <p className="whitespace-pre-wrap text-sm">{f.text}</p>
                    </div>
                    <div className="flex shrink-0 gap-1">
                      {!f.read && (
                        <Button
                          variant="outline"
                          size="icon"
                          className="h-8 w-8"
                          title="Отметить прочитанным"
                          onClick={() => setFeedback(markFeedbackRead(f.id))}
                        >
                          <Check className="h-4 w-4" />
                        </Button>
                      )}
                      <Button
                        variant="outline"
                        size="icon"
                        className="h-8 w-8 text-destructive"
                        title="Удалить сообщение"
                        onClick={() => setFeedback(removeFeedback(f.id))}
                      >
                        <Trash2 className="h-4 w-4" />
                      </Button>
                    </div>
                  </li>
                ))}
              </ul>
            )}
          </section>


          <div>
            <Button size="lg" className="h-12 gap-2" onClick={() => setCreateOpen(true)}>
              <UserPlus className="h-5 w-5" /> Создать пользователя
            </Button>
          </div>

          <div className="overflow-x-auto rounded-2xl border border-border">
            <Table>
              <TableHeader>
                <TableRow>
                  <TableHead>Логин</TableHead>
                  <TableHead>Роль</TableHead>
                  <TableHead>Создан</TableHead>
                  <TableHead>Статус</TableHead>
                  <TableHead>Схемы</TableHead>
                  <TableHead className="text-right">Действия</TableHead>
                </TableRow>
              </TableHeader>
              <TableBody>
                {users.map((u) => (
                  <TableRow key={u.id}>
                    <TableCell className="font-medium">{u.username}</TableCell>
                    <TableCell>{roleLabel(u.role)}</TableCell>
                    <TableCell className="text-muted-foreground">{formatStamp(u.createdAt)}</TableCell>
                    <TableCell>
                      <Badge variant={u.status === "active" ? "secondary" : "outline"}>{statusLabel(u.status)}</Badge>
                    </TableCell>
                    <TableCell>{counts[u.id] ?? 0}</TableCell>
                    <TableCell>
                      <div className="flex flex-wrap justify-end gap-2">
                        <Button
                          variant="outline"
                          size="sm"
                          className="h-10 gap-1"
                          title="Сбросить пароль и выдать временный"
                          onClick={() => {
                            const password = resetPassword(u.id);
                            setCredentials({ username: u.username, password });
                            refresh();
                          }}
                        >
                          <RotateCcw className="h-4 w-4" /> Сбросить пароль
                        </Button>
                        <Button
                          variant="outline"
                          size="sm"
                          className="h-10 gap-1"
                          title="Просмотреть проекты пользователя"
                          onClick={() => setViewing({ user: u, items: listProjects(u.id) })}
                        >
                          <FolderOpen className="h-4 w-4" /> Просмотреть проекты
                        </Button>
                        <Button
                          variant="destructive"
                          size="sm"
                          className="h-10 gap-1"
                          disabled={u.role === "admin"}
                          title={
                            u.role === "admin" ? "Администратора удалить нельзя" : "Удалить пользователя и его схемы"
                          }
                          onClick={() => setToDelete(u)}
                        >
                          <Trash2 className="h-4 w-4" /> Удалить
                        </Button>
                      </div>
                    </TableCell>
                  </TableRow>
                ))}
              </TableBody>
            </Table>
          </div>
        </DialogContent>
      </Dialog>

      {/* Создание пользователя */}
      <Dialog open={createOpen} onOpenChange={setCreateOpen}>
        <DialogContent className="max-w-sm">
          <DialogHeader>
            <DialogTitle className="font-display text-2xl">Создать пользователя</DialogTitle>
            <DialogDescription>
              Укажите логин — система выдаст одноразовый временный пароль для первого входа.
            </DialogDescription>
          </DialogHeader>
          <div className="space-y-2">
            <Label htmlFor="new-user-login">Логин</Label>
            <Input
              id="new-user-login"
              autoFocus
              value={newLogin}
              onChange={(e) => {
                setNewLogin(e.target.value);
                setCreateError(null);
              }}
              className="h-12"
            />
            {createError && <p className="text-sm text-destructive">{createError}</p>}
          </div>
          <Button size="lg" className="h-12 w-full" onClick={submitCreate}>
            <UserPlus className="h-5 w-5" /> Создать и выдать пароль
          </Button>
        </DialogContent>
      </Dialog>

      {/* Показ временного пароля */}
      <Dialog open={!!credentials} onOpenChange={(v) => !v && setCredentials(null)}>
        <DialogContent className="max-w-sm">
          <DialogHeader>
            <DialogTitle className="flex items-center gap-2 font-display text-2xl">
              <KeyRound className="h-6 w-6 text-accent" /> Временный пароль
            </DialogTitle>
            <DialogDescription>
              Передайте пароль пользователю «{credentials?.username}». При первом входе он задаст постоянный пароль.
            </DialogDescription>
          </DialogHeader>
          <div className="flex items-center gap-2">
            <code className="flex-1 rounded-xl border border-border bg-secondary px-4 py-3 text-center text-lg tracking-widest">
              {credentials?.password}
            </code>
            <Button
              variant="outline"
              size="lg"
              className="h-12 gap-2"
              title="Скопировать пароль"
              onClick={() => credentials && copy(credentials.password)}
            >
              <Copy className="h-5 w-5" />
            </Button>
          </div>
          <Button size="lg" className="h-12 w-full" onClick={() => setCredentials(null)}>
            Готово
          </Button>
        </DialogContent>
      </Dialog>

      {/* Проекты пользователя */}
      <Dialog open={!!viewing} onOpenChange={(v) => !v && setViewing(null)}>
        <DialogContent className="max-h-[80vh] max-w-3xl overflow-y-auto">
          <DialogHeader>
            <DialogTitle className="font-display text-2xl">Проекты «{viewing?.user.username}»</DialogTitle>
            <DialogDescription>Схемы, сохранённые этим пользователем.</DialogDescription>
          </DialogHeader>
          {viewing && viewing.items.length === 0 ? (
            <p className="py-8 text-center text-sm text-muted-foreground">У пользователя пока нет схем.</p>
          ) : (
            <div className="grid gap-4 sm:grid-cols-3">
              {viewing?.items.map((p) => (
                <article key={p.id} className="overflow-hidden rounded-2xl border border-border bg-card">
                  <img
                    src={p.thumb}
                    alt={`Превью схемы «${p.title}»`}
                    className="aspect-[4/3] w-full bg-secondary object-cover"
                  />
                  <div className="space-y-1 p-3">
                    <h3 className="truncate font-medium">{p.title}</h3>
                    <p className="text-xs text-muted-foreground">
                      {formatStamp(p.updatedAt)} · элементов: {p.elements}
                    </p>
                  </div>
                </article>
              ))}
            </div>
          )}
        </DialogContent>
      </Dialog>

      <AlertDialog open={!!toDelete} onOpenChange={(v) => !v && setToDelete(null)}>
        <AlertDialogContent>
          <AlertDialogHeader>
            <AlertDialogTitle>Удалить пользователя?</AlertDialogTitle>
            <AlertDialogDescription>
              Пользователь «{toDelete?.username}» и все его схемы будут удалены безвозвратно.
            </AlertDialogDescription>
          </AlertDialogHeader>
          <AlertDialogFooter>
            <AlertDialogCancel>Отмена</AlertDialogCancel>
            <AlertDialogAction
              onClick={() => {
                if (toDelete) {
                  removeProjectsOfOwner(toDelete.id);
                  deleteUser(toDelete.id);
                }
                setToDelete(null);
                refresh();
              }}
            >
              Удалить
            </AlertDialogAction>
          </AlertDialogFooter>
        </AlertDialogContent>
      </AlertDialog>
    </>
  );
}