"use client";

// ============================================================================
// External Channels List Page
// ============================================================================

import React, { useEffect, useState } from "react";
import Link from "next/link";
import { DashboardHeader } from "@/components/layout/dashboard-header";
import {
  Card,
  CardContent,
  CardDescription,
  CardHeader,
  CardTitle,
} from "@/components/ui/card";
import { Button } from "@/components/ui/button";
import { Input } from "@/components/ui/input";
import { Badge } from "@/components/ui/badge";
import { externalChannelsApi, channelsApi } from "@/lib/api";
import {
  formatNumber,
  formatMetric,
  formatUsername,
  formatCompactNumber,
} from "@/lib/utils/format";
import {
  ExternalLink as ExternalLinkIcon,
  Loader2,
  AlertCircle,
  Plus,
  Search,
  FileUp,
  Eye,
  Pencil,
  Trash2,
  Users,
  ArrowUpDown,
  ArrowUp,
  ArrowDown,
  LayoutGrid,
  Table2,
} from "lucide-react";
import type { ExternalChannel } from "@/lib/types/api";
import { Alert, AlertDescription } from "@/components/ui/alert";
import {
  Table,
  TableBody,
  TableCell,
  TableHead,
  TableHeader,
  TableRow,
} from "@/components/ui/table";
import {
  Dialog,
  DialogContent,
  DialogDescription,
  DialogFooter,
  DialogHeader,
  DialogTitle,
  DialogTrigger,
} from "@/components/ui/dialog";
import { Label } from "@/components/ui/label";
import { Textarea } from "@/components/ui/textarea";
import { useTargetChannel } from "@/components/providers/target-channel-provider";

type ViewMode = "table" | "grid";
type SortField =
  | "title"
  | "username"
  | "subscribers_count"
  | "telegram_id"
  | null;
type SortDirection = "asc" | "desc" | null;

export default function ExternalChannelsPage() {
  const { selectedChannel } = useTargetChannel();
  const [channels, setChannels] = useState<ExternalChannel[]>([]);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);
  const [searchQuery, setSearchQuery] = useState("");
  const [isCreateDialogOpen, setIsCreateDialogOpen] = useState(false);
  const [isCreating, setIsCreating] = useState(false);
  const [viewMode, setViewMode] = useState<ViewMode>("table");
  const [sortField, setSortField] = useState<SortField>(null);
  const [sortDirection, setSortDirection] = useState<SortDirection>(null);

  // Form state
  const [formData, setFormData] = useState({
    title: "",
    username: "",
    link: "",
    subscribers_count: "",
    description: "",
  });

  useEffect(() => {
    if (selectedChannel) {
      loadChannels();
    } else {
      setLoading(false);
    }
  }, [selectedChannel]);

  const loadChannels = async () => {
    if (!selectedChannel) return;

    try {
      setLoading(true);
      setError(null);
      const response = await externalChannelsApi.list(selectedChannel.id);
      setChannels(response.external_channels);
    } catch (err: any) {
      const errorMsg =
        typeof err?.detail === "string"
          ? err.detail
          : err?.error?.message || "Ошибка загрузки каналов";
      setError(errorMsg);
    } finally {
      setLoading(false);
    }
  };

  const handleCreate = async () => {
    try {
      setIsCreating(true);
      // Получаем первый доступный target channel
      const targetChannelsRes = await channelsApi.list();
      if (targetChannelsRes.target_channels.length === 0) {
        alert("Добавьте сначала целевой канал");
        setIsCreating(false);
        return;
      }

      await externalChannelsApi.create({
        telegram_id: 0, // Временно, пока не получим реальный ID
        title: formData.title,
        username: formData.username || null,
        subscribers_count: formData.subscribers_count
          ? parseInt(formData.subscribers_count)
          : null,
        description: formData.description || null,
        target_channel_ids: [targetChannelsRes.target_channels[0].id],
      });
      setIsCreateDialogOpen(false);
      setFormData({
        title: "",
        username: "",
        link: "",
        subscribers_count: "",
        description: "",
      });
      loadChannels();
    } catch (err: any) {
      const errorMsg =
        typeof err?.detail === "string"
          ? err.detail
          : err?.error?.message || "Ошибка создания канала";
      alert(errorMsg);
    } finally {
      setIsCreating(false);
    }
  };

  const handleDelete = async (id: string, title: string) => {
    if (!confirm(`Удалить канал "${title}"?`)) return;

    try {
      await externalChannelsApi.delete(id);
      loadChannels();
    } catch (err: any) {
      alert(err?.error?.message || "Ошибка удаления канала");
    }
  };

  // Обработка сортировки
  const handleSort = (field: SortField) => {
    if (sortField === field) {
      // Переключение: asc -> desc -> null -> asc
      if (sortDirection === "asc") {
        setSortDirection("desc");
      } else if (sortDirection === "desc") {
        setSortField(null);
        setSortDirection(null);
      }
    } else {
      setSortField(field);
      setSortDirection("asc");
    }
  };

  const getSortIcon = (field: SortField) => {
    if (sortField !== field) {
      return <ArrowUpDown className="ml-2 h-4 w-4 inline" />;
    }
    if (sortDirection === "asc") {
      return <ArrowUp className="ml-2 h-4 w-4 inline" />;
    }
    return <ArrowDown className="ml-2 h-4 w-4 inline" />;
  };

  const filteredChannels = channels
    .filter(
      (channel) =>
        channel.title.toLowerCase().includes(searchQuery.toLowerCase()) ||
        channel.username?.toLowerCase().includes(searchQuery.toLowerCase())
    )
    .sort((a, b) => {
      if (!sortField || !sortDirection) return 0;

      let aValue: string | number | null = "";
      let bValue: string | number | null = "";

      switch (sortField) {
        case "title":
          aValue = a.title;
          bValue = b.title;
          break;
        case "username":
          aValue = a.username || "";
          bValue = b.username || "";
          break;
        case "subscribers_count":
          aValue = a.subscribers_count || 0;
          bValue = b.subscribers_count || 0;
          break;
        case "telegram_id":
          aValue = a.telegram_id;
          bValue = b.telegram_id;
          break;
      }

      // Сравнение строк
      if (typeof aValue === "string" && typeof bValue === "string") {
        return sortDirection === "asc"
          ? aValue.localeCompare(bValue)
          : bValue.localeCompare(aValue);
      }

      // Сравнение чисел
      if (typeof aValue === "number" && typeof bValue === "number") {
        return sortDirection === "asc" ? aValue - bValue : bValue - aValue;
      }

      return 0;
    });

  return (
    <>
      <DashboardHeader
        breadcrumbs={[
          { label: "Главная", href: "/" },
          { label: "Внешние каналы" },
        ]}
      />
      <div className="flex flex-1 flex-col gap-4 p-4 pt-0 mt-4">
        <div className="flex items-center justify-between">
          <div>
            <h1 className="text-3xl font-bold tracking-tight">
              Внешние каналы
            </h1>
            <p className="text-muted-foreground mt-1">
              Каналы, в которых покупаете рекламу
            </p>
          </div>
          <div className="flex gap-2">
            <Button asChild variant="outline">
              <Link href="/external-channels/import">
                <FileUp className="mr-2 h-4 w-4" />
                Импорт из Excel
              </Link>
            </Button>

            <Dialog
              open={isCreateDialogOpen}
              onOpenChange={setIsCreateDialogOpen}
            >
              <DialogTrigger asChild>
                <Button>
                  <Plus className="mr-2 h-4 w-4" />
                  Добавить канал
                </Button>
              </DialogTrigger>
              <DialogContent className="sm:max-w-[500px]">
                <DialogHeader>
                  <DialogTitle>Добавить внешний канал</DialogTitle>
                  <DialogDescription>
                    Добавьте канал, в котором планируете покупать рекламу
                  </DialogDescription>
                </DialogHeader>
                <div className="grid gap-4 py-4">
                  <div className="grid gap-2">
                    <Label htmlFor="title">Название *</Label>
                    <Input
                      id="title"
                      value={formData.title}
                      onChange={(e) =>
                        setFormData({ ...formData, title: e.target.value })
                      }
                      placeholder="Название канала"
                    />
                  </div>
                  <div className="grid gap-2">
                    <Label htmlFor="link">Ссылка *</Label>
                    <Input
                      id="link"
                      value={formData.link}
                      onChange={(e) =>
                        setFormData({ ...formData, link: e.target.value })
                      }
                      placeholder="https://t.me/channel_name"
                    />
                  </div>
                  <div className="grid gap-2">
                    <Label htmlFor="username">Username</Label>
                    <Input
                      id="username"
                      value={formData.username}
                      onChange={(e) =>
                        setFormData({ ...formData, username: e.target.value })
                      }
                      placeholder="@channel_name"
                    />
                  </div>
                  <div className="grid gap-2">
                    <Label htmlFor="subscribers">Количество подписчиков</Label>
                    <Input
                      id="subscribers"
                      type="number"
                      value={formData.subscribers_count}
                      onChange={(e) =>
                        setFormData({
                          ...formData,
                          subscribers_count: e.target.value,
                        })
                      }
                      placeholder="50000"
                    />
                  </div>
                  <div className="grid gap-2">
                    <Label htmlFor="description">Описание</Label>
                    <Textarea
                      id="description"
                      value={formData.description}
                      onChange={(e) =>
                        setFormData({
                          ...formData,
                          description: e.target.value,
                        })
                      }
                      placeholder="Краткое описание канала"
                      rows={3}
                    />
                  </div>
                </div>
                <DialogFooter>
                  <Button
                    variant="outline"
                    onClick={() => setIsCreateDialogOpen(false)}
                  >
                    Отмена
                  </Button>
                  <Button onClick={handleCreate} disabled={isCreating}>
                    {isCreating ? (
                      <>
                        <Loader2 className="mr-2 h-4 w-4 animate-spin" />
                        Создание...
                      </>
                    ) : (
                      "Создать"
                    )}
                  </Button>
                </DialogFooter>
              </DialogContent>
            </Dialog>
          </div>
        </div>

        {error && (
          <Alert variant="destructive">
            <AlertCircle className="h-4 w-4" />
            <AlertDescription>{error}</AlertDescription>
          </Alert>
        )}

        <div className="flex items-center justify-between gap-2">
          <div className="flex items-center gap-2">
            <div className="relative flex-1 max-w-sm">
              <Search className="absolute left-2.5 top-2.5 h-4 w-4 text-muted-foreground" />
              <Input
                placeholder="Поиск по названию или username..."
                value={searchQuery}
                onChange={(e) => setSearchQuery(e.target.value)}
                className="pl-8 rounded-lg"
              />
            </div>
            <Badge variant="secondary">
              Всего: {formatNumber(filteredChannels.length)}
            </Badge>
          </div>
          <div className="flex items-center gap-1 border rounded-md">
            <Button
              variant={viewMode === "table" ? "default" : "ghost"}
              size="sm"
              onClick={() => setViewMode("table")}
              className="rounded-r-none"
            >
              <Table2 className="h-4 w-4" />
            </Button>
            <Button
              variant={viewMode === "grid" ? "default" : "ghost"}
              size="sm"
              onClick={() => setViewMode("grid")}
              className="rounded-l-none"
            >
              <LayoutGrid className="h-4 w-4" />
            </Button>
          </div>
        </div>

        {loading ? (
          <div className="flex items-center justify-center p-12">
            <Loader2 className="h-8 w-8 animate-spin text-muted-foreground" />
          </div>
        ) : filteredChannels.length === 0 ? (
          <Card>
            <CardContent className="flex flex-col items-center justify-center p-12">
              <ExternalLinkIcon className="h-12 w-12 text-muted-foreground mb-4" />
              <p className="text-lg font-medium text-muted-foreground">
                {searchQuery ? "Каналы не найдены" : "Нет внешних каналов"}
              </p>
              <p className="text-sm text-muted-foreground mt-1">
                {searchQuery
                  ? "Попробуйте изменить поисковый запрос"
                  : "Добавьте каналы вручную или импортируйте из Excel"}
              </p>
            </CardContent>
          </Card>
        ) : viewMode === "grid" ? (
          <div className="grid gap-4 md:grid-cols-2 lg:grid-cols-3">
            {filteredChannels.map((channel) => (
              <Card
                key={channel.id}
                className="hover:shadow-md transition-shadow"
              >
                <CardHeader>
                  <div className="flex items-start justify-between gap-2">
                    <div className="flex-1 min-w-0">
                      <CardTitle className="truncate flex items-center gap-2">
                        <ExternalLinkIcon className="h-4 w-4 shrink-0" />
                        {channel.title}
                      </CardTitle>
                      <CardDescription className="truncate mt-1">
                        {channel.username ? (
                          <a
                            href={`https://t.me/${channel.username}`}
                            target="_blank"
                            rel="noopener noreferrer"
                            className="hover:underline"
                          >
                            {formatUsername(channel.username)}
                          </a>
                        ) : (
                          <span className="text-xs">
                            ID: {channel.telegram_id}
                          </span>
                        )}
                      </CardDescription>
                    </div>
                  </div>
                </CardHeader>
                <CardContent className="space-y-3">
                  {channel.description && (
                    <p className="text-sm text-muted-foreground line-clamp-2">
                      {channel.description}
                    </p>
                  )}

                  <div className="flex items-center gap-2">
                    <div className="flex-1 rounded-lg border bg-muted/50 p-2">
                      <div className="flex items-center justify-center gap-1">
                        <Users className="h-3 w-3 text-muted-foreground" />
                        <div className="text-sm font-medium">
                          {channel.subscribers_count
                            ? formatCompactNumber(channel.subscribers_count)
                            : "—"}
                        </div>
                      </div>
                      <div className="text-xs text-muted-foreground text-center">
                        Подписчики
                      </div>
                    </div>
                  </div>

                  <div className="flex gap-2 pt-2">
                    <Button
                      variant="destructive"
                      size="sm"
                      className="flex-1"
                      onClick={() => handleDelete(channel.id, channel.title)}
                    >
                      <Trash2 className="mr-2 h-4 w-4" />
                      Удалить
                    </Button>
                  </div>
                </CardContent>
              </Card>
            ))}
          </div>
        ) : (
          <Card>
            <CardHeader>
              <CardTitle>Список внешних каналов</CardTitle>
              <CardDescription>
                Каналы, в которых покупаете рекламу
              </CardDescription>
            </CardHeader>
            <CardContent>
              <Table>
                <TableHeader>
                  <TableRow>
                    <TableHead
                      className="cursor-pointer hover:bg-muted/50"
                      onClick={() => handleSort("title")}
                    >
                      Название
                      {getSortIcon("title")}
                    </TableHead>
                    <TableHead className="cursor-pointer hover:bg-muted/50">
                      Username
                    </TableHead>
                    <TableHead>Описание</TableHead>
                    <TableHead
                      className="text-right cursor-pointer hover:bg-muted/50"
                      onClick={() => handleSort("subscribers_count")}
                    >
                      Подписчики
                      {getSortIcon("subscribers_count")}
                    </TableHead>
                    <TableHead className="text-right cursor-pointer hover:bg-muted/50">
                      Telegram ID
                    </TableHead>
                    <TableHead></TableHead>
                  </TableRow>
                </TableHeader>
                <TableBody>
                  {filteredChannels.map((channel) => (
                    <TableRow key={channel.id}>
                      <TableCell className="font-medium">
                        <div className="flex items-center gap-2">
                          <a
                            href={`https://t.me/${channel.username}`}
                            target="_blank"
                            rel="noopener noreferrer"
                            className="flex items-center gap-2 hover:underline text-primary whitespace-nowrap"
                            tabIndex={0}
                            aria-label={`Открыть канал ${channel.title} в Telegram`}
                            onClick={(e) => e.stopPropagation()}
                            onKeyDown={(e) => {
                              if (e.key === "Enter" || e.key === " ") {
                                window.open(
                                  `https://t.me/${channel.username}`,
                                  "_blank",
                                  "noopener,noreferrer"
                                );
                              }
                            }}
                          >
                            <span className="inline-flex items-center gap-2">
                              <span>{channel.title}</span>
                              <ExternalLinkIcon className="h-4 w-4 text-muted-foreground shrink-0" />
                            </span>
                          </a>
                        </div>
                      </TableCell>
                      <TableCell>
                        {channel.username ? (
                          <div>{formatUsername(channel.username)}</div>
                        ) : (
                          "—"
                        )}
                      </TableCell>
                      <TableCell>
                        <div className="max-w-[300px] truncate text-muted-foreground">
                          {channel.description || "—"}
                        </div>
                      </TableCell>
                      <TableCell className="text-right">
                        {channel.subscribers_count
                          ? formatNumber(channel.subscribers_count)
                          : "—"}
                      </TableCell>
                      <TableCell className="text-right">
                        {channel.telegram_id}
                      </TableCell>
                      <TableCell className="text-right">
                        <Button
                          variant="ghost"
                          size="sm"
                          onClick={() =>
                            handleDelete(channel.id, channel.title)
                          }
                        >
                          <Trash2 className="h-4 w-4 text-destructive" />
                        </Button>
                      </TableCell>
                    </TableRow>
                  ))}
                </TableBody>
              </Table>
            </CardContent>
          </Card>
        )}
      </div>
    </>
  );
}