import { Fragment, type ReactNode } from "react";
import Link from "next/link";
import { ArrowLeft, DatabaseZap, RadioTower, Trophy } from "lucide-react";
import { LeaderboardSearch, LeaderboardTabs } from "./client";
import { ThemeToggle } from "@/components/theme-toggle";
import { Badge } from "@/components/ui/badge";
import { Button } from "@/components/ui/button";
import {
  Card,
  CardContent,
  CardDescription,
  CardFooter,
  CardHeader,
  CardTitle,
} from "@/components/ui/card";
import {
  Pagination,
  PaginationContent,
  PaginationEllipsis,
  PaginationItem,
  PaginationLink,
  PaginationNext,
  PaginationPrevious,
} from "@/components/ui/pagination";
import {
  Table,
  TableBody,
  TableCaption,
  TableCell,
  TableHead,
  TableHeader,
  TableRow,
} from "@/components/ui/table";
import {
  formatInteger,
  formatVoiceDuration,
  resolveLeaderboardName,
  shortenDiscordId,
  type LeaderboardPage,
  type VoiceLeaderboardRow,
  type XpLeaderboardRow,
} from "@/lib/leaderboard/ranking";

type LeaderboardBoardProps =
  | {
      kind: "xp";
      data: LeaderboardPage<XpLeaderboardRow>;
      searchQuery: string;
      channelId?: never;
    }
  | {
      kind: "vc";
      data: LeaderboardPage<VoiceLeaderboardRow>;
      searchQuery: string;
      channelId?: string;
    };

function rankVariant(rank: number) {
  if (rank === 1) return "default";
  if (rank === 2) return "secondary";
  return "outline";
}

function Identity({
  displayName,
  username,
  userId,
}: {
  displayName: string | null;
  username: string | null;
  userId: string;
}) {
  const unresolved = !displayName?.trim() && !username?.trim();

  return (
    <div className="flex min-w-40 flex-col gap-0.5">
      <span className="font-medium">
        {resolveLeaderboardName({ displayName, username, userId })}
      </span>
      <span className="text-xs text-muted-foreground">
        {unresolved
          ? `Discord ID: ${shortenDiscordId(userId)}`
          : displayName?.trim() && username?.trim()
            ? `@${username}`
            : `Discord ID: ${shortenDiscordId(userId)}`}
      </span>
    </div>
  );
}

function Podium({ data }: LeaderboardBoardProps) {
  if (data.podium.length === 0) return null;

  return (
    <section aria-labelledby="podium-title" className="flex flex-col gap-3">
      <h2 id="podium-title" className="text-lg font-medium">สามอันดับนำ</h2>
      <div className="grid gap-3 md:grid-cols-3">
        {data.podium.map((row) => (
          <Card
            key={row.userId}
            size="sm"
            className={row.rank === 1 ? "md:-translate-y-1" : undefined}
          >
            <CardHeader>
              <CardTitle className="flex items-center justify-between gap-3">
                <span className="truncate">
                  {resolveLeaderboardName(row)}
                </span>
                <Badge variant={rankVariant(row.rank)}>
                  {row.rank === 1 && <Trophy data-icon="inline-start" />}
                  #{row.rank}
                </Badge>
              </CardTitle>
              <CardDescription>
                {"level" in row
                  ? `เลเวล ${row.level}`
                  : "เวลารวมในห้องเสียง"}
              </CardDescription>
            </CardHeader>
            <CardContent className="text-xl font-semibold tabular-nums">
              {"totalXp" in row
                ? `${formatInteger(row.totalXp)} XP`
                : formatVoiceDuration(row.totalSeconds)}
            </CardContent>
          </Card>
        ))}
      </div>
    </section>
  );
}

function visiblePages(page: number, totalPages: number) {
  const pages = new Set([1, totalPages, page - 1, page, page + 1]);
  return [...pages]
    .filter((value) => value >= 1 && value <= totalPages)
    .sort((a, b) => a - b);
}

function pageHref(
  path: string,
  page: number,
  channelId?: string,
  searchQuery?: string,
) {
  const params = new URLSearchParams();
  if (channelId) params.set("channel", channelId);
  if (searchQuery) params.set("q", searchQuery);
  if (page > 1) params.set("page", String(page));
  const query = params.toString();
  return query ? `${path}?${query}` : path;
}

function LeaderboardPagination({
  path,
  page,
  totalPages,
  channelId,
  searchQuery,
}: {
  path: string;
  page: number;
  totalPages: number;
  channelId?: string;
  searchQuery?: string;
}) {
  if (totalPages <= 1) return null;
  const pages = visiblePages(page, totalPages);

  return (
    <Pagination aria-label="หน้าอันดับ">
      <PaginationContent>
        {page > 1 && (
          <PaginationItem>
            <PaginationPrevious
              href={pageHref(path, page - 1, channelId, searchQuery)}
              text="ก่อนหน้า"
              aria-label="ไปหน้าก่อนหน้า"
            />
          </PaginationItem>
        )}

        {pages.map((value, index) => (
          <Fragment key={value}>
            {index > 0 && value - pages[index - 1] > 1 && (
              <PaginationItem>
                <PaginationEllipsis />
              </PaginationItem>
            )}
            <PaginationItem>
              <PaginationLink
                href={pageHref(path, value, channelId, searchQuery)}
                isActive={value === page}
                aria-label={`ไปหน้า ${value}`}
              >
                {value}
              </PaginationLink>
            </PaginationItem>
          </Fragment>
        ))}

        {page < totalPages && (
          <PaginationItem>
            <PaginationNext
              href={pageHref(path, page + 1, channelId, searchQuery)}
              text="ถัดไป"
              aria-label="ไปหน้าถัดไป"
            />
          </PaginationItem>
        )}
      </PaginationContent>
    </Pagination>
  );
}

export function LeaderboardBoard(props: LeaderboardBoardProps) {
  const { kind, data, channelId, searchQuery } = props;
  const firstRow = data.totalRows === 0
    ? 0
    : (data.page - 1) * data.pageSize + 1;
  const lastRow = Math.min(data.page * data.pageSize, data.totalRows);

  return (
    <>
      <Podium {...props} />

      <Card>
        <CardHeader>
          <CardTitle>
            {kind === "xp" ? "อันดับ XP ทั้งหมด" : "อันดับเวลาในห้องเสียง"}
          </CardTitle>
          <CardDescription>
            {data.totalRows > 0
              ? `แสดง ${firstRow}–${lastRow} จาก ${formatInteger(String(data.totalRows))} คน`
              : searchQuery
                ? "ไม่พบสมาชิกที่ตรงกับคำค้นหานี้"
                : "ยังไม่มีข้อมูลในขอบเขตนี้"}
          </CardDescription>
        </CardHeader>
        <CardContent className="px-0">
          <Table>
            <TableCaption>
              {kind === "xp"
                ? "ตารางอันดับจาก XP รวมของสมาชิกเลเวล 1 ขึ้นไป"
                : "ตารางอันดับจากเวลารวมในห้องเสียงและห้องเวทีปัจจุบัน"}
            </TableCaption>
            <TableHeader>
              <TableRow>
                <TableHead className="pl-6">อันดับ</TableHead>
                <TableHead>สมาชิก</TableHead>
                {kind === "xp" && <TableHead>เลเวล</TableHead>}
                <TableHead className="pr-6 text-right">
                  {kind === "xp" ? "XP รวม" : "เวลารวม"}
                </TableHead>
              </TableRow>
            </TableHeader>
            <TableBody>
              {data.rows.map((row) => (
                <TableRow key={row.userId}>
                  <TableCell className="pl-6">
                    <Badge variant={rankVariant(row.rank)}>#{row.rank}</Badge>
                  </TableCell>
                  <TableCell>
                    <Identity {...row} />
                  </TableCell>
                  {"level" in row && (
                    <TableCell className="tabular-nums">{row.level}</TableCell>
                  )}
                  <TableCell className="pr-6 text-right font-medium tabular-nums">
                    {"totalXp" in row
                      ? formatInteger(row.totalXp)
                      : formatVoiceDuration(row.totalSeconds)}
                  </TableCell>
                </TableRow>
              ))}
            </TableBody>
          </Table>
        </CardContent>
        <CardFooter>
          <LeaderboardPagination
            path={`/leaderboard/${kind}`}
            page={data.page}
            totalPages={data.totalPages}
            channelId={channelId}
            searchQuery={searchQuery}
          />
        </CardFooter>
      </Card>
    </>
  );
}

export function LeaderboardError({ source }: { source: "database" | "discord" }) {
  const Icon = source === "database" ? DatabaseZap : RadioTower;

  return (
    <Card role="alert">
      <CardHeader>
        <CardTitle className="flex items-center gap-2">
          <Icon />
          {source === "database"
            ? "โหลดข้อมูลอันดับไม่สำเร็จ"
            : "โหลดรายชื่อห้อง Discord ไม่สำเร็จ"}
        </CardTitle>
        <CardDescription>
          {source === "database"
            ? "ฐานข้อมูลอันดับยังไม่พร้อมใช้งาน ลองเปิดหน้านี้ใหม่อีกครั้ง"
            : "ยังเลือกขอบเขตห้องเสียงไม่ได้ ลองเปิดหน้านี้ใหม่เมื่อ Discord พร้อมใช้งาน"}
        </CardDescription>
      </CardHeader>
      <CardContent className="text-sm text-muted-foreground">
        หน้านี้ไม่มีการดึงข้อมูลซ้ำอัตโนมัติระหว่างที่ระบบขัดข้อง
      </CardContent>
    </Card>
  );
}

type LeaderboardShellProps = {
  active: "xp" | "vc";
  title: string;
  description: string;
  searchQuery: string;
  children: ReactNode;
};

export function LeaderboardShell({
  active,
  title,
  description,
  searchQuery,
  children,
}: LeaderboardShellProps) {
  return (
    <div className="relative mx-auto flex w-full max-w-6xl flex-col gap-6 px-4 py-6 sm:px-6 lg:py-10">
      <nav aria-label="ทางลัด" className="flex items-center justify-between gap-3">
        <Button variant="ghost" asChild>
          <Link href="/">
            <ArrowLeft data-icon="inline-start" />
            กลับหน้าหลัก
          </Link>
        </Button>
        <ThemeToggle />
      </nav>

      <Card>
        <CardHeader>
          <CardTitle>
            <h1 className="text-2xl font-semibold sm:text-3xl">{title}</h1>
          </CardTitle>
          <CardDescription className="max-w-2xl">{description}</CardDescription>
        </CardHeader>
        <CardContent className="flex flex-col gap-4 sm:flex-row sm:items-end sm:justify-between">
          <LeaderboardTabs active={active} searchQuery={searchQuery} />
          <LeaderboardSearch query={searchQuery} />
        </CardContent>
      </Card>

      {children}
    </div>
  );
}