"use client";

import { useEffect, useState } from "react";
import { Trophy } from "lucide-react";
import { Button } from "@/components/ui/button";
import { cn } from "@/lib/utils";
import type { PresenceParticipant } from "@/hooks/useRealtimePresence";

type LeaderboardTab = "score" | "accuracy" | "messages" | "time";

interface ApiUser {
  id: number;
  username?: string | null;
  displayName?: string | null;
  payloadDisplayName?: string | null;
}

interface ApiProfile {
  id: number;
  profileTitle?: string | null;
  user?: ApiUser | number | null;
  progression?: {
    minigames?: {
        radioTraffic?: {
          totalMessages?: number | null;
          bestScore?: number | null;
          bestAccuracy?: number | null;
          bestSprintTimeMs?: number | null;
        } | null;
    } | null;
  } | null;
}

interface LeaderboardRow {
  id: number;
  name: string;
  totalMessages: number;
  bestScore: number;
  bestAccuracy: number;
  bestSprintTimeMs: number;
  isCurrentUser: boolean;
  isOutsideTopTen?: boolean;
}

interface TabConfig {
  readonly label: string;
  readonly sort: string;
  readonly matches: (row: LeaderboardRow) => boolean;
  readonly empty: string;
}

interface RadioLeaderboardProps {
  refreshKey?: number;
  currentUserId?: number | string;
  activeOperators?: PresenceParticipant[];
}

const TAB_ORDER = ["score", "accuracy", "messages", "time"] as const satisfies readonly LeaderboardTab[];
const TAB_CONFIG = {
  score: {
    label: "Top Score",
    sort: "-progression.minigames.radioTraffic.bestScore",
    matches: (row) => row.bestScore > 0,
    empty: "No scored transmissions yet. Take the first slot!",
  },
  accuracy: {
    label: "Top Accuracy",
    sort: "-progression.minigames.radioTraffic.bestAccuracy",
    matches: (row) => row.bestAccuracy > 0,
    empty: "No accuracy records yet. Relay a perfect transmission!",
  },
  messages: {
    label: "Most Messages",
    sort: "-progression.minigames.radioTraffic.totalMessages",
    matches: (row) => row.totalMessages > 0,
    empty: "No accurate messages yet. Get on frequency!",
  },
  time: {
    label: "Fastest Sprint",
    sort: "progression.minigames.radioTraffic.bestSprintTimeMs",
    matches: (row) => row.bestSprintTimeMs > 0,
    empty: "No sprint times yet. Complete a 10-message sprint!",
  },
} satisfies Record<LeaderboardTab, TabConfig>;

function rankClass(index: number) {
  if (index === 0) return "font-bold text-amber-400";
  if (index === 1) return "font-semibold text-slate-300";
  if (index === 2) return "font-semibold text-amber-700";
  return "text-muted-foreground";
}

export function RadioLeaderboard({
  refreshKey = 0,
  currentUserId,
  activeOperators = [],
}: RadioLeaderboardProps) {
  const [tab, setTab] = useState<LeaderboardTab>("score");
  const [rows, setRows] = useState<LeaderboardRow[] | null>(null);
  const [failed, setFailed] = useState(false);
  const tabConfig = TAB_CONFIG[tab];

  useEffect(() => {
    let cancelled = false;
    setFailed(false);
    setRows(null);

    const params = new URLSearchParams({ sort: tabConfig.sort, limit: "100", depth: "1" });
    fetch(`/api/profiles?${params.toString()}`)
      .then((res) => {
        if (!res.ok) throw new Error("leaderboard fetch failed");
        return res.json() as Promise<{ docs?: ApiProfile[] }>;
      })
      .then((data) => {
        if (cancelled) return;
        const mapped: LeaderboardRow[] = (data.docs ?? []).map((doc) => {
          const radioTraffic = doc.progression?.minigames?.radioTraffic ?? {};
          const user = typeof doc.user === "object" && doc.user !== null ? doc.user : null;
          return {
            id: doc.id,
            name: user?.displayName || doc.profileTitle || user?.username || `Operator #${doc.id}`,
            totalMessages: radioTraffic.totalMessages ?? 0,
            bestScore: radioTraffic.bestScore ?? 0,
            bestAccuracy: radioTraffic.bestAccuracy ?? 0,
            bestSprintTimeMs: radioTraffic.bestSprintTimeMs ?? 0,
            isCurrentUser: user ? String(user.id) === String(currentUserId) : false,
          };
        });
        const visible = mapped.filter(tabConfig.matches).slice(0, 10);
        const current = mapped.find((row) => row.isCurrentUser);
        if (current && !visible.some((row) => row.id === current.id)) {
          visible.push({ ...current, isOutsideTopTen: true });
        }
        setRows(visible);
      })
      .catch(() => {
        if (!cancelled) setFailed(true);
      });

    return () => {
      cancelled = true;
    };
  }, [currentUserId, refreshKey, tabConfig.matches, tabConfig.sort]);

  return (
    <div className="w-full max-w-[520px] rounded-xl border border-border bg-card">
      <div className="border-b border-border px-4 py-3">
        <div className="flex items-center gap-2">
          <Trophy className="size-4 text-amber-400" />
          <h2 className="text-sm font-semibold">Radio Traffic Leaderboard</h2>
          <span className="ml-auto text-xs text-muted-foreground">Top 10</span>
        </div>
        <div
              className="mt-3 grid grid-cols-4 gap-1 rounded-lg bg-muted p-1"
          role="tablist"
          aria-label="Radio traffic leaderboard"
        >
          {TAB_ORDER.map((value) => (
            <Button
              key={value}
              type="button"
              role="tab"
              aria-selected={tab === value}
              variant={tab === value ? "secondary" : "ghost"}
              size="sm"
              className="px-2 text-xs"
              onClick={() => setTab(value)}
            >
              {TAB_CONFIG[value].label}
            </Button>
          ))}
        </div>
      </div>
      <div className="border-b border-border px-4 py-2 text-xs text-muted-foreground" aria-live="polite">
        <span className="font-medium text-emerald-400">
          {activeOperators.length} {activeOperators.length === 1 ? "operator" : "operators"} on frequency
        </span>
        {activeOperators.length > 0 && (
          <span className="ml-1 text-foreground">
            ({activeOperators.map((operator) => operator.name).join(", ")})
          </span>
        )}
      </div>

      {failed ? (
        <p className="px-4 py-4 text-sm text-muted-foreground">Could not load the leaderboard.</p>
      ) : rows === null ? (
        <div className="flex flex-col gap-2 px-4 py-4">
          <div className="h-4 w-full animate-pulse rounded bg-border" />
          <div className="h-4 w-3/4 animate-pulse rounded bg-border" />
          <div className="h-4 w-1/2 animate-pulse rounded bg-border" />
        </div>
      ) : rows.length === 0 ? (
        <p className="px-4 py-4 text-sm text-muted-foreground">{tabConfig.empty}</p>
      ) : (
        <div className="overflow-x-auto">
          <table className="w-full text-sm">
            <thead>
              <tr className="text-left text-xs uppercase tracking-wider text-muted-foreground">
                <th className="px-4 py-2 font-medium">#</th>
                <th className="px-2 py-2 font-medium">Operator</th>
                <th className="px-2 py-2 text-right font-medium">Score</th>
                <th className="px-2 py-2 text-right font-medium">Accuracy</th>
                <th className="px-2 py-2 text-right font-medium">Time</th>
                <th className="px-4 py-2 text-right font-medium">Messages</th>
              </tr>
            </thead>
            <tbody className="divide-y divide-border">
              {rows.map((row, index) => (
                <tr
                  key={row.id}
                  className={cn(
                    row.isCurrentUser && "bg-accent/40",
                    row.isOutsideTopTen && "text-muted-foreground opacity-70",
                  )}
                  title={
                    row.isOutsideTopTen
                      ? "Operator status: not currently ranked in the top 10"
                      : undefined
                  }
                >
                  <td className="px-4 py-2">
                    <span className={rankClass(index)}>{row.isOutsideTopTen ? "—" : index + 1}</span>
                  </td>
                  <td className="px-2 py-2 font-medium">
                    <span className="flex items-center gap-2">
                      <span className="max-w-[180px] truncate">{row.name}</span>
                      {row.isCurrentUser && (
                        <span className="shrink-0 text-xs text-muted-foreground">(you)</span>
                      )}
                      {row.isOutsideTopTen && (
                        <span className="shrink-0 text-[10px] font-normal uppercase tracking-wide text-muted-foreground">
                          unranked
                        </span>
                      )}
                      {activeOperators.some((operator) => operator.id === row.id) && (
                        <span
                          className="size-2 rounded-full bg-emerald-400"
                          title="Transmitting now"
                          aria-label="Transmitting now"
                        />
                      )}
                    </span>
                  </td>
                  <td className="px-2 py-2 text-right font-semibold tabular-nums">
                    {row.bestScore.toFixed(2)}
                  </td>
                  <td className="px-2 py-2 text-right font-semibold tabular-nums">
                    {(row.bestAccuracy * 100).toFixed(2)}%
                  </td>
                  <td className="px-2 py-2 text-right tabular-nums">
                    {row.bestSprintTimeMs > 0 ? `${(row.bestSprintTimeMs / 1000).toFixed(1)}s` : "—"}
                  </td>
                  <td className="px-4 py-2 text-right tabular-nums text-muted-foreground">
                    {row.totalMessages}
                  </td>
                </tr>
              ))}
            </tbody>
          </table>
        </div>
      )}
    </div>
  );
}