"use client";

import { useEffect, useState } from "react";
import { Trophy } from "lucide-react";

import type { OpordDifficulty } from "@/lib/opord-recall";
import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/components/ui/card";
import { Skeleton } from "@/components/ui/skeleton";
import type { PresenceParticipant } from "@/hooks/useRealtimePresence";
import { cn } from "@/lib/utils";
import { OPORD_LEADERBOARD_FIELDS, readOpordProfiles } from "./opordLeaderboardData";

type LeaderboardRow = {
  readonly id: number;
  readonly userId: number | null;
  readonly name: string;
  readonly gamesPlayed: number;
  readonly bestScore: number;
  readonly bestAccuracy: number;
  readonly isCurrentUser: boolean;
  readonly isOutsideTopTen?: boolean;
};

function rankClass(index: number): string {
  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 OpordLeaderboard({
  refreshKey = 0,
  difficulty,
  currentUserId,
  activeOperators = [],
}: {
  readonly refreshKey?: number;
  readonly difficulty: OpordDifficulty;
  readonly currentUserId?: number | string;
  readonly activeOperators?: readonly PresenceParticipant[];
}) {
  const [rows, setRows] = useState<readonly LeaderboardRow[] | null>(null);
  const [failed, setFailed] = useState<string | null>(null);
  const tier = OPORD_LEADERBOARD_FIELDS[difficulty];

  useEffect(() => {
    let cancelled = false;
    setFailed(null);
    setRows(null);
    const field = `progression.minigames.opordRecall.${tier.scoreField}`;
    const params = new URLSearchParams({
      sort: `-${field}`,
      limit: "100",
      depth: "1",
    });

    fetch(`/api/profiles?${params.toString()}`)
      .then(async (response) => {
        if (!response.ok) throw new Error("leaderboard fetch failed");
        const payload: unknown = await response.json();
        return readOpordProfiles(payload);
      })
      .then((profiles) => {
        if (cancelled) return;
        const mapped: LeaderboardRow[] = profiles.map((profile) => {
          const user =
            typeof profile.user === "object" && profile.user !== null ? profile.user : null;
          const userId = user?.id ?? (typeof profile.user === "number" ? profile.user : null);
          const name =
            user?.displayName ||
            user?.payloadDisplayName ||
            profile.profileTitle ||
            user?.username ||
            `Operator #${profile.id}`;
          const opordRecall = profile.opordRecall;
          return {
            id: profile.id,
            userId,
            name,
            gamesPlayed: opordRecall?.gamesPlayed ?? 0,
            bestScore: opordRecall?.[tier.scoreField] ?? 0,
            bestAccuracy: opordRecall?.bestAccuracy ?? 0,
            isCurrentUser: userId !== null && String(userId) === String(currentUserId),
          };
        });
        const scored = mapped
          .filter((row) => row.bestScore > 0)
          .sort(
            (left, right) =>
              right.bestScore - left.bestScore || right.bestAccuracy - left.bestAccuracy,
          );
        const visible = scored.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((error: unknown) => {
        if (cancelled) return;
        setFailed(error instanceof Error ? error.message : "leaderboard fetch failed");
      });

    return () => {
      cancelled = true;
    };
  }, [currentUserId, difficulty, refreshKey, tier.scoreField]);

  return (
    <Card className="w-full max-w-3xl overflow-hidden">
      <CardHeader className="gap-1 border-b border-border px-4 py-3">
        <div className="flex items-center gap-2">
          <Trophy aria-hidden="true" className="size-4 text-amber-400" />
          <CardTitle className="text-sm">OPORD Recall leaderboard</CardTitle>
          <span className="ml-auto text-xs text-muted-foreground">{tier.label} · Top 10</span>
        </div>
        <CardDescription>Best score for the selected briefing tier.</CardDescription>
      </CardHeader>
      <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}</span>{" "}
        {activeOperators.length === 1 ? "operator is" : "operators are"} studying briefings
        {activeOperators.length > 0 && (
          <span className="ml-1 text-foreground">
            ({activeOperators.map((operator) => operator.name).join(", ")})
          </span>
        )}
      </div>

      <CardContent className="p-0">
        {failed !== null ? (
          <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">
            <Skeleton className="h-4 w-full motion-reduce:animate-none" />
            <Skeleton className="h-4 w-3/4 motion-reduce:animate-none" />
            <Skeleton className="h-4 w-1/2 motion-reduce:animate-none" />
          </div>
        ) : rows.length === 0 ? (
          <p className="px-4 py-4 text-sm text-muted-foreground">
            No scores logged for this tier yet. Be the first to brief up.
          </p>
        ) : (
          <div className="overflow-x-auto">
            <table className="w-full min-w-lg 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">Games</th>
                  <th className="px-2 py-2 text-right font-medium">Accuracy</th>
                  <th
                    aria-sort="descending"
                    className="px-4 py-2 text-right font-medium text-foreground"
                  >
                    Score
                  </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-48 truncate">{row.name}</span>
                        {row.isCurrentUser && (
                          <span className="shrink-0 text-xs text-muted-foreground">(you)</span>
                        )}
                        {row.isOutsideTopTen && (
                          <span className="shrink-0 text-xs font-normal uppercase tracking-wide text-muted-foreground">
                            unranked
                          </span>
                        )}
                        {row.userId !== null && activeOperators.some((operator) => operator.id === row.userId) && (
                          <span
                            className="size-2 rounded-full bg-emerald-400"
                            title="Playing now"
                            aria-label="Playing now"
                          />
                        )}
                      </span>
                    </td>
                    <td className="px-2 py-2 text-right font-mono tabular-nums text-muted-foreground">
                      {row.gamesPlayed}
                    </td>
                    <td className="px-2 py-2 text-right font-mono tabular-nums text-muted-foreground">
                      {Math.round(row.bestAccuracy * 100)}%
                    </td>
                    <td className="px-4 py-2 text-right font-mono font-semibold tabular-nums">
                      {row.bestScore}
                    </td>
                  </tr>
                ))}
              </tbody>
            </table>
          </div>
        )}
      </CardContent>
    </Card>
  );
}