import { useState, useEffect } from "react";
import { getGameTitle, getShortenedGameName } from "../utils.ts";
import { useSearchParams } from "react-router-dom";
import { useTranslation } from "react-i18next";

export interface NewsData {
  date: string;
  identifier: string;
  type: string | null;
  timestamp: number;
  headline: string | null;
  content: string;
  url: string | null;
  images: Array<{
    image: string;
    link: string | null;
  }>;
  en_headline: string | null;
  en_content: string | null;
  is_ai_summary: boolean | null;
  archive_hash: string | null;
}

interface NewsFeedProps {
  newsItems: NewsData[];
}

type Sentinel = { _sentinel: "nothing-new" | "caught-up" };

const VIEWED_KEY = "viewedNewsIds";

const computeNewsId = (news: NewsData): string => {
  const contentHash =
    news.content
      .split("")
      .reduce(
        (hash, char) => (hash << 5) + hash + char.charCodeAt(0),
        5381,
      ) >>> 0;
  const headlineHash =
    (news.headline || "null")
      .split("")
      .reduce(
        (hash, char) => (hash << 5) + hash + char.charCodeAt(0),
        5381,
      ) >>> 0;
  const legacyId = `${news.identifier}-${news.timestamp}-${contentHash.toString(16)}-${headlineHash.toString(16)}`;
  return news.archive_hash || legacyId;
};

export const NewsFeed: React.FC<NewsFeedProps> = ({ newsItems }) => {
  const { t } = useTranslation();
  const [showEnglish, setShowEnglish] = useState<Record<string, boolean>>({});
  const [expanded, setExpanded] = useState<Record<string, boolean>>({});
  const [currentImageIndex, setCurrentImageIndex] = useState<
    Record<string, number>
  >({});
  const [loadingImages, setLoadingImages] = useState<Record<string, boolean>>(
    {},
  );
  const [searchParams] = useSearchParams();
  const isMoe = searchParams.has("moe");
  const pfpBaseUrl = import.meta.env.VITE_PFP_BASE_URL;
  const middlewareBase = import.meta.env.VITE_MIDDLEWARE_BASE_URL;

  const [initialViewedIds] = useState<Set<string>>(() => {
    try {
      const raw = localStorage.getItem(VIEWED_KEY);
      if (!raw) return new Set();
      const parsed = JSON.parse(raw) as Array<{ id: string } | string>;
      return new Set(parsed.map((e) => (typeof e === "string" ? e : e.id)));
    } catch {
      return new Set();
    }
  });

  useEffect(() => {
    try {
      const raw = localStorage.getItem(VIEWED_KEY);
      const prev: { id: string; timestamp: number }[] = raw
        ? (JSON.parse(raw) as Array<{ id: string; timestamp?: number } | string>).map(
            (e) => (typeof e === "string" ? { id: e, timestamp: 0 } : { id: e.id, timestamp: e.timestamp ?? 0 }),
          )
        : [];
      const map = new Map(prev.map((e) => [e.id, e.timestamp]));
      for (const news of newsItems) {
        const id = computeNewsId(news);
        if (!map.has(id)) map.set(id, news.timestamp);
      }
      const next = [...map.entries()]
        .map(([id, timestamp]) => ({ id, timestamp }))
        .sort((a, b) => b.timestamp - a.timestamp)
        .slice(0, 100);
      localStorage.setItem(VIEWED_KEY, JSON.stringify(next));
    } catch {
      console.error("Failed to update viewed news items");
    }
  }, [newsItems]);

  const toggleLanguage = (id: string) =>
    setShowEnglish((prev) => ({ ...prev, [id]: !prev[id] }));
  const toggleExpand = (id: string) =>
    setExpanded((prev) => ({ ...prev, [id]: !prev[id] }));
  const changeImage = (id: string, i: number) => {
    if (currentImageIndex[id] == i) return;
    setCurrentImageIndex((p) => ({ ...p, [id]: i }));
    setLoadingImages((p) => ({ ...p, [id]: true }));
  };
  const handleImageLoad = (id: string) =>
    setLoadingImages((p) => ({ ...p, [id]: false }));
  const PREVIEW_CHAR_LIMIT = 600;

  useEffect(() => {
    const initialImageIndex: Record<string, number> = {};
    newsItems.forEach((news) => {
      initialImageIndex[computeNewsId(news)] = 0;
    });
    setCurrentImageIndex(initialImageIndex);
  }, [newsItems]);

  useEffect(() => {
    const fragment = window.location.hash.slice(1);
    if (fragment) {
      const el = document.getElementById(fragment);
      if (el) {
        el.scrollIntoView({ behavior: "smooth", block: "start" });
      } else {
        alert("News Post doesn't or no longer exists...");
      }
    }
  }, [newsItems]);

  const unviewed = newsItems
    .filter((n) => !initialViewedIds.has(computeNewsId(n)))
    .sort((a, b) => b.timestamp - a.timestamp);
  const viewed = newsItems.filter((n) => initialViewedIds.has(computeNewsId(n)));
  const nothingNew = unviewed.length === 0 && newsItems.length > 0;

  const feed: (NewsData | Sentinel)[] = [];
  if (nothingNew) feed.push({ _sentinel: "nothing-new" });
  feed.push(...unviewed);
  if (unviewed.length > 0 && viewed.length > 0) feed.push({ _sentinel: "caught-up" });
  feed.push(...(nothingNew ? newsItems : viewed));

  return (
    <div className="max-w-[600px] w-full mx-auto py-8 space-y-4 font-[Zen_Maru_Gothic]">
      {feed.map((item, idx) => {
        if ("_sentinel" in item) {
          const isFirstSentinel = idx === 0;
          return (
            <div
              key={item._sentinel}
              className={`flex font-bold items-center gap-3 ${isFirstSentinel ? "py-2" : "py-24"} ${isMoe ? "text-pink-400" : "text-gray-100"}`}
            >
              <div className={`flex-1 h-px ${isMoe ? "bg-pink-300" : "bg-gray-700"}`} />
              <span className="text-sm">
                {item._sentinel === t("nothing_new") ? t("nothing_new") : t("caught_up")}
              </span>
              <div className={`flex-1 h-px ${isMoe ? "bg-pink-300" : "bg-gray-700"}`} />
            </div>
          );
        }

        const news = item;
        const date = new Date(news.timestamp * 1000).toLocaleDateString(
          "ja-JP",
          { year: "numeric", month: "2-digit", day: "2-digit" },
        );
        const newsId = computeNewsId(news);
        const isEnglish = showEnglish[newsId];
        const hasTranslation = news.en_headline || news.en_content;
        const displayHeadline =
          isEnglish && news.en_headline ? news.en_headline : news.headline;
        const displayContent =
          isEnglish && news.en_content ? news.en_content : news.content;
        const isLong = displayContent.length > PREVIEW_CHAR_LIMIT;
        const isExpanded = !!expanded[newsId];
        const contentToShow =
          isLong && !isExpanded
            ? displayContent.slice(0, PREVIEW_CHAR_LIMIT) + "…"
            : displayContent;

        return (
          <div
            id={newsId}
            key={newsId}
            className={`${isMoe ? "bg-pink-100 border-pink-300 text-pink-900 font-[Zen_Maru_Gothic]" : "bg-gray-900 border-gray-800 text-white font-sans"} border rounded-lg shadow-lg overflow-hidden`}
          >
            <div className="flex items-center p-3 justify-between">
              <div className="flex items-center space-x-3">
                <a href={`/game/${getShortenedGameName(news.identifier)}`}>
                  <img
                    src={
                      pfpBaseUrl +
                      `/` +
                      getShortenedGameName(news.identifier) +
                      `.webp`
                    }
                    alt={getGameTitle(news.identifier) || ""}
                    className="hover:animate-pulse rounded-full h-8 w-8 object-cover"
                    onError={(e) => {
                      const target = e.target as HTMLImageElement;
                      target.style.display = "none";
                      const placeholder = document.createElement("div");
                      placeholder.className =
                        "hover:animate-pulse rounded-full h-8 w-8 flex items-center justify-center bg-gray-500 text-white font-bold text-sm";
                      placeholder.textContent = (getGameTitle(
                        news.identifier,
                      ) || "G")[0].toUpperCase();
                      target.parentNode?.replaceChild(placeholder, target);
                    }}
                  />
                </a>
                <div className="flex flex-col leading-tight">
                  <span className="text-sm font-semibold hover:underline">
                    <a href={`/game/${getShortenedGameName(news.identifier)}`}>
                      {getGameTitle(news.identifier)}
                    </a>
                  </span>
                  <span className="text-xs opacity-80">{date}</span>
                  {news.type && (
                    <span className="text-xs italic">{news.type}</span>
                  )}
                </div>
              </div>
              {hasTranslation && (
                <button
                  onClick={() => toggleLanguage(newsId)}
                  className={`${isMoe ? "bg-pink-200 hover:bg-pink-300" : "bg-gray-800 hover:bg-gray-700"} text-xs py-1 px-2 rounded`}
                >
                  {isEnglish ? t("view_in_original_text") : t("view_in_english_text")}
                </button>
              )}
            </div>

            <div className="px-3 pt-1 pb-3">
              {displayHeadline && (
                <p className="font-semibold text-sm mb-2">{displayHeadline}</p>
              )}
              <p className="text-sm whitespace-pre-line mb-2">
                {contentToShow
                  .split(/(\[.*?\]\(.*?\)|https?:\/\/[^\s]+)/g)
                  .map((part, idx) => {
                    const m = part.match(/\[(.*?)\]\((.*?)\)/);
                    const u = part.match(/https?:\/\/[^\s]+/);
                    if (m)
                      return (
                        <a
                          key={idx}
                          href={m[2]}
                          className="text-blue-500 underline"
                          target="_blank"
                        >
                          {m[1]}
                        </a>
                      );
                    if (u)
                      return (
                        <a
                          key={idx}
                          href={u[0]}
                          className="text-blue-500 underline"
                          target="_blank"
                        >
                          {u[0]}
                        </a>
                      );
                    return part;
                  })}
              </p>
              {isLong && (
                <button
                  onClick={() => toggleExpand(newsId)}
                  className="text-sm text-blue-500 hover:underline"
                >
                  {isExpanded ? "Show less" : "Show more"}
                </button>
              )}
            </div>

            {/* Copy Link to Post */}
            <div className="px-3 pb-2 text-right">
              <a
                href={`#${newsId}`}
                onClick={(e) => {
                  e.preventDefault();
                  const pathname =
                    window.location.pathname === "/"
                      ? "/news"
                      : window.location.pathname.replace(/^\/game/, "");
                  const url = middlewareBase
                    ? `${middlewareBase}${pathname}?post=${newsId}${isEnglish ? '&lang=en' : ''}`
                    : `${window.location.origin}${pathname === "/news" ? "" : pathname}#${newsId}`;
                  navigator.clipboard.writeText(url);
                  alert(
                    `${t('copy_link_notif')}`
                  );
                }}
                title="Copy permalink"
                className="text-xs text-blue-400 hover:underline cursor-pointer"
              >
                🔗 {`${t('copy_link_to_post')}`}
              </a>
            </div>

            {/* AI Disclaimer */}
            {news.is_ai_summary && (
              <div
                className={`${isMoe ? "bg-pink-200 text-pink-800" : "bg-gray-800 text-white"} px-3 py-2 text-xs text-center`}
              >
                {`${t('ai_summary_note')}`}
              </div>
            )}

            {/* Machine TL Disclaimer */}
            {hasTranslation && isEnglish && (
              <div
                className={`${isMoe ? "bg-pink-200 text-pink-800" : "bg-gray-800 text-white"} px-3 py-2 text-xs text-center`}
              >
              {`${t('machine_tl_note')}`}
              </div>
            )}

            {/* Images */}
            {news.images.length > 0 && (
              <div className="w-full">
                {(() => {
                  const idx = currentImageIndex[newsId] || 0;
                  const img = news.images[idx];
                  return (
                    <div className="relative">
                      {loadingImages[newsId] && (
                        <div className="absolute inset-0 flex items-center justify-center bg-black bg-opacity-50">
                          <div className="loader border-t-2 border-b-2 border-white w-6 h-6 rounded-full animate-spin" />
                        </div>
                      )}
                      <img
                        src={img.image}
                        alt="news visual"
                        className={`w-full object-cover py-2 ${loadingImages[newsId] ? "opacity-0" : "opacity-100"}`}
                        onLoad={() => handleImageLoad(newsId)}
                      />
                    </div>
                  );
                })()}

                {news.images.length > 1 && (
                  <div className="pb-3 overflow-x-auto px-3">
                    <div className="flex space-x-2 w-max mx-auto">
                      {news.images.map((_, idx) => (
                        <button
                          key={idx}
                          onClick={() => changeImage(newsId, idx)}
                          className={`w-9 h-9 shrink-0 rounded-sm flex items-center justify-center ${
                            currentImageIndex[newsId] === idx
                              ? isMoe
                                ? "bg-pink-500 text-white"
                                : "bg-blue-600 text-white"
                              : isMoe
                                ? "bg-pink-200 text-pink-800 hover:bg-pink-300"
                                : "bg-gray-700 text-gray-300 hover:bg-gray-600"
                          }`}
                        >
                          {idx + 1}
                        </button>
                      ))}
                    </div>
                  </div>
                )}
              </div>
            )}

            {news.url && (
              <div
                className={`${isMoe ? "bg-pink-200" : "bg-gray-800"} px-3 py-2 text-center`}
              >
                <a
                  href={news.url}
                  target="_blank"
                  rel="noopener noreferrer"
                  className="text-sm underline font-bold"
                >
                  READ MORE
                </a>
              </div>
            )}
          </div>
        );
      })}
    </div>
  );
};