import { Link } from "@remix-run/react";
import AppInput from "../AppInput";
import { useState } from "react";
import {
  useGetUserThreads,
  useGetStoreThreads,
} from "../../requestHandler/use-chat-hooks";
import {
  ThreadList,
  ThreadParticipant,
  UserProfile,
} from "../../../src/api/types";
import { useServiceGetProfile } from "../../requestHandler/use-profile-hooks";
import UiProvider from "../UiProvider";
import SellerLogo from "../SellerLogo";
import { CheckCheck, MessageCircleWarning, Search, User } from "lucide-react";
import ProfilePagesHeader from "../ProfilePagesHeader";

// Persian-style relative timestamp for the inbox list. Older messages need a
// day label so the seller can tell "today's message" from "3 months ago"
// without reading the date.
function formatThreadTimestamp(iso: string | null | undefined): string {
  if (!iso) return "";
  const d = new Date(iso);
  if (isNaN(d.getTime())) return "";
  const now = new Date();
  const startOfDay = (x: Date) =>
    new Date(x.getFullYear(), x.getMonth(), x.getDate()).getTime();
  const dayDiff = Math.round(
    (startOfDay(now) - startOfDay(d)) / (1000 * 60 * 60 * 24),
  );
  const timePart = d.toLocaleTimeString("fa-IR", {
    hour: "2-digit",
    minute: "2-digit",
  });
  if (dayDiff <= 0) return timePart; // today: just HH:MM
  if (dayDiff === 1) return `دیروز ${timePart}`;
  if (dayDiff < 7) return `${dayDiff} روز پیش`;
  // Older than a week: show the date in Persian calendar.
  return d.toLocaleDateString("fa-IR");
}

interface ThreadsPageProps {
  type: "user" | "store";
  storeId?: string;
}

export default function ThreadsPage({ type, storeId }: ThreadsPageProps) {
  const [searchValue, setSearchValue] = useState("");
  // Seller dashboard shows the STORE's inbox; the profile page shows the user's
  // personal (buyer) chats. Two different endpoints so the two never mix.
  const userThreads = useGetUserThreads();
  const storeThreads = useGetStoreThreads(type === "store" ? storeId : undefined);
  const {
    data: threads,
    isLoading,
    isError,
    refetch,
  } = type === "store" ? storeThreads : userThreads;
  const sortedThreads = threads?.sort((a, b) => {
    const dateA = new Date(a.lastMessageTime || "2025-01-18T00:00:00.000Z");
    const dateB = new Date(b.lastMessageTime || "2025-01-18T00:00:00.000Z");
    return dateB.getTime() - dateA.getTime();
  });
  const { data: dataProfile, isFetching: isFetchingProfile } =
    useServiceGetProfile();

  return (
    <div
      className={`flex flex-col w-full ${isLoading || isFetchingProfile ? "" : "pb-20"}`}
    >
      <ProfilePagesHeader title="پیام‌ها" />
      <div className="w-full px-4 py-2">
        <div className="w-full h-[40px] flex items-center gap-2 bg-WHITE2 rounded-[10px]">
          <AppInput
            inputIcon={Search}
            inputDir="rtl"
            inputTitle={""}
            className="bg-WHITE2"
            inputValue={searchValue}
            inputPlaceholder={"جستجو..."}
            inputOnChange={(e: React.ChangeEvent<HTMLInputElement>) => {
              const value = e.target.value;
              setSearchValue(value);
            }}
          />
        </div>
      </div>
      <UiProvider
        isLoading={isLoading || isFetchingProfile}
        isError={isError}
        isEmpty={!!(threads && threads.length === 0)}
        onRetry={refetch}
        type="threads"
      >
        <ThreadsList
          searchValue={searchValue}
          threads={sortedThreads}
          dataProfile={dataProfile}
          type={type}
          storeId={storeId}
        />
      </UiProvider>
    </div>
  );
}

const ThreadsList = ({
  searchValue,
  threads,
  dataProfile,
  type,
  storeId,
}: {
  searchValue: string;
  threads: ThreadList[] | undefined;
  dataProfile: UserProfile | undefined;
  type: "user" | "store";
  storeId?: string;
}) => {
  const filteredThreads = threads?.filter((thread) => {
    return thread.participants?.some((participant: ThreadParticipant) =>
      participant.username?.toLowerCase().includes(searchValue.toLowerCase())
    );
  });

  return (
    <div className="flex flex-col w-full">
      {filteredThreads?.map((thread) => {
        const otherParticipant = thread.participants?.find(
          (participant: ThreadParticipant) =>
            participant.username !== dataProfile?.username
        );
        const hasUnread = Number(thread.unreadCount || "0") > 0;

        // Seller-inbox only. Shows what state the thread is in so the team
        // can see at a glance which chats need attention.
        //   - "needs-reply"   → last message is from the customer (or nobody
        //                       on the team has replied yet).
        //   - "unread-by-customer" → team replied, customer hasn't seen it.
        //   - "seen"          → team replied and the customer opened it.
        const showStatus = type === "store";
        const lastFromTeam = !!thread.lastMessageFromTeam;
        const otherSeen = !!thread.otherPartySeenLast;
        const status: "needs-reply" | "unread-by-customer" | "seen" | null =
          !showStatus
            ? null
            : !lastFromTeam
              ? "needs-reply"
              : otherSeen
                ? "seen"
                : "unread-by-customer";

        // Generate link based on type
        const linkTo =
          type === "user"
            ? `/profile/threads/${thread.id}`
            : `/store/${storeId}/threads/${thread.id}`;

        return (
          <Link to={linkTo} key={thread.id} className="w-full">
            <div className={`w-full h-[80px] flex items-center px-4 gap-4`}>
              {thread.isCreator ? (
                <SellerLogo
                  src={otherParticipant?.storeLogo}
                  alt="Participant Avatar"
                />
              ) : (
                <User size={48} className="text-GRAY" />
              )}
              <div className="flex flex-col w-full">
                <div className="w-full flex justify-between items-center">
                  <div className="flex items-center gap-1 min-w-0">
                    {status === "needs-reply" && (
                      <MessageCircleWarning
                        size={16}
                        className="text-RED shrink-0"
                        aria-label="در انتظار پاسخ شما"
                      />
                    )}
                    {status === "seen" && (
                      <CheckCheck
                        size={16}
                        className="text-blue-500 shrink-0"
                        aria-label="پیام دیده شده"
                      />
                    )}
                    <p className={`text-R14 truncate ${hasUnread || status === "needs-reply" ? "font-bold" : ""}`}>
                      {thread.isCreator
                        ? otherParticipant?.storeName ||
                          otherParticipant?.username
                        : otherParticipant?.name}
                    </p>
                  </div>
                  <div className="flex flex-col items-end justify-center">
                    {thread.lastMessageTime && (
                      <p className="text-R10 text-GRAY">
                        {formatThreadTimestamp(thread.lastMessageTime)}
                      </p>
                    )}
                    {hasUnread && (
                      <div className="w-5 h-5 flex items-center justify-center bg-blue-500 text-WHITE text-R10 rounded-full">
                        {thread.unreadCount}
                      </div>
                    )}
                  </div>
                </div>
                <p
                  className={`text-R14 ${hasUnread ? "text-BLACK font-bold" : "text-GRAY"}`}
                >
                  {thread.lastMessage?.content ||
                    (thread.lastMessage?.imageUrl
                      ? "📷 تصویر"
                      : thread.lastMessage?.product
                        ? `🛍 ${thread.lastMessage.product.title || "محصول"}`
                        : "بدون پیام")}
                </p>
              </div>
            </div>
          </Link>
        );
      })}
    </div>
  );
};