import { getRoom, getRoomMessages, getMember } from "../../../../db/chat-rooms";
import { getUsersMeta } from "../../../../utils/getUsersMeta";

/** GET /api/chat/rooms/[roomId] – Room detail + messages */
export default defineEventHandler(async (event) => {
  const user = await requireUser(event);
  const roomId = getRouterParam(event, "roomId");
  if (!roomId) throw createError({ statusCode: 400, message: "roomId fehlt" });

  const room = await getRoom(roomId);
  if (!room)
    throw createError({ statusCode: 404, message: "Raum nicht gefunden" });

  // Access check: public rooms or member
  const member = await getMember(roomId, user.id);
  if (!room.isPublic && (!member || member.status !== "active")) {
    throw createError({ statusCode: 403, message: "Kein Zugang" });
  }

  const cursor = getQuery(event).cursor as string | undefined;
  const messages = await getRoomMessages(roomId, cursor, 50);

  // Resolve user meta for all message senders
  const userIds = [...new Set(messages.map((m) => m.userId))];
  // Also collect replyTo userIds
  messages.forEach((m) => {
    if (m.replyTo?.userId && !userIds.includes(m.replyTo.userId)) {
      userIds.push(m.replyTo.userId);
    }
  });
  const meta = userIds.length > 0 ? await getUsersMeta(userIds) : {};

  // Get member list
  const memberIds = room.members.map((m) => m.userId);
  const memberMeta = await getUsersMeta(memberIds);

  return {
    room: {
      id: room.id,
      name: room.name,
      description: room.description,
      isPublic: room.isPublic,
      isDefault: room.isDefault,
      joinMode: room.joinMode,
      avatarUrl: room.avatarUrl ?? null,
      inviteCode:
        member?.role === "owner" || member?.role === "admin"
          ? room.inviteCode
          : null,
      memberCount: room.memberCount,
      createdBy: room.createdBy,
      myRole: member?.role ?? null,
      isMember: !!member && member.status === "active",
    },
    members: room.members.map((m) => ({
      userId: m.userId,
      role: m.role,
      nickname: memberMeta[m.userId]?.nickname ?? "Anonym",
      avatar: memberMeta[m.userId]?.avatar ?? null,
    })),
    messages: messages.reverse().map((m) => ({
      id: m.id,
      userId: m.userId,
      nickname: meta[m.userId]?.nickname ?? "Anonym",
      avatar: meta[m.userId]?.avatar ?? null,
      content: m.content,
      replyTo: m.replyTo
        ? {
            id: m.replyTo.id,
            userId: m.replyTo.userId,
            nickname: meta[m.replyTo.userId]?.nickname ?? "Anonym",
            content: m.replyTo.content.slice(0, 100),
          }
        : null,
      attachmentUrl: m.attachmentUrl,
      attachmentType: m.attachmentType,
      attachmentName: m.attachmentName,
      likesCount: m.likesCount,
      createdAt: m.createdAt,
      isOwn: m.userId === user.id,
    })),
    hasMore: messages.length === 50,
  };
});