"use client";
import useSWR from "swr";
import { useMemo, useState } from "react";

const fetcher = (url: string) => fetch(url).then((r) => r.json());

export default function AdminBoardsPage() {
  const { data: boardsResp, mutate: mutateBoards } = useSWR<{ boards: any[] }>("/api/admin/boards", fetcher);
  const { data: catsResp, mutate: mutateCats } = useSWR<{ categories: any[] }>("/api/admin/categories", fetcher);
  const boards = boardsResp?.boards ?? [];
  const categories = (catsResp?.categories ?? []).sort((a: any, b: any) => (a.sortOrder ?? 0) - (b.sortOrder ?? 0));
  const groups = useMemo(() => {
    const map: Record<string, any[]> = {};
    for (const b of boards) {
      const cid = b.categoryId ?? "uncat";
      if (!map[cid]) map[cid] = [];
      map[cid].push(b);
    }
    return categories.map((c: any) => ({ ...c, items: (map[c.id] ?? []).sort((a, b) => (a.sortOrder ?? 0) - (b.sortOrder ?? 0)) }));
  }, [boards, categories]);

  const [savingId, setSavingId] = useState<string | null>(null);
  async function save(b: any) {
    setSavingId(b.id);
    await fetch(`/api/admin/boards/${b.id}`, { method: "PATCH", headers: { "content-type": "application/json" }, body: JSON.stringify(b) });
    setSavingId(null);
    mutateBoards();
  }

  // DnD: 카테고리 순서 변경
  async function reorderCategories(next: any[]) {
    // optimistic update
    await Promise.all(next.map((c, idx) => fetch(`/api/admin/categories/${c.id}`, { method: "PATCH", headers: { "content-type": "application/json" }, body: JSON.stringify({ sortOrder: idx + 1 }) })));
    mutateCats();
  }

  // DnD: 보드 순서 변경 (카테고리 내부)
  async function reorderBoards(categoryId: string, nextItems: any[]) {
    await Promise.all(nextItems.map((b, idx) => fetch(`/api/admin/boards/${b.id}`, { method: "PATCH", headers: { "content-type": "application/json" }, body: JSON.stringify({ sortOrder: idx + 1, categoryId }) })));
    mutateBoards();
  }

  return (
    <div className="space-y-6">
      <h1 className="text-xl md:text-2xl font-bold text-neutral-900">게시판 관리</h1>
      {/* 대분류 리스트 (드래그로 순서 변경) */}
      <div className="rounded-xl border border-neutral-200 overflow-hidden bg-white">
        <div className="px-4 py-2 border-b border-neutral-200 text-sm font-semibold">대분류</div>
        <ul className="divide-y divide-neutral-100">
          {groups.map((g, idx) => (
            <CategoryRow key={g.id} idx={idx} g={g} onMove={(from, to) => {
              const arr = [...groups];
              const [moved] = arr.splice(from, 1);
              arr.splice(to, 0, moved);
              reorderCategories(arr);
            }} onSave={async (payload) => {
              await fetch(`/api/admin/categories/${g.id}`, { method: "PATCH", headers: { "content-type": "application/json" }, body: JSON.stringify(payload) });
              mutateCats();
            }} />
          ))}
        </ul>
      </div>

      {groups.map((g) => (
        <section key={g.id} className="rounded-xl border border-neutral-200 overflow-hidden bg-white">
          <div className="px-4 py-2 border-b border-neutral-200 flex items-center justify-between">
            <div className="text-sm font-semibold">대분류: {g.name}</div>
            <div className="text-xs text-neutral-500">slug: {g.slug}</div>
          </div>
          <div className="overflow-x-auto">
            <table className="min-w-full text-sm">
              <thead className="text-xs text-neutral-500 border-b border-neutral-200">
                <tr>
                  <th className="px-3 py-2 text-left">이름</th>
                  <th className="px-3 py-2 text-left">slug</th>
                  <th className="px-3 py-2">읽기</th>
                  <th className="px-3 py-2">쓰기</th>
                  <th className="px-3 py-2">익명</th>
                  <th className="px-3 py-2">비밀댓</th>
                  <th className="px-3 py-2">승인</th>
                  <th className="px-3 py-2">유형</th>
                  <th className="px-3 py-2">성인</th>
                  <th className="px-3 py-2">정렬</th>
                  <th className="px-3 py-2"></th>
                </tr>
              </thead>
              <tbody className="divide-y divide-neutral-100">
                {g.items.map((b, i) => (
                  <DraggableRow
                    key={b.id}
                    index={i}
                    onMove={(from, to) => {
                      const list = [...g.items];
                      const [mv] = list.splice(from, 1);
                      list.splice(to, 0, mv);
                      reorderBoards(g.id, list);
                    }}
                  >
                    <Row b={b} onSave={save} saving={savingId === b.id} />
                  </DraggableRow>
                ))}
              </tbody>
            </table>
          </div>
        </section>
      ))}
    </div>
  );
}

function Row({ b, onSave, saving }: { b: any; onSave: (b: any) => void; saving: boolean }) {
  const [edit, setEdit] = useState(b);
  return (
    <tr className="align-middle">
      <td className="px-3 py-2"><input className="h-9 w-full rounded-md border border-neutral-300 px-2 text-sm" value={edit.name} onChange={(e) => setEdit({ ...edit, name: e.target.value })} /></td>
      <td className="px-3 py-2"><input className="h-9 w-full rounded-md border border-neutral-300 px-2 text-sm" value={edit.slug} onChange={(e) => setEdit({ ...edit, slug: e.target.value })} /></td>
      <td className="px-3 py-2 text-center">
        <select className="h-9 rounded-md border border-neutral-300 px-2 text-sm" value={edit.readLevel} onChange={(e) => setEdit({ ...edit, readLevel: e.target.value })}>
          <option value="public">public</option>
          <option value="member">member</option>
          <option value="moderator">moderator</option>
          <option value="admin">admin</option>
        </select>
      </td>
      <td className="px-3 py-2 text-center">
        <select className="h-9 rounded-md border border-neutral-300 px-2 text-sm" value={edit.writeLevel} onChange={(e) => setEdit({ ...edit, writeLevel: e.target.value })}>
          <option value="public">public</option>
          <option value="member">member</option>
          <option value="moderator">moderator</option>
          <option value="admin">admin</option>
        </select>
      </td>
      <td className="px-3 py-2 text-center"><input type="checkbox" checked={edit.allowAnonymousPost} onChange={(e) => setEdit({ ...edit, allowAnonymousPost: e.target.checked })} /></td>
      <td className="px-3 py-2 text-center"><input type="checkbox" checked={edit.allowSecretComment} onChange={(e) => setEdit({ ...edit, allowSecretComment: e.target.checked })} /></td>
      <td className="px-3 py-2 text-center"><input type="checkbox" checked={edit.requiresApproval} onChange={(e) => setEdit({ ...edit, requiresApproval: e.target.checked })} /></td>
      <td className="px-3 py-2 text-center">
        <select className="h-9 rounded-md border border-neutral-300 px-2 text-sm" value={edit.type} onChange={(e) => setEdit({ ...edit, type: e.target.value })}>
          <option value="general">general</option>
          <option value="special">special</option>
        </select>
      </td>
      <td className="px-3 py-2 text-center"><input type="checkbox" checked={!!edit.isAdultOnly} onChange={(e) => setEdit({ ...edit, isAdultOnly: e.target.checked })} /></td>
      <td className="px-3 py-2 text-center"><input className="h-9 w-20 rounded-md border border-neutral-300 px-2 text-sm" type="number" value={edit.sortOrder} onChange={(e) => setEdit({ ...edit, sortOrder: Number(e.target.value) })} /></td>
      <td className="px-3 py-2 text-right"><button className="h-9 px-3 rounded-md bg-neutral-900 text-white text-sm disabled:opacity-60" onClick={() => onSave(edit)} disabled={saving}>{saving ? "저장중" : "저장"}</button></td>
    </tr>
  );
}

function DraggableRow({ index, onMove, children }: { index: number; onMove: (from: number, to: number) => void; children: React.ReactNode }) {
  return (
    <tr
      draggable
      onDragStart={(e) => {
        e.dataTransfer.setData("text/plain", String(index));
        e.dataTransfer.effectAllowed = "move";
      }}
      onDragOver={(e) => e.preventDefault()}
      onDrop={(e) => {
        e.preventDefault();
        const from = Number(e.dataTransfer.getData("text/plain"));
        const to = index;
        if (!Number.isNaN(from) && from !== to) onMove(from, to);
      }}
      className="align-middle"
    >
      {children}
    </tr>
  );
}

function CategoryRow({ idx, g, onMove, onSave }: { idx: number; g: any; onMove: (from: number, to: number) => void; onSave: (payload: any) => void }) {
  const [edit, setEdit] = useState({ name: g.name, slug: g.slug });
  return (
    <li
      className="px-4 py-3 flex items-center gap-3"
      draggable
      onDragStart={(e) => {
        e.dataTransfer.setData("text/plain", String(idx));
        e.dataTransfer.effectAllowed = "move";
      }}
      onDragOver={(e) => e.preventDefault()}
      onDrop={(e) => {
        e.preventDefault();
        const from = Number(e.dataTransfer.getData("text/plain"));
        const to = idx;
        if (!Number.isNaN(from) && from !== to) onMove(from, to);
      }}
    >
      <div className="w-6 text-xs text-neutral-500">≡</div>
      <input className="h-8 rounded-md border border-neutral-300 px-2 text-sm w-48" value={edit.name} onChange={(e) => setEdit({ ...edit, name: e.target.value })} />
      <input className="h-8 rounded-md border border-neutral-300 px-2 text-sm w-48" value={edit.slug} onChange={(e) => setEdit({ ...edit, slug: e.target.value })} />
      <div className="flex-1" />
      <button className="h-8 px-3 rounded-md border border-neutral-300 text-sm hover:bg-neutral-100" onClick={() => onSave(edit)}>수정</button>
    </li>
  );
}