import Link from "next/link";
import { CategoryNavigation } from "./CategoryNavigation";
import { Icon } from "@/components/Icon";
import { useEffect, useRef, useState, type ReactNode } from "react";
import type { DocLink } from "@/lib/docs";
import { collectionEntries, collectionIcon, collectionLabel, collectionTone } from "@/lib/collections";


export function Brand() {
  return (
    <Link className="brand" href="/" aria-label="Tabularium 首页">
      <span className="brand-mark" aria-hidden="true">
        <i />
        <i />
        <i />
      </span>
      <span>
        <strong>Tabularium</strong>
      </span>
      <span className="docs-badge">Docs</span>
    </Link>
  );
}
export function Navigation({
  docs,
  current,
  onNavigate,
}: {
  docs: DocLink[];
  current?: string;
  onNavigate?: () => void;
}) {
  const collection = docs.find((d) => d.slug === current)?.collection;
  const scopedDocs = docs.filter((d) => d.collection === collection);
  const groups = [...new Set(scopedDocs.map((d) => d.group))];
  const collections = collectionEntries(docs);
  return (
    <nav aria-label="文档导航">
      {collection ? <>
        <Link className="collection-identity" href={`/docs/${collections.find((c) => c.name === collection)!.entry.slug}`} onClick={onNavigate}>
          <Icon name={collectionIcon(collection)} size={22} /><span>{collectionLabel(collection)}</span>
        </Link>
      </> : <div className="collection-identity"><Icon name="book" size={22} /><span>文档中心</span></div>}
      {!current && collections.map(({ name, entry }) => <Link
        onClick={onNavigate} className="collection-nav-link" href={`/docs/${entry.slug}`} key={name}
      ><Icon name={collectionIcon(name)} size={18} /><span>{collectionLabel(name)}</span><Icon name="chevron" size={13} /></Link>)}
      {groups.map((group) => (
        <div className="nav-group" key={group}>
          <p>{group === collection ? "章节目录" : group}</p>
          {scopedDocs.filter((d) => d.group === group).map((d) => (
            <Link onClick={onNavigate} aria-current={d.slug === current ? "page" : undefined}
              className="nav-item" href={`/docs/${d.slug}`} key={d.slug}>
              <span>{d.slug.endsWith("/overview") ? "概览" : d.title.replace("（草案）", "").replace(/^\d+\s*·\s*/, "")}</span>
              {d.draft && <span className="tiny-dot" aria-label="草案" />}
            </Link>
          ))}
        </div>
      ))}
    </nav>
  );
}

export function Shell({
  docs,
  current,
  children,
}: {
  docs: DocLink[];
  current?: string;
  children: ReactNode;
}) {
  const dialog = useRef<HTMLDialogElement>(null);
  const input = useRef<HTMLInputElement>(null);
  const trigger = useRef<HTMLButtonElement>(null);
  const [query, setQuery] = useState("");
  const [searchDocs, setSearchDocs] = useState(docs);
  const [searchLoaded, setSearchLoaded] = useState(false);
  const [searchStatus, setSearchStatus] = useState("");
  const [selected, setSelected] = useState(0);
  const [menu, setMenu] = useState(false);
  const collection = docs.find((d) => d.slug === current)?.collection;
  const results = searchDocs.filter((d) =>
    (!collection || d.collection === collection) &&
    `${d.title} ${d.description} ${d.searchText ?? ""}`
      .toLocaleLowerCase()
      .includes(query.trim().toLocaleLowerCase()),
  );
  async function openSearch() {
    setQuery("");
    setSelected(0);
    dialog.current?.showModal();
    input.current?.focus();
    if (searchLoaded) return;
    setSearchStatus("正在加载全文索引…");
    try {
      const response = await fetch("/api/search");
      if (!response.ok) throw new Error("Search unavailable");
      setSearchDocs(await response.json());
      setSearchLoaded(true);
      setSearchStatus("");
    } catch {
      setSearchStatus("全文搜索暂时不可用，当前仅搜索标题和摘要。关闭后重新打开可重试。");
    }
  }
  function closeSearch() {
    dialog.current?.close();
    trigger.current?.focus();
  }
  useEffect(() => {
    function keyboard(e: KeyboardEvent) {
      if ((e.metaKey || e.ctrlKey) && e.key.toLowerCase() === "k") {
        e.preventDefault();
        trigger.current?.click();
      }
    }
    document.addEventListener("keydown", keyboard);
    return () => document.removeEventListener("keydown", keyboard);
  }, []);
  return (
    <div className="docs-shell" data-tone={collectionTone(collection)}>
      <a className="skip-link" href="#content">
        跳到正文
      </a>
      <header className="site-header">
        <Brand />
        <CategoryNavigation docs={docs} current={current} />
        <button
          ref={trigger}
          className="search-trigger"
          aria-label="搜索文档"
          onClick={openSearch}
        >
          <Icon name="search" />
          <span>{collection ? `搜索${collectionLabel(collection)}…` : "搜索全部文档…"}</span>
          <kbd>⌘ K</kbd>
        </button>
        <button
          className="logout-button"
          aria-label="退出登录"
          onClick={async () => {
            const response = await fetch("/api/auth/logout", {
              method: "POST",
            });
            if (response.ok) {
              // Drop cached private document data when ending the session.
              // eslint-disable-next-line @next/next/no-location-assign-relative-destination
              window.location.assign("/login");
            }
          }}
        >
          退出
        </button>
      </header>
      <div className="mobile-bar">
        <button
          onClick={() => setMenu(!menu)}
          aria-expanded={menu}
          aria-controls="mobile-navigation"
        >
          <Icon name={menu ? "close" : "menu"} size={16} /> <span>{collection ? collectionLabel(collection) : "全部文档"}</span>
          <span>{menu ? "−" : "+"}</span>
        </button>
      </div>
      {menu && (
        <div className="mobile-navigation" id="mobile-navigation">
          <Navigation
            docs={docs}
            current={current}
            onNavigate={() => setMenu(false)}
          />
        </div>
      )}
      {children}
      <dialog
        ref={dialog}
        className="search-dialog"
        aria-label="搜索文档"
        onClick={(e) => {
          if (e.target === e.currentTarget) closeSearch();
        }}
        onClose={() => trigger.current?.focus()}
      >
        <div className="search-input-row">
          <Icon name="search" />
          <input
            ref={input}
            value={query}
            placeholder={collection ? `搜索${collectionLabel(collection)}的内容…` : "搜索全部文档、命令或概念…"}
            aria-label="搜索文档内容"
            aria-controls="search-results"
            onChange={(e) => {
              setQuery(e.target.value);
              setSelected(0);
            }}
            onKeyDown={(e) => {
              if (e.key === "ArrowDown") {
                e.preventDefault();
                setSelected((i) =>
                  Math.max(0, Math.min(i + 1, results.length - 1)),
                );
              }
              if (e.key === "ArrowUp") {
                e.preventDefault();
                setSelected((i) => Math.max(i - 1, 0));
              }
              if (e.key === "Enter") {
                e.preventDefault();
                dialog.current
                  ?.querySelector<HTMLAnchorElement>(
                    `[data-result="${selected}"]`,
                  )
                  ?.click();
              }
            }}
          />
          <button onClick={closeSearch} aria-label="关闭搜索">
            Esc
          </button>
        </div>
        {searchStatus && <p className="search-status" role="status">{searchStatus}</p>}
        <div id="search-results" className="search-results">
          <p className="eyebrow" role="status">
            {query ? `${results.length} 篇匹配文档` : "浏览文档"}
          </p>
          {results.map((d, i) => (
            <Link
              data-result={i}
              className={
                selected === i ? "search-result selected" : "search-result"
              }
              onClick={closeSearch}
              key={d.slug}
              href={`/docs/${d.slug}`}
            >
              <span>{d.group}</span>
              <strong>
                {d.title} <span aria-hidden="true">↗</span>
              </strong>
              <small>{d.description}</small>
            </Link>
          ))}
          {!results.length && (
            <p className="empty-search">
              没有找到相关内容，请尝试其他关键词。
            </p>
          )}
        </div>
        <div className="search-footer">
          ↑ ↓ 选择 <span>Enter 打开 · Esc 关闭</span>
        </div>
      </dialog>
    </div>
  );
}