"use client";

import { useMemo, useState, type CSSProperties } from "react";
import Link from "next/link";
import { FileDown, PenLine, Search, X } from "lucide-react";
import type { LibraryDocListItem } from "@/lib/api";
import { coverHue } from "@/lib/coverColor";
import { libraryDocPath, type UrlStyle } from "@/lib/urlStyle";
import { variantURL, widthSrcSet } from "@/lib/responsiveImage";
import { formatRelative } from "@/lib/format";
import Avatar from "@/components/Avatar";

function formatSize(n: number): string {
  if (!Number.isFinite(n) || n <= 0) return "0 B";
  if (n < 1024) return `${n} B`;
  if (n < 1024 * 1024) return `${(n / 1024).toFixed(1)} KB`;
  return `${(n / (1024 * 1024)).toFixed(1)} MB`;
}

/** 简介 markdown → 纯文本摘要（去标记、压平空白，卡片两行截断用） */
function plainExcerpt(md: string): string {
  return md
    .replace(/!\[[^\]]*\]\([^)]*\)/g, "") // 图片
    .replace(/\[([^\]]*)\]\([^)]*\)/g, "$1") // 链接保留文字
    .replace(/[*_~`#>]+/g, "") // 行内/块级标记
    .replace(/\s+/g, " ")
    .trim();
}

/** 文字封面：无图时用完整书名 + 书名派生稳定色相洗底（lib/coverColor.ts） */
function TextCover({ title }: { title: string }) {
  const name = title.trim() || "书";
  return (
    <div
      className="j13-text-cover w-full h-full flex items-center justify-center px-4 select-none"
      style={{ "--cover-h": coverHue(name) } as CSSProperties}
      aria-hidden
    >
      <span className="j13-library-title text-[17px] font-bold leading-snug text-center line-clamp-3 break-words tracking-wide">
        {name}
      </span>
    </div>
  );
}

function ExtChip({ ext, className = "" }: { ext: string; className?: string }) {
  return (
    <span
      className={`text-[10.5px] font-semibold px-1.5 py-0.5 rounded-md uppercase tracking-wide ${className}`}
      style={{
        color: "var(--accent)",
        background: "var(--accent-soft)",
        border: "1px solid color-mix(in srgb, var(--accent) 30%, transparent)",
      }}
    >
      {ext}
    </span>
  );
}

function DocCard({ doc, href }: { doc: LibraryDocListItem; href: string }) {
  const exts = Array.from(new Set(doc.files.map((f) => f.ext))).slice(0, 4);
  const totalSize = doc.files.reduce((acc, f) => acc + f.size, 0);
  const creatorName = doc.creator ? doc.creator.nickname || doc.creator.username : "";
  const excerpt = plainExcerpt(doc.description ?? "");
  return (
    <Link href={href} className="group flex flex-col min-w-0">
      {/* 横版封面框（宽大于高）：模糊底衬完整显示任意比例图 + 悬停浮出简介 */}
      <div
        className="relative w-full aspect-[3/2] overflow-hidden rounded-[10px] shadow-[var(--shadow-sm)] transition-[transform,box-shadow] duration-200 group-hover:-translate-y-1.5 group-hover:shadow-[var(--shadow-lg)]"
        style={{ background: "var(--panel-2)" }}
      >
        {doc.cover_url ? (
          <>
            {/* 底层：同图放大模糊填充，竖版/非 3:2 封面不露黑边 */}
            {/* eslint-disable-next-line @next/next/no-img-element */}
            <img
              src={variantURL(doc.cover_url, 384)}
              alt=""
              aria-hidden
              className="absolute inset-0 w-full h-full object-cover scale-125 blur-lg opacity-70"
              loading="lazy"
              decoding="async"
              draggable={false}
            />
            {/* 上层：完整封面居中显示 */}
            {/* eslint-disable-next-line @next/next/no-img-element */}
            <img
              src={variantURL(doc.cover_url, 384)}
              srcSet={widthSrcSet(doc.cover_url, [384, 512, 768])}
              sizes="(max-width:640px) 100vw, (max-width:1024px) 46vw, (max-width:1280px) 30vw, 300px"
              alt={doc.title}
              className="absolute inset-0 w-full h-full object-contain transition-transform duration-300 group-hover:scale-[1.04]"
              loading="lazy"
              decoding="async"
              draggable={false}
            />
          </>
        ) : (
          <TextCover title={doc.title} />
        )}
        {/* 边缘内阴影，营造卡片体积感 */}
        <div
          aria-hidden
          className="absolute inset-0 rounded-[inherit] pointer-events-none"
          style={{
            boxShadow: "inset 0 0 0 1px rgba(0,0,0,0.06)",
          }}
        />
        {excerpt ? (
          <div
            className="absolute inset-0 flex items-end p-3.5 opacity-0 group-hover:opacity-100 transition-opacity duration-200 pointer-events-none"
            style={{
              background:
                "linear-gradient(to top, rgba(18,20,26,0.92) 0%, rgba(18,20,26,0.55) 55%, rgba(18,20,26,0.15) 100%)",
            }}
          >
            <p className="text-[12px] leading-relaxed text-white/90 line-clamp-4">{excerpt}</p>
          </div>
        ) : null}
      </div>

      {/* 封面下方书目信息：衬线书名 + 作者 + 文件概要 */}
      <div className="pt-3 flex flex-col gap-1 min-w-0">
        <h2
          className="j13-library-title text-[15px] font-bold leading-snug line-clamp-2"
          style={{ color: "var(--ink)" }}
        >
          {doc.title}
        </h2>
        {doc.author ? (
          <p className="meta flex items-center gap-1.5 text-[12px] min-w-0">
            <PenLine size={11} className="shrink-0" style={{ color: "var(--accent)" }} aria-hidden />
            <span className="truncate" title={doc.author}>
              {doc.author}
            </span>
          </p>
        ) : null}
        <div className="mt-1 flex items-center gap-1.5 min-w-0">
          {exts.map((ext) => (
            <ExtChip key={ext} ext={ext} />
          ))}
          <span className="meta text-[11px] ml-auto inline-flex items-center gap-1 shrink-0">
            <FileDown size={11} />
            {doc.file_count > 0 ? `${doc.file_count} 个文件 · ${formatSize(totalSize)}` : "暂无文件"}
          </span>
        </div>
        <div className="flex items-center gap-1.5 min-w-0">
          {doc.creator ? (
            <span className="flex items-center gap-1.5 min-w-0 shrink">
              <Avatar size={16} name={creatorName} src={doc.creator.avatar} />
              <span className="meta text-[11px] truncate max-w-[6rem]" title={creatorName}>
                {creatorName}
              </span>
            </span>
          ) : null}
          <span className="meta text-[11px] truncate shrink min-w-0">
            {doc.creator ? "· " : ""}
            {formatRelative(doc.created_at)}
          </span>
        </div>
      </div>
    </Link>
  );
}

/**
 * 书库目录：横版封面卡片网格（手机端单列全宽）+ 书名/作者即时过滤（目录接口一次返回全部已发布
 * 条目，纯客户端过滤；上限与后端 ListPublished 的 100 条一致）。
 */
export default function LibrarySearchGrid({
  docs,
  urlStyle,
}: {
  docs: LibraryDocListItem[];
  urlStyle: UrlStyle;
}) {
  const [query, setQuery] = useState("");
  const q = query.trim().toLowerCase();

  const filtered = useMemo(() => {
    if (!q) return docs;
    return docs.filter(
      (d) => d.title.toLowerCase().includes(q) || d.author.toLowerCase().includes(q)
    );
  }, [docs, q]);

  if (docs.length === 0) {
    return (
      <div
        className="mt-8 rounded-[24px] px-6 py-16 text-center"
        style={{ background: "var(--panel)", border: "1px solid var(--line)" }}
      >
        <p className="text-[15px] font-medium" style={{ color: "var(--ink-2)" }}>
          书库还没有内容
        </p>
        <p className="meta text-[13px] mt-2">管理员可在后台「书库管理」发布条目</p>
      </div>
    );
  }

  return (
    <div className="mt-2">
      {/* 搜索：居中宽框，与大气 Hero 呼应 */}
      <div className="relative max-w-lg mx-auto">
        <Search
          size={16}
          className="absolute left-4 top-1/2 -translate-y-1/2 pointer-events-none"
          style={{ color: "var(--ink-3)" }}
          aria-hidden
        />
        <input
          type="text"
          value={query}
          onChange={(e) => setQuery(e.target.value)}
          placeholder="搜索书名或作者"
          aria-label="搜索书名或作者"
          className="j13-search-field w-full rounded-full pl-11 pr-10 py-3 text-[14px] shadow-[var(--shadow-sm)]"
          style={{ background: "var(--panel)", border: "1px solid var(--line)" }}
        />
        {query ? (
          <button
            type="button"
            onClick={() => setQuery("")}
            aria-label="清除搜索"
            className="absolute right-3 top-1/2 -translate-y-1/2 w-7 h-7 flex items-center justify-center rounded-full hover:bg-[var(--panel-2)] transition-colors"
            style={{ color: "var(--ink-3)" }}
          >
            <X size={14} />
          </button>
        ) : null}
      </div>

      {filtered.length === 0 ? (
        <div
          className="mt-8 rounded-[24px] px-6 py-16 text-center"
          style={{ background: "var(--panel)", border: "1px solid var(--line)" }}
        >
          <p className="text-[14px] font-medium" style={{ color: "var(--ink-2)" }}>
            没有找到与「{query.trim()}」相关的书籍
          </p>
          <p className="meta text-[12.5px] mt-2">换个书名或作者关键词试试</p>
        </div>
      ) : (
        <div className="mt-8 grid grid-cols-1 gap-x-5 gap-y-8 sm:grid-cols-2 lg:grid-cols-3 xl:grid-cols-4 2xl:grid-cols-5">
          {filtered.map((d) => (
            <DocCard key={d.id} doc={d} href={libraryDocPath(urlStyle, d.slug)} />
          ))}
        </div>
      )}
    </div>
  );
}