"use client";
import { useEffect, useLayoutEffect, useRef, useState } from "react";
import { Check, ChevronDown, Search } from "lucide-react";
import { captionFonts, captionFont } from "@/lib/video-canvas/smart-edit/fonts";
import type { CaptionStyle } from "@/lib/video-canvas/smart-edit/contract";
const loaded = new Map<string, Promise<FontFace>>();
export function loadCaptionFont(id: string) {
  const font = captionFont(id);
  if (!font) return Promise.resolve();
  if (!loaded.has(id)) {
    const face = new FontFace(
      font.family,
      `url(${font.url ? `/api/canvas/smart-edit/fonts/${font.id}` : `/fonts/smart-edit/${font.file}`})`,
      {
        weight: "400",
      },
    );
    loaded.set(
      id,
      face
        .load()
        .then((loadedFace) => {
          document.fonts.add(loadedFace);
          return loadedFace;
        })
        .catch((error) => {
          loaded.delete(id);
          throw error;
        }),
    );
  }
  return loaded.get(id)!;
}
export function CaptionFontPicker({
  value,
  onChange,
  onError,
}: {
  value: CaptionStyle["fontFamily"];
  onChange: (id: NonNullable<CaptionStyle["fontFamily"]>) => void;
  onError: (message: string) => void;
}) {
  const [open, setOpen] = useState(false),
    [query, setQuery] = useState(""),
    [category, setCategory] = useState("全部"),
    [categoriesOpen, setCategoriesOpen] = useState(false),
    [busy, setBusy] = useState(false),
    [scrollTop, setScrollTop] = useState(0);
  const root = useRef<HTMLDivElement>(null);
  const [placement, setPlacement] = useState({ left: 0, top: 0, width: 300, height: 300 });
  useLayoutEffect(() => {
    if (!open) return;
    const place = () => {
      const rect = root.current?.getBoundingClientRect();
      if (!rect) return;
      const below = window.innerHeight - rect.bottom - 16;
      const above = rect.top - 16;
      const up = below < 394 && above > below;
      const height = Math.max(40, Math.min(300, (up ? above : below) - 94));
      const width = Math.min(window.innerWidth - 16, rect.width + 32);
      setPlacement({
        left: Math.max(8, Math.min(rect.left - 16, window.innerWidth - width - 8)),
        top: up ? Math.max(8, rect.top - height - 94 - 8) : rect.bottom + 8,
        width,
        height,
      });
    };
    place();
    const scroll = (event: Event) => {
      if (!root.current?.contains(event.target as Node)) place();
    };
    window.addEventListener("resize", place);
    window.addEventListener("scroll", scroll, true);
    return () => {
      window.removeEventListener("resize", place);
      window.removeEventListener("scroll", scroll, true);
    };
  }, [open]);
  useEffect(() => {
    const close = (e: globalThis.PointerEvent) => {
      if (!root.current?.contains(e.target as Node)) setOpen(false);
    };
    document.addEventListener("pointerdown", close);
    return () => document.removeEventListener("pointerdown", close);
  }, []);
  const options = captionFonts.filter(
    (font) =>
      font.name.toLowerCase().includes(query.toLowerCase()) &&
      (category === "全部" ||
        (category === "常用" && font.common) ||
        (category === "推荐" && font.recommended) ||
        (category === "Google" && font.google)),
  );
  const first = Math.max(0, Math.floor(scrollTop / 40) - 4);
  useEffect(() => {
    setScrollTop(0);
  }, [query, category, open]);
  useEffect(() => {
    if (!open) return;
    let stopped = false,
      index = 0;
    const visible = options.slice(first, first + 18);
    const worker = async () => {
      while (!stopped && index < visible.length) {
        const font = visible[index++];
        try {
          await loadCaptionFont(font.id);
        } catch {
          /* Selection reports any download failure. */
        }
      }
    };
    void worker();
    void worker();
    return () => {
      stopped = true;
    };
  }, [open, first, query, category]);
  return (
    <div className="se-font-picker" ref={root}>
      <button
        className="se-font"
        aria-label="字幕字体"
        aria-expanded={open}
        onClick={() => setOpen(!open)}
      >
        {captionFont(value)?.name || "默认字体"}
        <ChevronDown size={14} />
      </button>
      {open && (
        <div
          className="se-font-menu"
          style={{
            position: "fixed",
            left: placement.left,
            top: placement.top,
            width: placement.width,
            right: "auto",
          }}
        >
          <div className="se-search">
            <Search size={14} />
            <input
              aria-label="搜索字体"
              placeholder="搜索字体"
              value={query}
              onChange={(e) => setQuery(e.target.value)}
            />
          </div>
          <div className="se-font-categories">
            <button
              type="button"
              aria-haspopup="menu"
              aria-expanded={categoriesOpen}
              onClick={() => setCategoriesOpen(!categoriesOpen)}
            >
              {category === "Google" ? "Google 字体" : `${category}字体`}
              <ChevronDown size={12} />
            </button>
            {categoriesOpen && (
              <div role="menu" aria-label="字体分类">
                {["全部", "常用", "推荐", "Google"].map((name) => (
                  <button
                    type="button"
                    role="menuitemradio"
                    aria-checked={category === name}
                    key={name}
                    onClick={() => {
                      setCategory(name);
                      setCategoriesOpen(false);
                    }}
                  >
                    {name === "Google" ? "Google 字体" : `${name}字体`}
                    {category === name && <Check size={14} />}
                  </button>
                ))}
              </div>
            )}
          </div>
          <div
            key={`${query}:${category}`}
            role="listbox"
            style={{ height: placement.height }}
            aria-label={`字体库，共 ${options.length} 项`}
            onScroll={(e) => setScrollTop(e.currentTarget.scrollTop)}
          >
            <div style={{ height: options.length * 40, position: "relative" }}>
              {options.slice(first, first + 18).map((font, index) => (
                <button
                  style={{
                    position: "absolute",
                    top: (first + index) * 40,
                    fontFamily: `"${font.family}", "Source Han Sans SC", sans-serif`,
                  }}
                  aria-posinset={first + index + 1}
                  aria-setsize={options.length}
                  role="option"
                  aria-selected={value === font.id}
                  key={font.id}
                  disabled={busy}
                  onClick={async () => {
                    setBusy(true);
                    try {
                      await loadCaptionFont(font.id);
                      onChange(font.id);
                      setOpen(false);
                    } catch {
                      onError("字体加载失败，请检查网络后重试");
                    } finally {
                      setBusy(false);
                    }
                  }}
                >
                  {font.name}
                  {value === font.id && <Check size={14} />}
                </button>
              ))}
            </div>
          </div>
          {!options.length && <div className="se-muted">没有匹配的字体</div>}
          {busy && <div role="status">正在加载字体…</div>}
        </div>
      )}
    </div>
  );
}