"use client";

import { Images, Loader2 } from "lucide-react";
import { useEffect, useState } from "react";
import Modal from "@/components/Modal";
import { apiMyMedia, type MediaAttachment } from "@/lib/api";
import { mediaURLFitsBackground, type BgSurface } from "@/lib/bg";

const SURFACE_LABEL: Record<BgSurface, string> = {
  site: "前台背景",
  admin: "后台背景",
};

const BG_MAX_BYTES = 8 * 1024 * 1024;
const BG_MAX_DIM = 8192;

function mediaFitsBackground(item: MediaAttachment): boolean {
  if (!mediaURLFitsBackground(item.url)) return false;
  if (item.size > 0 && item.size > BG_MAX_BYTES) return false;
  if (item.width > 0 && item.width > BG_MAX_DIM) return false;
  if (item.height > 0 && item.height > BG_MAX_DIM) return false;
  return true;
}

export default function BgMediaPicker({
  open,
  surface,
  onClose,
  onPick,
}: {
  open: boolean;
  surface: BgSurface;
  onClose: () => void;
  onPick: (item: MediaAttachment) => void;
}) {
  const [items, setItems] = useState<MediaAttachment[]>([]);
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState("");

  useEffect(() => {
    if (!open) return;
    let cancelled = false;
    setLoading(true);
    setError("");
    void apiMyMedia()
      .then((res) => {
        if (cancelled) return;
        if (res.error) {
          setError(res.error);
          setItems([]);
          return;
        }
        const all = res.attachments || [];
        setItems(all.filter(mediaFitsBackground));
      })
      .catch(() => {
        if (!cancelled) setError("加载媒体库失败");
      })
      .finally(() => {
        if (!cancelled) setLoading(false);
      });
    return () => {
      cancelled = true;
    };
  }, [open, surface]);

  return (
    <Modal
      open={open}
      title={`从媒体库选择 · ${SURFACE_LABEL[surface]}`}
      description="只列出 JPEG / PNG / WebP（≤8MB、边长≤8192）。保存后会复制到背景目录，之后删除原图不影响背景。"
      onClose={onClose}
      maxWidthClass="max-w-lg"
      dismissOnOverlay
    >
      {loading ? (
        <p className="meta text-[13px] flex items-center gap-2 py-6 justify-center">
          <Loader2 size={14} className="animate-spin" /> 加载中
        </p>
      ) : error ? (
        <p className="text-[13px] py-4" style={{ color: "var(--danger, #b42318)" }}>
          {error}
        </p>
      ) : items.length === 0 ? (
        <p className="meta text-[13px] py-6 text-center">
          没有可用图片。请先在发帖或媒体库上传 JPEG / PNG / WebP。
        </p>
      ) : (
        <div className="grid grid-cols-4 sm:grid-cols-5 gap-2">
          {items.map((item) => (
            <button
              key={item.id}
              type="button"
              onClick={() => {
                onPick(item);
                onClose();
              }}
              className="relative group aspect-square rounded-xl overflow-hidden"
              style={{ boxShadow: "0 0 0 1px var(--line)", background: "var(--panel-2)" }}
              data-tip="用作草稿预览，点保存后才生效"
            >
              {/* eslint-disable-next-line @next/next/no-img-element */}
              <img
                src={item.url}
                alt={`${SURFACE_LABEL[surface]}候选图`}
                className="w-full h-full object-cover"
                loading="lazy"
              />
              <span
                className="pointer-events-none absolute inset-0 flex items-center justify-center opacity-0 group-hover:opacity-100"
                style={{ background: "color-mix(in srgb, var(--ink) 40%, transparent)", color: "#fff" }}
              >
                <Images size={14} />
              </span>
            </button>
          ))}
        </div>
      )}
    </Modal>
  );
}