import nodeFs from "node:fs";
import npath from "node:path";
import { slash } from "../core/path.js";
import { cleanUrl } from "../vite-plugin-utils/index.js";
const FALLBACK_FLAG = "astroFallbackFlag";
function loadFallbackPlugin({
  fs,
  root
}) {
  if (!fs || fs === nodeFs || fs.default === nodeFs) {
    return false;
  }
  const tryLoadModule = async (id) => {
    try {
      return await fs.promises.readFile(cleanUrl(id), "utf-8");
    } catch {
      try {
        return await fs.promises.readFile(id, "utf-8");
      } catch {
        try {
          const fullpath = new URL("." + id, root);
          return await fs.promises.readFile(fullpath, "utf-8");
        } catch {
        }
      }
    }
  };
  return [
    {
      name: "astro:load-fallback",
      enforce: "post",
      async resolveId(id, parent) {
        if (parent) {
          const candidateId = npath.posix.join(npath.posix.dirname(slash(parent)), id);
          try {
            const stats = await fs.promises.stat(candidateId);
            if (!stats.isDirectory()) {
              const params = new URLSearchParams(FALLBACK_FLAG);
              return `${candidateId}?${params.toString()}`;
            }
          } catch {
          }
        }
      },
      load: {
        filter: {
          id: new RegExp(`(?:\\?|&)${FALLBACK_FLAG}(?:&|=|$)`)
        },
        async handler(id) {
          const code = await tryLoadModule(id.slice(0, -(1 + FALLBACK_FLAG.length)));
          if (code) {
            return { code };
          }
        }
      }
    },
    {
      name: "astro:load-fallback-hmr",
      enforce: "pre",
      handleHotUpdate(context) {
        const read = context.read;
        context.read = async () => {
          const source = await tryLoadModule(context.file);
          if (source) return source;
          return read.call(context);
        };
      }
    }
  ];
}
export {
  loadFallbackPlugin as default
};