import type { Plugin } from "vite";
import { bootLeaks, type ChunkLike } from "./src/lib/chunkLeaks";

// A lazily imported page, rail, dialog or player must stay out of the chunks loaded at boot (the
// entry, the shell and what they import): one static import of it on the boot path — a module's
// index.ts re-exporting it is the easy way — makes its import() a silent no-op. That rule used to be
// a hope; this makes it a build failure, naming each module and the boot chunk it landed in.
const SHELL = "src/shell/App.tsx";

export function chunkGuard(): Plugin {
  return {
    name: "siftlode-chunk-guard",
    apply: "build",
    generateBundle(_options, bundle) {
      const lazy = new Set(
        [...this.getModuleIds()].filter(
          (id) => (this.getModuleInfo(id)?.dynamicImporters.length ?? 0) > 0,
        ),
      );
      const chunks: ChunkLike[] = Object.values(bundle).flatMap((o) =>
        o.type === "chunk"
          ? [
              {
                fileName: o.fileName,
                isEntry: o.isEntry,
                imports: o.imports,
                moduleIds: o.moduleIds,
              },
            ]
          : [],
      );
      const leaks = bootLeaks(chunks, lazy, SHELL);
      if (leaks.length)
        this.error(
          `lazily imported, yet loaded at boot: ${leaks.join(", ")}. ` +
            "Something on the boot path imports it statically (an index.ts re-export?): import it lazily there too, or not at all.",
        );
    },
  };
}