import * as ESBuild from "https://deno.land/x/esbuild@v0.19.2/wasm.js";
import * as Mapper from "https://esm.sh/esbuild-plugin-importmaps@1.0.0"; // https://github.com/andstellar/esbuild-plugin-importmaps
import Introspect, {Root} from "./introspect.ts";

const prefix = "/_dot_importer_/";
const resolvePlugin:ESBuild.Plugin = {
  name: "resolve-plugin",
  setup(build) {
    build.onResolve({ filter: /^(\.\/|\.\.\/).*/ }, (args)=>
    {
      let resolveRoot = args.importer||Root;
      if(resolveRoot.startsWith(prefix))
      {
        resolveRoot = resolveRoot.substring(prefix.length);
      }
      const output:ESBuild.OnResolveResult = {
        path:prefix + new URL(args.path, resolveRoot).href,
        namespace:"http",
      }
      return output;
    });
    build.onLoad({ filter: /.*/, namespace:"http" }, async(args)=> {
      const fetchPath = args.path.substring(prefix.length);
      const result = await fetch(fetchPath);
      const contents = await result.text();
      return { contents, loader: `tsx` };
    });
  },
};

await ESBuild.initialize({ worker: false });
export type ImportMap = Parameters<typeof Mapper.importmapPlugin>[0];
export type BuildOptions = ESBuild.BuildOptions;
/**
 * 
 * @param buildOptions ESBuild "build" options (will be merged with "reasonable defaults") for docs: https://esbuild.github.io/api/#general-options
 * @param importMap 
 * @returns build result
 */
export default async function(buildOptions={} as BuildOptions, importMap:ImportMap|string|false = false):Promise<ESBuild.BuildResult<ESBuild.BuildOptions>>
{
  if(importMap === false)
  {
    importMap = await Introspect() as ImportMap;
  }
  else if(typeof importMap === "string")
  {
    importMap = await Introspect(importMap) as ImportMap;
  }

  const configuration:ESBuild.BuildOptions = {
    entryPoints: ["entry"],
    bundle: true,
    minify: true,
    format: "esm",
    jsx: "automatic",
    jsxImportSource: "react",
    ...buildOptions,
    plugins: [
      resolvePlugin,
      Mapper.importmapPlugin(importMap) as ESBuild.Plugin,
      ...buildOptions.plugins||[]
    ]
  };

  const result = await ESBuild.build(configuration);
  return result;
}
export { ESBuild };