import * as esbuild from 'esbuild'
import * as XLSX from 'xlsx';
import * as fs from 'fs';
XLSX.set_fs(fs);

/* plugin */
let sheetjsPlugin = {
  name: 'sheetjs',
  setup(build) {
    /* match NUMBERS, XLSX, XLS, and XLSB files */
    const EXTS = /.(numbers|xlsx|xls|xlsb)$/;

    /* this method will be called once for each referenced file */
    build.onLoad({ filter: EXTS }, (args) => {
      /* parse file from filesystem */
      const wb = XLSX.readFile(args.path);
      /* get first worksheet */
      const ws = wb.Sheets[wb.SheetNames[0]];

      /* workaround for JSON limitation */
      Date.prototype.toJSON2 = Date.prototype.toJSON;
      Date.prototype.toJSON = function() { return {d:this.toISOString()}; };

      /* generate row objects */
      const data = XLSX.utils.sheet_to_json(ws);

      /* generate final module code */
      const res = JSON.stringify(data);
      Date.prototype.toJSON = Date.prototype.toJSON2;
      const contents = `const data = ${res};
data.forEach(row => {
  Object.keys(row).forEach(k => {
    if(row[k]?.d) row[k] = new Date(row[k].d);
  })
});
export default data;`
      return { contents, loader: 'js' };
    });
  },
};

await esbuild.build({
  entryPoints: ['app.js'],
  bundle: true,
  outfile: 'out.js',
  plugins: [sheetjsPlugin],
});