// analyze.ts

import { strict as assert } from 'node:assert';

import type { Metafile } from 'esbuild';

export default function analyze(metafile: Metafile): {
  sourceBytes: number;
  moduleBytes: number;
  totalBytes: number;
} {
  const source = new Set(
    Object.keys(metafile.inputs).filter(
      (key) => !key.startsWith('node_modules'),
    ),
  );
  const modules = new Set(
    Object.keys(metafile.inputs).filter((key) =>
      key.startsWith('node_modules'),
    ),
  );

  const [output] = Object.entries(metafile.outputs);
  assert.ok(output !== undefined);
  const [, bundle] = output;

  const sourceBytes = Object.entries(bundle.inputs).reduce(
    (bytes, [file, value]) => {
      if (source.has(file)) {
        return bytes + value.bytesInOutput;
      }
      return bytes;
    },
    0,
  );

  const moduleBytes = Object.entries(bundle.inputs).reduce(
    (bytes, [file, value]) => {
      if (modules.has(file)) {
        return bytes + value.bytesInOutput;
      }
      return bytes;
    },
    0,
  );

  return {
    sourceBytes,
    moduleBytes,
    totalBytes: bundle.bytes,
  };
}