import { readFileSync } from 'node:fs'
import { defineConfig } from 'vite'
import dts from 'vite-plugin-dts'

// Build entries are derived from the public `exports` map so a new subpath
// added to package.json is picked up here (and by scripts/make-publish-package.mjs)
// without touching this config.
const pkg = JSON.parse(readFileSync(new URL('./package.json', import.meta.url), 'utf8')) as {
  exports: Record<string, string>
}

const entry = Object.fromEntries(
  Object.entries(pkg.exports)
    .filter(([, target]) => target.endsWith('.ts'))
    .map(([subpath, target]) => [subpath === '.' ? 'index' : subpath.slice(2), target]),
)

export default defineConfig({
  plugins: [
    dts({
      entryRoot: 'src',
      exclude: ['src/**/__tests__/**', 'src/**/*.test.ts', 'src/**/*.test-d.ts'],
    }),
  ],
  build: {
    target: 'es2021',
    outDir: 'dist',
    emptyOutDir: true,
    minify: false,
    // No source maps: they would embed the full original TypeScript source
    // (sourcesContent) in the published tarball.
    sourcemap: false,
    lib: {
      entry,
      formats: ['es'],
    },
    rollupOptions: {
      // zod is intentionally bundled — the published package has no runtime
      // dependencies, so external consumers install nothing else.
      output: {
        entryFileNames: '[name].js',
        // Shared modules (error classes, error-code registry, media side-effect
        // registrations) must land in common chunks so every entrypoint sees a
        // single copy — duplicating them would break instanceof and rehydration.
        chunkFileNames: 'chunks/[name]-[hash].js',
      },
    },
  },
})