import type { PostResourceTransformer } from '../types'

import path from 'path'
import { promises as fs } from 'fs'
import wabtModule from 'wabt'

const wabtModulePromise = wabtModule()

const transformer : PostResourceTransformer = {
  extension: "wat",
  transform: async (src) => {
    const wasmPath = path.join(process.cwd(), 'scripts', src)
    const wasmContents = await fs.readFile(wasmPath)

    const wasmTextFileName = path.basename(src)
    const wasmBinFileName = wasmTextFileName.replace(/\.wat$/, '.wasm')
    const wabt = await wabtModulePromise

    const wasmParsed = wabt.parseWat(wasmTextFileName, wasmContents)
    const { buffer: wasmBinary } = wasmParsed.toBinary({ write_debug_names: true })
    const wasmDestText = path.join(process.cwd(), '.next/static/scripts', src)
    const wasmDestBinary = wasmDestText.replace(/\.wat$/, '.wasm')
    const destDir = path.dirname(wasmDestText)
    await fs.mkdir(destDir, { recursive: true })
    await fs.writeFile(wasmDestText, wasmContents)
    await fs.writeFile(wasmDestBinary, wasmBinary)

    return {
      type: 'wasm',
      name: wasmBinFileName,
      binaryPath: path.join('/_next/static/scripts/', src.replace(/\.wat$/, '.wasm')),
      textPath: path.join('/_next/static/scripts/', src),
    }
  }
}

export default transformer