import { mkdirSync, readFileSync, writeFileSync } from 'fs'
import ts from 'typescript'
import { join, dirname } from 'path'
import { sync } from 'rimraf'

const { readJsonConfigFile, sys, parseJsonSourceFileConfigFileContent, createCompilerHost, createProgram } = ts

const rootDir = join(__dirname, '..')
const pkgJson = JSON.parse(readFileSync(join(rootDir, 'package.json')))
const srcFile = join(rootDir, 'src/ts/index.ts')
const outDir = dirname(join(rootDir, pkgJson.types))

const tsConfigPath = join(rootDir, 'tsconfig.json')

const configFile = readJsonConfigFile(tsConfigPath, (file) => {
  return sys.readFile(file)
})

const tsConfig = parseJsonSourceFileConfigFileContent(configFile, sys, dirname(tsConfigPath))

const compilerOptions = {
  ...tsConfig.options,
  declaration: true,
  declarationMap: true,
  emitDeclarationOnly: true,
  outDir
}

const host = createCompilerHost(compilerOptions)

host.writeFile = (fileName, contents) => {
  mkdirSync(dirname(fileName), { recursive: true })
  writeFileSync(fileName, contents)
}

export const compile = () => {
  // Clear the types dir
  sync(outDir)
  // Prepare and emit the d.ts files
  const program = createProgram([srcFile], compilerOptions, host)
  program.emit()
}