import * as fs from 'fs'
import * as path from 'path'

import {
  ExtractorConfig,
  IExtractorConfigPrepareOptions
} from '@microsoft/api-extractor'

export function apiExtractorConfig(packageJsonPath: string) {
  const cwd = path.dirname(packageJsonPath)
  const packageJson = JSON.parse(fs.readFileSync(packageJsonPath).toString())
  console.assert(packageJson.typings, 'package.json#typings is not valid')
  const typingsFullPath = path.resolve(packageJson.typings)

  const prepareOptions: IExtractorConfigPrepareOptions =
    ExtractorConfig.tryLoadForFolder({ startingFolder: cwd }) || {
      configObject: {
        projectFolder: cwd,
        mainEntryPointFilePath: path.resolve(
          packageJson.main.replace(/\.js$/, '.d.ts')
        ),
        compiler: {
          tsconfigFilePath: 'tsconfig.json'
        }
      },
      configObjectFullPath: undefined,
      packageJsonFullPath: packageJsonPath
    }

  prepareOptions.configObject.mainEntryPointFilePath = path.resolve(
    prepareOptions.configObject.mainEntryPointFilePath
  )

  if (!prepareOptions.configObject.dtsRollup) {
    prepareOptions.configObject.dtsRollup = {
      enabled: true,
      publicTrimmedFilePath: typingsFullPath,
      untrimmedFilePath: path.resolve(
        path.dirname(typingsFullPath),
        path.basename(typingsFullPath, '.d.ts') + '-full.d.ts'
      ),
      betaTrimmedFilePath: path.resolve(
        path.dirname(typingsFullPath),
        path.basename(typingsFullPath, '.d.ts') + '-beta.d.ts'
      )
    }
  }

  if (!prepareOptions.configObject.tsdocMetadata) {
    prepareOptions.configObject.tsdocMetadata = {
      enabled: true,
      tsdocMetadataFilePath: '<projectFolder>/tsdoc-metadata.json'
    }
  }

  let newentryPoint = null

  if (
    fs.existsSync(typingsFullPath) &&
    typingsFullPath ===
      path.resolve(prepareOptions.configObject.mainEntryPointFilePath)
  ) {
    newentryPoint = path.resolve(
      path.dirname(typingsFullPath),
      Math.random() + path.basename(typingsFullPath)
    )
    fs.copyFileSync(typingsFullPath, newentryPoint)
    fs.unlinkSync(typingsFullPath)
    prepareOptions.configObject.mainEntryPointFilePath = newentryPoint
  }

  return prepareOptions.configObject
}