import * as fs from 'fs'
import * as crypto from 'crypto'

import * as core from '@actions/core'
import {KNOWN_CHECKSUMS} from './known-checksums'
import {Architecture, Platform} from '../../utils/platforms'

export async function validateChecksum(
  checkSum: string | undefined,
  downloadPath: string,
  arch: Architecture,
  platform: Platform,
  version: string
): Promise<void> {
  let isValid = true
  if (checkSum !== undefined && checkSum !== '') {
    isValid = await validateFileCheckSum(downloadPath, checkSum)
  } else {
    core.debug(`Checksum not provided. Checking known checksums.`)
    const key = `${arch}-${platform}-${version}`
    if (key in KNOWN_CHECKSUMS) {
      const knownChecksum = KNOWN_CHECKSUMS[`${arch}-${platform}-${version}`]
      core.debug(`Checking checksum for ${arch}-${platform}-${version}.`)
      isValid = await validateFileCheckSum(downloadPath, knownChecksum)
    } else {
      core.debug(`No known checksum found for ${key}.`)
    }
  }

  if (!isValid) {
    throw new Error(`Checksum for ${downloadPath} did not match ${checkSum}.`)
  }
  core.debug(`Checksum for ${downloadPath} is valid.`)
}

async function validateFileCheckSum(
  filePath: string,
  expected: string
): Promise<boolean> {
  return new Promise((resolve, reject) => {
    const hash = crypto.createHash('sha256')
    const stream = fs.createReadStream(filePath)
    stream.on('error', err => reject(err))
    stream.on('data', chunk => hash.update(chunk))
    stream.on('end', () => {
      const actual = hash.digest('hex')
      resolve(actual === expected)
    })
  })
}

export function isknownVersion(version: string): boolean {
  const pattern = new RegExp(`^.*-.*-${version}$`)
  return Object.keys(KNOWN_CHECKSUMS).some(key => pattern.test(key))
}