const fs = require('fs')
const gulp = require('gulp')
const del = require('del')
const install = require('gulp-install')
const zip = require('gulp-zip')
const AWS = require('aws-sdk')

require('dotenv').config()

const clean = del.bind(null, ['dist/**/*', 'dist.zip'])

const js = done => {
  gulp.src('index.js').pipe(gulp.dest('dist'))
  done()
}

const npm = done => {
  gulp
    .src('package.json')
    .pipe(gulp.dest('dist'))
    .pipe(install({ production: true }, () => done()))
}

const env = done => {
  gulp.src('.env').pipe(gulp.dest('dist'))
  done()
}

const package = done => {
  gulp
    .src('dist/**/*')
    .pipe(zip('dist.zip'))
    .pipe(gulp.dest('.'))
  done()
}

const upload = done => {
  AWS.config.region = process.env.AWS_REGION
  const lambda = new AWS.Lambda()
  const functionName = process.env.LAMBDA_FUNCTION_NAME

  lambda.getFunction({ FunctionName: functionName }, (err, data) => {
    if (err) {
      if (err.statusCode === 404) {
        let warning = 'Unable to find lambda function ' + deploy_function + '. '
        warning += 'Verify the lambda function name and AWS region are correct.'
        console.log(warning)
      } else {
        let warning = 'AWS API request failed. '
        warning += 'Check your AWS credentials and permissions.'
        console.log(warning)
      }
    }

    const paramsCode = {
      FunctionName: functionName
    }

    const paramsConfig = {
      FunctionName: functionName,
      Environment: {
        Variables: {
          FORWARD_EMAIL: process.env.FORWARD_EMAIL,
          EMAIL_BUCKET: process.env.EMAIL_BUCKET,
          EMAIL_BUCKET_PREFIX: process.env.EMAIL_BUCKET_PREFIX
        }
      }
    }

    fs.readFile('dist.zip', (err, data) => {
      if (err) console.log(err)

      paramsCode['ZipFile'] = data

      lambda.updateFunctionCode(paramsCode, (err, data) => {
        if (err) console.log(err)

        lambda.updateFunctionConfiguration(paramsConfig, (err, data) => {
          if (err) console.log(err)

          done()
        })
      })
    })
  })
}

gulp.task('default', gulp.series(clean, js, env, npm, package))

gulp.task('deploy', upload)