import { graphqlExpress, graphiqlExpress } from 'graphql-server-express'
import bodyParser from 'body-parser'
import graphqlExpressUpload from 'graphql-server-express-upload'
import multer from 'multer'

import schema from './schema'

const upload = multer({
  dest: config.tmp.path,
})

app.use('/graphql',
  upload.array('files'),
  bodyParser.json(),
  graphqlExpressUpload({ endpointURL: '/graphql' }), // after multer and before graphqlExpress
  graphqlExpress((req) => {
    return {
      schema,
      context: {}
    }
  })
)

app.use('/graphiql', graphiqlExpress({
  endpointURL: '/graphql',
}))

scalar UploadedFile

const resolvers = {
  UploadedFile: {
    __parseLiteral: parseJSONLiteral,
    __serialize: value => value,
    __parseValue: value => value,
  }
  ...
}

function parseJSONLiteral(ast) {
  switch (ast.kind) {
    case Kind.STRING:
    case Kind.BOOLEAN:
      return ast.value;
    case Kind.INT:
    case Kind.FLOAT:
      return parseFloat(ast.value);
    case Kind.OBJECT: {
      const value = Object.create(null);
      ast.fields.forEach(field => {
        value[field.name.value] = parseJSONLiteral(field.value);
      });

      return value;
    }
    case Kind.LIST:
      return ast.values.map(parseJSONLiteral);
    default:
      return null;
  }
}

uploadProfilePicture(id: Int!, files: [UploadedFile!]!): ProfilePicture

async uploadProfilePicture(root, { id, files }, context) {
  // you can now access files parameter from variables
  console.log('uploadProfilePicture', { id, files })
  //...
}

import React, { Component, PropTypes } from 'react'
import { graphql } from 'react-apollo'
import gql from 'graphql-tag'

class UploadProfilePicture extends Component {

  onSubmit = (fields) => {
    const { user, uploadProfilePicture } = this.props
    // fields.files is an instance of FileList
    uploadProfilePicture(user.id, fields.files)
      .then(({ data }) => {
        console.log('data', data);
      })
      .catch(error => {
        console.log('error', error.message);
      })
  }

  render() {
    return (
      //...
    )
  }

}

const UPLOAD_PROFILE_PICTURE = gql`
  mutation uploadProfilePicture($id: Int!, $files: [UploadedFile!]!) {
    uploadProfilePicture(id: $id, files: $files) {
      id url thumb square small medium large full
    }
  }`

const withFileUpload = graphql(UPLOAD_PROFILE_PICTURE, {
  props: ({ ownProps, mutate }) => ({
    uploadProfilePicture: (id, files) => mutate({
      variables: { id, files },
    }),
  }),
})

export default withFileUpload(UploadProfilePicture)