const r2 = require('r2')
const path = require('path')
const fs = require('fs')
const getPost = require('mediumexporter').getPost
const { createClient } = require('webdav')

/**
 * function [fetchFromMedium]
 * @returns [string] status
*/

const fetchFromMedium = async (mediumUrl) => {
  console.info(`Fetching: ${mediumUrl}`);
  output = path.join(process.env.PWD, 'content')

  // use mediumexporter's getPost function to fetch a Medium post
  const post = await getPost(mediumUrl, {
      returnObject: true,
      output: output,
    }).catch((err) => {
      return {
        error: err,
      }
    })

  // set output folder path
  // this is based on what mediumexporter chooses as the output folder
  outputFolder = path.join(output, post.slug)

  console.info(`Saving to: ${outputFolder}`)

  if (!fs.existsSync(path.join(outputFolder, post.slug))) {
    fs.mkdirSync(outputFolder, { recursive: true })
  }

  // mediumexporter writes a plain .md file if the post has no media
  // if that is the case, we should create the subfolder manually
  // and copy the data there.
  if (fs.existsSync(path.join(output, post.slug + '.md'))) {
    fs.renameSync(
      path.join(output, post.slug + '.md'),
      path.join(outputFolder, 'index.md')
    )
  }

  // generate metadata
  const metadata = JSON.stringify({
    title: post.title,
    subtitle: post.subtitle,
    date: new Date(post.date),
    tags: post.tags,
    url: post.url,
    slug: post.slug,
    images: post.images,
    featuredImage: post.featuredImage,
  })

  // write metadata to output folder
  fs.writeFileSync(path.join(outputFolder, 'metadata.json'))
  return post
};

/**
 * function [pushToGhost]
 * @returns [string] status
*/
const pushToGhost = (postSlug) => {
  console.info('Pushing: ' + postSlug);
};

/**
 * function [mediumToGhost]
 * @returns [string] status
*/
const mediumToGhost = (mediumUrl) => {
  console.info('Copying: ' + mediumUrl);
};


async function fetchMediumJSON(mediumUrl) {
  console.debug(`Fetching: ${mediumUrl}`)
  const response = await fetch(mediumUrl)
  const text = await response.text()
  const json = await JSON.parse(text.substr(text.indexOf('{')))
  return json;
}

/**
 * function [createUser]
 * @returns [object] ghost data json
*/
const generateUserData = async (mediumUsername, email) => {
  console.debug('Creating: @' + mediumUsername + '(email: ' + email + ')');
  const mediumUrl = `https://medium.com/@${mediumUsername}/?format=json`;
  const json = await fetchMediumJSON(mediumUrl);

  if (!json.success) {
    console.error(`Error: ${json.error}`)
    return false
  }

  console.debug(`Name: ${json.payload.user.name}`)
  console.debug(`Bio: ${json.payload.user.bio}`)

  // Generate Ghost JSON

  const ghostData = {
    data: {
      users: [
        {
          id: 1,
          slug: json.payload.user.username,
          bio: json.payload.user.bio,
          email: email,
          name: json.payload.user.name,
        }
      ]
    },
    meta: {
      exported_on: new Date,
      version: '2.14.0'
    }
  }


  return(JSON.stringify(ghostData))
};

const createDirIfNotExist = async (client, folder) => {
  // recursively create subfolders if they don't exist.

  //safety: don't touch directories outside WEBDAV_PATH_PREFIX
  if (!folder.startsWith(process.env.WEBDAV_PATH_PREFIX)) {
    throw new Error(`Cannot create directories outside ${process.env.WEBDAV_PATH_PREFIX}`)
  }

  // check the folder
  await client.stat(folder)
  .catch(async (err) => {
    if (err.response.status == 404) {

      // it's a 404, so we'll create the directory
      console.debug(`Noting missing subdirectory: ${folder}`)

      // first, create the parent directory (if required)
      await createDirIfNotExist(client, path.dirname(folder))

      console.debug(`Creating missing subdirectory: ${folder}`)
      // then, create the current directory
      await client.createDirectory(folder)
      .catch(async (err) => {
        if (err.response.status == 405) { // Method Not Allowed
          // Maybe the directory's already been created in the meantime?
          await client.stat(folder)
          .catch((err2) => {
            // Bad guess. Panic (and raise the original error)
            console.debug(err.toJSON())
            throw err
          })
        } else {
          // what's this? Panic!
          console.debug(err.toJSON())
          throw err
        }
      })
    } else {

      // it's not a 404; we don't know how to handle this. Panic!
      console.debug(err.toJSON())
      throw err
    }
  })
}

/**
 * function [createUser]
 * @returns [string] status
*/
const uploadDav = async (dirPath, filePath) => {

  // connect to webdav
  client = createClient(
    process.env.WEBDAV_SERVER_URL,
    {
      username: process.env.WEBDAV_USERNAME,
      password: process.env.WEBDAV_PASSWORD,
      digest: process.env.WEBDAV_USE_DIGEST == 'true'
    })

  // create directory if not exists
  console.debug(`Loading ${dirPath}`)
  await createDirIfNotExist(client, dirPath)

  // upload a file
  console.debug('Uploading file')
  s = fs.createReadStream(filePath)
  .pipe(client.createWriteStream(
    path.join(dirPath, path.basename(filePath))
  ))
  .on('finish', () => console.debug('Uploaded successfully.'))

  return true
}

module.exports = {
  fetchFromMedium,
  pushToGhost,
  mediumToGhost,
  generateUserData,
  uploadDav
}