const formidable = require('formidable');
const fs = require('fs');
const config = require('../config');
const path = require('path');
const { format } = require("util");

const ensureDirectoryExistence = (filePath) => {
  const dirname = path.dirname(filePath);

  if (fs.existsSync(dirname)) {
    return true;
  }

  ensureDirectoryExistence(dirname);
  fs.mkdirSync(dirname);
}

const uploadLocal = (
  folder,
  validations = {
    entity: null,
    maxFileSize: null,
    folderIncludesAuthenticationUid: false,
  },
) => {
  return (req, res) => {
    if (!req.currentUser) {
      res.sendStatus(403);
      return;
    }

    if (
      validations.entity
    ) {
      res.sendStatus(403);
      return;
    }

    if (validations.folderIncludesAuthenticationUid) {
      folder = folder.replace(
        ':userId',
        req.currentUser.authenticationUid,
      );
      if (
        !req.currentUser.authenticationUid ||
        !folder.includes(req.currentUser.authenticationUid)
      ) {
        res.sendStatus(403);
        return;
      }
    }

    const form = new formidable.IncomingForm();
    form.uploadDir = config.uploadDir;

    if (validations && validations.maxFileSize) {
      form.maxFileSize = validations.maxFileSize;
    }

    form.parse(req, function (err, fields, files) {
      const filename = String(fields.filename);
      const fileTempUrl = files.file.path;

      if (!filename) {
        fs.unlinkSync(fileTempUrl);
        res.sendStatus(500);
        return;
      }

      const privateUrl = path.join(
        form.uploadDir,
        folder,
        filename,
      );
      ensureDirectoryExistence(privateUrl);
      fs.renameSync(fileTempUrl, privateUrl);
      res.sendStatus(200);
    });

    form.on('error', function (err) {
      res.status(500).send(err);
    });
  }
}

const downloadLocal = async (req, res) => {
    const privateUrl = req.query.privateUrl;
    if (!privateUrl) {
      return res.sendStatus(404);
    }
    res.download(path.join(config.uploadDir, privateUrl));
}

const initGCloud = () => {
  const processFile = require("../middlewares/upload");
  const { Storage } = require("@google-cloud/storage");

  const crypto = require('crypto')
  const hash = config.gcloud.hash

  const privateKey = process.env.GC_PRIVATE_KEY.replace(/\\\n/g, "\n");

  const storage = new Storage({
      projectId: process.env.GC_PROJECT_ID,
      credentials: {
          client_email: process.env.GC_CLIENT_EMAIL,
          private_key: privateKey
      }
  });

  const bucket = storage.bucket(config.gcloud.bucket);
  return {hash, bucket, processFile};
}

const uploadGCloud = async (folder, req, res) => {
  try {
    const {hash, bucket, processFile} = initGCloud();
    await processFile(req, res);
    let buffer = await req.file.buffer;
    let filename = await req.body.filename;

    if (!req.file) {
      return res.status(400).send({ message: "Please upload a file!" });
    }

    let path = `${hash}/${folder}/${filename}`;
    let blob = bucket.file(path);

    console.log(path);

    const blobStream = blob.createWriteStream({
      resumable: false,
    });

    blobStream.on("error", (err) => {
      console.log('Upload error');
      console.log(err.message);
      res.status(500).send({ message: err.message });
    });

    console.log(`https://storage.googleapis.com/${bucket.name}/${blob.name}`);

    blobStream.on("finish", async (data) => {
      const publicUrl = format(
        `https://storage.googleapis.com/${bucket.name}/${blob.name}`
      );

      res.status(200).send({
        message: "Uploaded the file successfully: " + path,
        url: publicUrl,
      });
    });

    blobStream.end(buffer)
  } catch (err) {
    console.log(err);

    res.status(500).send({
      message: `Could not upload the file. ${err}`
    });
  }
}

const downloadGCloud = async (req, res) => {
  try {
    const {hash, bucket, processFile} = initGCloud();

    const privateUrl = await req.query.privateUrl;
    const filePath = `${hash}/${privateUrl}`;
    const file = bucket.file(filePath)
    const fileExists = await file.exists();

    if (fileExists[0]) {
      const stream = file.createReadStream();
      stream.pipe(res);
    }
    else {
      res.status(404).send({
        message: "Could not download the file. " + err,
      });      
    }
  } catch (err) {
    res.status(404).send({
      message: "Could not download the file. " + err,
    });
  }
}

const deleteGCloud = async (privateUrl) => {
  try {
    const {hash, bucket, processFile} = initGCloud();
    const filePath = `${hash}/${privateUrl}`;

    const file = bucket.file(filePath)
    const fileExists = await file.exists();

    if (fileExists[0]) {
      file.delete();
    }
  } catch (err) {
    console.log(`Cannot find the file ${privateUrl}`);
  }
}

module.exports = {
  initGCloud,
  uploadLocal,
  downloadLocal,
  deleteGCloud,
  uploadGCloud,
  downloadGCloud
}