/*
 * decaffeinate suggestions:
 * DS102: Remove unnecessary code created because of implicit returns
 * DS207: Consider shorter variations of null checks
 * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
 */
const logger = require("logger-sharelatex");
const fs = require("fs");
const path = require("path");
const LocalFileWriter = require("./LocalFileWriter");
const Errors = require('./Errors');
const rimraf = require("rimraf");
const _ = require("underscore");

const filterName = key => key.replace(/\//g, "_");


module.exports = {
  sendFile( location, target, source, callback) {
    if (callback == null) { callback = function(err){}; }
    const filteredTarget = filterName(target);
    logger.log({location, target:filteredTarget, source}, "sending file");
    const done = _.once(function(err) {
      if (err != null) {
        logger.err({err, location, target:filteredTarget, source}, "Error on put of file");
      }
      return callback(err);
    });
    // actually copy the file (instead of moving it) to maintain consistent behaviour
    // between the different implementations
    const sourceStream = fs.createReadStream(source);
    sourceStream.on('error', done);
    const targetStream = fs.createWriteStream(`${location}/${filteredTarget}`);
    targetStream.on('error', done);
    targetStream.on('finish', () => done());
    return sourceStream.pipe(targetStream);
  },

  sendStream( location, target, sourceStream, callback) {
    if (callback == null) { callback = function(err){}; }
    logger.log({location, target}, "sending file stream");
    sourceStream.on("error", err => logger.err({location, target, err:err("error on stream to send")}));
    return LocalFileWriter.writeStream(sourceStream, null, (err, fsPath)=> {
      if (err != null) {
        logger.err({location, target, fsPath, err}, "something went wrong writing stream to disk");
        return callback(err);
      }
      return this.sendFile(location, target, fsPath, err => // delete the temporary file created above and return the original error
      LocalFileWriter.deleteFile(fsPath, () => callback(err)));
    });
  },

  // opts may be {start: Number, end: Number}
  getFileStream(location, name, opts, callback) {
    if (callback == null) { callback = function(err, res){}; }
    const filteredName = filterName(name);
    logger.log({location, filteredName}, "getting file");
    return fs.open(`${location}/${filteredName}`, 'r', function(err, fd) {
      if (err != null) {
        logger.err({err, location, filteredName:name}, "Error reading from file");
      }
      if (err.code === 'ENOENT') {
        return callback(new Errors.NotFoundError(err.message), null);
      } else {
        return callback(err, null);
      }
      opts.fd = fd;
      const sourceStream = fs.createReadStream(null, opts);
      return callback(null, sourceStream);
    });
  },

  getFileSize(location, filename, callback) {
    const fullPath = path.join(location, filterName(filename));
    return fs.stat(fullPath, function(err, stats) {
      if (err != null) {
        if (err.code === 'ENOENT') {
          logger.log({location, filename}, "file not found");
          callback(new Errors.NotFoundError(err.message));
        } else {
          logger.err({err, location, filename}, "failed to stat file");
          callback(err);
        }
        return;
      }
      return callback(null, stats.size);
    });
  },

  copyFile(location, fromName, toName, callback){
    if (callback == null) { callback = function(err){}; }
    const filteredFromName=filterName(fromName);
    const filteredToName=filterName(toName);
    logger.log({location, fromName:filteredFromName, toName:filteredToName}, "copying file");
    const sourceStream = fs.createReadStream(`${location}/${filteredFromName}`);
    sourceStream.on('error', function(err) {
      logger.err({err, location, key:filteredFromName}, "Error reading from file");
      return callback(err);
    });
    const targetStream = fs.createWriteStream(`${location}/${filteredToName}`);
    targetStream.on('error', function(err) {
      logger.err({err, location, key:filteredToName}, "Error writing to file");
      return callback(err);
    });
    targetStream.on('finish', () => callback(null));
    return sourceStream.pipe(targetStream);
  },

  deleteFile(location, name, callback){
    const filteredName = filterName(name);
    logger.log({location, filteredName}, "delete file");
    return fs.unlink(`${location}/${filteredName}`, function(err) {
      if (err != null) {
        logger.err({err, location, filteredName}, "Error on delete.");
        return callback(err);
      } else {
        return callback();
      }
    });
  },

  deleteDirectory(location, name, callback){
    if (callback == null) { callback = function(err){}; }
    const filteredName = filterName(name.replace(/\/$/,''));
    return rimraf(`${location}/${filteredName}`, function(err) {
      if (err != null) {
        logger.err({err, location, filteredName}, "Error on rimraf rmdir.");
        return callback(err);
      } else {
        return callback();
      }
    });
  },

  checkIfFileExists(location, name, callback){
    if (callback == null) { callback = function(err,exists){}; }
    const filteredName = filterName(name);
    logger.log({location, filteredName}, "checking if file exists");
    return fs.exists(`${location}/${filteredName}`, function(exists) {
      logger.log({location, filteredName, exists}, "checked if file exists");
      return callback(null, exists);
    });
  },

  directorySize(location, name, callback){
    const filteredName = filterName(name.replace(/\/$/,''));
    logger.log({location, filteredName}, "get project size in file system");
    return fs.readdir(`${location}/${filteredName}`, function(err, files) {
      if (err != null) {
        logger.err({err, location, filteredName}, "something went wrong listing prefix in aws");
        return callback(err);
      }
      let totalSize = 0;
      _.each(files, function(entry){
        const fd = fs.openSync(`${location}/${filteredName}/${entry}`, 'r');
        const fileStats = fs.fstatSync(fd);
        totalSize += fileStats.size;
        return fs.closeSync(fd);
      });
      logger.log({totalSize}, "total size", {files});
      return callback(null, totalSize);
    });
  }
};