const {app} = require('electron');
const fs = require('fs');
const path = require('path');


function normalizePath(filepath){
  let breakIndex = filepath.indexOf("://");
  if (breakIndex > 0){
    let basepath = app.getPath('home');
    let type = filepath.substring(0, breakIndex).toLowerCase()
    filepath = filepath.substring(breakIndex + 3, filepath.length - 1);

    switch(type){
      case "app":
        basepath = app.getAppPath();
        break;
      case "home":
        basepath = path.join(basepath, '.saam');
        break;
      case "user":
        basepath = app.getPath('userData');
    }
    return path.join(basepath, filepath);
  }
  return filepath;
}

function readFile(file, encoding = null){
  return new Promise((res, rej) => {
    fs.readFile(file, encoding, (err, data) => {
      if (err){rej(err);}
      res(data);
    });
  });
}

function writeFile(file, data){
  return new Promise((res, rej) => {
    fs.writeFile(file, data, (err) => {
      if (err){rej(err);}
      res();
    });
  });
}


async function load(filepath){
  filepath = normalizePath(filepath);
  try{
    return await readFile(filepath);
  } catch (e){
    throw e;
  }
}


async function loadJSON(filepath){
  filepath = normalizePath(filepath);
  let res = null;
  try {
    res = await readFile(filepath, 'utf8');
  } catch (e) {
    console.log("WARNING: Failed to load file '", filepath, "'. ", e.toString());
  }
  if (res !== null){
    try{
      return JSON.parse(res);
    } catch (e) {
      console.log("WARNING: Malformed data at ", filepath);
    }
  }
  return {};
}


async function save(filepath, data){
  filepath = normalizePath(filepath);
  try {
    await writeFile(filepath, data);
  } catch (err){
    throw err;
  }
}


async function saveJSON(filepath, data){
  if (typeof data !== 'object')
    throw new Error("Expected a data Object.");

  let jdat = "";
  try{
    jdat = JSON.stringify(data);
  } catch (e) {
    throw new Error("Failed to convert data to JSON string.");
  }

  try {
    await save(filepath, jdat);
  } catch (err){
    throw err;
  }
}


const SFS = {
  load,
  save,
  loadJSON,
  saveJSON
};


module.exports = SFS;