const config = require ('../config/config');
var ObjectID = require ('mongodb').ObjectID;

var db = null;

module.exports = {
  initModule: function (databaseObject) {
    db = databaseObject;
    db.collection ('intent_list');
  },

  loadTokens: function () {
    db
      .collection ('token_list')
      .findOne ()
      .then (tokens => {
        if (tokens !== null) {
          config.TOKEN = tokens.access_token;
          config.REFRESH_TOKEN = tokens.refresh_token;
          config.TOKEN_EXPIRES_IN = tokens.expires_in;
        } else {
          //Cannot continue without tokens
          console.log ('Cannot continue without tokens in database');
          process.exit (-1);
        }
      })
      .catch (e => {
        console.log (
          'Error loading tokens ! Cannot continue without tokens in database'
        );
        process.exit (-1);
      });
  },

  updateTokens: function (refresh_token, access_token, expires_in) {
    return new Promise ((resolve, reject) => {
      let newTokenDocument = {
        id: 1,
        refresh_token: refresh_token,
        access_token: access_token,
        expires_in: new Date () / 1000 + expires_in,
      };
      db
        .collection ('token_list')
        .update ({id: 1}, newTokenDocument, {upsert: true}, (err, result) => {
          if (err) { 
            reject (err)
          }else{
            config.REFRESH_TOKEN = refresh_token;
            config.TOKEN = access_token;
            config.TOKEN_EXPIRES_IN = newTokenDocument.expires_in;
            resolve ();
          }
        });
    });
  },

  getSkill: function (skillDbID) {
    return new Promise ((resolve, reject) => {
      db
        .collection ('skill_list')
        .findOne ({_id: ObjectID (skillDbID)}, (err, skill) => {
          if (skill) {
            resolve (skill);
          } else {
            reject (err);
          }
        });
    });
  },

  updateSkill: function (id, skill) {
    return new Promise ((resolve, reject) => {
      db
        .collection ('skill_list')
        .update ({_id: ObjectID (id)}, skill, {upsert: true}, (err, result) => {
          if (err){
            reject();
          }else{
            resolve();
          }
        });
    });
  },

  deleteSkill: function (id) {
    return new Promise ((resolve, reject) => {
      db
        .collection ('skill_list')
        .remove ({_id: ObjectID (id)}, (err, result) => {
          if (err){
            reject (err);
          }else{
            resolve (result);
          }
        });
    });
  }
};