let express = require ('express'), router = express.Router ();
const constants = require ('../config/constants');
let databaseHelper = require ('../helpers/database');
let amazonHelper = require ('../helpers/amazon');
let skillValidator = require('../helpers/skillValidator');
let bodyParser = require ('body-parser');
let alexa = require ('../models/alexa');

router.get ('/:id', async (req, res, next) => {
  const id = req.params.id;

  if (id.length !== constants.SKILL_ID_LENGTH) {
    res.json ([]);
  } else {
    databaseHelper
      .getSkill (id)
      .then (result => {
        res.json (result);
      })
      .catch (err => {
        res.json ([]);
      });
  }
});

router.put ('/:id', bodyParser.json (), async (req, res, next) => {
  let id = req.params.id;
  let dataFromWeb = JSON.stringify (req.body);
  let skill = JSON.parse (dataFromWeb);
  let updateOnAmazon = skill.updateOnAmazon;

  delete skill.updateOnAmazon;
  delete skill._id;

  //Validate skill
  if (!skillValidator.validateSkill(skill)){
    //skill not valid
    res
    .status (
      constants.HTTPResultCodes.INTERNAL_SERVER_ERROR
    )
    .json ({
      result: constants.apiResultCodes.INVALID_SKILL,
      message: '',
    });
    return;
  }

  //First get current skill from DB
  databaseHelper
    .getSkill (id)
    .then (currentSkillState => {
      //Now let's update skill in DB
      databaseHelper
        .updateSkill (id, skill)
        .then (() => {
          //Ok, done, now update skill on Amazon (if needed)
          if (updateOnAmazon) {
            //We need to update skill on Amazon
            amazonHelper
              .updateSkill (skill)
              .then (amazonResult => {
                if (
                  amazonResult === constants.amazonResultCodes.OK ||
                  amazonResult === constants.amazonResultCodes.ACCEPTED
                ) {
                  res.json ({result: constants.apiResultCodes.OK, message: ''});
                  alexa.updateModel ();
                } else {
                  //Update on amazon failed, revert changes in database and send error to user
                  databaseHelper
                    .updateSkill (id, currentSkillState)
                    .then (() => {
                      res
                        .status (
                          constants.HTTPResultCodes.INTERNAL_SERVER_ERROR
                        )
                        .json ({
                          result: constants.apiResultCodes.AMAZON_ERROR,
                          message: amazonResult,
                        });
                    })
                    .catch (() => {
                      //This should never happen, something is seriously wrong, like no database connection
                      res
                        .status (
                          constants.HTTPResultCodes.INTERNAL_SERVER_ERROR
                        )
                        .json ({
                          result: constants.apiResultCodes.INCONSISTENT_STATE,
                          message: '',
                        });
                    });
                }
              })
              .catch (e => {
                //Update on amazon failed, revert changes in database and send error to user
                databaseHelper
                  .updateSkill (id, currentSkillState)
                  .then (() => {
                    res
                      .status (constants.HTTPResultCodes.INTERNAL_SERVER_ERROR)
                      .json ({
                        result: constants.apiResultCodes.AMAZON_FAIL,
                        message: e,
                      });
                  })
                  .catch (() => {
                    //This should never happen, something is seriously wrong, like no database connection
                    res
                      .status (constants.HTTPResultCodes.INTERNAL_SERVER_ERROR)
                      .json ({
                        result: constants.apiResultCodes.INCONSISTENT_STATE,
                        message: '',
                      });
                  });
              });
          } else {
            //No need to update on Amazon, tell to user it's ok
            res.json ({result: constants.apiResultCodes.OK, message: ''});
            alexa.updateModel ();
          }
        })
        .catch (() => {
          //Update in database didn't go well, no need to revert since it failed to write in the first place
          //just send error to user
          res
          .status (
            constants.HTTPResultCodes.INTERNAL_SERVER_ERROR
          )
          .json ({
            result: constants.apiResultCodes.DATABASE_ERROR,
            message: '',
          });
        });
    })
    .catch (e => {
      //I don't know why, but something went wrong, possibly ID of skill is wrong, doesn't exist in DB
      res
        .status (constants.HTTPResultCodes.INTERNAL_SERVER_ERROR)
        .json ({result: constants.apiResultCodes.NO_SKILL, message: ''});
    });
});

module.exports = router;