"use strict";

// modules
const express = require('express');
const fs = require('fs');
const logger = require('debug')('me2u5:users');

// HTTP status codes by name
const codes = require('./http-codes');

const apiAuthenticationMiddleware = require('../middleware/auth-middleware');
const checkHl = require('../middleware/permission-check').checkHl;
const sortCollectionBy = require('../middleware/util').sortCollection;
const routerHandling = require('../middleware/router-handling');

// Mongoose Model using mongoDB
const UserModel = require('../models/user');
const RankModel = require('../models/rank');
const AwardingModel = require('../models/awarding');

const resultSet = {'__v': 0, 'updatedAt': 0, 'timestamp': 0};


const users = express.Router();

// routes **********************
users.route('/')
  .get((req, res, next) => {
    if (req.query.simple) {
      UserModel.find({}, res.locals.filter, res.locals.limitskip, (err, items) => {
        if (err) {
          err.status = codes.servererror;
          return next(err);
        }
        // if the collection is empty we do not send empty arrays back.

        res.locals.items = items;
        res.locals.processed = true;
        next();
      })
    }
    else {
      const nameQuery = req.query.q;
      const fractionFilter = req.query.fractFilter;
      const squadFilter = req.query.squadId;

      UserModel.find({}, (err, users) => {
        if (err) return next(err);
        if (users.length === 0) {
          res.locals.items = users;
          res.locals.processed = true;
          next();
        }
        let resUsers = [];
        let rowsLength = users.length;
        users.forEach((user) => {
          // filter by name
          if (!nameQuery || (nameQuery && user.username.toLowerCase().includes(nameQuery.toLowerCase()))) {
            getExtendedUser(user, next, (extUser) => {

              // filter by squad
              if (squadFilter) {
                if (extUser.squad && extUser.squad._id.toString() === squadFilter) {
                  resUsers.push(extUser);
                }
                else {
                  rowsLength -= 1;
                }
              }
              // filter by fraction
              else if (!fractionFilter ||
                (fractionFilter && extUser.squad && extUser.squad.fraction.toLowerCase() === fractionFilter) ||
                (fractionFilter && fractionFilter === 'unassigned' && !extUser.squad)) {
                resUsers.push(extUser);
              } else {
                rowsLength -= 1;
              }
              if (resUsers.length === rowsLength) {
                resUsers = sortCollectionBy(resUsers, 'username');
                res.locals.items = resUsers;
                res.locals.processed = true;
                return next();
              }
            });
          } else {
            rowsLength -= 1;
            // no user matching query - return empty []
            if (rowsLength === 0) {
              res.locals.items = resUsers;
              res.locals.processed = true;
              next();
            }
          }
        })
      })
    }
  })

  .post(apiAuthenticationMiddleware, checkHl, (req, res, next) => {
    const user = new UserModel(req.body);
    // timestamp and default are set automatically by Mongoose Schema Validation
    user.save((err) => {
      if (err) {
        err.status = codes.wrongrequest;
        return next(err);
      }
      res.status(codes.created);
      getExtendedUser(user, next, (extUser) => {
        res.locals.items = extUser;
        res.locals.processed = true;
        return next();
      })
    });
  })

  .all(routerHandling.httpMethodNotAllowed);


users.route('/:id')
  .get((req, res, next) => {

    UserModel.findById(req.params.id, (err, item) => {
      if (err) {
        err.status = codes.servererror;
        return next(err);
      }
      else if (!item) {
        err = new Error("item not found");
        err.status = codes.notfound;
        return next(err);
      } else if (req.query.simple) {
        res.locals.items = item;
        next();
      }
      getExtendedUser(item, next, (extUser) => {
        res.locals.items = extUser;
        res.locals.processed = true;
        return next();
      })

    });
  })

  .patch(apiAuthenticationMiddleware, checkHl, (req, res, next) => {
    if (!req.body || (req.body._id && req.body._id !== req.params.id)) {
      // little bit different as in PUT. :id does not need to be in data, but if the _id and url id must match
      const err = new Error('id of PATCH resource and send JSON body are not equal ' + req.params.id + " " + req.body._id);
      err.status = codes.notfound;
      next(err);
      return; // prevent node to process this function further after next() has finished.
    }

    // optional task 3: increment version manually as we do not use .save(.)
    req.body.updatedAt = new Date();
    req.body.$inc = {__v: 1};

    // PATCH is easier with mongoose than PUT. You simply update by all data that comes from outside. no need to reset attributes that are missing.
    UserModel.findByIdAndUpdate(req.params.id, req.body, {new: true}, (err, item) => {
      if (err) {
        err.status = codes.wrongrequest;
      }
      else if (!item) {
        err = new Error("item not found");
        err.status = codes.notfound;
      } else if (req.query.simple) {
        res.locals.items = item;
        res.locals.processed = true;
        return next();
      }
      else {
        UserModel.findById(item._id, (err, user) => {
          if (err) {
            err.status = codes.servererror;
            return next(err);
          }
          if (!user) {
            res.locals.items = {};
            res.locals.processed = true;
            return next();
          }
          getExtendedUser(user, next, (extUser) => {
            res.locals.items = extUser;
            res.locals.processed = true;
            return next();
          })
        })
      }
    })
  })

  .put(apiAuthenticationMiddleware, checkHl, (req, res, next) => {
    // first check that the given element id is the same as the URL id
    if (!req.body || req.body._id !== req.params.id) {
      // the URL does not fit the given element
      var err = new Error('id of PATCH resource and send JSON body are not equal ' + req.params.id + " " + req.body._id);
      err.status = codes.notfound;
      next(err);
      return; // prevent node to process this function further after next() has finished.
    }
    // main difference of PUT and PATCH is that PUT expects all data in request: checked by using the schema
    var user = new UserModel(req.body);
    UserModel.findById(req.params.id, req.body, {new: true}, function (err, item) {
      // with parameter {new: true} the TweetNModel will return the new and changed object from the DB and not the old one.
      if (err) {
        err.status = codes.wrongrequest;
        return next(err);
      }
      else if (!item) {
        err = new Error("item not found");
        err.status = codes.notfound;
        return next(err);
      }
      //  optional task 3b: check that version is still accurate
      else if (user.__v !== item.__v) {
        err = new Error("version outdated. Meanwhile update on item happened. Please GET resource again")
        err.status = codes.conflict;
        return next(err);
      }
      // now update all fields in DB item with body data in variable video
      for (var field in UserModel.schema.paths) {
        if ((field !== '_id') && (field !== '__v')) {
          // this includes undefined. is important to reset attributes that are missing in req.body
          item.set(field, user[field]);
        }
      }

      // optional task 3: update updatedAt and increase version
      item.updatedAt = new Date();
      item.increment(); // this sets __v++
      item.save(function (err) {
        if (!err) {
          res.locals.items = item;
        } else {
          err.status = codes.wrongrequest;
          err.message += ' in fields: ' + Object.getOwnPropertyNames(err.errors);
        }
        getExtendedUser(item, next, (extUser) => {
          res.locals.items = extUser;
          res.locals.processed = true;
          return next();
        })
      });
    })
  })

  .delete(apiAuthenticationMiddleware, checkHl, (req, res, next) => {
    UserModel.findByIdAndRemove(req.params.id, (err, item) => {
      if (err) {
        err.status = codes.wrongrequest;
      }
      else if (!item) {
        err = new Error("item not found");
        err.status = codes.notfound;
      }

      // deleted all awardings linked to this user
      AwardingModel.find({userId: req.params.id}).remove().exec();

      // check if signature exists and delete compressed and uncompressed file
      const fileMinified = __dirname + '/../resource/signature/' + req.params.id + '.png';
      if (fs.existsSync(fileMinified)) {
        fs.unlink(fileMinified, (err) => {
        });
      }
      const file = __dirname + '/../resource/signature/big/' + req.params.id + '.png';
      if (fs.existsSync(file)) {
        fs.unlink(file, (err) => {
        });
      }

      // we don't set res.locals.items  and thus it will send a 204 (no content) at the end. see last handler user.use(..)
      res.locals.processed = true;
      next(err); // this works because err is in normal case undefined and that is the same as no parameter
    });
  })

  .all(
    routerHandling.httpMethodNotAllowed
  );


// this middleware function can be used, if you like or remove it
// it looks for object(s) in res.locals.items and if they exist, they are send to the client as json
users.use(routerHandling.emptyResponse);

/**
 * Create model for single extended user and
 * return via callback
 */
let getExtendedUser = (user, next, callback) => {
  let extUser = {};
  UserModel.findById(user._id, resultSet)
    .populate('squadId', resultSet).exec((err, member) => {
    if (err) {
      err.status = codes.servererror;
      return next(err);
    }
    extUser._id = user._id;
    extUser.username = user.username;
    extUser.squad = member.squadId;

    if (extUser.squad) {
      RankModel.findOne({
        level: member.rankLvl,
        fraction: member.squadId.fraction
      }, resultSet, (err, rank) => {
        if (err) {
          err.status = codes.servererror;
          return next(err);
        }
        extUser.rank = rank;
      }).then(() => {
        addAwards(extUser).then(() => {
          callback(extUser);
        })
      })
    } else {
      extUser.rank = {level: user.rankLvl};
      addAwards(extUser).then(() => {
        callback(extUser);
      })
    }
  })
};

let addAwards = (extUser) => {
  return AwardingModel.find({userId: extUser._id}, resultSet, {sort: {date: 'desc'}})
    .populate('decorationId', resultSet)
    .exec((err, awards) => {
      if (err) {
        err.status = codes.servererror;
        return next(err);
      }
      extUser.awards = awards;
    })
};

module.exports = users;