'use strict';

// modules
const fs = require('fs');
const express = require('express');
const multer = require('multer');
const storage = multer.memoryStorage();
const upload = multer({storage: storage});

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

const apiAuthenticationMiddleware = require('../middleware/auth-middleware');
const checkHl = require('../middleware/permission-check').checkHl;

const genericGetById = require('./_generic').genericGetById;
const routerHandling = require('../middleware/router-handling');
const idValidator = require('../middleware/validators').idValidator;
const resourceLocation = require('../middleware/resource-location').resourceLocation().concat('/decoration/');

// Mongoose Model using mongoDB
const DecorationModel = require('../models/decoration');
const AwardingsModel = require('../models/awarding');

// util
const getFileBuffer = require('../tools/util').getFileBuffer;
const imageDimensionValidator = require('../middleware/validators').imageDimensionValidator;
const MAX_MEDAL_IMAGE_WIDTH = 100;
const MAX_MEDAL_IMAGE_HEIGHT = 150;
const MAX_RIBBON_IMAGE_WIDTH = 150;
const MAX_RIBBON_IMAGE_HEIGHT = 50;

const decorationRouter = new express.Router();

// routes **********************
decorationRouter.route('/')
                .get((req, res, next) => {
                  const filter = {};
                  if (req.query.fractFilter) {
                    filter.fraction = {
                      '$in': req.query.fractFilter
                                .toUpperCase()
                                .split(','),
                    };
                  }
                  if (req.query.q) {
                    filter.name = {$regex: req.query.q, $options: 'i'};
                  }
                  DecorationModel.find(filter, {}, {
                    sort: {
                      fraction: 'asc',
                      isMedal: 'asc',
                      sortingNumber: 'asc',
                      name: 'asc',
                    },
                  }, (err, items) => {
                    if (err) {
                      err.status = codes.servererror;
                      return next(err);
                    }
                    if (items && items.length > 0) {
                      res.locals.items = items;
                    } else {
                      res.locals.items = [];
                    }
                    res.locals.processed = true;
                    next();
                  });
                })

                .post(apiAuthenticationMiddleware, checkHl, upload.single('image'), (req, res, next) => {
                  if (req.file) {
                    const decoration = new DecorationModel(req.body);

                    const imageFileBuffer = getFileBuffer(req.file);
                    const err = imageDimensionValidator(imageFileBuffer,
                      (decoration.isMedal ? MAX_MEDAL_IMAGE_WIDTH : MAX_RIBBON_IMAGE_WIDTH),
                      (decoration.isMedal ? MAX_MEDAL_IMAGE_HEIGHT : MAX_RIBBON_IMAGE_HEIGHT));
                    if (err) {
                      return next(err);
                    }

                    // timestamp and default are set automatically by Mongoose Schema Validation
                    decoration.save((err) => {
                      if (err) {
                        err.status = codes.wrongrequest;
                        err.message += ' in fields: ' + Object.getOwnPropertyNames(err.errors);
                        return next(err);
                      }
                      res.status(codes.created);
                      res.locals.items = decoration;
                      fs.appendFile(resourceLocation + decoration._id + '.png', imageFileBuffer, (err) => {
                        if (err) next(err);
                      });
                      next();
                    });
                  } else {
                    const err = new Error('no image file provided');
                    err.status = codes.wrongmediasend;
                    next(err);
                  }
                })

                .all(
                  routerHandling.httpMethodNotAllowed
                );

decorationRouter.route('/:id')
                .get(idValidator, (req, res, next) => {
                  return genericGetById(req, res, next, DecorationModel);
                })

                .patch(apiAuthenticationMiddleware, checkHl, upload.single('image'), (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} vs ${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};

                  DecorationModel.findById(req.params.id, (err, item) => {
                    if (err) {
                      return next(err);
                    }
                    if (req.file) {
                      const imageFileBuffer = getFileBuffer(req.file);
                      const imageDimensionError = imageDimensionValidator(imageFileBuffer,
                        (item.isMedal ? MAX_MEDAL_IMAGE_WIDTH : MAX_RIBBON_IMAGE_WIDTH),
                        (item.isMedal ? MAX_MEDAL_IMAGE_HEIGHT : MAX_RIBBON_IMAGE_HEIGHT));
                      if (imageDimensionError) {
                        return next(imageDimensionError);
                      }

                      const file = resourceLocation + req.params.id + '.png';
                      fs.unlink(file, (err) => {
                        if (err) next(err);
                        fs.appendFile(file, imageFileBuffer, (err) => {
                          if (err) next(err);
                        });
                      });
                    }

                    // 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.
                    DecorationModel.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 {
                        res.locals.items = item;
                      }
                      next(err);
                    });
                  });
                })

                .delete(apiAuthenticationMiddleware, checkHl, (req, res, next) => {
                  const id = req.params.id;
                  DecorationModel.findByIdAndRemove(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 decoration
                    AwardingsModel.find({decorationId: id}).deleteMany();

                    // delete graphic
                    fs.unlink(resourceLocation.concat(id).concat('.png'),
                      (err) => {
                        // we don't set res.locals.items and thus it will send a 204 (no content) at the end. see last
                        // handler
                        res.locals.processed = true;
                        next(err);
                      });
                  });
                })

                .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
decorationRouter.use(routerHandling.emptyResponse);


module.exports = decorationRouter;