eHealthAfrica/direct-delivery-dashboard

'use strict'

/**
 * @name storageService
 * @desc
 */
angular.module('db')
  .service('dbService', function (config, pouchDB, $rootScope) {
    var _this = this
    var remoteDB = pouchDB(config.db)

    function emitAuthError (err) {
      var dbAuthErr = 'unauthorized'
      if (err.status === 401 || err.name === dbAuthErr) {
        $rootScope.$broadcast(dbAuthErr, err)
      }
      throw err
    }

    _this.addTimeInfo = function (doc) {
      var now = new Date().toJSON()
      if (!doc.createdOn) {
        doc.createdOn = now
      }
      doc.modifiedOn = now
      return doc
    }

    /**
     * This does the following:
     * 1. Update an existing document.
     * 2. Insert a new document that has _id property.
     * 3. Insert a new document that does not have _id property and assign it an _id.
     *
     * @param {Object} doc - document to be saved.
     * @returns {$promise}
     */
    _this.save = function (doc) {
      doc = _this.addTimeInfo(doc)
      function saveDoc (doc) {
        if (doc._id) {
          return _this.update(doc)
            .catch(function () {
              return remoteDB.put(doc, doc._id)
                .then(function (res) {
                  doc._id = res.id
                  doc._rev = res.rev
                  return doc
                })
            })
        } else {
          return _this.insert(doc)
        }
      }

      return saveDoc(doc)
        .catch(emitAuthError)
    }

    _this.get = function (id) {
      return remoteDB.get(id)
        .catch(emitAuthError)
    }

    _this.delete = function (doc) {
      return remoteDB.get(doc._id)
        .then(function (doc) {
          return remoteDB.remove(doc)
        })
        .catch(emitAuthError)
    }

    /**
     * Used to save a new document without an _id property, Pouchdb or
     * underlying service should generate the _id.
     *
     * @param doc - a new document without an _id.
     * @returns {$promise}
     * @see http://pouchdb.com/api.html#create_document
     */
    _this.insert = function (doc) {
      doc = _this.addTimeInfo(doc)
      return remoteDB.post(doc)
        .then(function (res) {
          doc._id = res.id
          doc._rev = res.rev
          return doc
        })
        .catch(emitAuthError)
    }

    _this.insertWithId = function (doc, id) {
      doc = _this.addTimeInfo(doc)
      return remoteDB.put(doc, id)
        .catch(emitAuthError)
    }

    /**
     * Updates document only if it exists.
     *
     * @param doc - existing document with _id property.
     * @returns {$promise}
     */
    _this.update = function (doc) {
      doc = _this.addTimeInfo(doc)
      return remoteDB.get(doc._id)
        .then(function (res) {
          // TODO: investigate this this wont cause an overwrite i.e assigning doc._rev to res._rev
          doc._rev = res._rev
          return remoteDB.put(doc, doc._id)
            .then(function (res) {
              doc._id = res.id
              doc._rev = res.rev
              return doc
            })
        })
        .catch(emitAuthError)
    }

    _this.getView = function (view, options) {
      return remoteDB.query(view, options)
        .catch(emitAuthError)
    }

    _this.saveDocs = function (docs, options) {
      var opt = {all_or_nothing: true}
      if (options) {
        opt = options
      }
      return remoteDB.bulkDocs(docs, opt)
        .catch(emitAuthError)
    }
  })