eventric/src/repository/repository.coffee

behavior-first application development

class Repository

  constructor: (params, @_eventric) ->
    @_aggregateName  = params.aggregateName
    @_AggregateRoot  = params.AggregateRoot
    @_context        = params.context
    @_eventric       = params.eventric

    @_command = {}
    @_aggregateInstances = {}
    @_store = @_context.getDomainEventsStore()


  findById: (aggregateId, callback = ->) =>
    new Promise (resolve, reject) =>
      @_findDomainEventsForAggregate aggregateId, (err, domainEvents) =>
        if err
          callback err, null
          reject err
          return

        if not domainEvents.length
          err = "No domainEvents for #{@_aggregateName} Aggregate with #{aggregateId} available"
          @_eventric.log.error err
          callback err, null
          reject err
          return

        aggregate = new @_eventric.Aggregate @_context, @_eventric, @_aggregateName, @_AggregateRoot
        aggregate.applyDomainEvents domainEvents
        aggregate.id = aggregateId
        aggregate.root.$id = aggregateId
        aggregate.root.$save = =>
          @save aggregate.id

        commandId = @_command.id ? 'nocommand'
        @_aggregateInstances[commandId] ?= {}
        @_aggregateInstances[commandId][aggregateId] = aggregate

        callback null, aggregate.root
        resolve aggregate.root


  _findDomainEventsForAggregate: (aggregateId, callback) ->
    @_store.findDomainEventsByAggregateId aggregateId, (err, domainEvents) =>
      return callback err, null if err
      return callback null, [] if domainEvents.length == 0
      callback null, domainEvents


  create: (params) =>  new Promise (resolve, reject) =>
    aggregate = new @_eventric.Aggregate @_context, @_eventric, @_aggregateName, @_AggregateRoot
    aggregate.id = @_eventric.generateUid()

    if typeof aggregate.root.create isnt 'function'
      err = "No create function on aggregate"
      @_eventric.log.error err
      reject new Error err

    aggregate.root.$id = aggregate.id
    aggregate.root.$save = =>
      @save aggregate.id

    # TODO: needs refactoring
    commandId = @_command.id ? 'nocommand'
    @_aggregateInstances[commandId] ?= {}
    @_aggregateInstances[commandId][aggregate.id] = aggregate

    createAggregate = aggregate.root.create params

    Promise.all [createAggregate]
    .then ->
      resolve aggregate.root
    .catch ([error]) ->
      reject error


  save: (aggregateId, callback = ->) =>
    new Promise (resolve, reject) =>
      commandId = @_command.id ? 'nocommand'
      aggregate = @_aggregateInstances[commandId][aggregateId]
      if not aggregate
        err = "Tried to save unknown aggregate #{@_aggregateName}"
        @_eventric.log.error err
        err = new Error err
        callback? err, null
        reject err
        return

      domainEvents = aggregate.getDomainEvents()
      if domainEvents.length < 1
        err = "Tried to save 0 DomainEvents from Aggregate #{@_aggregateName}"
        @_eventric.log.debug err, @_command
        err = new Error err
        callback? err, null
        reject err
        return

      @_eventric.log.debug "Going to Save and Publish #{domainEvents.length} DomainEvents from Aggregate #{@_aggregateName}"

      # TODO: this should be an transaction to guarantee consistency
      @_eventric.eachSeries domainEvents, (domainEvent, next) =>
        @_store.saveDomainEvent domainEvent
        .then =>
          @_eventric.log.debug "Saved DomainEvent", domainEvent
          next null
      , (err) =>
        if err
          callback err, null
          reject err
        else
          @_eventric.eachSeries domainEvents, (domainEvent, next) =>
            @_eventric.log.debug "Publishing DomainEvent", domainEvent
            @_context.getEventBus().publishDomainEvent domainEvent
            .then ->
              next()
          , (err) =>
            if err
              callback err, null
              reject err
            else
              resolve aggregate.id
              callback null, aggregate.id


  setCommand: (command) ->
    @_command = command


module.exports = Repository